,illustration3 ,eight ,cylinder 8,v0 ,type ,curtiss ,aero ,motor ,having ,two ,rows of ,four ,cylinders ,per ,row4 ,the ,carburetor is ,shown at the ,left ,hand ,lower ,corner ,below the ,motor4 ,for ,front ,elevation ,see ,fig4 ,f-#c on ,page #bc4 ,,practical ,,hand ,,book of ,,gas1 ,,oil ,,and ,,steam ,,engines ,,stationary1 ,,marine1 ,,traction ,,gas ,,burners1 ,,oil ,,burners1 ,,etc4 ,,farm1 ,,traction1 ,,automobile1 ,,locomotive ,a simple1 practical and comprehensive book on the construction1 operation and repair of all kinds of engines4 ,dealing with the various parts in detail and the various types of engines and also the use of different kinds of fuel4 ,by ,,john ,b4 ,,rathbun1 ,consulting ,gas ,engineer1 ,editor 8,ignition10 ,instructor ,chicago ,technical ,college1 ,author ,gas ,engine ,troubles and ,installation4 ,published by ,,charles ,c4 ,,thompson ,,co4 ,,chicago1 ,u4 ,s4 ,a4 ,copyright #aiaf ,,charles ,c4 ,,thompson ,,co4 ,copyright ,,mcmxiii ,,charles ,c4 ,,thompson ,,co4 ,practical ,hand ,book ,gas1 ,oil ,steam ,engines ---------------------------------------- -------------------------------- ,table of ,contents ,,chapter ,i--,,heat ,,and ,,power ,heat ,energy--,mechanical ,equivalent of ,heat--,expansion ,heat ,units--,heat ,engines--,efficiency--,external and ,internal ,combustion ,engines--,compression--,working ,medium #e ,,chapter ,,ii--,,fuels ,calorific ,values of ,fuels--,solid1 ,liquid and ,gaseous ,fuels--,kerosene--,gasoline--,crude ,oil--,producer ,gas--,illuminating ,gas--,coal--,benzol #bg ,,chapter ,,iii--,,working ,,cycles ,definitions of ,cycle--,four ,stroke ,cycle--,two ,stroke ,cycle--,two ,port1 ,two ,stroke--,three ,port1 ,three ,stroke--,reversing--,scavenging--,junke r ,two ,stroke ,cycle #eh ,,chapter ,,iv--,,indicator ,,diagrams ,practical ,use of the ,indicator--,pressure ,measurement--,reading the ,card--,four ,stroke ,cycle ,card--,defects in ,practical ,working--,two ,stroke ,cycle ,card--,diesel ,card--,effects of ,mixture--,effects of ,ignition #gb ,,chapter ,v--,,typical ,,four ,,stroke ,,cycle ,,engines ,single ,cylinder--,four ,cylinder ,automobile--,opposed ,type--,v ,type--,tandem--,twin ,tandem--,rotary ,cylinder--,radial ,diesel--,knight--,argyle--,rotary ,valve #hg ,,chapter ,,vi--,,typical ,,two ,,stroke ,,cycle ,,engines ,two ,port--,three ,port--,marine--,controlled ,port--,aeronautic--,oechehauser--,gnome ,rotary ,two ,stroke1 ,koerting #add ,,chapter ,,vii--,,oil ,,engines ,elyria--,marine ,diesel--,installation--,aspiration ,types--,fairbanks ,morse--,kerosene--,carburetion ,diesel--,semi ,diesel--,combustion of ,heavy ,oils #afj ,,chapter ,,viii--,,ignition ,,systems ,hot ,tube ,system--,low ,tension ,system--,high ,tension ,system--,details of ,make and ,break ,batteries--,low ,tension ,magnetos--,high ,tension ,magnetos--,coils--,adjustment--,trouble s #aie ,,chapter ,,ix--,,carburetors ,principles of ,carburetion--,jet ,carburetors--,water ,jacketing--,fuel ,supply--,different ,types of ,auto ,carburetors--,adjustment ,carburetor ,troubles #bga ,,chapter ,x--,,lubrication ,forced ,feed--,splash ,system--,oil ,pumps--,lubrication ,troubles #bhe ,,chapter ,,xi--,,cooling ,,systems ,evaporation ,systems--,radiators--,air ,cooling #bii ,,chapter ,,xii--,,speed ,,governors ,automobiles--,stationary--,adjustment-- ,mixture--,control--,hit and ,miss--,mixed ,systems #cjh ,,chapter ,,xiii--,,tractors ,gasoline and ,oil ,tractors--,mechanism of ,various ,types #cbd ,,chapter ,,xiv ,steam ,tractors #cdi ,,chapter ,,xv--,,oil ,,burners ,combustion--,high ,pressure ,system--,low ,pressure ,system--,mixed ,system--,burners for ,furnaces1 ,locomotives1 etc4 #cfc ,gas1 ,oil and ,steam ,engines ,,chapter ,i ,,heat ,,and ,,power 7#a7 ,the ,heat ,engine4 ,heat engines1 of which the steam engine and gas engine are the most prominent examples1 are devices by which heat energy is transformed into mechanical power or motion4 ,in all heat engines1 this transformation of energy is accomplished by that property of heat known as 8expansion10 by which an increase or decrease of temperature causes a corresponding increase or decrease in volume of the material subjected to the varying temperatures4 ,the substance whose expansion and contraction actuates the heat engine is known as the 8working medium10 and may be either a solid1 liquid1 or a gas4 ,the extent to which the working medium is expanded depends not only upon the change of temperature but also on its composition4 ,in all practical heat engines1 the heat energy is developed by the process of combustion1 which is a chemical combination of the oxygen of the air with certain substances1 such as coal or gasoline1 known as 8fuels40 ,the heat producing elements of the fuels are generally compounds of carbon and hydrogen1 which when oxydized or burnt by the oxygen form products that are unlike either of the original components4 ,it is due to this chemical change that heat energy is evolved1 for the heat represents the energy expended by the sun in building up the fuel in its original form1 and as energy can neither be created nor destroyed1 heat energy is liberated when the fuel is decomposed4 ,the heat energy thus liberated is applied to the expansion of the working medium to obtain its equivalent in the form of mechanical power4 ,during the period of expansion1 the heat obtained by the combustion is absorbed by the working medium in proportion to its increase in volume1 and as this increase is proportional to the mechanical effort exerted by the engine1 it will be seen that the output of the engine in work is a measure of the heat applied to the medium4 ,the quantity of heat absorbed by the medium represents the energy required to set the molecules of the medium into their new positions in the greater volume1 or to increase their paths of travel4 ,in the conversion of heat1 each heat unit applied to the medium results in the production of #ggh foot pounds of energy1 providing that there are no heat or frictional losses4 ,in explanation of these terms or units1 we wish to say1 that the unit of heat quantity1 called the ,,british ,,thermal ,,unit is the quantity of heat required to raise one pound of water1 one degree ,fahrenheit1 and the ,,foot ,,pound is the work required to raise one pound through the vertical distance of one foot4 ,as the ,british ,thermal ,unit #ggh foot pounds it is equivalent to the work required to raise #ggh pounds one foot or one pound #ggh feet1 or any other product of feet and pounds equal to the figure #ggh4 ,as liquids expand more than solids with a given temperature1 and gases more than either1 the mechanical work returned for a given amount of thermal energy 7the ,,efficiency7 will be greater with an engine using gas as a working medium than one using a solid or liquid working medium4 ,the steam engine and the gas engine are both examples of heat engines using gaseous working mediums1 the medium in the steam engine being water vapor and in the gas engine1 air and the gaseous products of combustion4 ,for this reason the working medium will be considered as a gas in the succeeding chapters4 ,practically the only way of obtaining mechanical effort from an expanding gas is to enclose it in a cylinder 7c7 fitted with a freely sliding plunger or piston 7p7 as shown in ,fig4 #a4 ,two positions of the piston are shown1 one at ,m indicated by the dotted lines1 and one at ,n indicated by the full lines4 ,it will be assumed that the space between the cylinder head ,p and the piston at ,m represents the volume of the gas before it is heated and expanded1 and that the volume between ,o and ,n represents the volume after heating and expansion have occurred4 ,the vessel ,b represents a chamber containing air that is periodically heated by the lamp ,l1 and which is connected to the working cylinder ,c by the pipe ,o4 ,illustration3 ,figs4 #a-b-c4 ,showing ,expansion in an ,external ,combustion ,engine1 the ,cycle of ,operations in an ,internal ,combustion ,engine1 and the ,pressure ,diagram of the ,latter ,engine ,giving the ,pressures at ,various ,points in the ,stroke4 ,with the piston at ,m1 the lamp ,l is lighted and placed under the retort ,b which results in the immediate expansion of the air in ,b4 ,the expanded air passes through ,o into the cylinder1 and if sufficient heat is supplied1 exerts pressure against the piston since it occupies much more than its original volume4 ,providing that the friction of the device and the load on the shaft ,s are low enough the pressure on the piston will1 move it to the position ,n in the direction of the arrow1 thus accomplishing mechanical work4 ,the motion of the piston revolves the crank to which it is connected by the rod ,x from ,d to ,e4 ,during the trip from ,m to ,n the volume of gas has greatly increased being supplied continuously with heat from the lamp4 ,as a considerable amount of heat has been radiated from the cylinder during the piston travel1 and a considerable portion of the mechanical work lost through the friction of the piston on the cylinder walls1 and by the crank1 not all of the heat units are represented at the crank as mechanical effort4 ,because of the limiting length of the cylinder1 and the temperature limits of the lamp it is not possible to expand the working medium and increase the temperature indefinitely1 therefore there must be a point where the application of heat must cease and the temperature be reduced in order to bring the gas back to its original volume and the piston to its original position so that the expansion may be repeated4 ,this condition results in a very considerable loss of heat and power in addition to the losses previously mentioned1 as the heat taken from the medium to reduce it to its original volume is thrown away as far as the production of power is concerned4 ,to return the piston to its former position without expending energy on the engine1 the volume and pressure may be reduced either by allowing the gas to escape to the atmosphere by means of a valve1 or by removing the lamp and cooling the air by the application of water1 but in any case the heat of the air is lost and the efficiency of the engine reduced4 ,to increase the efficiency of the engine and reduce the loss just mentioned1 nearly all heat engines1 either steam or gas1 have the working medium at the highest temperature for only a small portion of the stroke1 after which no heat is supplied to the cylinder4 ,as the pressure forces the piston forward the volume increases1 and as no more heat is supplied1 both the pressure and the temperature continue to decrease until the end of the stroke is reached1 thus utilizing the greater part of the heat in the expansion4 ,since the temperature at the end of the stroke is comparatively low1 very little heat is rejected when the valve is opened for the return stroke4 ,this loss would be the least when the temperature of the gas at the end of the stroke was equal to the temperature of the surrounding air4 ,with both the internal and external temperatures equal1 there would be no difference between the pressure of the gas in the cylinder and that of the surrounding air4 ,illustration3 ,fig4 #a-;a4 ,fairbanks-,morse ,two ,cylinder1 ,type 8,r ,e0 ,stationary ,engine ,direct ,connected to a ,dynamo4 ,it will be seen from the example just given that the heat engine performs mechanical work by dropping the working medium from a high to a low temperature1 as it receives the medium at a high temperature from the lamp and rejects it at atmospheric temperature after delivering a small percentage of useful work4 ,this may be compared to a water wheel which receives the working medium 7water7 at a high pressure and rejects it at a lower pressure4 ,carrying this comparison still further1 it is evident that an increase in the range of the working temperatures 7high and low7 would increase the output of the heat engine in the same way that an increase in the range of pressures would increase the output of the water wheel4 ,the temperature at which the engine receives the working medium and the temperature at which it is rejected determines the number of heat units that are available for conversion into mechanical energy1 and therefore1 if the range be increased by either raising the upper limit of temperature or by reducing the lower limit1 or by the combined increase and decrease of the limits1 the available heat will be increased4 ,based on the temperature range1 the maximum possible efficiency of the heat engine may be expressed by the ratio-- ,reception ,temperature--,rejection ,temperature ,e ---------------------------------------- ---------------------------------------- ------ ,reception ,temperature ,this maximum defined by ,carnot establishes a limit that can be exceeded by no engine1 whatever the construction or working medium4 ,according to the methods adopted in applying the heat of combustion to the working medium1 heat engines are divided into two general classes1 7#a7 ,external combustion engines1 7#b7 ,internal combustion engines4 ,the expressions 8,internal0 or 8,external0 refer to the point at which combustion takes place in regard to the working cylinder1 thus an internal combustion engine is one in which the combustion takes place in the working cylinder1 and an external combustion engine is one in which the combustion takes place outside of the working cylinder4 ,the steam engine is an example of an external combustion engine1 the fuel being burned in the furnace of a boiler which is independent of the engine cylinder proper4 ,as the fuel is burned directly in the cylinder of a gas engine it is commonly known as an internal combustion engine4 ,an external combustion engine1 such as the steam engine is subject to many serious heat losses because of the indirect method by which the heat is supplied to the working cylinder1 aside from the losses in the cylinder4 ,much of the heat goes up the smoke stack and much is radiated from the boiler settings and the steam pipes that lead to the engine4 ,the greatest loss however is due to the fact that the range of temperatures in the working cylinder is very low compared to the temperatures attained in the boiler furnace1 for it is practically impossible to have a greater range than #cej;,f to #ajj;,f with a steam engine1 while the furnace temperatures may run up to #bejj;,f and even beyond4 ,high temperatures with a steam engine result in the development of enormous pressures1 a temperature of #edg;,f corresponding to an absolute pressure of #ajjj pounds per square inch4 ,this pressure would require an extremely heavy and inefficient engine because of the terrific strains set up in the moving parts4 ,the pressures established by air as a working medium are very much lower than those produced by air or any permanent gas at the same temperature1 and for this reason it is possible to exceed a working temperature of over #cjjj;,f in the cylinder of a gas engine without meeting with excessive pressures4 ,this high working temperature is one of the reasons of the extremely high efficiency of the gas engine4 ,in order to compete with the gas engine from the standpoint of efficiency1 the steam engine builders have resorted to super-heating the steam after it has left the boiler in order to increase the temperature range in the cylinder4 ,by applying additional heat to the steam after it has passed out of contact with the water it is possible to obtain up to #fjj;,f without material increase in the pressure1 but the practical gains have not been great enough to approach the gas engine with its #cjjj;,f4 ,after reaching his maximum temperature at this comparatively low pressure1 the steam engineer has still to eliminate a number of other losses that do not obtain with the gas engine4 ,since the radiation losses of a burning fuel are proportional to the time required for burning1 it is evident that the rate of combustion has much to do with the efficient development of the heat contained in it1 and it is true that rapid combustion develops more useful heat from a given fuel than slow4 ,in the gas engine the combustion is practically instantaneous with a low radiation loss1 but in the steam engine the rate is slow1 and with the excess of air that must necessarily be supplied1 a great part of the value of the fuel is lost before reaching the water in the boiler4 ,the temperature of the medium determines the efficiency of the engine and as rapid combustion increases the temperature it is evident that the gas engine again has the best of the problem4 ,in the case of the gas engine where the fuel 7in gaseous form7 is drawn directly into the working cylinder in intimate contact with the working medium 7air7 and in the correct proportions for complete combustion1 each particle of fuel1 when ignited1 applies its heat to the adjacent particle of air instantly and increases its volume with a minimum loss by radiation4 ,a gas engine is practically a steam engine with the furnace placed directly in the working cylinder with all intervening working mediums removed1 the gases of combustion acting as the working medium4 ,it derives its power from the instantaneous combustion of a mixture of fuel and air in the cylinder1 the expansion of which causes pressure on the piston4 ,under the influence of the pressure on the piston1 the crank is turned through the connecting rod and delivers power to the belt wheel where it is available for driving machinery4 ,whether the fuel be of solid1 liquid1 or gaseous origin it is always introduced into the cylinder in the form of a gas4 ,illustration3 ,fig4 #a-;b4 ,the ,english ,adams ,automobile ,motor 7,end ,view71 ,showing the ,magneto ,driven by ,spiral ,gears at ,right ,angles to the ,crank-,shaft4 7#c7 ,combustion ,in the ,cylinder4 ,as the working medium in an internal combustion engine is in direct contact with the fuel it must not only be uninflammable but it must also be capable of sustaining combustion and must have a great expansion for a given temperature range4 ,since atmospheric air possesses all of these qualifications in addition to being present in all places in unlimited quantities it is natural that it should be used exclusively as the working medium for gas engines4 ,unlike the vapor working medium in a steam engine the medium in the gas engine not only acts in an expansive capacity but also as an oxydizing agent for burning the fuel1 and therefore must bear a definite relation to the quantity of the fuel in the cylinder to insure complete combustion4 ,in the gas engine the use of gaseous fuel is imperative since there must be no solid residue existing in the cylinder after combustion and also for the reason that the fuel must be in a very finely subdivided state in order that the combustion shall proceed with the greatest possible rapidity4 ,in addition to the above requirements the introduction of a solid fuel into the cylinder would involve almost unsurmountable mechanical problems in regard to fuel measurement for the varying loads on the engine4 ,this limits the fuel to certain hydrocarbon or compounds of hydrogen and carbon in gaseous form of which the following are the most common examples3 7a7 ,,carbureted ,,air consisting of a mixture of atmospheric air and the vapor of some hydrocarbon 7liquid7 such as gasoline1 kerosene or alcohol4 7b7 ,,oil ,,gas formed by the distillation of some heavy1 nonvolatile oil1 or the distillation of tar or paraffine4 7c7 ,,natural ,,gas obtained from natural accumulations occurring in subterranean pockets in various parts of the country4 7d7 ,,coal ,,gas1 made artificially by the distillation of coal1 commonly called 8illuminating0 gas4 7e7 ,,producer ,,gas1 some times known as 8fuel gas10 produced by the incomplete combustion of coal in a form of furnace called a 8producer40 7f7 ,,blast ,,furnace ,,gas1 the unconsumed gas from the furnaces used in smelting iron1 somewhat similar to producer gas but lower in heat value4 ,it should be noted that there is no essential difference between engines using a permanent gas or an oil as in either case the fuel is sent into the cylinder in the form of a vapor4 ,in the case of oil fuel1 the vapor is formed by an appliance external to the engine proper4 ,in this book1 the heat action of an engine using one form of fuel applies equally to the engine using another4 ,the selection of a particular fuel for use with a gas engine depends not only upon its value in producing heat1 but also upon its cost1 the ease with which it meets the peculiar conditions under which the engine is to work1 and its accessibility4 ,neglecting for the moment1 all of the items that do not affect the operation of the engine from a power producing standpoint1 the principal requirement of a fuel is the production of a high temperature in the cylinder since the output is directly proportional to the temperature range4 ,since a very considerable mass of air is to be raised to this high temperature1 the heat value1 or ,,calorific ,,value of the fuel in ,british ,thermal units is of as much importance as the temperature attained in the combustion4 ,the calorific value of different fuels vary widely when based either on the cubic foot or pound1 and a considerable variation exists even among fuels of the same class owing to the different methods of production or to the natural conditions existing at the mine or well from which they originated4 ,the principal elements of gas engine fuels1 carbon and hydrogen1 exist in many different combinations and proportions1 and require different quantities of air as oxygen for their combustion because of this difference in chemical structure4 ,since complete combustion is never obtained under practical working conditions1 the actual evolution of heat and the actual temperatures are always much lower than those indicated by the ,,calorimeter or heat measuring device4 ,besides the loss of heat due to imperfect combustion1 there are many other losses such as the loss by radiation1 connection1 and slow burning1 the latter being the principal cause of low combustion temperatures4 ,from the statements in the foregoing paragraphs it will be seen that the theoretical or absolute calorific value of a fuel is not always a true index to its efficiency in the engine4 ,complete combustion results in the carbon of the fuel being reduced to carbon dioxide 7,,co#b7 and the hydrogen to water 7,h#b,o71 with the liberation of atmospheric nitrogen that was previously combined with the fuel1 and some oxygen4 ,the reduction of the fuel to carbon dioxide and water produces every heat unit available since the latter compounds represent the lowest state to which the fuel can be burned4 ,carbon however may be burned to an intermediate state without the production of its entire calorific contents when there is not sufficient oxygen present to thoroughly consume the fuel4 ,incompletely consumed carbon produces a gas1 carbon monoxide1 as a product of combustion1 and a quantity of solid carbon in a finely subdivided state known as 8soot40 ,unlike the products of complete combustion1 both the carbon monoxide and soot may be burned to a lower state with a production of additional heat when furnished with sufficient oxygen1 both the soot and the monoxide being reduced to carbon dioxide during the process4 ,illustration3 ,fig4 ,f-#b4 ,sunbeam ,engine with ,six ,cylinders ,cast 8,en ,bloc0 7in one piece74 ,at the ,right and ,under the ,exhaust ,pipe is the ,compressed ,air ,starting ,motor that ,starts the ,motor ,through the ,gear ,teeth ,shown on ,flywheel4 ,from 8,internal ,combustion40 ,as the soot and monoxide have a calorific value it is evident that much of the heat of the fuel is wasted if they are exhausted from the cylinder without further burning at the end of the stroke4 ,to gain every possible heat unit it is necessary to furnish sufficient oxygen or air to reduce the fuel to its lowest state4 ,as the free oxygen and nitrogen contained in the fuel are without fuel value1 their rejection from the cylinder occasions no loss except for that heat which they take from the cylinder by virtue of their high temperature4 ,with complete combustion the ,,temperature attained increases with the rate of burning1 while the number of heat units developed remain the same with any rate of combustion4 ,because of the conditions under which the fuel is burned in the gas engine the fuel is burned almost instantaneously with the result that high temperatures are reached with fuels of comparatively low calorific value4 ,with a given gas the rate of combustion is increased with an increase in the temperature of the gas before ignition and remains constant for all mixtures of this gas in the same proportion when the initial temperature is the same4 ,the rate of combustion also varies with the composition of the gas1 hydrogen burning more rapidly than methane4 ,as a rule it might be stated that the rate of burning decreases with the specific gravity of the gas1 the light gases such as hydrogen burn with almost explosive rapidity1 while the heavier gases such as carbon dioxide are incombustible or have a zero rate of combustion4 ,in practice an increased rate of burning is obtained by heating the charge before ignition by a process that will be explained later4 ,another factor governing the output of an engine with a given size cylinder is the amount of air required to burn the fuel4 ,the quantity of air necessary for the combustion of the fuel determines the amount of fuel that can be drawn into a given cylinder volume1 and as we are dependent upon the fuel for the expansion it is evident that with two fuels of the same calorific value1 the one requiring the least air will develop the most power4 ,since the air required to burn hydrogen gas is only one fourth of that required to burn the same amount of methane it is clear that more hydrogen can be burned in the cylinder than methane4 ,this great increase in output due to the hydrogen charge is however1 considerably offset by the greater calorific value of the methane4 ,should the air be in excess of that required for complete combustion1 or should a great quantity of incombustible gas1 such as nitrogen be present in the mixture1 the fuel will be completely burned1 but the speed of burning will be reduced owing to the dilution4 ,as the air is increased beyond the proper proportions the explosions become weaker and weaker as the gas becomes leaner until the engine stops entirely4 ,because of the fact that it is impossible in practice to so thoroughly mix the gas and air that each particle of gas is in contact with a particle of air1 the volume of air used for the combustion is much greater than that theoretically required4 ,a ,,slight excess of air1 making a lean mixture1 increases the efficiency of combustion although it reduces the temperature and pressure attained in the cylinder4 ,this is due to the fact that while the temperature of the mixture is lower than with the theoretical mixture the temperature of the burning gas itself is much higher4 ,a mixture that is too lean to burn at ordinary temperatures will respond readily to the ignition spark if the temperature or pressure is raised4 7#d7 ,compression4 ,in the practical gas engine the gas is not ignited at the beginning of the suction stroke by which it is drawn into the cylinder1 but is compressed in the front end of the cylinder by the return stroke of the piston1 and then ignited4 ,the process of compression adds greatly to the power output of a given sized cylinder and increases the efficiency of the fuel and expansion4 ,in order to understand the relation that the compression bears to the expansion let us refer to ,fig4 #b in which ,c is the working cylinder1 ,p the piston and ,g the crank4 ,while the piston is moving towards the crank in the direction of the arrow ,a it draws the mixture1 indicated by the marks x x x x x1 into the cylinder1 the quantity being proportional to the position of the piston4 ,in this particular case let us assume that the area of the piston is #ej square inches and that the entire stroke 7,b7 of the piston is #ab inches4 ,to prevent confusion due to considerations of heat loss we will further assume that the cylinder is constructed of non-conducting material4 ,with the piston at the position ,h1 midway between ,j and ,i1 the volume ,d is filled with the explosive mixture at atmospheric pressure and a temperature of #ejj absolute4 ,since ,d #f inches and the area of the piston is #ej square inches1 the volume ,d is equal to #f #ej #cjj cubic inches1 and the entire volume is #b #cjj #fjj cubic inches4 ,on igniting this mixture 7at atmospheric pressure7 the temperature will rise immediately1 say to #ajjj;,f with the piston at ,h4 ,according to a law governing the expansion of gases1 known as ,gay-,lussac's ,law1 the expansion 7v ,t7_/t ,v where v the initial volume of the gas before ignition #cjj cubic inches2 t the temperature before ignition #ejj absolute2 ,v the volume of the gas after expansion2 and ,t temperature after ignition #ajjj absolute4 ,inserting the values in numerical form we have as the final volume3--7#cjj #ajjj7_/ejj #fjj cubic inches the volume after expansion1 or twice the original volume of gas4 ,this means that the expansion is capable of driving the piston from ,h to ,i before the pressure is reduced again to atmospheric pressure4 ,as the volume is expanded to twice that of the original volume at atmospheric pressure 7#ad4g pounds per square inch71 the pressure against the piston before it starts moving will be #b #ad4g #bi4d pounds per square inch4 ,let us now consider the case in which the charge is compressed before ignition occurs and compare the expansion and pressure established with that produced by ignition at atmospheric pressure4 ,to produce the compression the piston will travel through the entire stroke to the position ,i on the suction stroke filling the entire cylinder volumes of #fjj cubic inches with the mixture4 ,on the return stroke the piston stops at ,h1 reducing the original volume of #fjj cubic inches to #cjj cubic inches1 doubling the pressure of the gas4 ,the initial and final temperatures will be considered as being the same as those in the first example1 #ejj and #ajjj4 ,from ,gay-,lussac's ,law--7v ,t7_/t ,v and substituting the numerical values 7#fjj #ajjj7_/ejj #abjj cubic inches1 or the expanded volume will be four times the compressed volume1 or four times the initial volume of the first case where the gas was ignited at atmospheric pressure4 ,it should be noted however1 that while the expansion has been greatly increased by the compression1 that this is not all gain1 as equivalent work has been expended in compressing the charge4 ,with the exception of doubling the fuel taken into the cylinder1 and consequently doubling the output for a certain cylinder capacity1 there has been no increase in fuel efficiency except that due to conditions other than the mere reduction in volume4 ,in the second case the volume was increased four fold which resulted in a piston pressure of #d #ad4g #eh4h pounds per square inch before the piston increased the volume by moving from ,h to ,i4 ,the work done by the engine on the charge in compressing is converted into heat energy causing a rise in the temperature of the gas4 ,this would not be a loss as it would reappear as mechanical energy on the return stroke of the piston through its expanding effect on the gas4 ,this heat would1 in effect1 be added to the temperature due to ignition1 and the sum would produce its equivalent expansion4 ,the temperature due to the combustion may be determined by reversing ,gay-,lussac's ,law-- t ,i ,pt -- -- or ,t ---- p ,p p ,where t initial temperature2 ,t temperature combustion2 ,p pressure after combustion2 p pressure before combustion4 ,because of the fact that the act of compressing the charge in the cylinder before ignition increases the temperature of the working medium1 the compression will increase the speed of combustion and efficiency of the fuel as the rate of combustion increases with the initial temperature4 ,this increased temperature due to initial compression of course results in a greater temperature range and output due to the increased rate of burning1 and this rate of combustion may be varied for different fuels by changing the compression pressure4 ,in a previous paragraph it was explained that the fuel efficiency was increased by a slight dilution or excess of air1 and that while the temperature and pressure of the mixture were reduced by the dilution the temperature of the fuel was increased1 provided that the inflammability was not decreased4 ,compression affords a means of using dilute mixtures without loss of inflammability1 as the heat gained by the compression restores the inflammability lost by the effects of dilution4 ,increased compression pressures increases the possible range of dilution1 so that extremely lean gases and mixtures may be used with success with appropriately high compression4 ,as an example of this fact we can refer to the engine using blast furnace gas1 a fuel that is so lean that it cannot be ignited under atmospheric pressure4 ,by increasing the piston speed1 the heat of the compression can be made more effective as the gas lies in contact with the cylinder walls for a shorter time which of course reduces the heat to the jacket water4 7#e7 ,efficiency and ,heat ,losses4 ,up to the present time we have considered an engine in which there is no heat loss or loss from friction1 but in the actual engine such losses are large and tend to materially reduce the values of heat and pressure to be obtained from a fuel with a given calorific content4 ,applying the rule for heat engines given in a previous section where the efficiency is-- ,t - t ,e ---------- ,t ,we have the theoretical efficiency of a gas engine1 neglecting friction1 loss to the cylinder walls1 and loss through the rejection of heat with the exhaust gas1 equal to-- #aifj - #ebj ,e -------------------- #gc4e percent4 #aifj ,in substituting the numerical values in the above calculation it was assumed that the temperature of the burning mixture would be #aejj ,f above zero1 and that the exhaust temperature would be as low as #fj4 ,since the calculation is made from absolute zero1 which is #dfj below the zero marked on our thermometers1 the temperature of the burning charge1 ,t #aejj #dfj #aifj above absolute zero4 ,similarly the absolute temperature of the exhaust would be1 t #fj #dfj #ebj absolute4 ,the application of the absolute temperatures will be seen from the calculation for efficiency4 ,the value given1 #gc4e per cent1 it should be understood is the theoretical efficiency and is at least #bj per cent above the best results obtained in practice4 ,the best record that we have had to date1 is that established by a ,diesel engine which returned #dh4b per cent of the calorific value of the fuel in the form of mechanical energy4 ,in order that the reader may have some idea of the losses that occur in the engine1 and their extent we submit the following table4 ,these are the results of actual tests obtained from different sources and represent engines built for different services and of various capacities3 ,,losses--,,data ,automobile,stationary,stationary ,motor ,engine ,engine ,horse-power #cj4 #bjj #ajjj ,loss at per ,heat lost to jacket water #ce4h #ca4j #bigj ,b4,t4,u4,horse-power in ,b4,t4,u4's ,heat lost in exhaust #bd4f #cj4j #bhce ,b4,t4,u4 ,friction loss #h4f #f4e #haj ,b4,t4,u4 ,heat lost by radiation #ae4d #h4b #edj ,b4,t4,u4 ,heat available as power #bgjj ,b4,t4,u4 ,efficiency 7per cent7 #ae4f #bd4c ,fuel ,gasoline ,producer ,gas ,the remarkable efficiency of the ,diesel engine is due principally to the extremely high compression pressure1 which was from #ejj to #fjj pounds per square inch4 ,when this is compared to the #fj to #gj pounds compression pressure used with automobile engines it is easy to see where the ,diesel gains its efficiency4 ,it is evident that as much depends on the manner in which the fuel is used in the engine as on the calorific value of the fuel4 7#f7 ,expansion of the ,charge4 ,when an explosive mixture is ignited in the cylinder with the piston fixed in one position thus making the volume constant1 the increase of temperature is accompanied by an increase of pressure4 ,if the piston is now allowed to move forward increasing the volume1 the increase of volume decreases the pressure4 ,since in the operation of the gas engine the piston continuously expands the volume on the working stroke it is evident that there is no point in the stroke where the pressures are equal1 and that the pressure is the least at the end of the stroke1 it being understood of course that no additional heat is supplied to the medium after the piston begins its stroke4 ,this distribution of pressure in the cylinder in relation to the piston position is best represented graphically by means of a diagram as shown by ,fig4 #c1 in which ,k is the cylinder and ,p the piston4 ,above the cylinder is shown the diagram ,,hgde the length of which 7,,he7 is equal to the stroke of the piston shown by 7,,bc74 ,intersecting the line ,,hi are vertical lines1 ,a1 a1 b1 c1 ,c1 which represent certain positions of the piston in its stroke4 ,the height of the diagram ,h ,g represents to scale the maximum explosion pressure in pounds per square inch1 and the line ,,hg is drawn immediately above the piston position ,b which is at the inner end of the stroke4 ,to the left of the line ,,hs is drawn a scale of pressures ,,ml divided in pounds per square inch so that the pressures may be read off of the pressure curve ,,gd4 ,the line ,,ji represents atmospheric pressure1 and the divisions on ,,ml1 of course1 begin from this line and increase as we go up the column4 ,as an example in the use of the scale we find that the point ,f is at #ej pounds pressure above the atmospheric line ,,ji4 ,we will consider that the clearance space ,,ab is full of mixture at the point ,b1 and that it is moved toward the left to the point ,c filling the space ,,ac full of mixture at atmospheric pressure4 ,the location of the piston on the diagram is shown by ,d and ,e4 ,the opening through which the gas was supplied to the cylinder is now closed1 and the piston starts on its compression stroke1 moving from ,c to ,a4 ,as the volume is reduced from ,,ac to ,,ab1 there is an increase of pressure which is shown graphically by the rising line ,,ef4 ,this line rises gradually from the line ,,ji in proportion to the reduction in volume until the piston reaches the end of the compression stroke at ,b1 at which point the compression is at a maximum4 ,the extent of this pressure is shown by the length of ,,hf which on referring to the scale of pressure at the left will be found to be #ej pounds per square inch4 ,ignition now occurs and the pressure increases instantly from the compression pressure at ,f to the maximum pressure at ,g which on referring to the scale will be found to equal #bjj pounds4 ,the actual increase of pressure due to ignition above the compression pressure will be shown by the length of the line ,,fg which is equal to #aej pounds4 ,as the pressure is now established against the piston it will begin to move forward with an increase of volume and a corresponding decrease in pressure1 until it reaches the point ,c4 ,this point at the end of the stroke is indicated on the diagram by ,d which by reference to the scale will be found equal to #be pounds above atmosphere4 ,an exhaust valve is now opened allowing the gas to escape to the atmosphere which reduces the pressure instantly from ,d to ,e on the atmospheric line4 ,expansion along the line ,,gd is not complete as the pressure is not decreased to atmospheric pressure in the cylinder which means that there is a considerable loss of heat in the exhaust4 ,in practice the expansion is never complete1 but ends considerably above atmospheric pressure as shown4 ,illustration3 ,fig4 ,f-#c4 ,front ,elevation of ,curtiss 8,v0 ,type ,aeronautical ,motor4 ,this is the ,front ,view of the ,motor ,shown in the ,frontispiece4 ,see ,chapter ,v for ,description of this ,type of ,motor4 ,complete expansion is shown by the dotted line ,,ge which terminates at ,e on the atmospheric line4 ,by following the vertical lines up from the points a1 b1 c1 and d1 the pressures corresponding to these piston positions can be found by measuring the distance of the curve from the atmospheric line1 on the given lines a1 b1 c or d4 ,to find the pressure at the position a1 for instance1 follow upwards along the line a to the point c on the curve1 the length of the line ef from the curve to the atmospheric represents the pressure1 which by reference to the scale ,,ml will be found equal to #abe pounds4 ,the pressure at any other point can be found in a like manner4 ,compression pressures may be found at any point by measuring from the atmospheric line to the compression curve ,,fe along the given line4 ,it will be noted that the combustion is so quick that the pressure rises in a straight line along ,,gh1 indicating that combustion was complete before the piston had time to start on the outward stroke4 ,the expansion curves ,,ge and ,,gd are similar to the compression curve ,,fe4 ,with the actual engine the shape of the ideal card as shown by ,fig4 #c is sometimes considerably deformed owing to the effects of defective valves1 leaks1 or improperly timed ignition4 ,pressure curves of actual engines are of the greatest value as they show the conditions within the cylinder at a glance and make it possible to detect losses due to leaks1 poor valve settings1 etc4 ,these curves are traced by means of the ,,indicator which is an instrument consisting of a small cylinder which is connected to the cylinder of the engine1 and an oscillating drum that is driven to and fro by the engine piston4 ,the piston in the indicator cylinder is provided with a spring that governs its movements and communicates its motion to a recording pencil through a system of levers4 ,the spring is of such strength that a pressure of so many pounds per square inch in the cylinder causes the pencil to draw a line of a definite length1 this line being equivalent to the pressure line ,,gh in ,fig4 #c4 ,a piece of paper is wrapped about the indicator drum1 and the drum is attached to the piston in such a manner that it turns a certain amount for every piston position1 the complete stroke of the piston turning the drum through about three-quarters of a revolution4 ,rotation of the drum traces the horizontal lines of the diagram and the movement of the piston draws the vertical lines1 so the combined movements of the drum and piston records the pressures and piston positions as shown by ,fig4 #c4 ,since the movement of the indicator piston represents the pressures in the cylinder to scale it is possible to compute the power developed in the cylinder as the output in mechanical units is equal to the product of the average force acting on the piston multiplied by the speed of the piston in feet per minute4 ,this product of the force and velocity 7known as 8foot pounds per minute07 divided by #cc1jjj 7one horse-power #cc1jjj foot pounds7 gives the output of the engine1 in horse-power4 ,as the pressure on the piston fluctuates throughout the stroke1 it would be wrong to consider the force1 in the calculation for power as being equal to the explosion pressure1 and so the effective pressure is taken as being the average of all the pressures from the point of explosion to the exhaust4 ,the average pressure or 8mean effective pressure0 as it is called is computed from the indicator diagram by dividing it into a number of equal parts along the horizontal line1 adding the lengths of the pressure lines such as ,,ch1 ,,cf1 etc41 and dividing the total length by the number of the lines4 ,after the average height of the diagram is thus determined1 the average length is multiplied by the scale of the indicator or the pressure that is shown by it per inch4 ,illustration3 ,fairbanks-,morse ,gasoline ,pumping ,engine4 ,pump is ,gear ,driven ,from the ,engine ,crank-,shaft at ,reduced ,speed4 ,knowing the mean effective pressure1 the total pressure on the piston1 or the force is found by multiplying the area of the piston in square inches by the average pressure per square inch4 ,this product is multiplied by the piston speed in feet per minute and is divided by the product of the number of strokes to the explosion and the quantity #cc1jjj4 ,should there be more than one cylinder the result is multiplied by the number of cylinders1 and this is multiplied by #b in the case of a double acting engine4 ,stated as a formula this rule becomes3 ,a ,p #b,r ,l ,n ,o ,h4,p4 ---------------------------------------- ---- #ccjjj ,c ,when ,a ,area of piston in square inches4 ,p ,average or mean effective pressure per square inch4 ,about #ge pounds for ,gasoline ,engines4 ,see ,table on ,page #ca4 ,r ,revolutions per minute4 ,l ,stroke of piston in feet4 ,n ,number of cylinders4 ,o #b when engine is double acting1 that is when explosions occur on both sides of the piston4 ,c ,number of strokes per explosion4 ,c #d in a four cycle engine1 and #b in a two cycle4 ,it should be specially noted that the area of the piston is given in square inches and the stroke of the piston in feet4 ,the number of revolutions per minute1 ,r1 is multiplied by two in order to obtain the number of strokes1 as there are two strokes per revolution4 ,when the engine governs its speed by dropping explosions to meet varying loads1 the quantity ,c should be omitted and the explosions counted4 99 99 99 99 99 ,due to the fact that the incoming charge of the mixture is expanded by the heat of the passages1 a full charge computed at atmospheric temperature is never obtained in the cylinder and for this reason the gas should be kept as cold as possible before entering the passages in order to obtain the maximum output4 ,friction due to restricted passages and valve openings also reduces the amount of mixture available4 ,small exhaust valves and pipes prevent the gases from escaping freely to the atmosphere and produces a back pressure on the piston which cuts down the effective pressures4 ,all of these items are recorded by the indicator and makes it possible to make alterations that will increase the output of the engine4 ,because of the reduced atmospheric pressures at high altitudes the output and compression are reduced for every foot of elevation above sea level4 ,as the weight of the atmosphere is reduced1 less mixture is drawn into the cylinder4 ,taking the output of the engine as #ajj per cent at sea level1 it is reduced to less than #fb per cent at an elevation of #ae1jjj feet4 ,,chapter ,,ii ,,fuels ,,and ,,combustion 7#g7 ,combustion4 ,the phenomenon called combustion by which we obtain the heat energy necessary for the operation of the internal combustion engine is a chemical combination of the air with the fuel4 ,this process results in heat and some light which is equal in quantity to the energy required to separate the fuel compound into its elements or to build it up in its present form from the original elements4 ,if the process is comparatively slow1 the compound is called a fuel1 if it is instantaneous it is called an explosive4 ,some substances produce mechanical force through an instant1 without the evolution of much heat1 due to the disintegration of an unstable compound4 ,the effect of the latter type of which dynamite is an example is static1 that is to say1 it is not capable of producing power1 but only pressure4 ,for this reason1 compounds having an instantaneous effect without the ability to produce the pressure through a distance1 or an expansion1 are not considered as suitable fuels for a heat engine4 ,a fuel is essentially a substance which is capable of generating heat1 which is a form of energy1 and not static pressure4 ,the heat engine is an instrument which transforms this energy into power which is again dissipated into heat through the friction of the engine itself and by the load that it drives4 ,this is an illustration of the physical law that 8energy can neither be created nor destroyed10 that is1 the heat energy developed by the fuel is converted into mechanical energy which is again transformed into heat energy through friction4 ,it should be understood that fuel belongs to that class of substances that will not burn nor evolve energy under any temperature1 pressure1 or shock1 without an outside supply of oxygen4 ,this is the characteristic property of all fuels used with the internal combustion engine4 ,each element1 such as carbon and hydrogen1 in a compound fuel1 develops a certain definite amount of heat during their complete combustion1 and at the close of the process certain compounds are formed that represent the lowest chemical form of the compound4 ,to restore the products of combustion to their original form as fuel would require an expenditure of energy equal to that given out in the combustion4 ,while all substances that are capable of oxydization or combustion can be made to liberate heat energy1 it does not follow that all of them can be successfully used as fuels4 ,a fuel suitable for the production of power must be cheap1 accessible and of small bulk1 and must burn rapidly4 ,such fuels must also be products of nature that require no expenditure of energy in their preparation or completion4 ,illustration3 ,fig4 ,f-#d4 ,fairbanks-,morse ,producer ,plant and ,engine1 ,connected for ,operation4 ,in practical work1 the natural fuels are coal1 mineral oils1 natural gas1 and wood1 which are compounds of the elements carbon and hydrogen4 ,when these fuels are burned to their lowest forms the products of combustion consist of carbon dioxide and water1 the first being the result of the oxydization of carbon1 and the latter a compound of oxygen and hydrogen4 ,in solid fuels1 such as coal1 a portion of the compound consists of free carbon and the remainder of a compound of carbon and hydrogen known as a ,,hydrocarbon4 ,in liquid fuels there is little1 if any1 free carbon1 the greater proportion being in the form of a hydrocarbon compound4 ,natural gas is a hydrocarbon compound4 ,it should be noted that a definite amount of oxygen is required for the complete combustion of the fuel elements1 and that a smaller amount of oxygen than that called for by the fuel element results in incomplete combustion1 which produces a product of higher form than that produced by the complete reduction4 ,the product of incomplete combustion represents a smaller evolution of heat than that of the complete process1 but if reburned in a fresh supply of oxygen the sum of the second combustion together with that of the first will equal the heat of the complete oxydization4 ,when pure carbon is incompletely burned the product is carbon monoxide 7,,co7 instead of carbon dioxide 7,,co#b74 ,carbon completely burned to carbon dioxide produces #ad1ejj ,british thermal units per pound of carbon1 while the incomplete combustion to carbon monoxide evolves only #d1deb ,british thermal units1 or less than one-third of the heat produced by the complete combustion4 ,theoretically one pound of carbon requires #b4ff pounds of oxygen to burn it to carbon dioxide4 ,on supplying additional oxygen1 the carbon monoxide may be burned to carbon dioxide and the remainder of the heat may be recovered1 or #aj1jdh ,british thermal units4 ,when a hydrocarbon1 either solid1 liquid or gaseous is burned with insufficient oxygen1 solid carbon is precipitated together with lower hydrocarbons1 and tar4 ,in an internal combustion engine the precipitated solid carbon is evident in the form of smoke4 ,since the carbon and hydrogen elements of a fuel exist in many different proportions and conditions in coal and oil1 different amounts of oxygen are required for the consumption of different fuels4 ,it should also be borne in mind that a greater quantity of air is required for the combustion of a fuel than oxygen1 as the air is greatly diluted by an inert gas1 nitrogen1 which will not support combustion4 ,because of the impossibility of obtaining perfectly homogenous mixtures of air and the fuel1 a greater quantity of air is used in practice than is theoretically required4 ,in a steam engine the fuel can be used in any form1 solid1 liquid1 or gaseous1 but in an internal combustion1 it must be in the form of a gas no matter what may have been the form of the primary fuel4 ,fortunately there is no fuel which may not be transformed into a gas by some process if not already in a gaseous state4 ,the petroleum products are vaporized by either the heat of the atmosphere or by spraying them on a hot surface4 ,coal is converted into a gas by distilling it in a retort or by incomplete combustion4 ,the heat energy developed by a gas when burning in the open air depends on its chemical combustion1 but its mechanical equivalent in power when burned in the cylinder of the engine depends not only upon its composition but upon the conditions under which it is burned as stated in the chapter devoted to the subject of heat engines4 7#h7 ,gaseous ,fuels4 ,while the calorific values of the different gases given in the accompanying table are approximately correct for gases burning in the open air at atmospheric pressure they develop widely different values in the cylinder of an engine because of the effects of compression and preheating4 ,the table serves1 however1 as an index to the relative values of the fuels under ordinary conditions without compression4 ,while natural gas has nearly eight times the calorific value of producer gas in the open air1 its actual heat value in the cylinder is only about #de per cent greater4 ,while acetylene has an exceedingly high calorific value and explodes five times as fast as gasoline gas1 it develops only #bj per cent more power in the same cylinder4 ,another item affecting the value of a gas is the rate at which it burns1 which is in part a characteristic of the fuel and partly a factor of the conditions under which it is burnt4 ,this subject is treated of in the chapter devoted to the heat engine4 ,the calorific value of a gas may either be computed from its chemical composition or by burning it in an instrument known as a calorimeter4 ,a gas calorimeter consists of a small boiler or heating tank which is carefully covered with some non-conducting material so as to prevent a loss of heat to the atmosphere4 ,the gas under test is burned in the boiler whose extended surface catches as much of the heat as possible and transfers it to the water in the boiler4 ,the weight of the water heated and its temperature are taken when a certain amount of the gas has been burned 7say #ajj cubic feet71 and from this data1 the heat units per cubic foot of gas are computed4 ,,fuel ,,gases4 ,,gas ,b4,t4,u4 ,cubic ,feet of ,air ,usual ,ratio per ,required to ,burn #a ,cubic ,compressionof ,gas ,cubic ,foot of ,gas ,lbs4 per to ,air ,foot ,sq4 ,inch ,actual ,theoretical ,natural ,gas #ajjj4 #ab4fj #i #acja-ab4f ,natural ,gas #ajjj4 #aaja-f ,coal ,gas #fej4 #i4jj #e4he #hja-i ,producer #adj4 #a4bj #a4he #afja-a4b ,anthracite ,producer #afj4 #c4bj #b4bj ,bituminous ,water ,gas #bij4 #c4fj #b4bj 7,uncarb47 ,water ,gas #ejj4 #h4ej #e4ae #a4h 7,carb47 ,blast ,furnace #id4 #a4aj #j4gj #agj ,gas ,acetylene #aejj4 #bj4jj #ab4fj ,gasolene ,vapor #ebj4,see ,table of ,liquid ,fuels #gja4ab ,gasolene ,vapor #ebj4,see ,table of ,liquid ,fuels #gja4h ,gasolene ,vapor #ebj4,see ,table of ,liquid ,fuels #gja4f ,kerosene ,vapor ,see ,table of ,liquid ,fuels #fja4h ,coke ,oven ,gas #ebj4 #g4 #e4d ,alcohol #ahj ,,gas ,explosion,temperature ,ignition ,weight,candle ,mean ,pressure of ,temperature per ,power ,effective in ,lbs4 ,combustion ,f ,cubic ,pressure per ,sq4 ,f ,foot1 ,in4 ,lbs4 ,natural ,gas #cge #aajj4jdei #id4jj ,natural ,gas #bde #ajjj #gb4jj ,coal ,gas #bhe #abjj4jce #ah4jj #he4jj ,producer #cfj #adej4jfe #hh4jj ,anthracite ,producer #acej ,bituminous ,water ,gas 4#jdd 7,uncarb47 ,water ,gas #bb4jj 7,carb47 ,blast ,furnace #aefj4jhj #gg4e ,gas ,acetylene ,gasolene ,vapor #bde #ahfe #aeej #gi4jj ,gasolene ,vapor #cfj #biej #ibe #hb4jj ,gasolene ,vapor #daj #cafj #iaj #hd4ej ,kerosene ,vapor #bhe #ide #he4jj ,coke ,oven ,gas 4#jdb ,alcohol #dej ,as a ,british thermal unit is the amount of heat required to raise the temperature of one pound of water through one ,fahrenheit degree 7at about #ci4a ,f471 the total heat per cubic foot of gas as observed by the calorimeter is equal to the weight of the water multiplied by its rise in temperature in degrees1 divided by the number of cubic feet of gas burned in the calorimeter4 ,since a ,british thermal unit is equal to #ggh foot pounds in mechanical energy1 its mechanical equivalent is equal to the number of ,british thermal units multiplied by #ggh4 ,another difference between the actual and theoretical results obtained is that due the perfect combustion in the calorimeter and the imperfect combustion in the engine4 ,since some gases require more air for their combustion than others1 less of the first gas will be taken into the cylinder on a charge than the latter1 which tends still further to balance the heating effect of rich and lean gases in the cylinder4 7#i7 ,gasifying ,coal4 ,coal ,gas or ,illuminating ,gas is generated by baking the coal in a closed retort or chamber out of contact with the air so that no combustion takes place either complete or incomplete4 ,the hydrocarbon gases and tars are set free from the coal as permanent gases and are then piped to a gas holder after going through various purifying processes to remove the tars1 oils1 moisture and dust4 ,the free or solid part of the coal remains in the retort in the form of coke1 which is again burned for fuel4 ,because of its high carbon content1 coal gas burns with a yellowish-white flame and is extensively used for lighting purposes1 hence the name illuminating gas4 ,in many ways coal gas is an ideal fuel for power purposes as it has a high calorific value 7#fej-gej ,b4,t4,u4 per cubic ft471 is supplied by the illuminating company at practically a constant pressure1 and is uniform in quality4 ,its only drawback is its comparatively high cost4 ,this gas is always obtained from the city service mains as its preparation is too expensive and complicated for the gas engine owner4 ,because of its cost1 the use of coal gas is restricted to small engines4 7#aj7 ,water ,gas4 ,water gas is made by blowing air through a thick bed of some coal that is low in hydrocarbons until the coal becomes incandescent1 the gases that are formed are allowed to escape to the atmosphere4 ,at this point a jet of steam is blown into the incandescent bed1 which is broken up into its elements1 oxygen and hydrogen1 by the heat of the fuel4 ,as there is no air present the oxygen combines with the carbon of the fuel to form carbon monoxide while the hydrogen goes free4 ,both of these gases1 carbon monoxide and hydrogen1 are collected and supplied to the engine4 ,the production of water gas is intermittent1 as the steam blast cools down the fuel bed1 and requires further blowing before more steam can be passed4 ,while this gas has a lower heating value than coal gas1 it is much cheaper to make and all of the coal is consumed in the process4 ,water gas is high in hydrogen and is too 8snappy0 for gas engines2 the hydrogen places a limit on the allowable compression4 ,for each thousand feet of water gas generated1 approximately #bd pounds of water are required4 ,by the introduction of hydrocarbons or vaporized oil1 illuminating value is given to water gas1 this process is called carburetion4 ,carbureted gas is not usually used for power1 as it is expensive1 and is not proportionately high in heating value4 7#aa7 ,blast ,furnace ,gas4 ,many steel companies are utilizing the unconsumed gas of the blast furnaces for power4 ,blast furnace gas is of very low calorific value1 rarely if ever1 exceeding #he ,b4,t4,u4 per cubic foot4 ,this allows of very high compression1 which greatly increases the actual power delivered by the engine4 ,a smelter produces approximately #hh1jjj cubic feet of gas per ton of iron smelted4 ,blast furnace gas is so lean that it cannot be burned satisfactorily under a boiler2 the high compression of the gas engine makes its use possible4 7#ab7 ,producer ,gas4 ,producer gas which is generated by the incomplete combustion of fuels in a deep bed is the most commonly used gas for engines having a capacity of #ej horsepower and over1 because of the simplicity and economy of its production4 ,while producer gas has been obtained from practically every solid fuel1 of which coal1 coke1 wood1 lignite1 peat1 and charcoal are examples1 the fuel most generally used is either coal or coke4 ,while producer gas is much lower in calorific value than either natural or illuminating gas it gives admirable results in the gas engine and is a much cheaper fuel than coal gas in units above #ej horse-power capacity4 ,the fuel is completely burned to ash in the producer without the intermediate coke product that exists in the manufacture of coke4 ,a producer consists of three independent elements as shown by ,fig4 ,f-#f2 the ,,producer or generator 7,a71 the steam boiler 7,b71 and the ,,scrubber or purifier 7,c74 ,the incandescent fuel 7,f7 in the form of a cone lies on the grate bars 7,g7 at the lower end of the producer4 ,above the burning fuel is a deep bed of coal 7,d7 which reaches to the top of the producer at which point it is admitted to the bed through the charging valve or gate 7,h74 ,the gas resulting from the combustion in the producer is drawn out of the tank through the gas outlet pipe 7,e7 by the suction of the engine4 ,the air for the combustion is drawn up through an opening in the ash pit 7,j7 by the engine4 ,when the oxygen of the air strikes the incandescent fuel on the grate it combines with a portion of it forming carbon dioxide 7,,co#b7 which is an incombustible gas1 but on passing through the burning fuel above this point1 one atom of the oxygen in the ,,co#b recombines with the fuel forming the combustible gas--carbon monoxide 7,,co74 ,because of the distilling effect of the heat in the bed1 the volatile hydrocarbons of the coal are set free and mingle with the ,,co formed by the combustion4 ,the producer gas consists1 therefore1 principally of ,,co1 with a certain proportion of the volatile hydrocarbons of the coal such as marsh gas1 ethylene1 and some oil vapor4 ,since the hydrocarbons are easily condensed on coming into contact with the coal walls of the piping1 to form trouble making tars and oils1 they must either be washed out of the gas in the purifier or passed again through the high temperature zone to convert them into permanent gases4 ,in the usual producer1 the hydrocarbons are reheated1 as they form a considerable percentage of the heat of the gas4 ,after the volatile constituents are reheated1 the gases pass through the boiler 7,b71 which absorbs the heat of the gas in generating steam1 and from this point the gases enter the scrubber where the dust and the residual tars are removed4 ,the scrubber1 which is a sort of filter1 is an important factor in the generating plant1 for if the dust and dirt were allowed to pass into the cylinder of the engine it would only be a question of a short time until the valves and cylinder would be ground to pieces4 ,when the steam from the boiler is allowed to flow into the ash pit of the producer and up through the incandescent fuel1 the heat separates the water vapor into its two elements1 oxygen and hydrogen4 ,the oxygen set free combines with the carbon in the coal forming more carbon monoxide1 while the hydrogen which is unaffected by the combustion adds to the heat value of the gas4 ,the last additions to the combustion due to the disassociation of the steam are really what is known as 8water gas40 ,a limited amount of steam may be admitted continuously in this manner without lowering the temperature of the fuel below the gasifying point1 and its presence is beneficial for it not only provides more ,,co and hydrogen but produces it without introducing atmospheric nitrogen4 ,the steam is also a great aid in preventing the formation of clinkers on the grate bars4 ,since the air used in burning the fuel in the first reaction contains about #gi per cent of nitrogen1 which is an inert gas1 the producer gas is greatly diluted by this unavoidable admixture1 which accounts for its low calorific value4 ,illustration3 ,fig4 ,f-#f4 ,diagram of ,suction ,gas ,producer ,showing the ,generator1 ,boiler and ,washer4 ,while the air required for the combustion of the fuel is drawn through the producer by the suction of the engine in the example shown 7,,suction ,,producer71 there is a type in common use called a ,,pressure ,,producer in which the air is supplied under pressure to the ash pit by a small blower1 which causes a continuous flow of gas above atmospheric pressure4 ,gas producers are divided into two classes3 suction producers and pressure producers4 ,the suction producer presents the following advantages3 #a4 ,the pipe line is always less than atmospheric pressure1 hence no leaks of gas to the air are possible4 #b4 ,the regulation of the gas supply is automatic4 #c4 ,no gas storage tank is required4 #d4 ,the production of gas begins and stops with the engine4 #e4 ,uniform quality of gas4 ,the suction producer is limited to power application and cannot be used where the gas is to be used for heating1 as in furnaces1 ovens1 etc41 or where the engine is at a distance from the producer1 unless pumped to its destination4 ,the pressure producer does not yield a uniform quality of gas1 hence requires a storage tank where low quality gas will blend with gas of higher calorific values and produce a gas of fairly uniform quality4 ,the pressure producer is adapted to the use of all grades of fuels1 such as bituminous coal and lignite4 ,anthracite coal contains little volatile matter and is an ideal fuel for the manufacture of producer gas1 while bituminous coal with its high percentage of volatile matter and tar1 requires more efficient scrubbing1 as these substances must be removed from the gas4 ,on starting the producer shown by ,fig4 #f1 the producer is filled with the proper amount of kindling and coal1 and a blast of air is sent into the ash pit by a small blower1 the products of combustion being sent through the by-pass stack 7,k7 until the escaping gas becomes of the quality required for the operation of the engine4 ,the by-pass valve is now closed1 and the gas is forced through the scrubber to the engine until the entire system is filled with gas4 ,when good gas appears at the engine test cock the engine is started1 and the blower stopped1 the gas now being circulated by the engine piston4 ,the volume of gas generated by the producer is always equal to that required by the engine so that no gas receiver or reservoir is required4 ,because of the friction of the gas in passing through the fuel1 scrubber and piping1 its pressure at the engine is always considerably below that of the atmosphere1 which of course reduces the amount of charge taken into the cylinder4 ,because of the weak gas and the low pressure in the piping1 it is necessary to carry a much higher compression with producer gas than with natural or illuminating gas4 ,the efficiency of a producer is from #ge to #he per cent1 that is1 the producer will furnish gas that has a calorific value of an average of #hj per cent of the calorific value of the fuel from which it is made1 the remaining #ae to #bj per cent being consumed in performing the combustion4 ,this is far above the efficiency of the furnace in a steam boiler1 as an almost theoretically exact amount of air can be supplied in the producer to effect the combustion1 while in the boiler furnace about ten times the theoretical amount is passed through the fuel bed to burn it4 ,heating up this enormous volume of air to the temperature of the products of combustion consumes a large amount of fuel and reduces the efficiency of the furnace considerably4 ,because of the reduction in the air supply1 a gas fired furnace is always more efficient than one fired with coal4 ,producer gas with #cjj1jjj ,british thermal units per thousand cubic feet1 and oil having #acj1jjj ,british thermal units per gallon will result in #a1jjj cubic feet of gas being equal to about #b4cj gallons of fuel oil4 ,if the gas is to be used for heating ovens or furnaces in connection with the generation of power1 the character of the fuel will be determined to a great extent by the requirements of the ovens and by the type of producer used1 as each fuel will give the gas certain properties4 ,thus gas used for firing crockery will not be suitable for use in open hearth steel furnaces1 as the impurities in the various fuels may have an injurious effect on the manufactured product4 ,the cost of the fuel1 cost of transportation1 heat value1 purity1 and ease of handling are all factors in the selection of a fuel4 ,the size and condition of a fuel is also of importance4 ,exceedingly large lumps and fine dust are both objectionable4 ,wet fuel reduces the efficiency of the producer1 as the water must be evaporated1 this causing a serious heat loss4 ,with careful attention a producer gas engine will develop a horse-power hour on from #a to #a pounds of anthracite pea coal1 and in many instances the consumption has been less than this figure4 ,the efficiency in dropping from full load to half load varies by little1 one test showing a consumption of #a4a pounds of coal per horse-power hour at full load and #a4f pounds of coal at half load4 ,producer gas power is nearly as cheap as water power1 in fact the producer gas engine has displaced at least two water plants to the writer's knowledge4 ,according to an estimate made by a well known authority1 ,mr4 ,bingham1 it is possible for a producer gas engine to generate power for only 4#a of one cent more per ,k4,w4 hour than it is generated at ,niagara ,falls4 ,according to the ,united ,states ,bureau of ,mines1 8,the tests in the gas producer have shown that many fuels of so low grade as to be practically valueless for steaming purposes1 such as slack coal1 bone coal and lignite1 may be economically converted into producer gas and may thus generate sufficient power to render them of high commercial value4 8,it is estimated that on an average each coal tested in the producer-gas plant developed two and one-half times the power that it would develop in the ordinary steam-boiler plant4 8,it was found that the low-grade lignite of ,north ,dakota developed as much power when converted into producer gas as did the best ,west ,virginia bituminous coals burned under the steam boiler4 8,investigations into the waste of coal in mining have shown that it probably aggregates #bej1jjj1jjj to #cjj1jjj1jjj tons yearly1 of which at least one-half might be saved4 ,it has been demonstrated that the low-grade coals1 high in sulphur and ash1 now left underground1 can be used economically in the gas producer for the ultimate production of power1 heat and light1 and should1 therefore1 be mined at the same time as the high-grade coal4 8,as a smoke preventer1 the gas producer is one of the most efficient devices on the market1 and furthermore1 it reduces the fuel consumption not #aj to #ae per cent1 as claimed for the ordinary smoke preventing device offered for use in steam plants1 but #ej to #fj per cent40 7#ac7 ,producer ,gas ,from ,peat4 ,the production of gas from peat having a low water content 7up to about #bj per cent7 for use in suction gas engines has already met with considerable success in ,germany1 but for a number of years efforts have been made to utilize peat with a water content as high as #ej to #fj per cent and thus eliminate the costly process of drying the raw material4 ,difficulties have been encountered in preventing a loss of heat through radiation and other causes1 and in getting rid of the dust and tar vapors carried over by the gases to the engine2 but great strides have been made recently in overcoming these obstacles4 ,peat with a water content up to #fj per cent has been found to be a suitable fuel4 ,owing to its great porosity and low specific gravity it presents a large combustion surface in the generator1 so that the oxygen in the air used as a draft can easily unite with the carbon of the peat4 ,illustration3 ,fig4 ,f-#g4 ,german ,producer for ,generating ,producer ,gas from ,peat4 ,one of the great difficulties is to eliminate the tar vapors that clog up many of the working parts of the engine4 ,the passing of the gas through the wet coke washers and dry sawdust cleansers does not appear to have thoroughly remedied the evil4 ,efforts were therefore made to remove the tar-forming particles of the gas in the generator itself or to render them harmless4 ,that of the ,aktien-,gesellschaft ,gorlitzer ,maschinenbau ,ansalt und ,eissengiesserei of ,gorlitz1 was displayed at the exposition at ,posen in #aiaa4 ,the gas from the generating plant was employed in a gas suction engine of #cjj horse-power used to drive a dynamo for developing the electric energy for the exposition4 ,the fuel used was peat with a water content of about #dj per cent4 ,the efficiency and economy results obtained were very promising4 ,the advantages claimed for the ,gorlitz engine are that the sulphurous gases and those containing great quantities of tar products are drawn down by the suction of the engine through burning masses of peat and thus rid of their deleterious constituents4 ,the air for the combustion purposes is well heated before entering the combustion chamber1 thereby producing economical results4 ,it is claimed also that the gas produced by its system is so free from impurities that the cleaning and drying apparatus may be of the simplest kind4 ,in ,stahl und ,eisen1 an abstract is given of a paper by ,carl ,heinz describing a peat gas producer1 built by the ,goerlitzer ,maschinenbauanstalt4 ,we are indebted to ,metallurgical and ,chemical ,engineering for the translation of this paper3 ,air and fuel enter the producer at the top1 and the gas exit is in the center of the bottom so that the air is forced to pass through the center of the producer1 decomposing the volatile matter into gases of calorific value4 ,the moisture which is present in the peat fuel in considerable quantities must be taken into consideration4 ,for its decomposition which passing through the hot-fire zone only a certain amount of heat is available4 ,it is1 therefore1 important that the heat from the gasification be fully utilized4 ,there are two kinds of heat losses in a gas producer1 due to radiation and to the sensible heat of escaping gases4 ,both these amounts of heat1 however1 are utilized according to the special design of this producer4 ,the air circulates first through the lower conduit and comes so in contact with the warm scrubber water4 ,a part of the air which has been preheated is carried upwards through the pipe ,a in the center of the producer where it is thoroughly preheated by the hot gases and enters then the air superheater ,b in which the temperature rises to a still higher degree4 ,the other part of the air passes through the feet of the producer into an air jacket which envelops the whole shell of the producer and enters finally the producer by the reversing valve ,c on top of the producer4 ,in this way the outer surface of the producer is maintained at a temperature hardly higher than that of the surrounding air4 ,the escaping gases are cooled down so far that the gas outlet into the scrubber may be touched by hand4 ,all ordinary heat losses are thus made use of in the gasification process4 ,if there is a large excess of moisture in peat1 the process is somewhat modified by regulating both air supplies in such a way that the gasification in the upper part of the fuel-bed takes place in two directions1 one downwards and the other upwards4 ,it seems that a content of #hj per cent moisture and #bj per cent dry fuel in the peat is about the limit permitting evaporation of the water1 but it is1 of course1 impossible to obtain in this case a gas of calorific value4 ,the modification of the process for very wet fuel is as follows3 ,when the fire on top of the fuel bed appears to disappear1 the heater opens the stack and valve ,d4 ,valve ,c is then closed1 to prevent air from entering on top4 ,the preheated air enters by ,d causing a down draft combustion due to the suction of the gas engine and an upward combustion due to the draft in the stack4 ,the moisture is evaporated and escapes through the stack4 ,when the fire has burned through at the top1 the valve is switched over4 ,the bad smelling gases rising from the scrubber enter the producer together with air and are there consumed4 ,in commercial use at the exhibition in ,posen the whole plant worked continuously day and night and cleaning of the gas engines was necessary only every three months4 ,slagging of ashes is done during the operation of the producer1 without any nuisance from dust4 ,the highest percentage of moisture in peat gasified was #ej per cent4 ,the fuel consumption per horse-power hour is #b4b lb4 7#a kg47 of peat4 ,careful tests made by ,prof4 ,baer1 of ,breslau1 showed that with a cost of peat of #a per ton the kw-hour at the switchboard costs #j4ae cent4 7#ad7 ,crude ,oil ,producers4 ,the development of the crude oil gas producer1 for which there is great demand1 in oil regions remote from the coal field1 has been exceedingly slow but it is believed that definite progress has recently been made along this line4 ,the most recent notes on this subject relate to the ,grine oil producer4 ,in this type steam spray is used for atomizing the oil which is introduced into the upper part of the generator where partial combustion takes place4 ,the downdraft principle is then applied and the hydrocarbon broken up and the tar fixed by passing through a bed of incandescent coke4 ,mr4 ,grine reports that a power plant using one of these producers has been in operation a year in ,california4 ,with crude oil as a fuel costing #ie cents per barrel1 or #b4c cents per gallon1 the plant is reported to develop the same amount of power per gallon of crude as is ordinarily developed by the standard internal combustion engine operating on distillates at #g cents per gallon4 ,including the cost of fuel1 labor1 supplies1 interest1 depreciation and taxes1 ,mr4 ,grine states the cost per b4h4p4 hour to be #j4gf cents for a plant of #ajj h4p4 rating4 7#ae7 ,operation of ,producers4 ,a good producer operator is simply a good fireman1 he must know how to keep a uniform bed of coal and how to draw the fire4 ,while there are many thousands of men running producer plants without previous mechanical training1 there are now but few steam engineers running steam engines of the same capacity but what have had at least two years' training and sufficient mechanical knowledge to pass an examination and obtain a license4 ,while a considerable amount of skill is necessary to obtain the best efficiency from a producer1 it is a knack that is easily acquired in a short time by 8sticking around0 the plant4 ,skill in operating a producer consists chiefly in keeping the right sort of a fire without damage to the lining by poking down ashes and clinkers4 ,when a new plant is installed1 the manufacturer generally sends an instructor to operate the plant for a short time so that with a few days running in his hands any man with ordinary intelligence can overcome the difficulties which arise from time to time4 ,while there are many types of producers1 the main difference will be found in the character of the draft1 that is whether it is up1 down1 or crossways4 ,down draft producers are generally used with bituminous coals1 as the tars and oils that emanate from the coal are drawn through the fire which converts them into a permanent gas1 and avoids the difficulty of removing great quantities of the tar from the producer4 ,an up draft producer will not do this as the gas is drawn directly into the mains without coming into contact with the fire4 ,this would result in considerable expense due to the frequent cleaning4 ,anthracite coal which does not contain much tar can be used successfully in an up draft producer4 ,a compromise between the up draft and down draft producer is had in the ,,double ,,zone producer1 which 8burns the candle at both ends0 as it were1 a fire being at both the top and bottom of the producer4 ,nearly any class of fuel may be used with this type4 ,it should be remembered that a hot fire and fuel are required for the manufacture of gas1 and that the ash pit and grate must be kept clear of the ashes and clinkers that not only reduce the temperature of the fire1 but also reduce the gas available at the cylinder by increasing the friction4 ,shaking down and cleaning out will in nearly every instance start a bucking producer into operation4 ,when operating under full load a much hotter fire is required than when operating under a reduced load1 or the producer will not furnish the necessary gas4 ,according to the size of the producer1 the depth of the incandescent fuel will run from #cj inches in the large sizes to #ae inches in the smaller4 ,after being charged up1 suction producers will continue to give gas in sufficient quantities with the bed at half this depth4 ,this is only possible with a hot producer1 and when no fuel is being fed1 as the feeding of a cold charge will reduce the output4 ,a steady depth of fire should be kept to maintain a uniform quality of gas4 ,in suction producers careful watch should be kept for leaks1 as the gas being below atmospheric pressure gives no outward signs of dilution4 ,if water seals are used in the system they should be given careful attention4 ,when using coals that are rich in tar or hydrocarbons1 or with fuels that have much fine dust1 considerable trouble is had with some types of producers due to 8caking0 or to the adhesion of the coal particles to the walls of the producers or to their adhesion to one another4 ,in the latter case the 8stickiness0 of the fuel prevent the proper feed4 ,this difficulty may often be overcome by a change in the rate of feeding or by regulating the depth of the incandescent bed4 ,porosity of the fuel1 and the rate at which the air is supplied to the producer determines the depth of the incandescent bed4 ,particular care should be taken that the blast or draft occurs evenly over the fire surface1 and that no holes occur in the fire which will cause more rapid combustion in one spot than in another4 ,neglect of this precaution not only causes a waste of fuel but often results in the fuel 8arching0 and preventing further feed4 ,the producer should be so proportioned that at full load1 the rate of combustion does not exceed #bd pounds of fuel per square foot of producer area per hour4 ,in his researches1 ,professor ,bone 7,iron and ,steel ,institute1 ,may1 #aijg7 has shown that up to #j4cb lbs4 of steam per lb4 of coal can be completely decomposed in a producer1 but that1 from #j4de lbs4 to #j4ee lbs4 should be used1 approximately #hj more4 ,now1 in considering the question of the proper proportion of steam for the production of gas for power purposes we must bear in mind that as much heat as possible should be utilized in the producer itself4 ,some manufacturers of plant go so far as to state that as much as #a lb4 of steam per lb4 of coal should be used1 but we are safe in saying that #j4e lb4 to #j4g lb4 should be the figure for a power plant4 ,the common practice is to use a blast saturation of #ee whenever the clinkering character of the coal renders it possible4 ,this figure corresponds to about 4#eg of steam per lb4 of coal gasified4 ,it is of the utmost importance that the proportion of steam and air should be constant1 and the best figure being determined1 it should not be varied to any degree4 ,it is equally important that the fuel depth should be left constant4 ,by this ,i mean that not only should the coal in the producer be kept at a specific level1 but the position of the fire on the ash bed should be kept as near as possible a fixed point4 ,ashes should be drawn at regular intervals1 or1 if desired1 continuously by mechanical means4 ,further1 the supply of air and steam should be regularly distributed1 so that the velocity of the gases through the fuel shall be as nearly as possible regular across its whole area4 ,in some cases the by-products of a producer1 such as ammonia1 tar1 etc41 have a commercial value1 and if a large amount of gas is generated it will sometimes pay to select a fuel that is rich in these particular substances4 7#af7 ,coal4 ,coal which is the basis of producer gas1 is composed generally speaking of the combustible matter1 moisture1 ash and sulphur4 ,the combustible element may be subdivided into the ,,hydrocarbons1 ,,or ,,volatiles1 and the solid fixed carbon4 ,the exact composition of coal is generally given by what is known as ,,proximate analysis1 which analysis divides the constituents of the coal into five groups1 viz43 ,,moisture1 ,,volatiles1 ,,fixed ,,carbon1 ,,ash1 and ,,sulphur4 ,ultimate analysis resolves the coal into its ultimate chemical elements1 such as hydrogen1 carbon1 nitrogen1 sulphur1 etc41 and being a difficult and tedious process it is not much used4 ,the proximate analysis gives all the necessary information and takes less time to perform4 ,,values ,,of ,,coal ,location of ,mine ,,proximate ,,analysis ,calorific ,value in ,b4,t4,u4 per ,lb4 of ,coal ,moisture,volatile ,fixed ,ash ,sulphur ,matter ,carbon ,,anthracite ,northern ,pa4 #c4ci #d4da #hc4cj #h4ag 4#gc #ac1bjj ,eastern ,pa4 #c4gj #c4jg #hf4db #f4ah 4#fc #ac1ddj ,western ,pa4 #c4ab #c4gf #ha4fj #aj4fa 4#ec #ab1hge ,,semi-,,anthracite #a4be #h4ae #hc4cj #f4bg #a4fc #ac1ijj ,,semi-,,bituminous ,pennsylvania 4#hj #ae4fj #gg4dj #e4ce 4#he #ad1ijj ,pennsylvania #a4ee #af4de #ga4ej #h4fc #a4hg #ad1bjj ,pocahontas ,va4 #a4jj #ba4jj #bd4dj #c4jb 4#eh #ae1ajj ,west ,virginia 4#ij #ag4hc #gg4gj #c4cj 4#bg #ae1bcj ,,bituminous ,youghiogheny ,pa4 #a4jj #cf4ej #ei4jj #b4ei 4#hf #ad1djj ,sample ,no4 #b #a4bj #cj4ah #ei4jj #h4hd 4#gh #ad1djj ,hocking ,valley #f4e #ce4jf #dh4hj #h4je #a4ei #ab1ajj ,kentucky #d4jj #cd4jj #ed4gj #g4jj 4#jc #ab1hjj ,indiana #h4jj #cj4bj #ed4bj #g4fj #ab1ejj ,illinois #aj4ej #cf4ae #cg4jj #ab4ij #c4de #aj1ejj ,colorado #f4jj #ch4ja #dg4ij #h4ji #ab1bjj ,,lignite #i4jj #db4bf #dd4cj #c4bg #a4ah #aa1jjj ,the ,,calorific ,,value of a fuel may be calculated from its analysis1 or may be determined by means of the ,,calorimeter from a sample of the coal2 the latter method is the most reliable4 ,table gives approximately the calorific values1 and the proximate analysis of several representative coals from various sections of the country4 ,the values given in the table are not exact1 as the coal from each locality varies considerably in quality1 but the figures will indicate what may be expected from each type of coal4 ,connellsville1 ,pa41 ,coke has a calorific value of approximately #ac1jjj ,b4,t4,u4's per pound1 contains no volatile matter1 and has an approximate content of #aj ash4 ,coke is a valuable fuel for the gas producer1 but is rather expensive4 ,it is clean and the absence of volatile matter reduces the 8scrubbing0 problem to a minimum4 ,small coal such as buckwheat and pea contain a much higher percentage of moisture than given in the table1 running from #e to #aj higher than the given values4 ,bituminous coal is high in hydrocarbons or volatiles which condense easily and form tar4 ,if the tar is not removed or converted into a permanent gas1 it will clog the passages of the producer and the engine and cause trouble4 ,the removal of the tar and ash from a gas is called ,,scrubbing1 and is performed by a device much resembling a filter4 ,anthracite coal and coke are low in volatiles or hydrocarbons1 and therefore do not cause trouble with tar deposits4 ,a high percentage of volatile matter also causes trouble by the tar cementing the particles of fuel together4 ,this interferes with the proper action of the producer4 ,fuels having a high percentage of ash call for perfect filtering or 8scrubbing0 as such fuels will fill the gas passages with dust4 ,dust should be kept out of the engine at all costs1 for the dust even in a quantity will cause wear in the cylinder4 ,depending on the quality of the fuel1 bituminous coal will produce about #d pounds of ammonia and #ab gallons of tar with about #e of sulphur4 ,anthracite coal will produce approximately six pounds of tar1 and two pounds of ammonia with traces of sulphur4 ,loose ,anthracite coal requires approximately #dj cubic feet of storage space per ton of #bbdj pounds and weighs about #ef pounds per cubic foot 7market sizes74 ,loose ,bituminous coal requires approximately #de cubic feet of storage space per ton of #bbdj pounds1 and weighs about #eb pounds per cubic foot in market sizes4 ,dry coke requires approximately #he cubic feet of storage space per ton of #bbdj pounds1 and weighs about #bf pounds per cubic foot4 7#ag7 ,fuel ,oils4 ,crude oil1 a natural product1 is the base of the fuels most commonly used in internal combustion engines1 especially in the smaller sizes4 ,from this compound the following derivatives are obtained by the process of distillation1 a separation possible because of the different boiling points of the various oils4 ,as each derivative or ,,distillate has a different boiling point1 the temperature of the crude oil is maintained at the boiling point of that product that is desired1 and the resulting vapor is condensed4 ,the following list is not anywhere near complete for there are several hundred distinctly different distillates1 but it contains those that are of the most interest to the engine man4 #a4 ,crude ,oil4 #b4 ,gasoline4 #c4 ,naphtha4 #d4 ,solar ,oil4 #e4 ,kerosene4 ,the specific gravity of the crude oil as obtained in the field will range from #ab to #ef ,beaum scale4 ,the crude from ,pennsylvania will average #dj ,beaum while that from ,texas will average #bj4 ,the accompanying table will give the calorific values and general properties of the principle liquid fuels4 ,it should be noted that the weight or density of the liquids is given in terms of specific gravity or ,beaum scale1 in which the ,,specific ,,gravity of the fuel is the ratio of its weight per unit volume to the weight of an equivalent volume of water4 ,the specific gravity of a liquid is generally determined by an instrument known as a ,,hydrometer which consists of a glass tube sealed at both ends carrying a graduated scale on the upper portion of the stem1 and a ballast weight of shot or mercury at the bottom4 ,the hydrometer is floated in the liquid to be tested1 and the lower the specific gravity1 the lower the hydrometer sinks1 and vice versa4 ,the specific gravity of the liquid is read directly from the graduation on the stem that are on a level with the surface of the liquid under test4 ,as in the case of thermometers1 hydrometers are all graduated in two different scales1 the specific gravity scale and the ,beaum scale4 ,the specific gravity scale reads at #a4jj when floated on distilled water1 and the ,beaum at #aj4jj when floated on the same liquid4 ,a difference in temperature affects the density of a liquid1 hence all hydrometers are graduated for a standard temperature of #fj;,f unless otherwise specified4 ,for a difference of #aj;,f there is a variation of one degree gravity in the ,beaum scale1 and for a difference of #bj;,f in temperature there is a change of one degree on the specific gravity scale4 ,if the temperature differs from #fj;,f1 the corresponding correction should be made in the reading4 ,to convert the ,beaum reading 7,b7 to terms of the specific gravity scale 7,s7 use the following formula3 #adj ,s -------------- specific gravity4 #acj ,b #adj ,b ------ ,beaum scale4 ,s ,,properties ,,of ,,oils ,degrees ,specific ,weight ,b4,t4,u4',s ,b4,t4,u4',s ,beaum ,gravity per gal4 per lb4 per gal4 ,gasoline #fg4b 4#gabe #e4icb #baabj #abe1bhd ,heavy naphtha #fd4f 4#gbaf #f4jaa #bjebg #abc1chh ,kerosene #dh4h 4#ghdh #f4ech #bjjah #acj1hgg ,w4 ,virginia crude #dj4j 4#hbea #f4hgd #aigff #ace1hga ,penn4 fuel oil #ca4i 4#hffj #g4bae #aifef #ada1hah ,kansas crude #bi4j 4#hhaf #g4cde #aidce #adb1gej ,fuel oil #bb4g 4#iagf #g4fde #aiajc #adf1jdb ,california crude #bb4e 4#ibdh #g4gaj #ahggi #add1ghf ,california crude #ae4b 4#ifdf #h4jcf #ahehi #adi1cha ,alcohol1 #ie #da4i 4#haf #f4gih #ajejj #ga1chj ,it will be noted that the petroleum products contain an enormous amount of heat energy1 nearly #be more than that of the same weight of pure carbon4 ,it will also be noted that the lighter products such as gasoline1 kerosene1 etc41 have more heat per pound but less per gallon than the heavier oils4 ,this is rather confusing at first1 but as will be seen after deliberation that the heavier fuel is the most economical since the least is used per horse-power1 and is bought by the gallon4 ,the calorific values given in the table are obtained by a calorimeter1 and are burnt in the open air1 and consequently have a different heating value when under compression in the cylinder of the engine4 ,in all cases the liquids are vaporized before being introduced in the cylinder1 the more volatile liquids such as gasoline being converted into vapor at atmospheric temperature1 and the heavier non-volatiles by being sprayed into a heated vessel or preheated air4 ,the percentage of liquid fuel contained in a cubic foot of air vapor mixture depends on the temperature1 the boiling point of the liquid and upon the pressure and humidity4 ,gasoline consists principally of compounds of the methane series1 the one representative of gasoline being ,hexane 7,c#f;,h#ad74 ,it requires #ae4e pounds of air for combustion theoretically and about #aj per cent4 more in practice4 ,the formation of gasoline vapor produces a drop in temperature of #ej;,f1 and should be heated #ajj;,f above the atmosphere for the best results4 ,the volume of air required for the combustion is about #aib cubic feet4 ,with alcohol at #bj cents per gallon and gasoline at #ab cents the number of ,b4,t4,u4's for one cent in the case of alcohol is #ceid and #ibfe in the case of gasoline4 ,in the engine the difference is not so great owing to the difference in compression pressures4 7#ah7 ,tar for ,fuel4 ,because of the increasing interest in the ,diesel type engine and the low grade fuels that it has made possible1 we quote the specifications laid down by ,dr4 ,rudolph ,diesel1 the inventor1 before the ,english ,institution of ,engineers4 7#a47 ,tar-oils should not contain more than a trace of constituents insoluble in xylol4 ,the test on this is performed as follows3--#be grammes 7#j4hh oz4 av47 of oil are mixed with #be cm4#c 7#a4ebe cub4 in47 of xylol1 shaken and filtered4 ,the filter-paper before being used is dried and weighed1 and after filtration has taken place it is thoroughly washed with hot xylol4 ,after re-drying the weight should not be increased by more than #j4a gr4 7#b47 ,the water contents should not exceed #a per cent4 ,the testing of the water contents is made by the well-known xylol method4 7#c47 ,the residue of the coke should not exceed #c per cent4 7#d47 ,when performing the boiling analysis1 at least #fj per cent4 by volume of the oil should be distilled on heating up to #cjj ,c4 ,the boiling and analysis should be carried out according to the rules laid down by the ,trust4 7,german ,tar ,production ,trust on ,essen-,ruhr47 7#e47 ,the minimum calorific power must not be less than #h1hjj cal4 per kg4 ,for oils of less calorific power the purchaser has the right of deducting #b per cent of the net price of the delivered oil1 for each #ajj cal4 below this minimum4 7#f47 ,the flash-point1 as determined in an open crucible by ,von ,holde's method for lubricating oils1 must not be below #fe ,c4 7#g47 ,the oil must be quite fluid at #ae ,c4 ,the purchaser has not the right to reject oils on the ground that emulsions appear after five minutes' stirring when the oil is cooled to #h4 ,purchasers should be urged to fit their oil-storing tanks and oil-pipes with warming arrangements to redissolve emulsions by the temperature falling below #ae ,c4 7#h47 ,if emulsions have been caused by the cooling of the oils in the tank during transport1 the purchaser must redissolve them by means of this apparatus4 ,insoluble residues may be deducted from the weight of oil supplied4 ,coal tar oil is the distillate of the tar obtained from gas works1 from which all valuable commercial materials such as aniline have been removed4 ,coal oil tar is also known as creosote oil and anthracene oil1 the heat value of which is not quite #af1jjj ,b4,t4,u4 per pound4 7#ai7 ,residual ,oils4 ,residual oil is the residue left after the lighter oils have been distilled from the petroleum1 which before the advent of the ,diesel engine were useless4 ,residual oil which was hardly fluid at ordinary temperatures has been successfully used in the ,diesel and semi-,diesel types of engines1 by preheating it before admission to the inlet valves4 ,the enormously increased demand for gasoline has resulted in a great increase of the formerly useless residual oil so that it is possible that the demand for gasoline will make the production of the residual great enough so that it can be seriously considered as a fuel4 7#bj7 ,gasoline4 ,gasoline is by the far the most widely used fuel for internal combustion engines because of its great volatility and the ease with which it forms inflammable mixtures with the air at ordinary temperatures4 ,another point in its favor is the fact that it burns with a minimum of sooty or tarry deposits1 without a disagreeable smell with moderate compression pressures and without preheating through a wide range of air ratios4 ,gasoline is a product of crude oil from which it is obtained by a process of distillation1 and as it forms but a small percentage of the crude oil it is rapidly becoming more and more expensive as the demand increases4 ,some ,pennsylvania crude oils will yield as much as #bj per cent of their weight in gasoline1 while the low grade ,texas and ,california crudes very seldom contain more than #c per cent4 ,when considered as a term applying to some specific product1 the word 8,gasoline0 is a very flexible expression as it covers a wide range of specific gravities1 boiling points1 and compositions1 the latter items depending on the demand for the fuel and the taste of the manufacturer4 ,since the specific gravity of gasoline is a factor that determines its suitability for the engine1 at least in regard to its evaporating power or volatility1 it is graded according to its density in ,beaum degrees as determined by the hydrometer4 ,according to this scale gasoline will range from #he to #fj ,beaum1 and even lower1 although #fj is supposed to mark the lowest limit and to form the dividing line between gasoline and naphtha4 ,the density of the gasoline in ,beaum degrees is an index to the volatility1 for the higher the degree as indicated on the hydrometer1 the higher is the volatility at a given temperature1 consequently a high degree gasoline will give a better mixture at a low temperature than one of a low degree4 ,in cold weather all gasoline should be tested with a hydrometer when purchased to insure a grade that will be volatile enough for easy starting when the engine is cold4 ,in cold weather the gasoline should not be lower than #fh1 and for the best results should be above #gb1 at least for starting the engine4 ,good gasoline should evaporate rapidly and should produce quite a degree of cold when a small amount is spread on the palm of the hand1 and it should leave neither a greasy feeling nor a disagreeable odor after its evaporation4 ,the high gravity gasoline is of course the most expensive1 as there is less of it in a gallon of the crude oil from which it is made2 gasoline of #gf ,beaum being approximately #ae;c4 per gallon in carload lots1 while naphtha of #eh ,beaum brings #h;c4 per gallon4 ,the calorific value of gasoline increases as the gravity ,beaum decreases per gallon2 #he gasoline having approximately #aac1jjj ,b4,t4,u4 per gallon while #eh naphtha has an approximate value of #abb1jjj ,b4,t4,u4 per gallon4 ,the calorific value remains nearly constant per pound for all gravities4 ,it should be remembered that heat is absorbed in evaporating gasoline as well as in evaporating water1 and that effects of cold weather are greatly increased by the amount of heat absorbed1 7or cold produced7 by the vaporization of the fuel4 ,while the heat absorbed by evaporating a given quantity of gasoline is only 4#de per cent of that absorbed by an equal amount of water1 it is a fact that this heat must be supplied from some source to prevent a reduction in the vapor density4 ,in starting the engine1 the heat of evaporation is supplied by the atmosphere1 and should the temperature of the air be below that required for a given vapor density1 the engine will refuse to start4 ,by the use of two tanks and a three way valve1 it is possible to use two grades of fuel3 one tank containing high gravity gasoline1 and the other low gravity2 the high gravity being used for starting the engine in cold weather1 and the cheaper1 low gravity1 being used for continuous running after the engine is warmed up--the change of fuels being made by throwing over the three way valve4 ,the ,,vapor ,,density of gasoline vapor is the ratio of the weight of the vapor compared with the weight of an equal volume of dry air at the same temperature4 ,if the weight of a cubic foot of gasoline vapor is divided by the weight of a cubic foot of air at the same temperature the result will be the vapor density of the gasoline vapor4 ,compared to air1 the gasoline vapor is quite heavy so that if a small quantity of gasoline is poured on the top of a table1 the vapor will flow over the edge of the table and drop to the floor where it will remain until it has united with the air by the process of diffusion4 ,experiments have shown that pure1 dry gasoline vapor has a density of about #c4bh1 or in other words weighs #c4bh times as much as an equal volume of dry air4 ,this weight of course is the weight of pure vapor which is considerably heavier than the mixture of vapor and air that is used in the cylinder of the engine4 ,dampness1 or the presence of water vapor in the air reduces the quantity of gasoline vapor taken up by the air1 but only by a small amount1 the maximum difference being only about #b per cent4 ,since it is very likely that the water vapor is broken up into its original elements1 oxygen and hydrogen1 by the heat of the combustion it is likely that there is no heat loss due to the vapor passing out through the exhaust4 ,the principal trouble due to dampness is the mixture of water and liquid gasoline caused by the condensation of the water vapor4 ,all gasolines and oils contain water to a more or less degree1 hence provision should be made for the draining of the water which collects in the bottom of the tank4 ,water in liquid fuels is the cause of much trouble4 ,water in gasoline may be detected by dropping scrapings from an indelible pencil into a sample of the suspected fluid4 ,if water is present in any quantity the gasoline will assume a violet color4 ,in filling a supply tank with gasoline1 a chamois filter or chamois lined funnel should always be used1 as the chamois skin allows the gasoline to pass but retains the water and impurities contained therein4 ,there are many funnels of this type now on the market4 ,the rate at which gasoline burns depends on the amount of surface presented to the air by the fluid1 for a given quantity of gasoline burns faster in a wide shallow vessel than in a deep jar4 ,since a spray of minute particles presents an enormously greater surface than the liquid its burning speed is correspondingly greater1 and as a true vapor has an almost limitless area1 its speed is much greater than that of the spray1 the combustion under the latter condition being almost instantaneous4 ,besides the question of subdivision of the liquid1 the rate of combustion also depends on the intimacy of contact of the vapor with the air and on the pressure applied to the vapor as previously explained under the head of 8,,compression0 in another chapter4 ,,carbureting ,,air1 or producing an explosive mixture of gasoline vapor and air is accomplished by two different methods1 first by passing the air over the surface of the liquid1 or by passing it through the liquid in bubbles2 second by spraying the liquid into the air4 ,the latter is the method most generally in use at the present time1 the spray being formed by the suction of the intake air upon the open end of the spray nozzle4 ,the vapor density of the mixture thus formed depends on the suction of the air and upon the nozzle opening1 either of which may be varied in the modern carburetor to vary the richness of the mixture4 ,as a suggestion to the users of gasoline we append the following remarks4 ,gasoline vapor will readily combine with air to form explosive mixtures1 at ordinary temperature4 ,this property at once makes it the most suitable fuel and the most dangerous to handle4 ,never fill tanks or expose gasoline to the air in the presence of an open flame1 or do not attempt to determine the amount of gasoline in a tank with the aid of a match4 ,there are a number of people who have successfully accomplished this feat1 and a very great number who have not4 ,be very sparing in the use of matches around a gasoline engine2 there are such things as leaks4 ,always carefully replace the stopper or filler cap in a gasoline tank after filling4 ,never use the same funnel for water and gasoline1 and avoid any possibility of water finding its way into the tank4 ,if you do succeed in igniting a quantity of free gasoline1 do not attempt to extinguish the fire with water4 ,pouring water on burning gasoline spreads the fire4 ,extinguish it with earth or sand1 or by the use of one of the dry powder extinguishers now on the market4 ,water may be removed from gasoline by placing a few lumps of desiccated calcium chloride in the tank1 the amount depending on the quantity of water4 ,calcium chloride1 has a great capacity for absorbing water1 and in a short space of time will absorb all of the moisture contained in the tank4 ,the best way to introduce the chloride is to wrap the lumps in a sheet of wire gauze and lower into tank with a wire1 the wire allowing it to be easily removed when saturated with water4 7#ba7 ,benzol4 ,benzol has been used to some extent in ,europe as a fuel1 its use being due to the rapidly increasing cost of gasoline4 ,benzol is a distillate of coal tar1 and is a by-product of the coke industry4 ,in ,england benzol brings approximately the same price as gasoline 7called petrol71 but benzol proves economical for the reason that it develops more power per gallon4 ,benzol is not as volatile as gasoline1 but is sufficiently volatile to allow of easy motor starting4 ,benzol is also used for denaturing alcohol4 7#bb7 ,alcohol4 ,alcohol is of vegetable origin1 being the result of the destructive distillation of various kinds of starchy plants or vegetables4 ,starch is the base of alcohol4 ,as a fuel1 alcohol has much in its favor1 as it causes no carbon deposit1 has smokeless and odorless exhaust1 can stand high compression1 and requires less cooling water than gasoline1 as the heat loss is less through the cylinder walls1 and for this reason it is more efficient fuel than gasoline4 ,at the present time the price of alcohol prohibits its general use4 ,in order that alcohol equal gasoline in price per horse-power hour1 it should sell for #aj;c4 per gallon1 the price of gasoline being #ae;c4 per gallon4 ,alcohol can be used in any ordinary gasoline engine with readjustment of carburetor and the compression4 ,the nozzle in the carburetor has to be of larger bore for alcohol than for gasoline1 and the compression for alcohol in the neighborhood of #ahj pounds per square inch4 ,the inlet air should be heated to about #bhj;,f for alcohol fuel2 approximately #f of the heat of the alcohol is required for its vaporization4 ,alcohol is much safer to handle than gasoline owing to its low volatility4 #ij alcohol has a calorific value of #aj1ajj ,b4,t4,u4 per pound1 its specific gravity being 4#hae4 ,,wood1 or ,,methyl alcohol is made by distilling the starch contained in the fibres of some species of wood 7,poisonous74 ,,grain1 or ,,ethyl alcohol is the result of the distillation of the starch contained in grains1 potatoes1 molasses1 etc4 ,,ethyl1 or ,,grain alcohol rendered unfit for drinking by the addition of certain substances1 is called ,,denatured ,,alcohol4 ,the process of denaturing does not affect the calorific value of alcohol to any extent4 7#bc7 ,kerosene ,oil4 ,kerosene is a fractional distillate of crude oil which has a considerably higher vaporizing temperature than gasoline4 ,it does not form an inflammable mixture with the air at ordinary temperatures1 but is vaporized in practice by spraying it into a chamber heated to above #bjj;,f4 ,kerosene forms a greater percentage of crude oil than gasoline and as there has been less demand for it up to the present time it is much cheaper4 ,pennsylvania crude oil produces only #bj per cent of gasoline while the kerosene contents will average nearly #db per cent according to figures at hand4 ,kerosene has a very high calorific value per gallon1 #h4e gallons of kerosene having the same heating effect as #aj gallons of gasoline4 ,because of its high calorific value and its low cost per gallon1 many types of engines have been developed for its use during the last few years1 several of which have been very successful4 ,before the advent of the modern kerosene engine much difficulty was experienced with the fuel because of its high vaporizing temperature and its tendency to carbonize in the cylinder1 but as the price of gasoline continued to rise1 the inventive genius of the gas engine builder overcame these troubles so that the kerosene engine is now as reliable as any form of prime mover4 ,illustration3 ,kerosene ,vaporizer on ,fairbanks-,morse ,engine4 ,the ,engine is ,started on ,gasoline and ,when ,hot1 the ,kerosene ,feed is ,turned on4 ,any gasoline engine will run on kerosene1 after a manner1 if the engine is thoroughly heated to insure the vaporization of the kerosene1 and if the fuel is heated in the carburetor4 ,such an arrangement is make-shift1 however1 and is not productive of good results in continuous service4 ,if kerosene is to be used as a regular fuel1 a kerosene engine should be used to avoid vaporizing and carbonizing difficulties as well as the sooty1 offensive exhaust1 and the loss of fuel represented by the soot4 ,many kerosene engines are arranged to start on gasoline1 and1 after becoming heated1 have the running feed of kerosene admitted through a three way valve4 ,the gasoline feed is then stopped4 ,the above arrangement admits of easy starting in all weathers and temperatures4 ,in the ,diesel engine there is no evaporating of fuel1 and no deposits of carbon because of the high temperature of the combustion chamber4 ,with engines that draw the mixture of vapor and air into the cylinder there are several methods of applying heat to the liquid1 and the combustion of the vapor thus formed is perfected by the injection of water into the combustion chamber4 ,it has been found by experiment that a small amount of water vapor introduced into the cylinder of a kerosene engine makes the engine run more smoothly and prevents a smoky exhaust and carbon deposits in the cylinder4 ,the water is introduced into the cylinder through an atomizer in the form of a mist or fog1 the particles of water being in a very finely subdivided state4 ,illustration3 ,kerosene ,vaporizer on ,fairbanks-,morse ,vertical ,engine4 ,started on ,kerosene ,directly by ,heating ,vaporizer with ,torch4 ,the deposits of free carbon 7soot7 caused by the 8cracking0 or decomposition of the kerosene vapor before ignition1 due to the high temperature of the cylinder1 are burnt to carbon dioxide by the oxygen of the water which is also set free by the heat of the cylinder4 ,this produces an odorless gas 7,,co#b7 which indicates complete combustion4 ,besides the increase of fuel efficiency due to the water vapor1 the cylinder is more thoroughly cooled and is more efficiently lubricated because of the reduction in temperature4 ,,chapter ,,iii ,,working ,,cycles 7#bd7 ,requirements of the ,engine4 ,in order that an internal combustion engine shall operate and develop power continuously the following routine of events must occur in the cylinder in the following order1 no matter what the type of engine4 7#a7 ,the cylinder must be filled with a combustible mixture of air and gaseous fuel at as nearly atmospheric pressure as possible4 7#b7 ,the mixture must be compressed in order to develop the value of the fuel4 7#c7 ,ignition must take place at the end of the compression stroke or at the highest point of compression4 7#d7 ,complete combustion of the fuel must follow the ignition of the charge1 with an increase of temperature and pressure which will act on the piston to the end of the power stroke4 7#e7 ,after the piston has completed the working stroke the products of combustion must be ejected from the cylinder completely to make way for the admission of the new combustible mixture4 ,with the exception of the ,diesel engine which 7#a7 fills the cylinder with pure air without the fuel1 and 7#b7 injects the fuel after compression1 all internal combustion engines not only perform each of these operations but proceed with events in the order given as well4 ,the accomplishment of the five acts is called a 8cycle of events10 or a 8,,cycle10 and the series is performed in different ways in different types of engines4 ,in the operation of the engine1 the series of events occur over and over again1 always in the same order1 #a-b-c-d-e1 #a-b-c-d-e1 #a-b-c-d-e1 etc4 ,the five events are generally given in terms of the number of strokes of the piston taken to accomplish the complete routine1 thus a two stroke cycle engine performs the series in two strokes1 and a four stroke cycle engine in four strokes1 and so on4 ,in order to obtain the benefits of high compression1 perfect scavenging of the products of combustion from the cylinder and perfect mixtures1 a great variety of engines have been developed in which the number of strokes taken to accomplish the five events varies4 ,in some engines the cycle is accomplished in two strokes1 in other engines it is accomplished in six strokes1 but in the great majority of cases the cycle is performed in either two or four strokes1 and as these are by far the most common routines1 we will confine our description to engines of these types4 7#be7 ,four ,stroke ,cycle ,engine4 ,the four stroke cycle engine1 some times improperly called the 8four cycle0 engine is the most widely used type for all classes of service1 except possibly for marine work4 ,its extended use is due to its superior scavenging1 high efficiency and reliability1 although it is somewhat more complicated than the two stroke cycle type4 ,its ability to function properly under a wide variation of speed has driven the two stroke cycle type out of the automobile field1 and its many admirable characteristics have cut a wide swath in the marine field1 the stronghold of the two stroke cycle type4 ,a four stroke cycle engine performs the cycle of events in four strokes or two revolutions1 only one of the strokes being a power of working stroke4 ,in a single cylinder engine the explosion in the working strokes supplies enough power to the fly-wheel to carry the engine and its load through the remaining three strokes4 ,thus the energy stored in the fly wheel is sufficient to carry not only the load during the idle strokes but to 8inhale0 and compress the charge as well4 ,due to the long interval that exists between explosions1 they are corresponding heavy and are productive of heavy strains in the engine and are the cause of considerable vibration4 ,to reduce the ill effects of the heavy intermittent blows1 the majority of automobile and stationary engines are provided with two or more cylinders1 the power being equally divided among them4 ,in a four cylinder engine1 there are four times as many impulses as in a single cylinder engine and the blow dealt by the individual cylinder is only one-quarter as great4 ,while a single cylinder engine has an impulse only once in every other revolution1 the four cylinder has two impulses in one revolution4 ,besides the advantages gained by increasing the impulses1 the mechanical balance of a multiple cylinder engine is always better than that of a single and is also much lighter in weight since less material is required to resist shocks of the explosions4 ,illustration3 ,fig4 #d4 ,diagrammatic ,view of ,four ,stroke ,cycle ,engine with the ,piston in ,various ,positions ,corresponding with the ,five ,events4 ,diagram ,a--,suction4 ,diagram ,b--,compression4 ,diagram ,c--,ignition4 ,diagram ,d--,working ,stroke4 ,diagram ,e--,release4 ,diagram ,f--,scavenging ,stroke4 ,engines with more than four cylinders have 8overlapping0 impulses1 that is some cylinder on the engine is always delivering power1 for before one cylinder reaches the end of the stroke1 another has fired its charge and has started to deliver power4 ,thus the impulses 8overlap0 one another1 and the result is an even and smooth application of power and a minimum of strain is imposed on the engine4 ,aeronautical and speed boat engine builders have carried the multiple cylinder idea to an extreme because of the nature of their work4 ,eight cylinder aeronautical engines are very common and there are several built having sixteen cylinders4 ,the latter type of engine gives eight impulses per revolution4 ,to avoid a great multiplicity of cylinders1 and to save on floor space1 the great majority of heavy duty stationary engines are built double acting1 that is an explosion occurs alternately in either end of the cylinder4 ,in effect1 a double acting cylinder is the same thing as a two cylinder single acting engine1 as it gives twice the number of impulses obtained with a single acting cylinder4 ,the order in which the events occur in a four stroke cycle engine is as follows3 ,,stroke #a4 ,first outward stroke of the piston causes a partial vacuum in the combustion chamber thus drawing a charge of combustible gas into the cylinder through the open inlet valve4 ,the exhaust valve is closed4 ,see diagram ,a in ,fig4 #d4 7,suction ,stroke47 ,,stroke #b4 ,inlet valve closes at the end of the suction stroke and the piston starts on the inward stroke compressing the charge in the combustion chamber4 ,see diagram ,b4 7,compression ,stroke47 ,at the end of the compression stroke1 or a little before1 the spark 8,s0 occurs causing the ignition of the charge4 ,see diagram ,c4 ,,stroke #c4 ,working ,stroke4 ,as the pressure is now established in the cylinder1 the piston moves down on the working stroke forcing the crank around against the load and supplying sufficient energy to the fly wheel to carry the engine through the three idle strokes4 ,see diagram ,d4 ,when the piston reaches the end of the working stroke1 or a little before1 the exhaust valve opens to reduce the pressure and to allow the greater part of the burnt gas to escape4 ,see diagram ,e4 ,,stroke #d4 ,scavenging ,stroke4 ,the exhaust valve remains open and the inwardly moving piston expels the remainder of the burnt gas through the exhaust valve1 clearing the cylinder for the next fresh charge of mixture4 ,see diagram ,f4 ,the next stroke is the suction stroke explained under 8,stroke #a40 ,in all of the diagrams the crank is supposed to turn in a right handed direction as indicated by the arrow1 the piston moving in the direction shown by the arrow under the piston head4 ,the valves are operated by cams on an intermediate shaft known as the 8cam shaft40 ,as the valves go through their series of movements in two revolutions of the crank shaft1 and as the cam shaft must perform all of these operations in one revolution1 it is evident that the cam shaft must run at exactly one-half the crank-shaft speed4 ,this change of speed is accomplished by means of gearing between the cam shaft and crank-shaft from which the cam shaft is driven4 ,in some engines1 notably the ,diesel engine1 pure air is drawn into the cylinder on stroke ,no4 #a instead of the entire mixture4 ,fuel is supplied in this type immediately after the end of the compression stroke4 ,while an electric spark is shown as the igniting medium in the diagrams1 the ignition is sometimes performed by a hot tube1 or simply by the heat of the compression as in the ,diesel engine4 ,in the sliding sleeve type of four stroke cycle motor1 the poppet or lifting type of valve as shown in ,fig4 #d1 is replaced by a peculiar type of slide valve similar in action to the slide valves used on steam engines1 except that it is cylindrical in form and entirely surrounds the piston4 ,while there is a change in the form of the valve1 and in a number of small details1 the gases are drawn into the cylinder1 compressed1 ignited1 and released in exactly the same way and in the same rotation1 as in the poppet valve engine just described4 ,a description of the ,knight engine which is the most prominent example of the slide sleeve motor will be found in a succeeding chapter4 ,since the success of the slide valve type has been acknowledged by many prominent automobile manufacturers1 there have been several similar types placed on the market1 some with two sleeves and some with one1 but in all cases the designers have had but two points in view1 that is quiet running and free passages4 7#bf7 ,two ,stroke ,cycle ,engine4 ,two stroke cycle engines perform the five events of aspiration 7suction71 compression1 ignition1 expansion and release in two strokes or one revolution4 ,providing that these events are performed as efficiently as in the four stroke cycle engine1 it is evident that with equal cylinder capacity1 the two stroke cycle engine would have twice the output of a four stroke cycle since it gives twice the number of impulses per revolution4 ,unfortunately it is impossible to attain twice the output of the four stroke cycle type with the small two stroke engines built at the present time because of their imperfect scavenging and poor fuel economy4 ,in the larger two stroke engines1 the pumps and blowers used for scavenging the cylinders consume a considerable percentage of the output4 ,illustration3 ,fig4 #e4 ,diagram of ,two ,port--,two ,stroke ,cycle ,engine1 ,showing the ,events in the ,crank-,case and ,cylinder4 ,a general classification of the two stroke cycle engine is not so simple a matter as that of the four stroke because of the differences in construction of large and small sizes4 ,this difference between the large stationary engine and the small type commonly used on boats is due to the efforts of the builders of the large engine to obtain great fuel economy1 while the chief endeavors of the builders of small engines is to build a simple and reliable engine for the use of inexperienced persons4 ,while the smaller type of two stroke engine 7less than #be horse-power7 has not been used in stationary practice to any extent1 owing to the defects just named1 or on automobiles1 it has been widely used on motor boats1 a service for which it is peculiarly adapted4 ,its extended use on boats is due to the fact that in such service it runs at practically a constant speed and works against a steady load1 the conditions that are most favorable to the type4 ,with automobiles where the motor speed is constantly varying1 as well as the load1 this type of motor is not flexible enough to meet the continually varying conditions4 ,the small two stroke motors are divided into two principal classes1 the two port and three port type1 depending on the method by which the charge is transferred to the cylinder4 ,no valves are used in the cylinders of either type for the admission or release of the gases4 ,as the two strokes of the cycle are the compression stroke and working stroke1 it is evident that the charge must be introduced into the cylinder by means other than by the suction of the piston and at a time when there is no pressure in the cylinder4 ,this is accomplished by a preliminary compression of the charge in the crank case which places the mixture under sufficient pressure to force it into the cylinder at the end of the working stroke and at the same time to displace the burnt gases left from the previous explosion4 ,it should be noted that the incoming mixture is a substitute for both the suction and scavenging strokes of the four stroke cycle engine4 ,a diagrammatic view of a two port1 two stroke cycle engine is shown by ,fig4 #e1 in which ,p is the piston1 ,c the crank case1 ,i the transfer port1 ,v the inlet valve1 ,e the exhaust1 and ,s the spark plug for igniting the charge4 ,it should be noted that there are no valves in the cylinder and only three moving parts4 ,the cycle of events for the two port type is as follows3 ,,stroke #a4 ,we will consider the piston to be moving up on the compression stroke as shown in view 7,a71 compressing the mixture in the combustion chamber ,d4 ,while moving upwards in the direction of the arrow1 the piston creates a vacuum in the crank case ,c drawing fresh mixture into the crank case4 ,the piston at this time is covering the opening of the transfer port ,i and the exhaust port ,e so that the compressed mixture in the cylinder cannot escape4 ,on reaching the end of the compression stroke1 a spark occurs at ,s which drives the piston down and turns the crank towards the right as shown by the arrow4 ,,stroke #b4 ,when the piston uncovers the exhaust port ,e on its downward working stroke as shown by view ,b1 the exhaust gases being under pressure rush out into the atmosphere as shown by the arrows1 and relieve the pressure in the cylinder4 ,some of the burnt gas remains in the cylinder at atmospheric pressure as there is no scavenging action up to this point4 ,while the piston has moved down on the working stroke it has compressed the mixture in the crank case ready for admission to the cylinder4 ,the valve ,v prevents the escape of the gas during the compression4 ,on reaching the end of the stroke the piston uncovers the transfer port which allows the compressed mixture in the crank case to rush into the cylinder through ,i1 as shown by view ,c4 ,owing to the shape of the deflector plate ,z on the piston head1 the stream of mixture issuing from ,i is thrown up toward the top of the cylinder1 as shown by the arrows1 and consequently sweeps the remainder of the burnt gas before it through the exhaust port ,e4 ,in this way the fresh mixture from the crank case scavenges the cylinder and fills it in one operation4 ,being filled with gas1 the piston now moves up on the compression stroke for the next explosion as shown by view ,a4 ,unfortunately the scavenging action of the incoming gas is not complete for the whirling motion of the charge causes it to mix with the residual gas to a certain extent which1 of course1 reduces the heating effect of the fuel and reduces the power output4 ,another factor that reduces the output of this type of engine is the loss of explosive mixture through the exhaust port at low engine speeds with an open throttle4 ,in this case1 the piston speed being low1 part of the mixture has time to pass over the deflector plate and through the exhaust opening before the piston closes the exhaust port4 ,at very high speeds the charge is diluted by a considerable quantity of burnt gas which has not had time to escape through the port causing a further loss of power4 ,with the throttle nearly closed on a light load1 the impact of the incoming mixture is so slight that the percentage of exhaust gas left in the cylinder is very high4 ,this dilution is so great that with moderately low speeds 7easily within the capacity of the four stroke cycle engine7 it is either impossible to ignite the charge or it is impossible to ignite two in succession4 ,in marine service where the loads are constant1 and the speeds fairly uniform1 there is but little trouble from the last mentioned source1 and as the fuel is usually a smaller item than the repair bill1 the simplicity of the small two stroke engine with its freedom from mechanical troubles usually gives satisfactory results in the hands of the novice4 7#bg7 ,three ,port--,two ,stroke ,cycle ,engine4 ,the principal difference between the three port and two port types of the two stroke cycle engine is in the manner in which the charge is admitted to the crank case for the initial compression4 ,in the two port motor1 as previously described1 the check valve 8,v0 opens to admit the charge1 and closes during its compression in order to prevent its escape through the opening by which it was admitted to the cylinder4 ,with the three port type there is no check valve in the crank case1 the admission and the retention of the charge being controlled by the movement of the piston in practically the same way that the piston controls the opening and closing of the exhaust and transfer ports in the cylinder4 ,illustration3 ,fig4 #f4 ,illustration3 ,fig4 #g ,figs4 #f-g4 ,diagram of ,three ,port--,two ,stroke ,cycle ,engine in ,two ,positions4 ,by the piston control of the gases in the crank case1 the valve is eliminated1 which makes one less moving part to cause trouble and expense1 and permits the use of the same type of carburetor that is used on the four stroke cycle engine4 ,as the check valve opens and closes at a high speed1 7twice that of the valves on a four stroke cycle engine71 there is considerable wear on the valve seats due to the continuous banging1 which results finally in a loss of the initial compression4 ,when the initial compression is reduced in this way the engine loses power because of the reduction of the charge in the cylinder4 ,while the three port type is free from valve leakage troubles1 it has a steady loss due to the high vacuum that exists in the crank chamber when the piston is on its upward stroke4 ,this vacuum drags against the piston and absorbs a considerable amount of power until the piston reaches the upper end of the stroke4 ,at this point the inlet port is opened and the vacuum is broken by the rush of the mixture through the inlet port4 ,besides the power loss1 the vacuum has a bad effect on the lubrication of the main crank shaft bearing4 ,illustration3 ,elevation of ,fairbanks-,morse ,three-,port ,two ,stroke ,marine ,motor ,showing ,warming ,device for ,carburetor ,air4 ,described by strokes1 the cycle of events in the three port1 two stroke cycle engine is as follows3 ,,stroke #a4 ,in ,fig4 #f1 the piston is shown at the end of the compression stroke with ignition taking place in the combustion chamber ,c4 ,the pressure due to the expansion drives the piston down on the working stroke at the same time causing the initial compression of the mixture in the crank case as shown by ,fig4 #g4 ,the gas in the crank case cannot escape during compression as the inlet port ,a is covered by the piston4 7a7 ,as the piston descends1 its upper edge uncovers the exhaust port ,d1 allowing the greater portion of the exhaust gases to escape and reduces the pressure in the cylinder to that of the atmosphere4 7b7 ,descending a little farther1 the top of the piston uncovers the opening of the transfer port ,b1 allowing the compressed gases in the crank case to enter the cylinder as shown by the arrows4 ,these gases1 guided by the deflector plate on the top of the piston are thrown upwardly1 as shown by the arrows1 and sweep the residual burnt gases before them through the exhaust port4 ,the cylinder is now filled with the combustible mixture ready for compression4 ,,stroke #b4 ,the piston now moves up on the compression stroke1 compressing the charge in the cylinder and at the same time creates a vacuum in the crank-case4 ,just before the piston reaches the end of the exhaust stroke1 the lower edge of the piston uncovers the inlet port ,a 7,see ,fig4 #g71 which allows the mixture from the carburetor to flow into the partial vacuum and fill the crank case ready for the next initial compression4 ,when the end of the stroke is reached1 the charge in the combustion chamber ,c is fired and the cycle is repeated4 ,it should be noted that the incoming gas and the initial compression are controlled entirely by the action of the lower edge of the piston on the inlet port ,a4 7#bh7 ,reversing ,two ,cycle ,motors4 ,as the admission and exhaust in the two stroke cycle engine each occur once per revolution1 and are controlled directly by the piston position at opposite ends of the stroke1 it is evident that the direction of rotation is not affected by gas control or valve timing1 as in the case of the four stroke cycle engine4 ,the factor that does determine the direction of rotation in the two stroke engine is the time at which ignition occurs in regard to the angular position of the crank4 ,by changing the relation between the crank position at the end of the compression stroke and the time at which the spark occurs1 it is possible to reverse the engine even when it is running4 ,should the engine be standing still in the position shown by ,fig4 #f1 with the crank on the dead center1 when ignition occurred1 there would be no more tendency to turn the crank to the right than to the left1 providing of course1 that there was no effect from the momentum of a revolving fly wheel4 ,if ignition occurred with the crank inclined ever so little toward the right1 the pressure of the piston would force the crank downwards in a right handed direction4 ,if the crank were inclined to the left1 the tendency would be for left handed rotation4 ,if the ignition system were arranged so that the spark occurred when the crank was inclined towards the right every time that the piston came up on the compression stroke1 we should have continuous rotation in a right hand direction4 ,by shifting the sequence of the spark so that it occurred with the crank on the left we would cause the engine to stop and reverse to left handed rotation4 ,this is exactly the method used in reversing two stroke motors in practice1 the change in the ignition being accomplished by advancing or retarding the mechanism that dispatches the spark 78,timer0 or 8,commutator074 ,illustration3 ,fig4 ,f-#i4 ,cross ,section of ,fairbanks-,morse ,three ,port--,two ,stroke ,cycle ,engine1 with ,parts ,named4 ,this is an advantage not possessed by the four stroke cycle engine of the ordinary type1 as the cams and valve mechanism require reversal as well as a reversal of the ignition system4 ,this relation between the valve action and rotation in a four stroke cycle engine may be illustrated by the following example4 ,consider the piston at the end of the compression stroke in an engine designed for right hand rotation4 ,after ignition1 under the proper conditions1 the piston would descend turning the crank to the right until it reached the bottom of the stroke1 at which point the exhaust valve would open and relieve the pressure in the cylinder4 ,let us now consider an attempt at reversing the engine by causing the spark to occur before the piston reached the end of the compression stroke with the crank still inclined toward the left4 ,in this case the piston would force the crank down in a left hand direction until it reached the end of the stroke4 ,the exhaust valve would not open to relieve the pressure1 as the exhaust cam would be moving away from the valve rod instead of toward it4 ,should the crank swing a little past the dead center1 because of its momentum1 the inlet valve would be opened instead of the exhaust1 and the contents of the cylinder would shoot through the intake pipe and carburetor4 ,this would bring matters to a close as far as rotation was concerned4 ,the opening of the inlet valve on the reversed working stroke would occur as the inlet valve closes one stroke1 or one-half revolution1 before the end of the compression stroke4 ,as the engine turned backward one-half revolution1 the inlet cam would again be brought into contact with the inlet valve rod1 opening the valve and allowing the burned gases to pass through the carburetor4 ,should the pressure be sufficiently reduced by inlet valve to allow the piston to reach the end of the second stroke1 it would start on the third stroke by inhaling a 8charge0 of burnt gas through the exhaust valve which would now be open4 7#bi7 ,scavenging ,engines4 ,as the piston does not sweep out all the cylinder volume because of the space left at the end of the cylinder for compression1 more or less burned gas remains in the combustion chamber which dilutes the active mixture taken in on the suction stroke4 ,not only are the residual gases useless in generating heat but they also occupy a considerable space in the cylinder that might otherwise be filled with a heat producing mixture4 ,their diluting effect also prevents the complete combustion of a certain percent of the fuel actually taken into the cylinder for which the burnt gas is incapable of supporting combustion4 ,the amount of burnt gas remaining in the cylinder depends upon the cycle of the engine and also upon the valve timing and size of the exhaust piping4 ,in the four stroke cycle engine the volume of residual gas is equal to the volume of the combustion chamber1 in the two stroke cycle it varies from one-tenth to one-third of the entire cylinder volume1 depending on the load and speed4 ,with correct design and free exhaust passages1 the gas held in the clearance space of a four stroke cycle engine is at a pressure considerably below that of the atmosphere1 and consequently its actual volume is even less than the volume of the combustion chamber4 ,many systems have been devised for the purpose of clearing the cylinder of burnt gas in order to minimize the loss of fuel in large engines1 but owing to their complication have never been successfully applied to small engines of the automobile or marine types4 ,in general1 the 8scavenging0 is accomplished by pumping out the clearance space at the end of the scavenging stroke1 while fresh air is admitted to the cylinder through the inlet valves1 or by blowing out the clearance space by a blast of pure air furnished from an air pump attached to the engine4 ,there have been several systems proposed by which the gas in the cylinder is withdrawn by the inertia of the exhaust gas in specially designed ejectors1 and by the compression of fresh air in the crank case of the engine4 ,the former system known as 8organ pipe ejection10 is by far the simplest method of all as the ejector is simply a tube without moving parts1 and it also possesses the additional advantage of reducing the back pressure on the piston4 ,unfortunately these advantages are obtained only at certain loads1 and with certain velocities of the exhaust gases1 which makes it impossible to obtain even approximately correct scavenging at other loads and speeds4 ,when air pumps are used for scavenging1 a great percentage of the economy obtained is offset by the power required to operate the pumps4 ,in addition to the frictional losses of the pumps1 are the increased maintenance charges and repair bills4 ,,chapter ,,iv ,,indicator ,,diagrams 7#ce7 ,general ,description4 ,a brief description of the indicator as a means of recording the pressures in the cylinder of a simple heat engine in relation to the piston position was given in paragraph 7#f71 ,chapter ,i1 and as this instrument is so peculiarly adapted to locating the events taking place in the cylinder we will devote some space on its application to the practical gas engine cycles described in the preceding chapter4 ,since each event in the cycle is accompanied by a corresponding increase or reduction in pressure1 the beginning or end of an event will be indicated on the diagram by a change in the vertical height of the curve above the atmospheric line1 at some particular piston position4 ,the piston position will be in the same relation to the total stroke as the pencil position will be to the horizontal length of the card4 ,if the event1 for example1 as indicated by a drop in pressure1 be at the center of the card1 it will show that the drop in pressure took place when the piston was in the center of the cylinder or at mid-stroke4 ,should the pressure change at a point one-quarter of the card length from the starting point of the pencil1 it shows that the event took place in the cylinder when the piston had accomplished the first quarter of its stroke1 and so on4 ,it should be noted that horizontal distances on the indicator card denote piston positions1 and the vertical distances1 pressures4 ,as explained in a former paragraph the length of the vertical lines represents certain definite pressures1 each inch of length representing so many pounds as per square inch1 the exact amount per inch depending on the indicator spring strength or adjustment4 ,to make this point clear1 all of the indicator diagrams shown in this chapter will be provided with a scale of pressures at the left of the diagram by which the pressure at any point may be accurately measured off for practice4 ,it should be noted that points on the curves which are above the atmospheric line represent positive pressures above the atmosphere1 and that the points lying below the atmospheric line represent partial vacuums which may be expressed as being so many pounds per square inch below the atmosphere4 ,the vacuum pressures indicate the extent of the 8suction0 created by the piston when drawing in a charge of air and gas4 ,straight vertical lines show that the increase of pressure along that line has been practically instantaneous in regard to the piston velocity1 for if the pressure increased at a slow rate this line would be inclined toward the direction in which the piston was moving1 as the piston would have moved a considerable distance horizontally while the pencil was moving vertically4 ,this inclination of the vertical line gives an idea of the rate at which the pressure increases in relation to the piston speed1 the greater the inclination1 the slower is the rate of pressure increase4 ,straight horizontal lines that lie parallel to the atmospheric line denote a constant pressure or vacuum4 ,the rate at which horizontal lines descend or incline to the atmospheric line represents the rate at which the pressure increases or decreases1 in respect to the piston position 7not piston velocity74 ,a steep curve represents a rapid expansion or compression from one piston position to the next4 ,a waving or rippling line indicates vibration due to valve chattering or explosion vibrations4 ,a straight inclined line shows that the pressure is decreasing or increasing in direct proportion to the piston position4 7#cf7 ,diagram of ,four ,stroke ,cycle ,engine4 ,by referring to paragraph #be1 ,chapter ,,iii1 it will be seen that the five events of suction1 compression1 ignition1 expansion and exhaust are accomplished in four strokes1 in the following order3 ,stroke #a4 ,suction--7,mixture drawn into cylinder74 ,stroke #b4 ,compression--7,mixture compressed74 ,stroke #c4 ,ignition4 ,expansion 7working stroke74 ,stroke #d4 ,exhaust--7,scavenging stroke74 ,these events with the pressures incident to each drawn to some relative scale are shown graphically in ,fig4 #aj by four lines representing the four strokes of the piston4 ,in order to show the relation between the diagram and the piston1 a sketch of the cylinder with a stroke equal to the length of the diagram is shown directly beneath the curve4 ,the vertical line ,,ij is the scale of pressures 7somewhat exaggerated in order that the small vacuum and scavenging pressures shall be clearly shown74 ,the line marked 8atmosphere0 represents atmospheric pressure and it is from this line that all measurements of pressure are taken4 ,illustration3 ,figs4 #aj-aa-ab4 ,showing ,respectively a ,typical ,four ,stroke ,diagram1 ,retarded ,combustion and ,retarded ,spark4 ,consider the piston starting on the suction stroke1 the piston moving from the position ,l to ,k1 or from left to right4 ,the movement creates a partial vacuum in the combustion chamber ,n which is shown on the diagram as the distance ,,oa1 equal to #b pounds below atmosphere according to the pressure scale4 ,the suction line remains at this distance below the atmospheric line until within a short distance of the end of the stroke when it rises to meet the atmospheric line at ,b when the piston reaches the end of the stroke at ,k4 ,this rise at the end of the stroke is due to the fact that the piston moves more slowly when approaching the end of the stroke while the velocity of the incoming gases remains nearly constant so that the piston exerts no pull nor suction4 ,on the diagram the entire suction stroke is represented by ,,ab4 ,the piston now returns on the compression stroke from ,k to ,j compressing the mixture in the combustion chamber ,n4 ,on the diagram this stroke is shown beginning at ,b1 with the pressure slowly rising until the pressure is a maximum at the point ,c at the end of the stroke4 ,during the compression1 the pressure has risen from that of the atmosphere at ,b to #abe pounds pressure at ,c as shown by the scale4 ,at a point slightly before ,c is reached1 ignition occurs1 and the pressure rapidly rises from ,c to ,d1 due to the expansion of the heated gas4 ,in this case the combustion is practically instantaneous as shown by the straight1 vertical combustion line ,,cd4 ,at ,d the piston starts on the working stroke from left to right increasing the volume of the gas and at the same time diminishing the pressure because of the expansion until the maximum pressure of #djj pounds per square inch at ,d is reduced to #cj pounds per square inch at ,e1 the line ,,de being called the expansion line4 ,during this time the heated gas has been performing work on the piston4 ,at ,e the exhaust valve opens and the pressure drops from ,e to ,t1 a point still about #aj pounds above atmospheric pressure4 ,theoretically the pressure should drop instantly from ,e to atmosphere1 or from #cj pounds per square inch to zero1 but practically this is impossible because of the back pressure due the slow escape of the exhaust gases through the comparatively small valve openings and exhaust pipes4 ,since considerable pressure is exerted by the piston on the return stroke in forcing the gases out of the exhaust valve1 the exhaust line ,,to on the diagram is nearly #aj pounds above the atmospheric pressure from ,t to ,o4 ,at a point near ,o1 the piston slows up on nearing the end of the stroke so the gases have more time to escape through the valves1 and the pressure drops to the atmosphere1 ready for the succeeding suction stroke4 ,it should be noted that the points ,a1 ,b1 ,e1 and ,f represent periods of valve action4 ,at ,a the inlet valve opens2 at ,b the inlet closes2 at ,e the exhaust opens2 at ,f the exhaust closes1 and at ,a the inlet again opens at the beginning of the suction stroke ,,ab4 ,that this is true is apparent from the fact the inlet must open at the beginning of the suction stroke1 and both valves must be closed from the point ,b to the point ,e in order to prevent the escape of the compressed charge and expanded gases from the cylinder4 ,at the end of the working stroke the exhaust valve must liberate the gases and remain open to the end of the scavenging stroke to eliminate the residual gas while the closed inlet valve prevents the burnt gases from being forced through the inlet pipe and carburetor4 ,as shown on the diagram1 the exhaust valve closes at the same time that the inlet opens1 as ,f1 and ,o both occur on the same vertical line ,,dl4 ,this is true theoretically1 but owing to the different conditions met in practice1 the actual setting of the valves may vary slightly from that shown on the diagram4 ,some makers of high speed engines open the inlet slightly before the exhaust closes as it is claimed that the inertia of the exhaust gas passing through the exhaust pipe creates a slight vacuum that is an aid in filling the cylinder with a fresh charge4 ,it should be borne in mind that this condition only exists when the piston has come to rest and exerts no pressure on the exhaust gas4 ,the vacuum is due to the velocity inertia of the gas after it has been reduced to atmospheric pressure4 ,other makers close the exhaust valve a very little before the inlet opens1 but no matter what the setting1 the difference in the time of opening and closing is very small1 and the results obtained probably differ by an almost negligible amount4 ,during the suction and scavenging strokes1 the fly wheel of the engine is expending energy on the gas since it is moving a considerable volume at a fairly high pressure4 ,in the case of the scavenging stroke1 the piston is working against #aj pounds back pressure1 which on a #aj inch piston would amount to a force of #ghe pounds4 ,with the #b pound vacuum the drag on the piston would amount to #aeg pounds1 no small item when the velocity of the piston is considered4 ,of course the pressure of #aj pounds per square inch is rather high1 but it is often attained with long and dirty exhaust pipes4 ,it is items of this nature that cut into the efficiency of the engine1 and increase the fuel bills1 and it is only by the indicator that we can determine the extent of such 8leaks0 and remedy them4 ,since the area of the indicator card represents the power of the engine1 it is evident that we lose the power represented by the area included in the rectangle ,,febo on the scavenging stroke plus the area ,,boa on the suction stroke4 ,the area included in ,,bco represents the work taken from the engine in compressing the charge1 but this is returned to us during the next stroke plus the benefits gained by compressing the mixture4 ,the arrows show the direction in which the piston is moving during that event4 ,an actual engine does not follow the form of the diagram shown by ,fig4 #aj exactly because of certain conditions met with in practice such as imperfect mixtures1 faulty valve and ignition timing1 small valve areas or leakage4 ,the combustion in the real engine is neither instantaneous nor complete but it approximates the 8,,ideal0 cycle just described more or less closely with a high compression and a fairly well proportioned mixture4 7#cg7 ,detecting ,faults ,with the ,indicator4 ,for the best results the gas must be completely ignited at the point of maximum compression1 and the pressure must be established on the dead center1 so that the indicator card will show a straight and vertical combustion line4 ,as all gases require a certain length of time in which to burn1 the ignition should have ,,lead1 that is1 should be started before the end of the stroke so that combustion will be complete at dead center4 ,the amount of ignition lead required depends on the fuel and the compression4 ,in ,fig4 #aj the point of ignition 7,i7 is shown as occurring before the end of the compression at 7,c71 which insures a straight combustion line ,,cd4 ,with a lean or slow burning gas1 that is1 a gas slower than used on the diagram1 combustion would not be complete at the end of the stroke if the same point of ignition were used4 ,this effect is shown by ,fig4 7#aa71 in which the full line diagram ,,bcde represents the ideal diagram 7,y71 and ,,bcfg represents the slow burning mixture with the same point of ignition 7,x74 ,the compression curves of both diagrams are coincident as far as ,c1 the ideal diagram shooting straight up at this point and the weak mixture diagram staying at the same level4 ,when under the influence of the mixture 7,x7 the piston starts from left to right and reaches the point ,f before the slow burning gas reaches its maximum pressure4 ,during this part of the stroke there has been very little pressure on the piston and it will be noticed that the maximum pressure is far below that of the ideal diagram4 ,this low maximum is due principally to the reduced compression under which the gas has been burning1 from ,c to ,f4 ,illustration3 ,figs4 #ac-ad4 ,the ,first ,diagram 7#ac7 ,shows a ,two ,port ,two ,stroke ,diagram1 the ,second ,shows a ,typical ,diesel ,card4 ,as the gas has but a small part of the stroke left in which to expand1 the pressure at the point of release is much higher than the release pressure of the ideal diagram1 which means that a considerable amount of heat and pressure have been wasted through the exhaust pipe4 ,besides the heat loss1 the high temperature of the escaping gas has a bad effect on the exhaust valve and passage4 ,the great volume of gas passing through the exhaust valve also increases the back pressure on the scavenging stroke4 ,delayed or retarded ignition will cause a low combustion pressure and slow combustion with any type of fuel or compression pressure as will be seen from ,fig4 #ab4 ,in this case the compression pressures of the ideal diagram ,y and the diagram ,x showing the retarded spark are of course the same1 the compression line extending from ,b to ,c in the direction of the arrows4 ,at ,c the ignition occurs for curve ,y1 and the pressure immediately rises to ,d4 ,in the case of curve ,x1 ignition does not occur until the point ,i is reached1 the compression falling on the line ,,ci with the forward movement of the piston as far as the point ,i4 ,at this point the compression pressure is very low which results in the slow combustion indicated by the slant of the combustion line ,,if4 ,the point of maximum pressure ,f is much below ,d of the ideal curve1 and as there is no opportunity for complete expansion during the rest of the stroke1 the release pressure is high causing a great heat loss4 ,if running on a ,,late or ,,retarded spark is continued for any length of time the excessive heat that passes out of the exhaust will destroy the valves4 ,it is apparent that for the best results1 the spark should occur slightly before ignition in order to gain the effects of the compression1 and a high working pressure on the piston4 ,it is also evident that the point of ignition should be varied for different mixtures that have different rates of burning4 ,with engines that govern their speeds by throttling or by changing the quality of the mixture it is necessary for the best results1 to vary the point of ignition with each quality of fuel that is admitted by the governor4 ,the retard and advance of the ignition is very necessary on an automobile engine because of the throttling control and constant variation of the load and speed4 ,all automobilists know of the heating troubles caused by running on a retarded spark4 7#ch7 ,two ,stroke ,cycle ,diagram4 ,in the two stroke cycle diagram1 the lines showing the suction and scavenging strokes are missing if the indicator is applied only to the working cylinder4 ,starting at the beginning of the working stroke as at ,a in ,fig4 #ac1 the gas expands during the working stroke until the piston uncovers the exhaust port at ,b where the pressure drops to ,c4 ,a slight travel uncovers the inlet port with the pressure still above atmosphere due to the pressure in the crank case filling the cylinder4 ,the crank case pressure continues from ,c to ,d or to the end of the stroke1 the pressure dropping slightly at the latter point4 ,the compression stroke now takes place with the piston moving from right to left1 the compression pressure reaching a maximum at ,f4 ,ignition occurs slightly before the point of greatest compression1 at ,i1 and the expanded gas increases in pressure until the point ,a is reached4 ,from this point the same cycle of events is repeated4 ,because of the dilution of the charge by the burnt gases of the preceding combustion1 the mixture burns slowly as will be seen from the inclined combustion line ,,fa4 ,due to this delayed combustion1 the piston travels the distance ,s on the working stroke before the pressure reaches a maximum4 ,this diagram is typical of the small marine type of two stroke cycle engine which has no further scavenging than that performed by the rush of the entering mixture4 ,the diagram of the pressures and vacuums in the crank case are similar to those of suction and compression in the four stroke cycle type4 7#ci7 ,diagram of ,diesel ,engine4 ,a diagram of the ,diesel engine is different in many particulars from that of an ordinary gas engine1 as will be seen from the diagram in ,fig4 #ad4 ,the pressures rise in an even1 gradual line from the end of the compression curve1 and instead of having a sharp peak at the end of the combustion1 as in a gas engine1 the top of the curve is broad and greatly resembles the indicator diagram of a steam engine4 ,the compression curve constitutes a greater proportion of the pressure line than that of a steam engine1 the rise of pressure due to the ignition being very slight in comparison to the height of the compression curve4 ,there is no explosion in the usual sense of the word1 only a slight increase in pressure as distinguished from the rapid combustion in the gas engine4 ,starting at the beginning of the compression stroke at ,h1 the pressure of the pure air charge increases to about #ejj pounds to the square inch at ,i1 the point at which the fuel is injected4 ,from ,i to ,c is the increase of pressure due to the combustion4 ,the pressure stays at a constant height from ,c to ,d as the fuel supply is continued between these points1 and is cut off when the piston reaches the position ,d4 ,it will be seen that the admission of the fuel through the distance ,a covers a considerable proportion of the working stroke1 and that the points of fuel injection and ignition are coincident4 ,from the point of fuel cut-off at ,d expansion begins and is continued in the usual manner to ,f1 the point of release4 ,when the load is increased1 the period of oil injection is also increased1 the other events remaining constant4 ,should the light load require an oil injection period as shown by ,a1 the greater load would require injection for the period ,b4 ,in the latter case1 the expansion line would be ,,eg1 which would produce a diagram having a greater area than the line ,,df1 and there would be a great increase in the release pressure ,,gh as well4 ,it will be seen from the diagram that the quantity of air taken into the cylinder and the compression pressure remain constant with any load1 and that for this reason it is possible to have a constant point of ignition1 or rather point of fuel injection4 ,as there is no mixture compressed1 there are no difficulties encountered at light loads due to attenuated mixtures4 ,an excess of air over that required to burn the fuel is also present at every load within the range of the engine4 ,for the sake of simplicity1 the suction and scavenging lines on the ,diesel engine have been omitted1 but they are the same in all respects as the corresponding lines shown in the diagram1 ,fig4 #ad4 7#dj7 ,gas ,turbine ,development4 ,in the attempt to gain mechanical simplicity1 small weight1 and diminutive size of the steam turbine1 many able experimenters have endeavored to obtain an internal combustion motor in which the energy of the expanding gas is converted into mechanical power by its reaction on a bladed wheel1 but so far the problem is far from being solved4 ,in #aijf two experimental turbines were built by ,ren ,armengand and ,m4 ,lemale1 of the constant pressure type1 one of which developed #cj ,brake horse-power and the other #cjj horse-power4 ,a #be horse-power ,de ,laval steam turbine was altered by ,armengand says ,dugald ,clerk so that it operated with compressed air instead of steam4 ,the compressed air was passed into a combustion chamber together with measured quantities of gasoline vapor1 and the mixture was ignited by an incandescent platinum wire as it entered the chamber1 thus maintaining a constant pressure with continuous combustion4 ,around the carborundum lined combustion chamber was imbedded a coil in which steam was generated by the heat of the burning gas1 the steam being used to reduce the temperature of the gas from #ahjj;,c to about #djj as it issued from the orifice and came into contact with the running wheel4 ,the working medium was therefore composed of two elements1 the products of combustion and the steam at the comparatively low temperature of #djj;,c4 ,the constant pressure maintained in the combustion chamber was about #aj atmospheres1 and the hot gases were allowed to expand through a conical ,lava jet in which the expansion produced a high velocity1 and reduced the temperature of the fluid4 ,at this reduced temperature and high velocity the gases impinged upon the ,laval wheel1 and rotated the wheel in the same way as steam would have done4 ,the experiments showed that under these conditions the total power obtained from the turbine separate from the compressor was double that necessary to drive the compressor4 ,in the large #cjj ,h4 ,p4 turbine the first part of the combustion chamber was lined with carborundum1 backed by sand1 but the second part was surrounded by a coil through which water was circulated4 ,the water kept the temperature of the combustion chamber within safe limits1 and after absorbing heat1 it passed also around the jet nozzle1 and was discharged into the passage leading to the jet1 and there converted into steam by the hot gases4 ,a mixture of products of combustion and steam thus impinged upon the turbine wheel4 ,the expanding jet was arranged to convert the whole of the energy into motion before the fluid struck the wheel2 the temperature was thus reduced to a minimum before the gases touched the blades4 ,notwithstanding this1 the wheel itself had passages through which cooling water flowed1 and each blade was supplied with a hollow into which water found its way4 ,in the large turbine the compressor was mounted on the turbine spindle2 it was of the ,rateau type1 and consisted of an inverted turbine of four stages1 which delivered the compressed air finally to the combustion chamber at a pressure of #aab lb4 per sq4 in4 absolute4 ,the efficiency of this turbine compressor was found to be about #fe per cent4 ,the total efficiency of the combined turbine and compressor was low1 as the fuel consumption amounted to nearly #c4i lb4 of gasoline per ,b4 ,h4 ,p4 hour4 ,an ordinary gasoline engine with a moderate compression can readily give its power at the rate of #j4e lb4 of gasoline per ,b4 ,h4 ,p4 hour4 ,the combined turbine and compressor was stated to have run at #d1jjj ,r4 ,p4 ,m4 and to have developed #cjj ,h4 ,p4 over and above the negative work absorbed by the compressor4 ,a gas turbine in which there was no compression was built in the following year by ,m4 ,karovodine which gave #a4f horsepower at a speed of about #aj1jjj revolutions per minute4 ,it contained four explosion chambers having four jets actuating a single turbine wheel1 which wheel was of the ,laval type1 about #f inches diameter1 having a speed of #aj1jjj ,r4 ,p4 ,m4 ,the explosion chambers were vertical1 and had a water jacket surrounding the lower end4 ,the upper portion contained the igniting plug on one side1 and the discharge pipe connecting with the expanding jet on the other4 ,in the lower water-jacketed part there was provided a circular cover1 held in place by a screwed cap4 ,this circular plate was perforated with many holes1 and it carried a light steel plate valve of the flap or hinging type1 which pulled down by a spring contained within the admission passage4 ,this spring could be adjusted1 and the lift of the valve was regulated by means of a set screw passing diagonally through the water jacket4 ,air was admitted at one side by a pipe leading into the valve inlet chamber and a corresponding passage or pipe admitted gasoline and air or gas to mix with the air before reaching the thin plate valve4 ,adjusting contrivances were supplied in both air and fuel ducts4 ,to start the apparatus1 an air blast was forced through the valve1 carrying with it sufficient gasoline vapor to make the mixture explosive4 ,the electrical igniter was started1 and the spark kept passing continuously4 ,whenever the inflammable mixture reached the upper part of the combustion chamber ignition took place1 and the pressure rose in the ordinary way1 due to gaseous explosion4 ,the gases were then discharged through the pipe and nozzle on the ,laval wheel4 ,the cooling of the flame after explosion and the momentum of the moving gas column reduced the pressure within the explosion chamber to about #b lb4 per sq4 in4 below atmosphere4 ,air and gasoline vapor then flowed in to fill up the chamber1 and as soon as the mixture reached the igniter1 explosion again occurred4 ,in this way a series of explosions was automatically obtained1 and a series of gaseous discharges was made upon the turbine wheel4 ,diagrams taken from the explosion chamber showed a fall in pressure during suction of #b lb4 per sq4 in42 ignition occurred while the pressure was low1 and the pressure rapidly rose to about #a #a-c atmospheres absolute4 ,the pressure propelling the gas column and jet was thus only #e lb4 per sq4 in4 above atmosphere4 ,the pressure rapidly fell1 and the whole process was repeated again4 ,according to the diagrams taken1 a complete oscillation required about #j4jbf second1 so that about #dj explosions per second were obtained4 ,illustration3 ,fig4 #ae4 ,cross-,section of the ,combustion ,chamber of the ,holzwarth ,gas ,turbine4 ,from the ,scientific ,american4 ,the most promising type of turbine that has been built to date is that designed by ,hans ,holzwarth1 an engineer of some prominence in the steam turbine field4 ,a #ajjj horse-power machine has been built at this writing and as experimental machines go has made most remarkable performance4 ,the turbine in general arrangement outwardly resembles the ,curtis steam turbine1 in that the turbine wheel rotates in a horizontal plane1 the spindle or shaft is vertical and a dynamo is mounted on this spindle above the turbine4 ,in the ,holzwarth turbine ten combustion chambers are provided1 each of a pear or bag shape4 ,they are arranged in a circle around the wheel1 and are cast so as to form the base of the machine4 ,the wheel is of the ,curtis type1 with two rows of moving and one row of stationary blades4 ,in this turbine the energy of the fuel is liberated intermittently by successive explosions1 instead of by continuous combustion1 and in much the same way that the explosions occur in a reciprocating engine4 ,tests made on the new machine have shown that it is in no way inferior in efficiency to the ordinary type of motor1 and that at full load1 the weight per horse-power is only about one-quarter of that of the reciprocating engine4 ,the weight factor1 as is well known1 is of the utmost importance in marine service and should prove of value to the marine engineer1 if this alone were its only characteristic4 ,any of the ordinary power gases may be used with success1 as well as vaporized liquid fuels1 and the lower grade oils such as crude and kerosene have given much better results in the turbine1 than in reciprocating engines1 even at this early stage of its development4 ,as the heat losses are much smaller than met with in ordinary practice1 the temperature is higher1 which1 of course1 greatly facilitates the vaporization of the lower grade liquids4 ,mr4 ,holzwarth does not give the dimensions of his turbine wheel1 but from the drawings and some of the velocities given by him it appears to be about #a m4 in external diameter4 ,the lower part of each combustion chamber carries gas and air inlet valves1 and the upper part carries a nozzle arranged to cause the gases to impinge upon the first row of moving blades4 ,this nozzle is connected to and disconnected from the combustion chamber by means of an ingeniously operated valve4 ,the explosion chambers are charged with a mixture of gas and air1 which appears to attain a pressure of about two atmospheres within the chamber before explosion4 ,the air and gas are supplied under sufficient pressure from turbine compressors1 actuated by steam raised from the waste heat of the explosion and the gases of combustion1 so that whatever work is done in compression is obtained by this regenerative action1 and does not put any negative work upon the turbine itself4 ,the combustion chambers are fired in series1 by means of high-tension jump spark ignition4 ,referring to the cut1 the explosion chamber ,a is filled intermittently with the explosive mixture at a low pressure 7about #h to #ab pounds per square inch74 ,when ignition has occurred1 the pressure of explosion opens the nozzle valve ,f1 allowing the compressed gases to flow through the nozzle ,g to the bladed turbine ,h1 on which the energy is to be expended4 ,the expansion of the heated gases in the nozzle reduces the pressure to that of the exhaust1 with the resulting increase in the velocity of the gas4 ,by means of fresh air1 the nozzle valve ,f is kept open throughout the expansion and scavenging periods4 ,after the expansion has been completed1 the air that is forced through the valve ,d1 at a low pressure1 thoroughly scavenges or removes the residual burned gases left in the combustion chamber and nozzle1 forcing it into the exhaust4 ,when the scavenging has been completed1 the nozzle valve and the air valve ,d are closed4 ,the combustion chamber ,a is now filled with pure cold air1 which not only enables a fresh charge of gas to be introduced into the chamber but which also aids in keeping the chamber cool4 ,pure fuel gas1 or atomized oil1 is now injected through the fuel valve ,e1 forming an explosive mixture ready for the ensuing cycle of events4 ,a number of these chambers are arranged around the turbine wheel in order to have a uniform application of power1 by having the several chambers working intermittently4 ,this is in effect1 the same proposition as increasing the number of cylinders on a reciprocating engine4 ,,chapter ,v ,,typical ,,four ,,stroke ,,cycle ,,engines 7#da7 ,essential ,parts of the ,gas ,engine4 ,on all gas engines of accepted type are found certain devices necessary for the performance of the events or cycles outlined in the preceding section4 ,for the sake of simplicity these devices are treated as a part complete in itself4 ,the details of construction1 and the refinements found necessary in the actual construction will be described in the succeeding chapters4 ,the names and purpose of these essential components1 and their relation to the operation of the engine as a whole1 will be found in the following outline3 #a4 ,the ,,carburetor is a device whose purpose is to vaporize the liquid fuel1 and mix the vapor thoroughly and in correct proportions with the air required for the combustion1 in the engine cylinder4 ,the combustible mixture thus formed is drawn into the cylinder of the four stroke cycle engine or into the crank chamber of the two stroke cycle engine4 ,,generator ,,valves or ,,mixing ,,valves are similar to the carburetor in principle but are slightly different in detail4 #b4 ,the ,,cylinder is the containing vessel in which the combustion and expansion of the gas takes place4 ,the cylinder as its name would suggest has a circular opening or bore extending from end to end1 the bore being smoothly finished to receive the reciprocating piston4 #c4 ,the ,,piston is a plunger or movable plug fitting the bore closely enough to prevent the escape of gas1 but at the same time is capable of sliding freely to and fro4 ,when pressure is established in the cylinder from the combustion1 pressure is also exerted on the end of the piston tending to force it out of the cylinder4 ,the extent of this force is governed by the area of the end of the piston and also by the pressure of the gas4 ,thus the purpose of the piston is to convert the pressure of the expanding gas into direct mechanical force1 and also to transform the increasing volume of gas into motion4 ,another1 and no less important function of the piston is to compress the combustible gas in the upper end of the cylinder for ignition4 ,illustration3 ,piston and ,connecting ,rod of the ,sturtevant ,aero ,motor1 ,showing ,three ,piston ,rings4 #d4 ,the ,,connecting ,,rod 7,sometimes called the ,pitman7 transmits the pressure on the piston to the crank1 the connecting rod being the means through which the to and fro motion of the piston is transmitted into the rotary motion of the crank2 its action being similar to that of the human arm turning the crank of a pump or windlass4 #e4 ,the ,,crank receives the pressure and motion of the piston from the connecting rod1 changing the reciprocating motion of the piston into the rotary motion required by the machinery which the engine drives4 ,in the majority of cases the crank revolves1 while the cylinder stands still1 but in some of the recently developed aeronautic motors this is reversed1 the cylinders revolving with the crank stationary4 ,the relative motion1 however1 is the same in both cases4 7#f47 ,the ,,crank ,,shaft1 of which the crank is an integral part1 transmits the rotary motion of the crank to the driving pulley4 7#g47 ,the admission and release of the gases to and from the cylinder are controlled by the ,,inlet ,,valve and ,,exhaust ,,valve1 respectively1 in a four stroke cycle engine4 ,the valves are merely gates1 allowing the gas to flow1 or stopping it1 at the proper intervals1 depending on the event taking place at that time in the cylinder4 ,in the two stroke cycle engine there are no valves1 the admission and release of the gas being controlled by the position of the piston1 and the openings cut in the cylinder walls4 #f4 ,,ignition or the firing of the combustible charge is accomplished by the ,,ignition ,,system4 ,in most modern engines the mixture is ignited when it is under the greatest pressure or at the end of the stroke4 ,for maximum efficiency the mixture should be ignited when it is under the greatest pressure or compression4 ,the time at which ignition occurs is also controlled by the ignition system4 #g4 ,the ,,governor regulates the speed of the engine2 either by changing the richness of the mixture1 by changing the number of working strokes in a given time or by altering the quantity of gas admitted to the cylinder1 or sometimes by a combination of these methods4 #h4 ,the ,,belt ,,wheels or ,,pulleys are the means of transmitting the power of the engine to the work to be performed4 ,the engine is generally connected to the driven machinery by a belt connecting the engine pulley with the pulley of the driven machine4 #i4 ,the ,,fly ,,wheels by reason of their mass and their momentum1 store up a portion of the energy expended during the working stroke1 and return it to the engine in order to carry it through the idle strokes of compression1 admission and expulsion4 ,in some engines the fly wheels serve in double the capacity as pulleys4 #aj4 ,the ,,base or ,,frame of the engine acts as a foundation for the various working parts1 holding them in their proper positions4 7#db7 ,application of the ,four ,stroke ,principle4 ,while the five events of every commercial four stroke cycle engine are accomplished in exactly the same order1 or routine as explained in paragraph 7#h71 ,chapter #c1 the actual design and method of applying the cycle varies greatly in different makes of engines4 ,this great difference in the details of construction often makes it difficult for the novice to identify the cycle of operations in that particular engine4 ,the different forms of valve gears that are used to perform the same functions in the cycle are good examples of the variation in design1 some makers using the poppet or disc type1 some the sliding sleeve1 and others the rotary type4 ,illustration3 ,fig4 #af4 ,ball ,bearing ,crank ,shaft1 ,pistons and ,connecting ,rods of the 8,maximotor10 in ,their ,relative ,positions4 ,multiple cylinder engines vary in the cylinder grouping or arrangement1 the arrangement and number of cylinders depending on the service for which the engine is intended1 the amount of vibration permissible1 or the weight4 ,the question of speed also introduces modifications in the design1 but no matter what valve arrangement is adopted or what grouping of cylinders is used1 a four stroke cycle engine performs the five events of suction1 compression1 ignition1 expansion and exhaust in four strokes1 in each and every cylinder4 ,with the exception of fuel injection 7which in reality corresponds to the ignition event7 in the four stroke ,diesel engine1 the indicator cards of all four stroke cycle engines passes the same characteristics as the diagram shown in ,fig4 #aj4 ,in this chapter1 the engine will be described without regard to the fuel used1 or to the means adopted in vaporizing it1 for the vaporizing appliances are considered as being external to the engine proper1 except in some of the heavy oil engines1 and as the fuel is gasified before entering the cylinder the question of fuel does not affect the general construction of the engine4 ,the majority of engines are readily converted from gasoline to gars1 or in some cases kerosene1 by changes in the vaporizing device1 and with the exception of changing the compression pressure1 little further alteration is needed4 ,since the vaporization and admission of the heavier oils1 such as crude oil and kerosene has a more intimate relation to the engine than the use of gasoline or gas1 the heavy oil engines will be described in a separate chapter in order that the process of oil burning may be more fully explained4 ,it should not be understood that the cycle1 or principle of the oil engine differs from that of any other engine1 but that the vaporizer forms such a close connection with the engine proper that they must be described as one unit4 7#dc7 ,horizontal ,single ,cylinder ,engine4 ,an example of a modern single cylinder engine operating on the four stroke cycle principle is the 8,muenzel0 engine shown in ,section by ,fig4 #ag4 ,it is of the single acting type1 that is1 the pressure of the gases acts only on the left end of the piston which reciprocates in a horizontal direction4 ,surrounding the cylinder in which the piston slides1 is the water jacket 7shown by the short horizontal dashes7 which keeps the cylinder walls from becoming overheated by the successive explosions of the mixture4 ,the cooling water is pumped into the jacket through the pipe shown over the cylinder1 and flows out of the jacket through an outlet near the bottom of the cylinder4 ,illustration3 ,fig4 #ag4 ,longitudinal ,section ,through the ,muenzel ,horizontal ,engine4 ,both the inlet and exhaust valves are situated in an extended portion of the combustion chamber to the left of the piston1 the upper valve being the inlet and the lower valve1 the exhaust4 ,the valves are held on their seats by means of coil springs that act on the upper ends of the valve springs4 ,admission of the explosive mixture is controlled by the upper valve1 and the release of the burnt gases by the lower4 ,pipes at the bottom of the cylinder marked 8,gas ,supply0 and 8,exhaust0 convey the gases to and from the inlet and exhaust valves respectively4 ,illustration3 ,fig4 #ah4 ,elevation of ,muenzel ,engine ,showing ,lay ,shaft and ,valve ,connections4 ,the inlet valve1 and the inlet valve spring are held in one unit by a removable metal housing known as a 8,valve ,cage01 which is arranged so that the cage1 valve1 and spring may be removed as one piece from the cylinder casting when the valves need attention by removing a few bolts4 ,as the cage is directly over the exhaust valve1 and is considerably larger in diameter1 it is possible to remove the exhaust valve through the opening left by the removal of the inlet valve cage4 ,both valves are surrounded by a water jacket1 as are the passages that lead to them4 ,both the inlet and exhaust valves are opened and closed at the proper moments in the stroke by means of cams mounted on the horizontal cam shaft shown by ,fig4 #ah through a system of levers4 ,the cam shaft is the shaft running parallel to the engine bed from the crank-shaft to the end of the cylinder and turns at one-half the speed of the crank-shaft4 ,at a point directly below the inlet valve in ,fig4 #ah1 will be seen an enlargement on the shaft on which rests the rod running from the inlet valve to the cam shaft4 ,this is the cam4 ,a cylindrical casing shown above the cylinder contains the governor which maintains a constant speed at all loads by operating a valve in the intake pipe which varies the quantity of mixture entering the cylinder in proportion to the load4 ,the governor is driven from the cam-shaft by spiral gears4 ,the igniter which furnishes the spark for igniting the gas is located between the two valves at the extreme left of the combustion chamber 7,fig4 #ag74 ,it should be noted that the cylinder head which closes the left end of the cylinder1 and which carries the valves is separate from the main body of the ,cylinder4 ,by unscrewing the bolts that hold it to the cylinder1 the head may be removed when it becomes necessary to remove dirt and carbonized oil from the combustion chamber1 or when it becomes necessary to remove the piston4 ,the cylinder barrel in which the piston works may also be removed through the opening left by the piston head when it becomes worn1 and another barrel or liner may be substituted1 thus practically renewing the engine at a small fraction of the cost of a new cylinder4 ,the liner is fastened firmly to the outer cylinder casting at the left but is free to slide back and forth in the casting at the right hand end1 this end being provided with a packed joint4 ,this play given to the liner allows it to expand and contract freely with the different changes of temperature without causing strains either in the cylinder or in the liner4 7#dd7 ,multiple ,cylinder ,engines4 ,since the power exerted by a single cylinder four stroke cycle engine is intermittent1 the explosive force exerted on each power stroke is much heavier than would be the case if the power application were continuous1 as the explosions must be heavier to compensate for the idle periods4 ,to reduce the strain on the engine and the vibration as well and to obtain an even turning moment it has been customary to provide more than one cylinder on engine of over #aj horse-power capacity4 ,in this way the total power is divided among a number of cylinders1 and as no two cylinders are under ignition at any one time the turning moment is more even1 the vibration is less1 and the strain on the engine is considerably reduced4 ,dividing the power in this way makes it possible to reduce the weight of the engine as less material is required to resist the strains and a small fly-wheel may be used because of the even engine torque4 ,in order to gain the full benefit of this reduction in weight1 the builders of aeronautic motors have carried the multiplication of cylinders to an extreme1 the ,antoinette for example having sixteen cylinders4 ,engines having more than six cylinders exert a continuous pull as the impulses 8overlap10 that is1 ignition occurs in one cylinder before another cylinder in the series ends its working stroke4 ,the greater the number of cylinders1 the more continuous will be the torque or turning moment4 ,the multiple cylinder engine may be considered as a group of single cylinder engines connected together1 and receiving their fuel from a common source1 the only difference between the single and multiple being in the inlet and exhaust piping and the ignition system4 ,illustration3 ,fig4 ,f-#ab4 ,six ,cylinder ,maximotor4 ,illustration3 ,fig4 ,f-#ac4 ,four ,cylinder ,buffalo ,motor for ,marine ,service4 ,as a single cylinder four stroke cycle engine has one working impulse in every two revolutions1 a two cylinder engine will have an impulse for every revolution as there are twice as many impulses in the same time4 ,it should be remembered that the number of impulses given per revolution by a four stroke cycle engine is equal to the number of cylinders divided by two4 ,thus1 a six cylinder engine has #f #b #c impulses per revolution1 and an eight cylinder1 #h #b #d impulses1 providing of course1 that the engine is single acting4 ,arrangement of the cylinders varies with the service for which the engine is intended and the perfection of balance that is required1 the principal arrangements being the 8,v10 the 8upright10 the opposed1 the 8radial10 8tandem10 and 8twin40 ,the upright engine has the cylinders all on one side of the crank-shaft in a straight line1 as in the four cylinder automobile engine4 ,in this form1 each cylinder has an individual crank throw the number of throws being equal to the number of cylinders4 ,this engine is fairly well balanced in the four1 six and eight cylinder types1 as one-half of the connecting rods and throws are up1 while the other half are down1 but as the connecting rods do not all make equal angles with the center line of the cylinder at the same time there is a slight unbalance in the four and six cylinder types4 ,because of the ignition sequence1 two cylinder vertical motors are in no better balance than the single cylinder type since both crank throws and connecting rods are on the same side of the shaft at the same time4 ,for this reason the two cylinder engine is most commonly built in the opposed type which gives perfect balance4 ,in 8,v0 type arrangement1 one-half of the cylinders are set at an angle of about #ij with the rest of the cylinders1 or in the two cylinder 8,v0 the cylinders are set in the same plane1 perpendicular to the shaft1 at angle varying from #eg to #ij4 ,the 8,v0 type arrangement is adopted where light weight and compactness are the principal requirements1 as the weight and length are both reduced by putting the cylinders opposite to one another by pairs1 the 8,v0 being practically one-half the length of an upright having the same number of cylinders4 ,this arrangement permits the use of one-half the number of crank throws used in the vertical type as each crank throw acts for two cylinders4 ,for the reason that both the cylinders of a two cylinder 8,v0 act on a common crank throw1 the two cylinder 8,v0 is in no better balance than a single cylinder engine4 ,illustration3 ,fig4 #ah-;a4 ,g4 ,h4 ,h4 ,double ,acting ,tandem ,cylinder ,engine 7,german74 ,it will be ,noted that an ,inlet and ,exhaust ,valve ,are ,placed at ,both ,ends of ,each ,cylinder4 ,the ,exhaust ,valves ,are ,below and the ,inlets ,above the ,cylinders4 ,as this ,engine is of the ,four ,stroke ,cycle ,type1 ,each ,cylinder ,gives ,one ,impulse per ,revolution1 or ,two ,impulses per ,revolution for ,both ,cylinders4 ,the ,piston and ,piston ,rod ,are ,both ,cooled by ,water1 and ,are ,supported by the ,cross ,heads so that ,their ,weight is ,taken ,off the ,cylinder ,bore4 ,an 8opposed0 type engine is in the most perfect mechanical balance of any engine as the crank shafts and connecting rods are not only on opposite sides of the crank-shaft1 but make equal angles with the center line of the cylinders as well1 at all points in the revolution4 ,the explosive impulses occur at equal angles in the revolution as in the four and six cylinder vertical type4 ,an opposed engine may be considered as a 8,v0 having a cylinder angle of #ahj4 ,in the opposed type1 one crank throw is provided for each cylinder1 the pistons of the opposite cylinders traveling in opposite directions at the same time4 ,a 8radial0 or 8,fan0 type motor1 as the name would suggest has the cylinders arranged in one or two rows around the crank case1 each cylinder being on a radial line passing through the center of the cylinder with one crank throw for each row4 ,the ,gnome engine illustrated elsewhere in the book is an example of this type1 the seven equally spaced cylinders acting on a common crank throw4 ,when more than seven cylinders are used on this engine1 as in the fourteen cylinder engine1 two cranks are provided1 each crank serving seven cylinders4 ,this arrangement cuts down the weight of a motor enormously because of the short crank shaft and case4 ,with the ignition properly timed and the cylinders correctly spaced the firing impulses occur at equal angles4 8,tandem0 cylinders are employed only on stationary engines1 the cylinders being placed on the same center line1 one in front of the other1 and when this arrangement is adopted it is the usual practice to make the cylinders double acting4 ,the two pistons are connected by a rod known as the 8piston rod0 which extends from the rear end of one cylinder into the front of the following cylinder4 ,tandem cylinders require too much room for use on automobiles or motor boats1 and for this reason are seldom seen in this service4 ,the 8twin0 engine is a modification of the vertical cylinder arrangement1 both cylinders being on the same side of the shaft and in line with one another4 ,it is the type most generally used on very large stationary engines that have more than one cylinder1 and instead of being vertical as in their prototype are generally laid horizontally4 ,since the twin engine is generally double acting1 the crank throws are placed on opposite sides of the shaft4 7#de7 ,four ,cylinder ,vertical ,auto ,motor4 ,a common type of four cylinder vertical motor is shown by ,fig4 #ai1 which is of the type commonly used on automobiles4 ,in order to show the general construction of the cylinder1 each cylinder is cut through at a different point4 ,the cylinder at the extreme left is shown in elevation1 or as we would see it from the outside4 ,in the second cylinder from the left1 the section is taken through the valve chamber1 which projects from the side of the cylinder4 ,a section through the center of the cylinder is shown on the third cylinder1 and the fourth cylinder is in elevation4 ,on cylinder ,no4 #a1 7left7 is seen the exhaust pipe 7#cb7 and the inlet pipe 7#ca7 entering to valve chamber and connected to the exhaust valve and inlet valve respectively4 ,the pipes are held in place by the clamp or 8crab0 7#cc74 ,the exhaust pipe connects with the exhaust valve of each cylinder1 and terminates at the fourth cylinder as shown by 7#cb74 ,screwed into the top of the valve chamber on cylinder ,no4 #a are the two spark plugs 7#cd7 and the relief cock 7#ce74 ,referring to cylinder ,no4 #b1 the inlet valve 7#db7 is shown at the left of the chamber and the exhaust valve also shown by 7#db7 is shown at the right4 ,above the valves are the spark plugs 7#cd7 which project into the space above the valves4 ,pressing against the lower ends of the valve stems and holding the valves tight on their seats are the springs 7#dd7 which fit into the washers 7#de7 fastened to the stems4 ,the valve stems terminate in a nut at 7#dh74 ,the valve stem guides 7#dc7 form a support for the valves and at the same time form an air tight connection for the stems to slide in4 ,immediately beneath the stems are the push rods 7#df7 which are provided with an adjustment 7#dh7 at the upper end1 and a roller 7#di7 at the lower end4 ,the rollers 7#di7 rest directly on the cams mounted on the cam shaft 7#bg71 and as the irregular cams revolve1 the push rods are moved up and down which in turn act on the valve stems and raise the valves at the proper moment4 ,the cams raise the valves and the springs close them4 ,the two cams 7exhaust and inlet7 appear as two rectangular enlargements on the shaft 7#bg74 ,the bearings 7#ec71 support the cam shaft1 one being supplied for each cylinder4 ,at the extreme left of the crank shaft is shown the half time gear 7#bj7 which meshes with the gear on the crank-shaft and drives the cams4 ,next to this gear is the large cam shaft bearing #bf4 ,it should be noted that the section through the valve chamber taken on cylinder ,no4 #b is at a point considerably back from the center line of the cylinders and not in the same plane as the section shown on cylinder ,no4 #c1 which is taken through the center line of the cylinders4 ,illustration3 ,fig4 #ai4 ,cross-,section ,through ,typical ,four ,cylinder ,automobile ,engine4 ,courtesy of the ,chicago ,technical ,college4 ,in the section of cylinder ,no4 #c1 we see the water space surrounding the upper portion of the cylinder with the opening 7#cg7 connected to the water manifold 7#cf71 through which the water leaves the cylinder and passes to the radiator4 ,at the lower end of the stroke is the piston1 one-half of which is shown in section and one-half in elevation so that internal and external appearance may be readily seen4 ,the piston pin 7#fj7 is located approximately in the center of the piston to which it is secured by means of the set-screw 7#fa74 ,by means of the connecting rod 7#ef71 the motion of the piston is transmitted to the crank-shaft throw 7#ed71 both ends of which are provided with bronze bushings 7#ei7 and 7#eh71 fitting on the piston pin and crank-pin respectively4 ,between each crank throw are the main crank shaft bearings 7#ee7 which are provided with the bronze bushings 7#ed74 ,below the connecting rod ends is the small drip trough containing oil into which the pipes on the rod ends dip when passing around the lower end of the stroke4 ,when the pipes enter the oil puddle a small amount of lubricating oil is driven into the crank-pin bearing because of the force of impact1 this force also causing oil to splash about in the crank case for the lubrication of the main crank shaft bearings and cam shaft4 ,in order to maintain a constant level of oil in the puddle so that the bearings shall receive a constant supply of oil1 a small overflow opening is placed in the center of the puddle which allows an excess of oil to overflow into the return oil sump below4 ,this excess of oil drains by gravity back to the oil circulating pump 7#gc71 at the right which again forces the oil to the various bearings4 ,in this way1 the same oil is used over and over again until it becomes unfit for lubricating purposes because of dirt or decomposition4 ,the oil pump is driven from the cam-shaft through the level gears 7#ff7 and the vertical shaft 7#gb74 ,to the right of the oil pump is the fly-wheel 7#ge7 which furnishes the power for the idle strokes of the engine4 ,at the upper end of the vertical shaft that drives the oil pump is an extension 7#fh7 which passes through the bearing 7#gj7 and drives the ignition timer shown at the top of the housing 7#fi74 ,the timer controls the period of ignition in the cylinders in regard to the piston position so that the spark occurs at the end of the compression stroke4 ,at the extreme left of the engine is the radiator fan 7#a7 which is driven from the crank-shaft pulley 7#af71 the belt 7#aj71 and the fan pulley 7#aabb74 ,this fan increases the amount of cold air that is drawn through the radiator1 7mounted to the left of the engine7 and increases its capacity for cooling the jacket water of the engine4 ,the water circulating pump is located on the opposite side of the motor4 ,illustration3 ,fig4 #ai-;a4 ,buda ,four ,cylinder ,automobile ,motor4 ,carburetor ,side4 ,illustration3 ,fig4 #ai-;b4 ,buda ,motor1 ,pump ,side1 ,cylinders 8,en ,bloc40 ,in this motor both the inlet and exhaust valves are located on the same side of the cylinder which arrangement classifies the engine as an 8,l0 type1 the extended valve pockets forming an 8,l0 with the center line of the cylinder4 ,in the motor shown by ,figs4 ,f-#ad-;,f-#ae1 the inlet and exhaust valves are on opposite sides of the cylinder as shown in the cross-section1 which classifies the motor as a 8,t0 type1 as the valve chambers together with the cylinder forms a 8,t40 ,the latter type of motor has several advantages over the 8,l0 type1 but as it requires two cam shafts1 one for the inlet and one for the exhaust valves1 it is not adopted by the builders of the cheaper grades of automobiles4 ,since the exhaust valves are on the opposite side of the cylinder1 in the 8,t0 type1 the inlet air is not expanded nor the output diminished by the heat of the exhaust passages4 ,the piping is less complicated which permits of a more effective arrangement of the carburetor and magneto4 ,since the piping in the latter type can be arranged to better advantage1 less back pressure is the result4 ,illustration3 ,fig4 ,f-#ad4 ,cross-,section ,through ,wisconsin ,truck ,motor4 8,t0 ,type4 ,illustration3 ,fig4 ,f-#ae4 ,longitudinal ,through ,wisconsin ,truck ,motor4 ,as in the previous case1 the valves are acted on directly by the cams and push rods1 one cam shaft being provided on each side of the cylinders4 ,in order to reduce the noise made by the push rods and springs1 all of the springs are enclosed by sheet metal housings or tubes4 ,the circulating pump is shown at the left nearly on a line with the left hand cam shaft1 the pump outlet being inclined toward the cylinder so that it enters the water jacket under the exhaust valves4 ,water leaves the jacket by the pipe shown on the cylinder tops4 ,from the longitudinal section it will be seen that the cylinders are cast in pairs1 two cylinders to the pair1 instead of singly as in the previous case4 ,the large pipe crossing at about the center of the cylinders is the exhaust pipe 7shown in front of the left pair71 and the pipe shown under the exhaust is the water inlet pipe from the circulating pump4 ,it will be seen from the longitudinal section that the main crank-shaft bearings are fastened to the upper half of the crank case1 and are entirely independent of the lower half which acts simply as an oil shield4 ,this construction allows the oil shield 7lower half7 to be removed without disturbing the adjustment of the bearings1 when it becomes necessary to inspect the internal mechanism4 ,illustration3 ,six ,cylinder ,rutenber ,automobile ,motor1 with ,cylinders ,cast in ,pairs4 ,large removable plates cover the top of the water jackets so that it is a simple matter to clean out the water space in case that it becomes coated with deposits from the water4 ,this is an important feature as a great many of the heating troubles may be overcome by having access to the interior of the water jacket4 ,the water outlet pipes connect with the jacket covers4 ,both cam shafts are driven by the gears at the right which connect with the crank shaft pinion4 ,fan is belt driven from an extension to the cam shaft4 ,all bearings are supplied with oil by a high pressure force feed pump1 the crank pins receiving their supply through channels drilled in the crank shaft and pin1 which in turn are connected to the oil supply of the main bearings1 no dependence being placed on a splash system4 ,after leaving the bearings1 the oil drops into the crank case and drains into the sump shown at the left of the longitudinal section4 ,from the sump1 the oil returns to the oil pump from which point it is returned to the circulating system under high pressure4 7#df7 ,stationary ,four ,cylinder ,engine4 ,an ,english stationary engine1 the ,browett-,lindly1 similar in many respects to the automobile engines just described1 is shown in longitudinal and cross-section by ,figs4 #bj and #ba4 ,this is of the 8,l0 type of valve arrangement1 but instead of having the valves side by side as in the preceding case1 the inlet valve is placed over the exhaust as will be seen from the cross-section view4 ,illustration3 ,fig4 #ba4 ,cross-,section ,through ,browett-,lindly ,engine4 ,the exhaust valve is operated directly from the cam shaft by the push rod as in the auto engines1 but the inlet valve receives its motion through a long vertical rod and horizontal lever1 the latter being located on the cylinder head as shown by the longitudinal section4 ,a supplementary valve is mounted loosely on the stem of the inlet valve1 and this valve is held against the seat of the gas inlet port by a short spring4 ,illustration3 ,fig4 #bj4 ,section ,through ,browett-,lindly ,four ,cylinder ,stationary ,engine4 ,a collar on the main valve spindle opens this gas valve1 and1 by adjusting the position1 a certain amount of lag can be given1 so that air first enters the cylinder and then1 by further travel of the main valve1 the gas valve opens and the combined charge is taken in4 ,this prevents any 8back fires0 as the gas and air are entirely separated until they enter the cylinder4 ,starting is effected by means of compressed air1 and is entirely automatic4 ,no compression release is provided1 as this is unnecessary under the system adopted4 ,by opening the main compressed air valve compressed air is admitted to two valve boxes placed underneath the cam shaft1 and the pressure of air raises the valves against their levers and cams4 ,should the swell on the cam be opposite a lever as it will be in the correct starting position1 the valve cannot close1 and the compressed air then passes to the cylinder through a check valve on the face of the cylinder1 and the engine starts4 ,the automatic check allows the cylinders to take in a charge of mixture on the second stroke and firing takes place immediately4 ,when the explosion pressure is greater than the air pressure the check remains closed and no more starting air enters the cylinder4 ,illustration3 ,fig4 #ba-;a4 ,section ,through ,cylinder of ,fairbanks-,morse ,type 8,r ,e0 ,engine1 with ,valves in the ,head4 ,governing is effected by varying both the quantity and quality of the mixture4 ,the main valve1 plunger1 and rod springs1 and all springs on the valves and valve motion1 are arranged to be in compression4 ,the exhaust valves are of cast-iron1 and are fitted with renewable seats in the cylinders4 ,the admission valves are of nickel steel1 and are arranged in boxes1 which1 when removed from the cylinders1 provide the ports which give access to and space for the removal of the exhaust valves which are withdrawn vertically4 ,forced lubrication is fitted throughout all bearings1 valves1 plunger guides1 governor1 cam shaft1 etc41 the oil under pressure being supplied by two valveless pumps1 either of which is sufficient to maintain the working pressure of oil4 ,the normal output of the engine is #djj brake horse-power1 with an allowable overload of #dj horse-power for hour4 ,the exhaust pipe is water jacketed1 each section being supplied from the small pump shown at the end of the cross section4 ,double ignition is provided for an emergency1 by two high tension magnetos1 each of which is connected to a separate set of plugs4 ,when starting the engine1 an ordinary spark coil and storage battery are used until the engine gets up to speed1 when the coil is cut out and the magneto is thrown in4 7#dg7 ,the 8,v0 ,type ,motor4 ,an example of the 8,v0 type motor is shown by ,fig4 #bb1 which is a front elevation of the ,frontier aeronautic motor1 a type that occupies a minimum of space with a minimum of weight4 ,illustration3 ,fig4 #bb4 ,end ,elevation of ,frontier #h ,cylinder 8,v0 ,type ,motor4 ,the cylinders are cast separately and are furnished either with iron or copper water jackets1 the copper jackets being deposited over the cylinder barrels by an electrolytic process in much the same way as that of the celebrated ,french ,antoinette4 ,bolts passing through flanges on the bottom of the cylinder fasten them to the base4 ,a special aluminum alloy is used for the base which is cast in a single piece with webs to receive the bearings4 ,a unit crank-case insures perfect alignment1 prevents a greater part of the oil leakage1 and forms a much stronger construction than the usual split pattern4 ,a chamber is provided for the cam shaft at the apex of the case through which issue the push-rods4 ,shafts and piston pins are hollow4 ,all push rods are adjustable for wear and have steel balls running on the cams which eliminate the possibility of mis-timing through wear4 ,lubrication is by a bronze pump geared from the crank-shaft and is connected to an oil tank located in the base from which the oil is forced through the crank-shaft up through the hollow connecting rods to the piston pins1 thence to the cylinder walls1 the surplus returning to the tank in which the strainer is located4 ,the circulating pump is driven from the cam shaft as shown in the cut and supplies the cylinders and radiator with water through the copper water manifolds which are designed to give an equal supply to each cylinder4 ,exhaust manifolds are of seamless steel tubing4 ,the cylinders are #d bore #d stroke1 and develop #fj to #gj horse-power at #a1ajj revolutions per minute1 which speed has been attained with an #h-;foot #f-;inch propeller having a pitch of #e feet4 ,without radiator or propeller1 the iron jacketed motor weighs #cab pounds1 and copper jacketed weighs #bij pounds1 the latter making a difference of #bb pounds in the weight4 ,a high tension ,bosch magneto is used which is mounted on a pad cast on the top of the crank-case and is driven from a gear meshing with the cam shaft gear4 ,connection is made from the magneto to plugs placed over the inlet valves in the valve caps4 ,a #ajj horse-power aero engine of the 8,v0 type is shown by ,figs4 #bc-bd-be1 which is built by the ,all ,british ,engine ,company for the aeronautical branch of the ,english ,war ,department4 ,it has eight cylinders of #e inch bore1 by #d inch stroke1 and develops its rated horse-power at #a1bjj revolutions per minute4 ,data from 8,aero10 ,london4 ,illustration3 ,fig4 #bc4 ,longitudinal ,section ,through ,a4 ,b4 ,c4 #ajj ,horse-,power 8,v0 ,motor4 ,the crankshaft1 which is of three per cent nickel chrome steel1 having an ultimate tensile strength of #aeg1jjj lbs4 per sq4 in41 is of distinctly large diameter1 and is carried in plain bearings lined with white metal4 ,it is provided with four throws1 each crank pin being arranged to take the big end bearings of two connecting rods from cylinders on opposite sides of the crank case4 ,there is a bearing between each throw1 and in order to reduce the overall length of the engine the cylinders are staggered on the crank case4 ,the ,h section connecting rods are stamped out of steel having a tensile strength of #ij1jjj lbs4 per sq4 in41 and for the purpose of lubrication a hole is drilled from end to end down the center of the web4 ,as mentioned before1 the cylinders are staggered1 and there is no overhanging of the big end bearings at the point of attachment to the connecting rod4 ,the bearings themselves are lined with white metal4 ,the small end bearings are provided with phosphor bronze bushes1 and the piston pin is of steel bored out hollow and hardened4 ,illustration3 ,fig4 #bd4 ,valves and ,valve ,motion of ,a4 ,b4 ,c4 ,motor4 78,aero10 ,london47 ,a very interesting detail of the engine is the combination of the water outlet pipe from the top of the cylinder with the bearings for the rocking arms 7which are steel stampings7 actuating the valves4 ,this is shown in ,fig4 #be4 ,a hollow steel column is bolted to the top of the cylinder and protrudes from the water jacket1 which is fastened to it with the usual shrunk ring4 ,to this column is attached a hollow ,t shaped pipe of phosphor bronze1 the column of the ,t piece forming the outlet for the water4 ,on one arm of the ,t piece the exhaust rocker takes its bearing and on the other the inlet rocker4 ,each ,t piece arm is connected to its fellow on the next cylinder by means of rubber pip4 ,illustration3 ,fig4 #be4 ,end ,elevation of ,a4 ,b4 ,c4 ,motor4 ,a small bracket projecting from the ,t piece forms a saddle on which the valve spring rests4 ,this is a plain semi-elliptical leaf spring which works both valves4 ,it is slotted at each end and slightly turned up so as to engage with a cotter pin passed through a slot in the end of the valve stem4 ,the crank case is of rather unusual design1 being absolutely circular in section and machined all over4 ,it is practically a tube with flanged portions bolted on to form the ends4 ,having no horizontal joints1 it is strong and easily kept oil tight4 ,three radial arms1 with slight webs and reinforced with steel columns down the center1 support each bearing4 ,the crank case is carried by four feet1 which are arranged to accommodate three different widths of engine bearer4 ,to the fore end of the crank case is bolted a long conical aluminum nose carrying at its extremity a compound push and pull ball bearing #f in4 in diameter1 which supports an extension shaft bolted to the crankshaft by means of a flanged coupling4 ,illustration3 ,fig4 #bd-;a4 8,sixteen0 ,cylinder ,favata ,radial ,type ,aero ,motor1 ,consisting of ,four ,groups of ,two ,cylinders ,per ,group4 ,cylinders are of the ,double ,acting ,type and are ,stationary4 ,at the outer end of this extension is a flange to which the propeller is bolted1 but the arrangement is specially devised to make quick detachment possible4 ,the boss of the propeller has a hollow hub and is plate bolted permanently to it by twelve bolts4 ,the direct nose is interchangeable with a speed reduction gear so that the propeller can be driven at a lower speed than the engine4 ,fitting this gear nose raises the center line of the propeller-shaft some #e in4 ,the gears are carried on substantial ball bearings1 plain bearings being used also in such a way that they take up the load if the ball bearings through any cause should fail4 ,the reduction is by means of silent chains4 ,the arrangement of the gear wheels is plain from the drawing1 and it will be noticed that there is no intermediate wheel between the crankshaft pinion and the camshaft wheel1 which are of steel and phosphor bronze respectively4 ,a separate gear wheel is provided on the camshaft for driving the magneto4 ,the water and oil pumps are carried low down outside the crank case1 and are driven by intermediate wheels at double the engine speed4 ,the shafts are joined together through ,oldham couplings1 so that it is possible to remove the pumps separately4 ,both these pumps are of the gear type4 ,the camshaft is made in one piece with the cams1 and is hardened1 being drilled out for lightness4 ,it is enclosed in a casing of steel tube1 which is practically separate from the crank case1 being attached thereto at one end by the timing gear case and at the other by a saddle4 ,the camshaft is carried in six bearings4 ,an interesting point is the fact that the gear wheels are bolted to flanges on the shafts instead of being attached by keys4 ,carried in the tube directly above the camshaft is a second shaft forming the fulcrum of the rocking arms for the cam rollers4 ,a very interesting point is the provision of an arrangement for lifting the exhaust valves4 ,the little rocking arms carrying the rollers which bear upon the cams are provided with webs1 parallel with the camshaft and between it and the shaft carrying the rockers is a third shaft1 the sides of which normally just clear the webs of the rocking arms on either side4 ,this shaft is provided with wedge shape pieces along it1 so that by sliding it along the wedges lift the rocking arms clear of the cams1 and thus1 through the tappet rods and rockers1 the valves themselves are opened4 ,illustration3 ,fig4 #bf4 ,mesta ,engines on ,test ,floor4 ,not the least interesting particular of this engine is the thorough way in which the lubrication is carried out4 ,four of the bolts which attach the caps of the main bearings are prolonged through the bottom of the crank case1 and serve to carry a detachable oil sump which holds sufficient oil for a run of six hours4 ,as already mentioned1 the oil pump is driven at twice the engine speed1 and maintains a pressure of something like #aaj pounds per square inch4 ,it delivers directly into a straight steel tube placed along the bottom of the crank case1 and from this tube a vertical tubular connection is taken to each of the caps of the main bearings4 ,the crankshaft and crank pins are hollow1 and1 as in the previous engine1 in the hollow portions tubes of a slightly smaller diameter are placed1 the tubes being expanded over at the ends1 so that closed annular spaces are formed which are used as lubrication leads4 ,the lubricating oil passes through the main bearings into these annular spaces in the shafts1 from them to the annular spaces in the crank pins1 and so to the big-end bearings4 ,from the big-end bearings it travels up the connecting rods to the gudgeon pins4 ,it is interesting to note at this point that the connecting rods work in slots in the crank case which just allow sufficient clearance for their travel1 in order to prevent the flooding of oil into the cylinders4 ,a steel-lined oil lead is taken up to the saddle which supports the tubular camshaft casing at the propeller end of the crank case4 ,the bearings carrying the camshaft are cut away at their lower edges clear of the tube so that the oil can flow along the full length of the casing1 the level being sufficient to allow the cams to dip4 ,precautions are taken to keep oil from flowing out of the bearings1 and the casing over the gears is specially arranged to prevent the oil from flooding below4 7#dh7 ,mesta ,gas ,engines4 ,the ,mesta four stroke cycle1 double acting gas engine1 built by the ,mesta ,machine ,co41 ,pittsburgh1 is an excellent example of ,american big engine practice4 ,mesta engines are built in sizes from #djj horse-power up to the largest used1 and is built either in tandem or twin tandem units4 ,while the engine does not differ widely in either principle or construction from engines of the same size it has several features worthy of note that are not found on other engines4 ,up to the medium sizes1 the cylinders are cast in one piece1 the largest cylinders being made in two parts of cast steel with air furnace iron bushings4 ,the central part of the cylinder is open as will be seen from the cuts1 and is covered with a cast iron split band bolted at the center line4 ,the valve chambers are located directly opposite one another on a vertical center line1 the inlet valve being at the top and the exhaust valve at the bottom4 ,this arrangement gives a better distribution of the mixture1 increases the output with given size of cylinder and equalizes the stresses occasioned by the explosions4 ,as the engine is double acting in all cases there is one inlet and one exhaust at each end of the cylinder4 ,both the inlet valve and the corresponding exhaust valve on each end of the cylinder are operated by a single eccentric on the horizontal lay-shaft shown running below and parallel to the cylinders4 ,the regulating valves which are controlled by the action of the governor are perfectly balanced against the pressure in the cylinder which results in a very small resistance to the governor action1 therefore no oil relay nor similar complications are required4 ,any of these valves are easily removed for clearing1 a point of great importance when running on a gas that is laden with tar or other impurities4 ,illustration3 ,fig4 #bg4 ,end ,view of ,mesta ,engine4 ,the chrome-vanadium piston rod carries the pistons floating free from the cylinder walls reducing the wear on the bore1 while the piston rings maintain a gas tight contact with the cylinder walls4 ,each piston rod is made in two halves1 the joint between the sections being made between the cylinders at which point the rods are supported by an intermediate cross-head and guide4 ,both parts of the rod are interchangeable4 ,the pistons are made in one casting4 ,as will be seen from the accompanying cuts the front end of the piston rod is carried by a cross-head which relieves the pressure on the piston and packing glands4 ,speed regulation is performed by the governor by controlling both the quantity and the quality of the mixture4 ,independent valves in the gas and air passages are actuated by the governor according to changes in the load4 ,this method of control combines all of the good features of quantity and quality regulation4 ,make and break ignition is used1 with the igniter trip gear so designed as to allow all of the igniters to be timed from one lever1 or adjusted independently as the case may require4 ,each combustion chamber is supplied with two igniters1 one at the top and one at the bottom1 which insures regular and rapid combustion and therefore gives a maximum of efficiency and reliability4 ,compressed air is introduced into the cylinders for starting at a period corresponding to the power stroke in normal operation4 ,this is accomplished by cam operated poppet valves located in the air main and check valves in the cylinders4 ,by this system the engine can be started and put on full load in less than one minute4 7#di7 ,knight ,sliding ,sleeve ,motor4 ,the ,knight motor was the first four stroke cycle automobile motor to employ an annular slide valve in place of the usual poppet valve4 ,its success has led to the development of several other motors of a similar type which follow the construction of the original engine more or less closely4 ,being free from the slap bang of eight to twelve cam actuated poppet valves which hammer on their seats at the rate of a thousand blows per minute1 the ,knight motor is free from noise and vibration4 ,instead of the jumping of a number of small parts1 there is only the slow sliding of the sleeves over well lubricated surfaces4 ,they make no noise because they strike nothing and can cause no vibration because they are a perfect sliding fit in their respective cylinders4 ,besides insuring noiseless operation1 the valves increase the output1 efficiency and flexibility of the motor for they are positively driven and are not affected in timing by fluctuations in the speed4 ,the wear of the reciprocating increases the efficiency of the sleeve instead of destroying it4 ,with poppet valves at high speeds1 the valves do not seat properly in relation to the crank position owing to the inertia of the valves and to the gradual weakening of the valve springs which delays the closing of the valves4 ,carbon also gets on the seats of the poppet valves and prevents proper closure4 ,these faults cannot exist with sliding sleeves when they are once set right as they are positively driven through a crank and connecting rod4 ,illustration3 ,fig4 #bh4 ,section ,through ,knight ,motor ,showing the ,sleeves1 ,eccentrics1 and ,automatic ,adjustment for ,lubrication4 ,inlet is at the ,right1 ,exhaust at the ,left4 ,at high engine speeds the velocity of the exhaust and inlet gases is very high in the poppet valve type due to the many restrictions and turns in the passages which causes back pressure and a considerable loss of power4 ,with the sliding sleeve type an ideal form of combustion chamber is possible and the passages to and from the chamber are short and direct4 ,very large port areas with a low gas velocity are also possible4 ,the sleeves are more effectively cooled than the poppet type1 being in direct contact with the water cooled walls for their entire length4 ,because of the large port areas1 the cylinders receive a full charge of mixture1 and as a result the engine accelerates and gets under way with remarkable ease4 ,illustration3 ,figs4 #bh-bi-cj4 ,showing ,sleeve ,positions on the ,inlet ,stroke4 7,knight ,motor47 ,the arrangement of the slide valves1 or sleeves1 is shown by ,fig4 #bh1 which also gives an idea of the cylinder form1 and the location of the piston4 ,fitting the engine cylinder closely1 one within the other1 are the two sliding valve sleeves1 and within the inner sleeve slides the power piston4 ,illustration3 ,figs4 #ca-cb-cc4 ,showing ,sleeve ,positions on the ,exhaust ,stroke4 ,each sleeve has two slots cut in it1 one on each side1 which form an outlet and inlet for the exhaust and inlet gases respectively4 ,when the slots on the intake side of both the outer and the inner sleeves register1 or come opposite to one another1 and also opposite to the intake pipe1 a charge of gas is drawn into the cylinder4 ,after the explosion has taken place1 the sliding motion of the sleeves brings the other two openings1 on the exhaust side1 opposite to one another1 and opposite the exhaust pipe1 which allows the burnt gas to escape to the atmosphere through the exhaust manifold4 ,the sleeves are driven from cranks on the half-time shaft shown at the side of each cut1 through the small connecting rods1 which gives them a reciprocating motion4 ,like the cam shaft on a poppet valve motor1 the lay shaft runs at half the crank shaft speed1 since the engine is of the four-stroke cycle type4 ,the lower ends of the sleeves1 to which the connecting rods are fastened1 are made thicker than the portion within the cylinder1 and are heavily ribbed for strength in the overhang4 ,the sleeves are of the same composition of cast iron as the cylinder and are provided with oil grooves cut in their outer surfaces for gas packing1 and the distribution of oil4 ,leakage between the inner sleeve1 and the cylinder head is prevented by a packing ring1 or 8junk0 ring that is fastened to the bottom of the inwardly projecting cylinder head4 ,the junk ring not only prevents the leakage of gas during the explosion1 but it also serves another purpose4 ,the exhaust ports or slots in the inner sleeve are above the junk ring during the explosion1 in which position they are protected from contact with the burning gas4 ,the life of valves is greatly increased by this protection4 ,it will be noted that the entire surface of the sleeves is in contact with water jacketed surfaces1 making perfect lubrication and smooth working possible4 ,the two spark plugs for the dual ignition system are shown in the depressed cylinder head4 ,complete water jacketing encircles the cylinders1 cylinder heads1 the circulation area enclosing the plugs and the gas passages so that a uniform heat is maintained the entire length of the piston travel4 ,the half-time shaft1 the magneto1 and the water pump are driven by a silent chain from the crank case2 this drive being found superior to the gears commonly used for this class of work4 ,the cranks on the half-time shaft are made in one integral piece with the shaft4 ,although the piston on the ,stoddard-,dayton ,knight motor has a stroke of #e inches1 it is scarcely as much as this considered as friction producing travel1 because the inner sleeve in which it rests moves down in the same direction #a inches4 ,this distribution of the working stroke to two surfaces reduces the wear on the side of the sleeve caused by the angularity or thrust of the main connecting rod4 ,on the compression stroke1 both outer and inner sleeves go up in the same direction as the piston1 the inner sleeve moving the faster4 ,on the exhaust stroke and suction stroke the sleeves move in a direction opposite to the direction of the piston1 but on these strokes there is very little work performed by the piston and consequently little thrust is produced on the sleeves and walls of the cylinder4 ,it is a valuable feature to have the sleeves descend with the piston on the working stroke because this is the stroke in which the piston has the greatest amount of side thrust4 ,the up and down movement of the sleeves is very little compared with that of the piston4 ,a stroke of #e inches gives a piston speed of #iaf feet per minute at a speed of #a1jjj revolutions per minute4 ,the stroke of the sleeves is #a inches and its speed is but #ic4g feet per minute1 or a little more than one-tenth that of the piston4 ,this fact makes the problem of lubrication a feasible one1 the slow-movement of the sleeves distributing the oil thoroughly between them as well as between the outer sleeves and the cylinder walls4 ,the action of the valves1 and their position at different points in the cycle1 is shown in diagrammatic form by ,figs4 #bh-bi-cj-ca-cb-cc1 the particular event to which each diagram refers being marked at the foot of the cuts4 ,the direction of the sleeve movement is indicated by the arrows at the bottom of the sleeves4 ,particular attention should be paid to the position of the slots in the sleeves4 ,the first three diagrams show the position of the inlet slots that govern the admission of the combustible gas from the carburetor4 ,fig4 #bh shows the slots coming together to form an opening in the inlet port as the lower edge of the outer sleeve separates from the upper edge of the inner sleeve4 ,the outer sleeve is now moving rapidly downward while the inner sleeve is slowly rising1 and as their motion is opposite the opening is quickly formed4 ,fig4 #bi shows the full opening with the slots in register4 ,when closing 7,fig4 #cj7 the outer sleeve is nearly stationary while the inner sleeve is rising rapidly4 ,when the inner sleeve port is covered by the lower edge of the junk ring1 the valve opening is closed1 the slot in the outer sleeve remaining opposite the inlet opening4 ,the exhaust port opens 7,fig4 #ca7 when the lower edge of the slot in the inner sleeve leaves the junk ring in the cylinder head1 the sleeve moving rapidly downward at the moment of opening4 ,to obtain a rapid opening of the exhaust1 the ports are arranged so that the inner sleeve is just about to reach its maximum speed at the time of opening4 ,the outer sleeve closes the port 7,fig4 #cc71 closure starting when the upper edge of the outer sleeve coincides with the lower edge of the cylinder wall port4 ,at this time the outer sleeve is traveling downward at maximum speed1 so that the closing of the exhaust is as rapid as the opening4 ,the lubrication of the ,knight motor is accomplished by what is known as the movable dam system1 which overcomes the tendency of the motor to over-lubricate4 ,a movable trough is placed under each connecting rod1 in the crank case1 that is connected to the carburetor throttle lever in such a way that the opening and closing of the throttle raises and lowers the troughs4 ,when the throttle is opened1 raising the troughs1 the points on the ends of the connecting rods dip deeper into the oil which creates a splashing of oil on the lower ends of the sliding sleeves4 ,in this way the oil is fed to the engine in direct proportion to the load and the heat produced in the cylinder4 ,when the motor is throttled down1 the points barely dip into the oil4 ,an excess of oil is fed to the troughs by an oil pump1 which keeps them constantly overflowing4 ,the overflow is caught in the pumps located in the crank case1 and returned to the circulation so that it is used over and over again4 ,claims of great efficiency are made for this system1 there having been many tests made showing #gej miles per gallon of oil1 while even as high as #a1bjj miles per gallon has been made under favorable conditions4 ,the oil pump is contained in the crank case1 and is of the gear type1 insuring positive action4 ,the pump also acts as a distributer1 a slot being cut in one of the gears which register successively with each of the six oil leads4 ,in this way it is possible to obtain the full pump pressure in each lead should they become obstructed in any way4 ,in the upper half of the crank case are cored passageways through which the air passes before reaching the carburetor4 ,these passages not only eliminate the rushing sound of the intake air1 but also form an efficient method of warming the air supplied to the carburetor and cooling the crank-case4 ,it is possible to furnish warm air after the engine has been idle for several hours1 as the oil in the crank case remains warm longer than any other part of the engine4 7#ej7 ,reeves ,slide ,sleeve ,valve4 ,a simple and compact form of slide sleeve valve gear has been developed in ,england that is of more than passing interest4 ,it permits of a maximum area for both the inlet and exhaust gases which of course keeps the velocity and back pressure at a minimum for a given valve lift4 ,the small lift also insures noiseless operation and a small amount of wear4 ,the sleeve is balanced at the end of the working stroke4 ,the combustion chamber is nearly hemispherical in shape which reduces the heat loss to the walls4 ,illustration3 ,fig4 #cd4 ,reeves ,slide ,valve ,gear4 ,referring to the section of the end of cylinder given in the diagram1 7#cd7 ,a is an open-ended water-jacketed cylinder in which the piston ,b works4 ,at the upper end of the cylinder is attached a ring ,c forming an extension of the stationary cylindrical head ,d carrying the sparking plug4 ,at the lower end of the head ,d is provided a seating ,e for the sliding cylindrical inlet valve ,f1 which takes its bearing around the circular head4 ,this inlet valve is provided with expanding rings ,g to keep it gas-tight4 ,surrounding the inlet valve ,f is a second cylindrical exhaust valve ,h1 which is provided with an angular seating at ,j4 ,the outer circumference of the cylindrical exhaust valve ,h bears against the walls of the cylinder4 ,cast in the cylinder is an annular space ,k communicating with a passage ,l for the admission of the inlet gases4 ,these pass through suitable ports cut in the sides of the exhaust valve ,h and the inlet valve ,f1 so that they are free to pass through the space made when the inlet valve ,f is lowered from its seat4 ,a similar type of annular space ,m is cast in the cylinder in connection with an opening ,o for the passage of the exhaust gas when the cylindrical valve ,h is raised from its seating at ,j4 ,the cylinder head is not water jacketed as the builder states that the continual passage of the intake gases keeps it reasonably cool4 ,the exhaust passages are thoroughly water cooled4 7#ea7 ,argyll ,single ,sleeve ,motor4 ,the ,argyll sliding sleeve automobile motor is unique in the fact that only one sleeve is used to control both the inlet and exhaust gases instead of the two sleeves commonly used on the ,knight motor4 ,this sleeve1 instead of having either a purely vertical or horizontal motion1 has a peculiar combination of the two1 that is to say1 it moves a certain amount in rotation within the cylinder1 and an equal amount vertically1 the combined motion constituting an ellipse4 ,the external appearance of the engine is shown by ,fig4 #ce1 which will give an idea of the general arrangement of the cylinders1 ports and piping4 ,in ,fig4 #cf1 is shown the successive movements and events determined by the sleeve1 and the method of opening and closing the inlet and exhaust ports by the elliptical movement of the sleeve4 ,the shaded ports are one of the inlet and one of the outlet ports1 respectively1 which are cast in the cylinder wall1 and are afterwards machined true4 ,the dotted port1 which changes its position in each diagram1 is one of the ports in the moving sleeve1 its position in each of the figures is marked by the event that is occurring in the cylinder at that time4 ,in diagram #a1 the shaded port to the right is the exhaust port1 and the shaded port to the left1 the inlet1 this relative arrangement being true1 of course1 in each of the succeeding diagrams4 ,it will be noted1 that in the position shown1 in the exhaust stroke 7beginning of stroke71 the sleeve port has just started on its downward stroke1 moving also a trifle to the right as it progresses4 ,its progress to the right may be more clearly seen by consulting diagram #b1 for the movement4 ,by consulting the other five figures it will be seen that the dotted port1 in its relation to the shaded ports1 first moves out to the right1 and then reverses1 moving to the left1 and this combined with the up and down movement constitutes an elliptical path4 ,in diagram #f the exhaust is closed1 and the inlet port has just begun to open1 the dotted port now starting to move out to the left1 and to rise4 ,illustration3 ,fig4 #ce4 ,elevation of ,argyll ,single ,sleeve ,motor from ,the ,motor1 ,london4 ,in diagram #aj1 the inlet is nearly closed1 the sleeve port passing away from the cylinder ports to the water jacketed portion of the cylinder above4 ,illustration3 ,fig4 #cf4 ,valve ,motion ,diagram of ,argyll ,motor ,showing the ,valve ,positions at ,different ,parts of the ,working ,stroke4 ,this series of diagrams shows the operation of the duplicated port of the sleeve 7which port is the one shown dotted7 in relation with one of the inlet ports and one of the exhaust ports in the cylinder wall1 the latter ports being marked respectively ,i and ,e4 ,the elliptical movement referred to in the text can be traced by following the different positions of the dotted port in the sleeve4 ,in the top row of diagrams it is seen to come downwards and also to move over to the left1 whilst in the lower set it rises--bearing still to the left--until1 after ,fig4 #aj1 it goes higher up for the compression and explosion strokes1 during which it bears over to the right and comes down again ready to commence once more the cycle1 as in ,fig4 #a4 ,the other ports in the cylinder wall are the same as those shown1 and the other ports in the sleeve are akin in shape to half of the dotted port1 but they are without the little tongue cut in the base of this double purpose port4 ,this little tongue in the duplicated port is designed to give as much lead to the exhaust opening as possible1 without interfering with the correct timing of the inlet port4 ,the way in which it just misses interfering with the closing of the inlet port is seen in ,fig4 #aj4 ,we are indebted to 8,the ,motor0 for these cuts4 7#ec7 ,sturtevant ,aeronautical ,motor4 ,the cylinders of the ,sturtevant aeronautical motor are of the 8,l0 type and are cast separately with the cylinder barrel and water jacket in one integral casting4 ,a special iron is used for these castings that has an ultimate tensile strength of #dj1jjj pounds per square inch4 ,the valves which are easily accessible through valve covers1 are operated directly from the cam shaft without valve rockers4 ,a hollow cam shaft is used with integral cams to insure a maximum of strength with a minimum of weight1 and bearings are placed between each set of cams4 ,a bronze gear fitted on the cam shaft meshes with a gear on the crank shaft without intermediate idlers4 ,illustration3 ,fig4 #da4 ,six ,cylinder ,sturtevant ,aero ,motor4 ,like the cam shaft1 the crank is bored out from end to end with a propeller flange applied on a taper at one end of the shaft4 ,a bearing is provided between each throw with an additional thrust bearing at the forward end of the shaft which may be arranged to take either the thrust or the pull of the propeller4 ,lubricating oil is applied to all the bearings under a pressure of twenty pounds per square inch1 this pressure being maintained by a gear pump attached directly to the end of the cam shaft4 ,the oil is transferred from the pump to the bearings through passages cast in the base1 no piping being used4 ,oil enters the hollow crank shaft at the main bearings and is conducted through the arms to the connecting rod bearings4 ,the oil flying from the crank shaft falls into the oil sump at the bottom of the case where it is cooled before being used again4 ,a second gear pump in tandem with the first takes the oil from the sump and forces it through a filter into the tank4 ,illustration3 ,fig4 #dc4 ,crank ,shaft of ,sturtevant ,motor4 ,illustration3 ,fig4 #db4 ,crank ,case of ,sturtevant ,motor4 ,this system enables the use of a more efficient filter than with the suction type and eliminates any danger of its becoming clogged and stopping the oil supply1 since1 in the event of such an occurrence the pump would furnish sufficient pressure to burst the filter4 ,however1 the filter is particularly accessible and may be instantly removed for cleaning without disturbing the oil4 ,the tank regularly fitted to the motor holds sufficient oil for three hours' use4 ,if the engine is required to operate for a longer time without opportunity for replenishing the oil supply1 a larger tank can be used4 ,as no oil is allowed to accumulate in the base with this system of lubrication1 the motor can be operated continuously at an angle4 ,water circulation is maintained by a centrifugal pump of large capacity1 the impeller of which is mounted directly on an extension of the crank shaft1 eliminating the usual bearings and its grease cup4 ,the ignition is provided by a high-tension ,mea magneto1 its special construction permitting the motor to be started under a retarded spark avoiding the danger of back kick from the propeller4 ,the cylinder and all exposed parts are rendered absolutely weather-proof by means of a heavy coat of nickel plating4 7#ed7 ,the ,rotating ,cylinder ,motor4 ,while it is the common belief that the rotary cylinder gasoline motor is of ,french origin it may safely be said that this type of motor was in actual use in ,america for several years before it even reached the experimental stage in ,europe4 ,the ,adams-,farwell ,company of ,dubuque1 ,iowa1 were driving automobiles successfully with a rotary cylinder motor before ,orville ,wright flew at ,fort ,meyer1 ,va4 ,although the original ,farwell motor more than proved its right to existence by faithful service under the most exacting conditions1 the motor never received the consideration that it deserved1 probably because of its great divergence from what is known as 8accepted practice40 ,in ,europe no such prejudice existed1 and consequently the type made rapid strides1 although1 to the writer's belief1 the ,european model is inferior in many ways to the original ,american type4 ,the fact that this type of motor holds practically all of the world's aviation records speaks for its practicability in spite of its unusual construction4 ,with the rotary motor1 the cylinders and crank case revolve about a stationary crank shaft1 the latter part not only serving as a point of reaction of the cylinders but as a support and intake pipe as well4 ,since the crank throw remains stationary1 the cylinders and pistons revolve about two different centers1 the cylinders revolving about the crank case and the pistons and connecting rods about the crank pin4 ,since the pistons1 cylinders1 and connecting rods must necessarily revolve together1 as one unit1 there is absolutely no reciprocating motion in regard to the crank shaft except for a very slight movement due to the difference in angularity of the connecting rods4 ,the motion of all the parts is strictly rotary in every sense1 except for the relation of the pistons to the cylinders1 and the motion is as continuous as in a turbine4 ,this insures freedom from vibration4 ,as the cylinders and crank case have considerable inertia there is no need of the added weight of a fly-wheel4 ,the movement of the piston in the cylinder bore is brought about by the difference in the centers about which these parts revolve4 ,this gives cylinder displacement without the reversal of stresses or shock or jar4 ,because of the revolving cylinders1 the mixture is supplied to the crank case through a hollow shaft1 the gas being drawn into the cylinder on the suction stroke through an inlet valve placed in the head of the piston4 ,as a rule1 the exhaust is direct to the air through the exhaust valves and without manifolds or mufflers4 ,the motion of the cylinders through the air multiplies the efficiency of the radiating ,fins4 7#ee7 ,the ,gyro ,rotary ,motor4 ,in the ,gyro motor1 made by the ,gyro ,motor ,company of ,washington1 ,d4 ,c41 are embodied all of the principles of the typical revolving motor1 but with extensive improvements in the design and in the details4 ,it weighs #c pounds per horse-power1 complete4 ,this light weight is due to the design of the motor and to the use of alloy steels1 and is attained without sacrificing strength or durability4 ,each cylinder is machined out of a heavy #c per cent tubular nickle steel forging that weighs nearly #dj pounds4 ,after the metal is removed and the cylinder worked down to size1 the shell weighs but #f pounds4 ,the radiating ribs on the outside of the cylinder are machined out of the solid bar1 and are arranged in helicoid or screw-like formation around the cylinder barrel4 ,this adds to the strength of the cylinder and also aids in the circulation of the air4 ,the comparative thickness of the cylinder wall may be seen from ,fig4 #dd4 ,the stiffening effect of the radiating ribs will also be noted4 ,the crank case to which the cylinders are fastened is of vanadium steel1 and is divided into two parts4 ,in addition to supporting the cylinders1 the crank case also serves as a mixing chamber for the gasoline and air4 ,by removing the bolts seen between each cylinder1 the entire working mechanism can be laid bare for inspection4 ,the exterior of the case carries the exhaust valve mechanism and the ignition distributer4 ,the crank shaft is a nickel steel forging with an elastic limit of #aaj1jjj pounds4 ,it is bored hollow throughout its length and serves as an intake manifold by conveying the mixture from the carbureter1 attached to its outer end1 to the crank case4 ,illustration3 ,fig4 #de4 ,section ,through ,rotary ,gyro ,motor4 ,the intake valves in the heads of the piston are mechanically operated by a specially patented movement which consists of two parts1 a counter-balancing member1 and an operating member4 ,the counter balance balances the valve against the disturbing influence of the centrifugal force1 while the operating member1 which is fastened to the connecting rod1 controls the opening or closing of the valve by the angular position of the connecting rod4 ,this valve action insures a full opening of the valve and a full charge during practically all of the suction stroke4 ,there are two separate paths provided for the exhaust gases1 one being through the auxiliary exhaust ports at the end of the stroke1 and the other path through the exhaust valve located in the cylinder head4 ,the auxiliary ports may be seen in the cross-section directly below the piston head in cylinders #d and #e4 ,the auxiliary ports are uncovered by the piston at the inner end of the working stroke1 and it is at this point that the greater percentage of the exhaust leaves the cylinder4 ,these ports or holes are formed on a projecting annular ring in which enough material is provided to make up for the strength lost by boring the ports4 ,as these ports are1 in the majority of cases1 bored at an acute angle with the center line of the cylinder1 it is impossible for the cylinder oil to escape4 ,all exhaust valves are operated by levers and push rods connected to a cam mechanism on the outside of the crank case4 ,a single cam ring operates all of the valves except where a step-by-step compression is desired4 ,the exhaust mechanism is provided with a simple device by which the closing of the exhaust valve may be delayed through any portion of the exhaust stroke1 thus reducing the compression and adding to the facility of cranking4 ,the motor is started with the compression entirely released in which condition it can be spun about its shaft with ease4 ,after giving the motor its initial spin1 the compression and spark are thrown in and the engine begins its normal operation4 ,the compression release lever may be used for starting or slow running and in cutting off the power regardless of the ignition advance or retard4 ,one connecting rod1 called the 8master0 rod1 is an integral part of the spider that contains the ball bearings of the crank pin1 thus controlling the angular relation between the connecting rods and cylinders4 ,the remaining six rods are1 of course1 articulated on the spider by pins so that the rods may move in regard to the spider when in different parts of the stroke4 ,the shell of the pistons is of a fine grade of iron1 very thin and elastic1 so that it may conform readily to the outline of the cylinder bore4 ,the head of the piston consists principally of the intake valve cage1 the cage carrying the piston pin as well as the valve4 ,oil is supplied by a positive pump that measures the lubricant in exact proportion to the load on the engine4 ,both the oil and the gasoline mixture enter the crank case through the hollow crank shaft and mingle in the form of a vapor4 ,this oil mist reaches every moving part and results in perfect lubrication4 ,the pistons are provided with oil shields which carry the oil directly to the cylinder walls and prevent the loss of oil through the exhaust valve4 ,ignition is performed by a high tension magneto through a distributer which directs the current to the proper cylinder4 ,as in all rotary engines1 the ,gyro has an uneven number of cylinders 7#c1 #e1 and #g7 in order that the cylinders receive firing impulses through equal angles of rotation4 ,an even distribution of firing is impossible with an even number of cylinders1 as two adjacent cylinders out of six alternately fire together and then #ahj apart4 ,this produces a very jerky turning movement1 and is productive of much vibration4 ,in the seven cylinder motor the magneto is driven by gears having a ratio of #d to #g1 and the high tension current is distributed to the cylinders by #g brushes1 the leads from the brushes being taken direct to the spark plugs4 7#ef7 ,gnome ,rotary ,motor4 ,the ,gnome was the first rotary aviation motor built in ,europe and is still one of the most capable flight motors abroad as its many victories and records prove4 ,it is built in four sizes1 #ej1 #gj1 #ajj1 and #adj horse-power1 the #ej and #gj horse-power motors having #g cylinders1 and the #ajj and #adj horsepower1 having #ad cylinders1 which consist of two rows of #g cylinders per row4 ,the cylinders of all sizes rotate about a stationary crank shaft while the pistons rotate in a circle1 the center of which is the crank pin4 ,vibration is practically eliminated at high speed as the pistons do not reciprocate in the ordinary sense of the word1 but simply revolve in a circle1 the reciprocating relation between the cylinders and pistons being obtained by the difference in the centers of the two revolving systems4 ,the cooling effect of the radiating ribs is greatly increased by the air circulation set up by the rotation of the cylinders4 ,this method of cooling introduces a great loss of power due to the blower action of the cooling ribs1 this loss often amounting to #ae per cent of the output of the engine4 ,illustration3 ,fig4 #ej4 ,cross-,section ,through the ,seven ,cylinder ,rotary ,gnome ,motor1 ,showing the ,crank ,shaft ,arrangement and ,valves4 ,the crank shaft is stationary and acts as a support for the engine1 one end being fastened into a supporting spider which forms a part of the aeroplane frame4 ,the crank shaft is hollow and also serves to conduct the mixture from the carburetor fastened at its outer end to the crank-case of the motor4 ,only one crank throw is provided on the seven cylinder engine as the cylinders are all arranged in one plane which passes through the center of the crank throw4 ,in the fourteen cylinder engine where the cylinders are in two rows1 there are two crank throws1 one for each row of cylinders4 ,the seven cylinders are arranged radially1 as will be seen in ,fig4 #ej1 each being spaced at an equal distance from the crank shaft and at equal angles with one another1 the arrangement in general being similar to that of the 8,gyro0 motor shown in the preceding section4 ,all cylinders are turned out of solid forged steel bars1 the cylinder walls being only #a4b millimeters thick after the machining operation4 ,this results in the strongest and lightest cylinder possible to build1 as all superfluous material is removed and the chances of defects in the material are reduced to a minimum as the character of the metal is revealed by the extended machining operations4 ,illustration3 ,fig4 #ea4 ,firing ,diagram of ,seven ,cylinder ,rotary ,motor4 ,on ,starting at ,cylinder ,no4 #a1 and ,following the ,zig-,zag ,line in the ,direction of the ,arrows1 it ,will be ,seen that ,ignition ,occurs at ,every other ,cylinder at even ,intervals ,through ,two ,revolutions1 ,ending at ,cylinder ,no4 #a4 ,as the motor operates on the four stroke cycle system1 an odd number of cylinders is chosen in order that the firing may be carried out through equal angles in the revolution to obtain a uniform turning movement4 ,since a four stroke motor must complete two revolutions before all of the cylinders have fired1 or completed their routine of events1 it is evident that the number of cylinders must be odd in order to bring the last cylinder into firing position in the last revolution4 ,when seven cylinders are used1 the cylinder are fired alternately as they pass a given fixed point1 that is1 one cylinder is fired1 the next skipped1 the third fired1 and the fourth skipped1 and so on around the circle1 so that the firing order in terms of the cylinder numbers is #a1 #c1 #e1 #g1 #b1 #d1 #f4 ,the cylinders fired in the first revolution in order are #a1 #c1 #e1 #g1 and in the second revolution1 #g1 #b1 #d1 #f1 the cylinder #g being common to both revolutions4 ,the cylinders are numbered according to their position on the engine1 and ,,not according to the firing sequence4 ,see ,fig4 #ea4 ,illustration3 ,fig4 #eb4 ,firing ,diagram of ,six ,cylinder ,rotary ,motor4 ,on ,following the ,zig-,zag ,line it ,will be ,seen that ,all of the ,cylinders ,are ,not ,fired at ,equal ,intervals4 ,in ,some ,cases ,two ,adjacent ,cylinders ,fire in ,sequence1 and in ,others ,two or ,three ,spaces are ,jumped4 ,with a six cylinder engine it is possible to fire the cylinders in two ways1 the first being in direct rotation2 #a1 #b1 #c1 #d1 #e1 #f thus obtaining1 six impulses in the first revolution1 and none in the second4 ,the second method is to fire them alternately1 #a1 #c1 #e1 #b1 #d1 #f1 in which case the engine will have turned through equal angles between impulses #a and #c1 and #c and #e1 but through a greater angle between #e and #b1 and even again between #b and #d1 and #d and #f4 ,see ,fig4 #eb4 ,mixture is drawn into the cylinder by the suction of the piston through an inlet valve in the piston head1 in practically the same way as in the 8,gyro0 motor1 but unlike the latter motor1 the valve is lifted by the suction 7automatic valve7 and not by the mechanical actuation of the connecting rod4 ,the inlet valve is balanced against the effects of centrifugal force by a small counter-weight in the piston head1 and the valve is held normally on its seat by a flat spring acting on the valve stem4 ,the gases are brought into the crank case from the carburetor through the hollow crank-shaft as described elsewhere4 ,see ,fig4 #ec4 ,illustration3 ,fig4 #ec4 ,longitudinal ,section ,through ,gnome ,rotary ,motor4 ,all exhaust valves are located in the cylinder head and are actuated by long push rods that are moved by individual cams in an extension of the crank case4 ,the exhaust valves are counter-balanced against centrifugal force and are retained on their seats by a flat spring4 ,the counter weights do not entirely overcome the effects of the centrifugal force but allow a slight excess to exist which will permit the engine to run with a broken spring4 ,all of the exhaust gases escape directly to the atmosphere without piping or mufflers4 ,owing to the fact that the advancing or leading face of the cylinder is cooler than the trailing face1 the cylinder bore is thrown out of line by the difference in expansion between the two sides4 ,because of this distortion of the bore1 a special form of piston ring is used1 which1 by its flexibility1 adapts itself to variations in the bore4 ,these rings are of brass and are shaped like the pump leathers of a water pump so that the pressure of the explosion acting on the inside of the ring tends to force the thin shell against the cylinder4 ,in spite of this precaution1 the compression pressure is very low at the best1 in the most of cases not over #de pounds per square inch4 ,the exhaust valve screws into the end of the cylinder and may be removed1 complete with its seat1 for the frequent regrinding necessary to efficient operation4 ,after the cylinders are ground with the greatest care and accuracy1 the finishing is carried still further by wearing-in the cylinder with an actual piston carrying an 8obturateur0 or piston ring4 ,illustration3 ,fig4 #ed4 ,gnome ,motor on ,testing ,stand4 ,from ,scientific ,american4 ,the bushing into which the spark plug screws is not integral with the cylinder as in a cast construction1 but is welded into the side of the cylinder head by means of the autogenous process4 ,it is also evident that this construction enables the inlet valves to be easily removed1 since these screw into the piston head4 ,both inlet and exhaust valves in the ,gnome engine are removed with the greatest ease1 special socket wrenches being supplied for the purpose4 ,the castor oil1 which is used as a lubricant1 and the gasoline1 are fed by a positive acting piston pump to the hollow crank shaft4 ,the lubricant and fuel then pass through the automatic inlet valve in the head of the cylinder4 ,illustration3 ,fig4 #ee4 ,gnome ,motor ,running ,on ,test ,stand4 ,from ,scientific ,american4 ,the spark produced by the high tension magneto is led to the proper cylinder through a brush that presses on a revolving ring of insulating material in which is imbedded #g metallic segments1 one of the segments being connected to a corresponding cylinder4 ,as the distributor ring revolves the segments come into contact with the brush in the proper order4 ,the magneto is stationary and is supported by a bracket in an inverted position4 ,a pinion on the magneto shaft meshes with a large gear mounted on the revolving crank case so that the armature of the magneto always bears a positive relation to the piston position4 ,as the engine requires seven sparks for every two revolutions1 or #c sparks per revolution it is evident that the magneto must turn #a4ge times as fast as the engine1 if the magneto is of the ordinary type that generates two sparks per revolution4 ,in other words the magneto speed is to the engine speed as #g is to #d4 ,illustration3 ,the 8,indian0 ,rotary ,aero ,motor4 ,the arrangement of connecting rods is interesting1 the big end of one rod being formed into a cage for the reception of the crank-pin ball race4 ,the outer circumference of the cage carries the pins to which the other six connecting rods are fastened4 ,it is necessary that one rod be integral with the cage to prevent its rotation in regard to the cylinders4 ,annular ball bearings are used on both the main bearings1 for the thrust bearing to take the thrust of the propeller1 and on the large end of the master connecting rod4 ,the large ends of the auxiliary connecting rods and the small ends of all the rods have plain bearings4 ,,chapter ,,vi ,,two ,,stroke ,,cycle ,,engines 7#cj7 ,the ,junker ,two ,stroke ,cycle ,engine4 ,the ,junker two stroke cycle engine stands unique among the large stationary units not only in the principle of its working cycle but in its construction as well1 and while it may be considered freakish when compared to standard practice it has proved its value in many ,european installations4 ,the combustion occurs in the center of an open ended cylinder between two pistons that are forced in opposite directions by the expansion of the gas1 and as there is a single acting piston in each end of the cylinder at the end of the stroke1 there is no need of stuffing boxes1 cylinder heads or valves4 ,it is apparent that by moving the pistons in opposite directions1 the effective piston velocity is twice that of the actual velocity of either of the pistons1 and that it is therefore possible to gain a high heat efficiency at high piston velocities with a low rate of rotation4 ,the double pistons increase the scavenging effects1 reduce the losses to the cooling water and increase the efficiency at light loads4 ,a marked reduction in weight over the four stroke cycle engine is made possible because of the absence of valves and valve gear4 ,this engine is of the injected fuel type that is the fuel is sprayed into the combustion chamber after the completion of the compression stroke in a manner similar to the ,diesel engine4 ,by prolonging the injection of fuel after the piston has started on the outward working stroke it is possible to maintain the maximum pressure due to the combustion for a considerable period4 ,this gives an indicator card that is very similar to that of a steam engine as the flat top of the ,junker's card due to the continued combustion and pressure corresponds to the admission line of the steam engine4 ,as ignition is caused by the high temperature of the compression1 almost any low grade oil may be used even down asphaltum oils and coal tar4 ,illustration3 ,fig4 #h4 ,the ,junker ,two ,stroke ,cycle ,engine4 ,in ,fig4 #h five piston positions corresponding to five events are shown by the diagrams a1 b1 c1 d1 e4 ,from the diagrams one may also get an idea of the arrangement of the principal parts of the engine and their relation to one another4 ,p and ,p#b are the two pistons1 ,c the open ended cylinder1 ,g the connecting rod of the inner piston ,p1 ,h-,h the two connecting rods of the piston ,p#b1 ,i-,i the side rods of the piston ,p#b1 and ,v is the three throw crank shaft which is acted on by the three connecting rods ,h-,h-,g4 ,the piston ,p#b is connected to the side rods through the yoke ,y4 ,it will be noted that the crank throws controlling the piston ,p#b are #ahj from the crank connected to piston ,p1 which causes the pistons to move in opposite directions4 ,with the pistons together at the inner dead center1 the space between them is filled with highly compressed air from the previous combustion stroke4 ,at this point the fuel is injected into the highly heated air1 and the expansion of the charge begins1 the combustion proceeding under constant pressure during the first part of the stroke1 or during that part of the stroke in which the fuel is admitted to the cylinder4 ,when the supply of fuel is cut off the working stroke continues by the increase of volume1 or expansion of the gas1 the gases being reduced to nearly atmospheric pressure at the end of the stroke with the pistons at the position shown by diagram 7b74 ,at this point the piston ,p is just opening the edge of the exhaust port ,m1 allowing the products of combustion to escape to the atmosphere through the annular exhaust passage that surrounds the port ,m4 ,as the pistons continue to move outwards the gases continue to issue from the exhaust port at practically atmospheric pressure until the position shown by diagram 7c7 is reached by piston ,p#b4 ,at this point ,p#b is just opening the inlet port ,n allowing fresh air to enter the cylinder for the purpose of scavenging the engine4 ,the passage of the air through the intake port ,n and out through the exhaust port ,m continues until the pistons pass the outer dead center1 shown by diagram 7d71 and begin to come back on the return stroke4 ,in diagram 7e7 the pistons have traveled far enough to close both ports1 and as the space between them is filled with pure air from that furnished by the port ,n1 the pistons will continue to move toward one another on the compression stroke4 ,when they have reached the end of their travel as shown by diagram ,a1 the fuel is injected into the cylinder and combustion occurs due to the temperature of the high compression temperature4 ,this is the complete cycle of events made in two strokes1 and it will be noted that the cycle has been accomplished without the use of valves4 ,the compressed air for scavenging the cylinder is provided by air pumps that are driven from the connecting rods by a link motion4 ,one low pressure pump for the scavenging and one high pressure pump for spraying the fuel into the cylinder against compression are provided4 ,as the inside of the piston is always exposed to the atmosphere through the open ends of the cylinder and is never exposed to the heat of combustion1 perfect cooling is secured1 and as a matter of course1 perfect lubrication4 ,in the two cylinder engine in which four pistons are used1 the cylinders are arranged in tandem with the two adjacent pistons1 and the two outer pistons connected respectively4 ,in fact the second cylinder pistons are duplicates of those just shown and are connected to the linkage in such a manner as to have the corresponding pistons in one cylinder act with the corresponding pistons in the second4 7#cd7 ,koerting ,two ,stroke ,cycle ,engine4 ,one of the most prominent of the two stroke cycle scavenging engines built for heavy stationary service is the ,koerting engine4 ,because of its peculiar scavenging arrangement1 and as it is of the double acting type1 it will serve to illustrate the cycle of that class of engine equipped with independent air pumps4 ,several of these engines are in use in ,europe that have an output of over #d1jjj horse-power1 the general arrangement of which is the same as shown in the accompanying diagram ,fig4 ,f-#aa4 ,illustration3 ,fig4 ,f-#aa4 ,koerting ,two ,stroke ,cycle ,engine with ,scavenging and ,charging ,cylinders4 ,since the engine is double acting1 two similar combustion chambers are provided at each end of the piston as shown by ,c and ,c#a1 and as each of the chambers gives one impulse per revolution because of the two stroke cycle1 the single cylinder shown in the figure delivers two impulses per revolution to the crank-shaft4 ,in order to have one exhaust port serve for both combustion chambers1 the annular port ,e is placed in the center of the cylinder so that it is alternately opened to ,c and then ,c#a as the piston travels to and fro1 the port being covered by the piston at intermediate points in its travel4 ,as the piston must cover the port for a considerable portion of the stroke1 it is made very long1 nearly as long as the stroke4 ,the piston rod ,r that connects the piston with the crank passes through the cylinder head of chamber ,c#a1 surrounded by a gas tight packing that prevents the leakage of the charge from ,c#a4 ,unlike the ordinary type of two stroke cycle engine1 the two combustion chambers are provided with mechanically operated inlet valves1 ,v-,v#a-,v#b-,v#c that are opened at definite points in the stroke by the lay shaft ,x which is driven from the crank shaft4 ,as the exhaust port ,e serves all of the functions of an exhaust valve1 there are no valves provided at this point4 ,exhaust pipes connected to ,e carry the burnt gases to the atmosphere4 ,two auxiliary air pumps of the double acting type are provided1 shown at ,a and ,a#b1 one pumping gas and the other air4 ,they are driven from the crank-shaft through the connecting rod ,y1 and are proportioned so that together they force a mixture of the correct proportion for complete combustion into the working cylinder at a pressure of about ten pounds per square inch4 ,air and gas are compressed on one side of each pump piston in the spaces ,b and ,b#b1 and the air and gas are drawn in on the other side as at ,h and ,h#b4 ,the connections from the compressor cylinders to the working cylinder are arranged so that the two crank ends of the compressor cylinders discharge into the crank end of the working cylinder1 and the front ends of the compressors discharge into the front end of the working cylinder1 the exact moment of discharge being controlled by the inlet valves ,v-,v#a-,v#b-,v#c4 ,the pumps are arranged so that only pure air is admitted at first in order to force the products of combustion through the exhaust port so that they will not contaminate the following mixture of air and gas4 ,the inlet valve opens immediately after the piston of the working cylinder uncovers the port ,e and reduces the pressure of the burnt gases to that of the atmosphere4 ,by the action of the admission control1 the scavenging air first admitted1 is prevented from mixing with the residual gas from the previous explosion1 and in the same way the device prevents the loss of fuel through the exhaust ports1 thus overcoming the principal objections of the simple two stroke types described earlier in this chapter4 ,the compressor cylinders provide only enough air and mixture for one stroke and no reservoir is provided for a surplus of air or mixture4 ,as the piston moves forward1 on the compression stroke and covers the exhaust port1 the inlet valves also close1 and the compressor pistons arrive at the end of their stroke so that no more air or mixture is delivered to the inlet valves4 ,at the end of the compression stroke ignition occurs and the expansion or working stroke begins4 ,the piston again moves to the right on the working stroke until the front edge uncovers the port ,e where the exhaust gases escape to the atmosphere4 ,the valve gear on the gas compressing cylinder is arranged so that no gas is delivered to the inlet valves of the working cylinder until the air cylinder has provided sufficient air to insure perfect scavenging of the products of combustion1 this preventing the fuel from becoming contaminated with the burnt gas4 ,speed regulation for varying loads is effected by shifting the valve gear of the gas pump so that the gas is delivered at an earlier or later period in the stroke of the working piston1 thus causing a variation in the quantity of gas delivered to the working cylinder4 ,this is controlled by the governor directly on the valve gear of the pump or upon a by-pass in the pump cylinder or both4 ,the by-pass1 when open returns all of the gas in the passage leading to the inlet valve1 that is beyond a certain pressure to the cylinder1 so that the gas is delivered to the cylinder at a constant pressure1 and therefore in proportion to the load and point of cut off4 ,this method of governing produces a mixture that varies in richness with the different loads that are carried by the engine1 but as the air enters the cylinder first and is prevented from mixing to any extent with the gas by the shape of the cylinder heads1 the igniting value of the mixture is not disturbed particularly as the rich gas remains in the cylinder heads and in contact with the igniters4 ,like all large engines1 the ,koerting is started by compressed air taken from a reservoir4 ,a special starting valve is provided for each end of the cylinder which is operated from the cam shaft by means of an eccentric4 ,the air valves may be thrown in or out of gear by a clutch4 7#eg7 ,two ,stroke ,cycle ,rail ,motor ,cars4 ,a unique application of the two stroke cycle motor will be seen in ,fig4 #ef which shows a ,fairbanks-,morse two stroke cycle motor direct connected to the driving wheel of a railway motor car4 ,the three cylinders are mounted between the driving wheel with the ends of the axle terminating in the crank cases of the motors4 ,access to the bearings is had through a cover on the crank-case4 ,the simplicity of this motor and its freedom from valves1 cams1 springs1 gears1 and other trouble causing parts makes it particularly adapted for the service that it performs in the hands of unskilled track laborers4 ,as there is no water to freeze or leak1 and as the lubricant is mixed with gasoline1 the car needs very little more attention than the old type hand car4 ,the car is started by opening the gasoline supply cock1 closing the ignition switch1 and pushing the car along the track until the first explosion occurs4 ,the speed is controlled in the usual manner by means of the spark advance and throttle4 ,as the motor is of the two stroke cycle type1 it may be reversed by simply changing the position of the timer without the use of the gears4 ,the speed is the same in either direction4 ,by the use of three cylinders1 three impulses are obtained per revolution which gives a distribution of power equal to that of the ordinary six cylinder1 four stroke cycle automobile motor4 ,illustration3 ,fig4 #ef4 ,two ,stroke ,cycle ,fairbanks ,motor for ,driving ,railway ,section ,cars4 ,for larger cars built for carrying large gangs of men1 a three cylinder motor is used which drives through a clutch and gears1 similar to that used on automobiles4 ,it is located near the center of the axle and is supported on a frame that is independent of the car proper4 ,this motor unit is easily removed from the car for inspection with all of the parts intact4 ,a universal coupling is provided on the motor shaft to prevent strains due to changes in the alignment from being thrown into the motor4 ,the motor of this car is started with a crank1 and may be left standing with the motor running4 ,as with the two cylinder car1 the engine is reversible1 and is lubricated by mixing the lubricating oil with the gasoline4 7#eh7 ,rotating ,cylinder ,two ,stroke ,cycle ,motor4 ,an unusual type of two stroke cycle engine is that designed by ,m4 ,farcot for aeronautic work4 ,it is of the rotating cylinder type in which the cylinders rotate about a stationary crankshaft1 and unlike all previous two stroke motors1 whether of the revolving or stationary cylinder type1 no initial compression is performed either in the crank-case or otherwise4 ,illustration3 ,fig4 #fc4 ,farcot ,rotary ,two ,stroke ,motor4 ,undoubtedly the two-cycle rotating multi-cylinder engine has a future when some of the particularly difficult designing problems involved in its production have been successfully tackled4 ,crank case compression has had its devotees1 but so far it has entailed the use of a low compression1 owing largely to the difficulties involved in lubricating the bearings and maintaining gas-tight joints1 besides other defects4 ,some of these barriers appear to have been surmounted in this design4 ,fig4 #fc of the accompanying drawings is a sectional side elevation of the engine1 which1 it will be seen1 is similar in general disposition to the usual arrangement of the rotating cylinder type4 ,in this particular case1 however1 the short end ,a of the stationary crankshaft is reduced in diameter at ,b1 and on this part are mounted ball bearings ,c carrying the circular casing of a rotating centrifugal blower ,d4 ,to the inner end of the hub of this blower is attached a gear wheel ,e1 the teeth of which mesh with small intermediate pinions carried on a spider ,f attached to the crankshaft4 ,these pinions are in turn driven by an internally toothed ring ,g attached to the hub of the crank case ,h4 ,thus the blower ,d is driven in the opposite direction to the crank-case and at a higher speed4 ,in the interior of the blower casing radial blades ,k are provided4 ,illustration3 ,fig4 #fd4 ,farcot ,fan ,plates4 ,a hollow annular casing ,l is bolted to the cylinders1 and communicates with their interiors by means of inlet ports ,m covered and uncovered by the pistons4 ,the blower casing ,d has on either side circumferentially flanged rings ,n1 which are a running fit in circular register slots provided in the annular casing ,l and its cover plate ,p1 in order to provide a gas-tight joint between the opposite revolving casings ,d and ,l4 ,fan blades ,q are also provided in the casing ,l to accelerate still further the incoming gas4 ,the arrangement of the two sets of blades is made clear in the sectional sketch 7,fig4 #fd74 ,it will be realized that by means of this compound blower device a considerable pressure can be attained4 ,the crankshaft is drilled to provide a feed for the gasoline1 which is atomized by a device ,r in the large central opening of the blower casing ,d by means of pressure fed from the annular casing ,l through suitable leads ,s4 ,as each piston nears the bottom of its stroke1 exhaust ports ,t1 provided with expansion cones for the purpose of increasing the velocity of the exhaust gases1 are opened4 ,the inlet port ,m is then uncovered1 and the compressed charge rushes into the combustion chamber4 ,the general design of the engine is made plain by ,fig4 #fc1 but there is one other point to which reference should be made1 and that is the provision of rings ,v1 one on either side of the cylinders1 to enhance the strength of the construction4 ,although the difficulty of compression appears to have been cleverly tackled in this invention1 the possibility of the compressed mixture in the inlet casing and blower becoming ignited at the moment of admission by a residue of exhaust gas in the combustion chamber still exists4 ,however1 the effect of such a backfire should not prove quite so serious as in some designs4 ,apart from other considerations1 owing to the large area of the blower intake1 such an occurrence should merely have a more or less elastic braking effect4 7#fj7 ,gnome ,radial ,two ,stroke ,motor4 ,the builders of the famous ,gnome four stroke cycle rotary motor1 ,sequin ,frres1 have recently developed a radial two stroke cycle motor that bids fair to supplant their original type4 ,referring to the diagrammatic cross-sections which show only a single cylinder unit1 a very long tubular piston will be seen that is divided into two independent chambers1 ,a and ,b4 ,both chambers are placed in communication with the outside space1 ,c and ,d4 ,the upper end of the piston is continued above the top division head of the chamber ,a1 and the extension is provided with the slot ,f4 ,near the center of the piston1 the walls of the piston are run out into a flat circular plate or trunk piston ,e1 which is the actual piston head that receives the force of the explosion4 ,the piston ,e reciprocates in the large cylinder ,h1 which is reduced at its upper end to the diameter of the main piston barrel1 for which it affords a sliding support1 or guide1 and also serves to aid the exhaust port closure4 ,the lower end of the cylinder ,h is enlarged in diameter as shown by ,k so that a clear annular space is left between the cylinder walls and the piston head ,e1 when the latter is at the bottom of the stroke4 ,the cylinder diameter is then reduced to the diameter of the main piston barrel4 ,the motor operates as follows3 ,suppose the piston to be ascending 7,fig4 #a71 compressing the mixture above the piston head in the cylinder ,e1 and at the same time the volume of the space ,m1 below ,e1 is being increased until the piston reaches the position shown in ,fig4 #b4 ,illustration3 ,fig4 #fe4 ,gnome ,rotary ,two ,stroke ,motor ,diagram4 ,diagrams #a and #b4 ,referring to ,fig4 #a2 the interior chamber ,a of the piston is in direct communication through the holes ,c with the space ,m1 consequently as the piston goes up1 a partial vacuum will be formed in these two chambers4 ,when the piston reaches the top of its stroke as shown in ,fig4 #b1 the holes ,d in the lower end ,b of the piston are uncovered as they rise into the increased diameter of the cylinder1 and therefore the mixture is sucked in from the crank case until the chambers ,a and ,m are filled to atmospheric pressure4 ,the spark now occurs at the plug ,s1 and the explosion takes place1 driving the piston downwards as shown by ,fig4 #c1 just before the exhaust takes place4 ,the volume of the chamber ,m has now been decreased with the result that the mixture will have been compressed into the chamber ,a4 ,in ,fig4 #d1 the piston has now reached the bottom of the stroke1 and the ports ,f have opened as the slots carry below the upper end of the cylinder where the bore is increased4 ,at the same time1 as the piston plate ,e passes the bottom of the cylinder ,h into the enlarged diameter ,k1 the compressed mixture in ,a and ,m rushes through the annular space opened around ,e into the combustion chamber and drives out the residual burned gases which still remain after the explosion4 ,on starting the second revolution the piston rises and the cycle repeats as shown by ,fig4 #a4 ,illustration3 ,gnome ,rotary1 ,diagrams #c and #d4 ,this engine may be built with any number of the cylinder units described1 preferably with an uneven number1 as in the case of the ,gnome radial four stroke cycle1 and with twice the number of impulses of the four stroke type a very uniform turning movement should be had4 ,illustration3 ,fig4 #fd-;b4 ,roberts ,two ,stroke ,aero ,motor ,using a ,rotating ,tubular ,valve that ,controls the ,mixture from the ,carburetor so that it ,enters ,only ,one ,crank ,case at a ,time4 ,this ,gives ,each ,cylinder an ,equal ,charge of ,gas4 ,illustration3 ,fig4 #fd-;c4 ,roberts ,distributor ,valve4 ,the ,ports ,are ,cut in the ,valve so that ,only ,one ,crank ,case is in ,communication with the ,carburetor at ,any ,one ,time4 ,the ,central ,hole ,connects with the ,carburetor4 ,since the valves are the parts that give the most trouble in the four-stroke cycle ,gnome1 this motor should be better adapted for aviation than the original type of ,gnome4 7#fb7 ,variable ,speed ,two ,stroke ,motor4 ,a variable speed two stroke cycle motor is described by ,c4 ,francis ,jenkins in the ,scientific ,american that seems to solve many of the problems encountered in designing a two stroke cycle motor for automobile purposes4 ,as is well known1 the present design of the crank-case compression type is wasteful of fuel1 and ignites irregularly at low speeds and light running1 and as nearly all automobiles are well throttled for a greater portion of the time it means that this type of motor is working under the greatest disadvantage4 ,illustration3 ,fig4 #ff4 ,jenkins ,two ,stroke ,cycle ,motor4 ,since the greater part of the trouble is due to the dilution of charge by the residual gases1 and as the spark plug of the motor is situated in the most diluted portion of the gas1 it would seem that a change of spark plug location1 or a change in the circulation of the fresh mixture in the cylinder would be a great aid in remedying the difficulty4 ,with the spark continually in contact with fresh undiluted mixture it would be possible to run it as low speeds as with the four stroke motor1 with a corresponding increase in the efficiency1 and opportunity to run with a constant advance of the point of ignition4 ,this is accomplished by any or all of the following conditions3 7#a47 ,by keeping good gas separate from bad4 7#b47 ,by placing the spark near the intake port4 7#c47 ,by leaving the plug in its present position and deflecting the fresh gas to meet it4 7#d47 ,by changing the location of the inlet port4 ,illustration3 ,fig4 #eh-;a4 ,two ,cylinder ,marine ,engine1 of the ,two ,stroke ,type4 ,built by ,fairbanks-,morse and ,company4 ,in the motor invented and described by ,mr4 ,jenkins1 the method given by 7#d7 is adopted as shown by ,fig4 #ff1 in which the spark plug is placed at the point of admission of the gas and in a confined passage4 ,the operation of the motor is as follows3 ,carbureted gas is drawn into crank-case from the carburetor 7not shown7 in the usual manner1 i4 e41 by the upward movement of the piston2 and by its downward movement is forced through the rectangular port in the wall of the piston into the combustion passage within the water-jacket when the port in the piston wall registers with the lower end of this combustion passage1 and drives ahead of it the bad gas remaining after the previous explosion4 ,if the throttle is wide open the combustion space above the piston will be completely filled1 and on the ignition of the charge the maximum pressure will be exerted on the piston4 ,if1 however1 the throttle is but slightly open1 the combustion passage only may be filled and none overflow into the combustion space above the piston4 ,this small charge will be just as efficient in proportion to its volume as was the large charge1 for it was compressed to practically the same extent and none was mixed with the bad gas of the previous explosion4 ,it will1 therefore1 be obvious that the spark-plug is always swept by the fresh charge1 be it large or small1 and the ignition will be just as certain in one case as in the other1 although the charge and consequent impulse may be only just sufficient to keep the engine turning over1 and without missing a single explosion4 ,illustration3 ,fig4 #fd-;d4 ,roberts ,cylinder ,showing ,cellular ,screen in the ,intake ,port4 ,this ,screen ,prevents ,crank ,case ,fires by ,chilling the ,cylinder ,flame ,before it ,enters the ,crank ,case4 ,in the motor built to test and demonstrate this design1 provision was made for a second spark-plug to be located in the top of the cylinder for speed work1 if this was found necessary4 ,no opportunity has yet been had for making track tests1 though without regret1 as this two-cycle motor will run idle without missing or 8stuttering10 which was the thing heretofore impossible4 ,,chapter ,,vii ,,oil ,,engines 7#ca7 ,diesel ,oil ,engine4 ,the ,diesel engine marks the greatest progress in the internal combustion field made in the last few years4 ,it marks a distinct advance in both thermal efficiency1 and in the character of the fuel that it has made a commercial possibility4 ,by the use of cheap fuel heretofore unavailable for any type of prime mover1 such as the asphaltum residual oils1 coal tar1 etc41 it has lowered the cost of power production to a point where it is unapproached by any type of heat engine4 ,besides its thermal efficiency1 the engine is free from the annoyances due to delicacy of the auxiliary appliances such as the carburetor1 and ignition system which are indispensable with the ordinary type of gasoline engine4 ,this engine belongs to that type of engine in which combustion takes place at constant pressure 7,brayton ,cycle71 that is the combustion pressure is maintained at a constant value for a considerable distance on the working stroke of the piston4 ,this method differs from the ,otto cycle in which the combustion proceeds at a constant volume1 or the type in which combustion is completed before the piston moves forward on the working stroke4 ,in the ,diesel cycle the first stroke of the piston draws pure air into the cylinder2 the piston then moves forward on the compression stroke1 compressing the air to #ejj or #fjj pounds per square inch and raising the temperature of the air to about #a1jjj degrees ,c1 the exact temperature and pressure depending on the character of the fuel used in the engine4 ,the high pressure is obtained by using a small clearance space in the end of the cylinder4 ,at the end of the compression stroke a spray of oil is injected into the cylinder which is instantly ignited by the high temperature of the compressed air4 ,the oil continues to burn as long as it is sprayed into the cylinder1 this period being from one-quarter to one-third of the working stroke4 ,after the oil is cut off1 the hot gas is expanded to the end of the stroke at which point the pressure is very considerably reduced due to the mechanical work performed4 ,it should be noted that the type of engine just described performs the complete cycle in four strokes1 the fourth stroke being the scavenging stroke as in the ordinary four stroke cycle engine4 ,while the four stroke cycle type of ,diesel engine is by far the most common type1 it is also built as a two stroke cycle that is similar to the two stroke cycle gas engine previously described except that pure air is received and compressed in the air compressor in place of the combustible mixture4 ,illustration3 ,fig4 #i4 ,cross ,section of ,four ,stroke ,cycle ,diesel ,engine4 ,the ,center ,valve is the ,fuel ,admission ,valve4 ,it will be noted1 that as there is no fuel in the cylinder during the compression stroke that there is no danger from preignition from an over heated charge1 nor is there trouble from decomposed fuels due to a gradually increasing temperature so often met with in oil engines that compress the entire mixture4 ,as the clearance space is exceptionally small there is a minimum of residual gas held in the cylinder after the explosion with the result that the fuel is completely consumed1 and that a full charge is taken into the cylinder4 ,the speed and output are regulated by controlling the point in the working stroke at which the oil spray is cut off1 and as this has no effect on the maximum pressure developed in the cylinder1 as in the case of the ordinary gas engine control1 the pressure charge under varying loads is not so severe4 ,because of the high compression1 and the continued combustion1 there is a very gradual increase of pressure4 ,since the amount of pure air admitted to the cylinder is the same at no load as at full load there is always sufficient air for the complete combustion of the fuel1 and as there is a constant compression pressure there is a constant ignition temperature and constant quantity of the working medium4 ,because of the high compression obtained by the ,diesel type1 it has an efficiency that is far beyond that of any other form of internal combustion motor4 ,illustration3 ,fuel ,nozzle of the ,koerting ,diesel ,engine ,showing ,operating ,cam and ,lever1 and ,compressed ,air ,connection4 ,since the fuel is introduced gradually into the combustion chamber the combustion pressure rises very slowly so that it is not an explosive engine in any sense of the word1 the combustion pressure rising steadily from the compression pressure to the maximum in proportion to the supply of fuel4 ,in the ordinary type of gas engine with a compression pressure of from #fj to #gj pounds per square inch the pressure rises abruptly to about three and one-half times the compression pressure1 with a correspondingly rapid drop in the pressure on the expansion stroke4 ,in the ,diesel engine the drop of pressure in expansion is much more gradual1 the indicator diagram expansion curve being nearly horizontal4 ,the uniform pressures thus obtained result in smooth action and even driving power1 obtained with no other type of engine4 ,illustration3 ,fuel ,pump of ,koerting ,diesel ,engine with ,operating ,cam4 ,as the fuels used vary from the lightest hydrocarbons to the heaviest crude oils1 there are many types of oil injection valves in use1 the valves being in general divided into two classes1 those in which the oil is vaporized mechanically by the pressure of a force pump1 and those in which the fuel is vaporized by the atomizing effect of compressed air4 ,atomization by compressed air is however1 the most common method since less trouble is experienced with the air pumps than with the liquid force pumps4 ,the compressed air is supplied by pumps that are either operated by the main engine or by an independent compressor engine4 ,the fuel valve is a plug screwed into the cylinder containing an inwardly opening check valve in the inward end4 ,the hole in the center of the plug receives the oil charge under a few pounds pressure from the tanks1 during the compression stroke of the engine1 and at the end of the compression stroke1 a blast of air at a pressure of about #bej pounds above the compression pressure blows it into the cylinder in the form of a fine spray4 ,injection valves of the forced feed type consist of a plug with a small passage and a needle valve for regulating the spray4 ,fuel is pumped into the valve at about #bej pounds above the compression pressure of the engine by a small single acting pump which is built so that the length of the stroke may be adjusted to meet the load4 ,in practice the length of stroke is regulated by the governor1 so that the full contents of the pump are delivered at full load1 and a reduced amount with a short stroke at small loads4 ,on issuing from the fuel nozzle1 the liquid strikes a gauze screen by which it is broken up into very fine spray4 ,fluidity is practically the only factor that governs the quality of fuel that may be used with the engine1 since exceptionally heavy oils and tars cannot be successfully sprayed4 ,in ,fig4 #i is shown a cross-section of a ,diesel engine cylinder in which the center valve in the cylinder head is the fuel valve1 and the valves to the right and left are the air inlet and exhaust valves respectively4 ,the two latter valves correspond to the inlet and exhaust valves of the ,otto cycle engine4 ,compressed air is used in starting the engine1 which is admitted to the cylinder through an auxiliary valve which is operated by a starting cam on the cam shaft4 ,by this mechanism1 high pressure air is furnished to the cylinder during a portion of the working stroke1 turning it over on the first few revolutions as a common air engine4 ,as soon as the engine picks up speed1 the starting valves are thrown out of operation1 and the engine proceeds on its regular working cycle with the oil fuel4 ,when used for marine purposes in sizes over #ajj horse-power1 where it is not possible to use reverse gears1 the ,diesel engine whether of the two stroke cycle or four stroke cycle type must be made reversible4 ,this may be accomplished by either of two methods1 first1 by changing the angular position of the cams in regard to the piston position1 and second by using two sets of cams1 one being for right hand rotation and the other for left hand4 ,when a single cam is used1 the relation of the cam shaft on which the oil pump cams and oil valve cams are located1 is advanced or retarded in respect to the crank shaft by means of sliding the two spiral gears that drive the cam shaft1 over one another1 in a direction parallel to their axes4 ,the spiral gears are moved back and forth by a hand controlled reverse lever4 ,this type is used principally on the two stroke cycle type of engine as there are not so many factors to contend with as on the four stroke cycle4 ,with double cams1 the system almost invariably used with the four stroke cycle engine1 the cams may be mounted either on one shaft1 or the ahead cams on one cam shaft and the reverse cams on another4 ,when two shafts are used they are arranged so that either set of cams may be swung under the valve lifters by swinging the shafts in a radial direction by brackets4 ,the single type of cam shaft is usually moved back and forth in a direction parallel to its axis1 the ahead cams coming under the valve lifts at one position1 and the reverse cams at the other4 ,in the four stroke cycle ,diesel it is evident that not only the relations of the oil pump and oil valves must be changed in respect to the piston position but the relations of the air inlet and exhaust valves must be changed as well4 ,this necessitates double cams for the inlet and exhaust valves in order to reverse rotation4 ,compressed air for starting and injection is generally supplied by a three stage air compressor or a compressor in which the pressure is built up in three different steps1 the second cylinder taking the air from the discharge of the first1 and the third cylinder taking the air from the second1 and compressing it to about #bej pounds above the compression pressure of the engine4 ,perfect scavenging is possible with this engine because of the large excess of air supplied during the suction stroke and the period of injection4 ,on the marine type the air pumps and water circulating pumps occupy about the same amount of space as the condenser and circulating pumps of a steam engine having the same outputs4 ,in a recent test made with an ,atlas-,diesel engine it was found that #aa per cent of the output was lost in driving the air pumps or more than #ej per cent of the total loss by friction and impact4 ,illustration3 ,fig4 #fg4 ,cross-,section ,through the ,working ,cylinders of the ,m4 ,s4 ,monte ,penado ,two ,stroke ,cycle ,diesel ,engine4 ,from the ,motor ,ship1 ,london4 ,unlike the ordinary gasoline engine in which an increase of speed increases the output in an almost direct proportion1 the output of the ,diesel engine decreases when the speed rises beyond a certain limit due to imperfect combustion at speeds much over #cej revolutions per minute4 ,because of this fact it has been practically impossible to apply the type to automobile service which ordinarily requires a speed of from #djj to #hjj revolutions per minute under ordinary conditions4 ,in addition to the speed limitations1 the ,diesel engine weighs approximately #gj pounds per horse-power against an average weight of #ag pounds per horse-power with the ordinary type of gasoline automobile motor4 ,of course these objections may be overcome in time1 as the engine is only in its infancy1 and the two stroke cycle ,diesel has not yet been fully developed1 but at the present time it does not seem probable that this engine will ever be an active competitor of the gasoline automobile motor1 at least from the standpoint of flexibility4 ,as the ,diesel engine depends entirely upon compression for its operation1 it is necessary that all of the parts such as the pistons1 valves1 etc41 shall be perfectly fitted and air tight under extremely high pressures4 ,the careful workmanship required for such fitting and the adjustments make the ,diesel much more expensive to build than the ordinary type of gas engine1 and for this reason the first cost and overhead charges cut into the fuel item to a considerable extent4 ,a description of the ,diesel engines will be found in the chapter devoted to oil engines4 7#fc7 ,diesel ,engine 7,marine ,type74 ,as a practical example of a ,diesel engine1 which was described in ,chapter ,,iii1 we will give a brief description of the two #hej horse-power ,diesel engines installed in the cargo vessel 8,m4 ,s4 ,monte ,penedo10 which were built by ,sulzer ,brothers of ,winterthur1 ,switzerland4 ,we are indebted to the ,motor ,ship1 ,london1 for the details4 ,the engines are of the two stroke cycle1 single acting type1 with four working cylinders1 a double acting scavenging pump cylinder1 and a three stage ignition compressor cylinder4 ,the bore of the working cylinders is #ah4h inches1 and the stroke #bg inches4 ,while the crank case is of the enclosed type1 there are two sets of covers which can be easily removed for inspection while the engine is running1 for as the scavenging pump performs the work of the crank case of the ordinary two stroke cycle engine there is no need of a tight case to retain the compression4 ,illustration3 ,fig4 #fh4 ,cross-,section ,through the ,air ,cylinders of the ,two ,stroke ,diesel ,motors on the ,m4 ,s4 ,monte ,penado4 ,the scavenging pump is mounted on one end of the engine and is driven from the crank-shaft1 the cross-head of the pump forming one piece with the piston of the low pressure cylinder of the injection air cylinder4 ,all of the compressor stages are water cooled and fitted with automatic valves4 ,the double acting scavenging pump has a piston valve driven by a link motion for reversing it when the engine is reversed4 ,the air enters the pump through the top valve chamber from a pipe leading into the engine room4 ,the air discharges a pressure of about #c pounds per square inch in a header that passes in front of all four working cylinders4 ,by means of a valve the air entering the low pressure stage of the compressor can be taken either from the atmosphere or from the discharge of the scavenging pump2 taking the air from the latter allows of a greater weight of air taken by the compressor and consequently a higher compression for use in emergencies4 ,as in the ordinary type of two stroke cycle engine1 two independent sets of exhaust ports are used1 one set being for the scavenging air and the other for the exhaust gases1 both sets being at the end of the stroke as usual4 ,the air inlet ports are divided into two groups1 however1 one group being controlled by the piston of the working cylinder1 and the other group by an independent piston valve driven from the cam-shaft4 ,both sets of ports connect with the main scavenging air header4 ,by means of the valve controlled ports it is possible to admit scavenging air even after the other ports are closed by the piston1 which greatly increases the scavenging effect4 ,with the air at #c pounds pressure the air from the valve controlled ports throw the scavenging air to the top of the cylinder even after the exhaust ports are closed4 ,this valve is provided with a reverse mechanism4 ,a single cam is used for operating the fuel inlet valve and the air starting valve1 and the reversal of the engine is obtained by turning the cam shaft through a small angle relative to the crank-shaft1 which of course also reverses the lead of the fuel valve4 ,starting is accomplished by compressed air1 with the air valve lever on the cam1 and the fuel valve lever off4 ,after turning through a few revolutions1 the air valve levers are raised1 and the fuel levers dropped back on the cams which results in the engine taking up its regular cycle4 ,by moving the tappet rod of the fuel valve out of or into a vertical position1 the time of the fuel valve opening is regulated and the amount of air is controlled4 ,this movement is normally performed by a compressed air motor1 but in an emergency hand wheels may be used4 ,one of these serves to rotate the camshaft through the required angle in order to set the cams in the positions for astern or ahead running and also reverses the link motion of the scavenging pump valve by the rotation of shaft1 as mentioned above4 ,the other auxiliary motor operates the fuel and starting air valves by moving the small spindle longitudinally to bring the tappet lever of the air valve about the required cam for ahead or reverse and also lifts this or the fuel valve tappet rod off its cam1 according as it is desired to run on fuel or air4 ,the spindle on which the valve levers are pivoted is in two parts1 divided at the center4 ,this is to allow two of the cylinders to run on air whilst the other two are running on fuel1 and1 as can be seen from the dial where the pointer indicates the position1 in starting up1 whether astern or ahead1 first two cylinders are put on air1 then four on air1 next two on air and two on fuel1 and finally all four on fuel4 ,this allows very rapid attainment of full speed4 ,the amount of fuel entering each cylinder can be regulated separately by small hand wheels4 ,below the fuel pumps are arranged three auxiliary pumps1 two of these being oil pumps for the oil circulation1 whilst the other is of the piston cooling water4 ,on the left of the engine and driven in a similar manner from the cross-head by links are three other pumps1 one for the circulating water and the other for the general water supply of the ship4 ,lubrication for the cylinders is furnished by #h small pumps1 just above the water pumps1 two oil pumps being provided for each cylinder4 ,as the supply pipe is divided into two parts1 the oil reaches the cylinder at four points in its circumference4 ,four oil pumps are provided for the air compressor4 ,four steel columns are provided for the support of each cylinder in addition to the cast iron frame of the base1 and by this means the explosion stresses are transmitted directly to the bed plate4 ,the cast iron columns provide guide surfaces for the cross-head shoes4 ,the guides are all water cooled4 7#fd7 ,the ,m4,a4,n4 ,diesel ,engine4 ,the ,maschinenfabrik ,augsburg-,nrnberg1 ,a4 ,g41 a ,german firm have built some remarkably large ,diesel engines both of the vertical and horizontal types4 ,the peculiar merits of the horizontal type of ,diesel engine of which the ,m4,a4,n4 company are pioneers are still open to discussion at present1 but there is no doubt but what this type will be the ultimate form of very large engines when certain alterations are made in the design4 ,illustration3 ,fig4 #fi4 ,horizontal ,m4 ,a4 ,n4 ,diesel ,engine at the ,halle ,municipal ,plant4 ,illustration3 ,fig4 #gj4 ,high ,speed ,mirlees-,diesel ,engine4 ,in ,fig4 #fi is shown a #b1jjj brake-horse-power horizontal ,m4,a4,n4 ,diesel engine of the four stroke cycle type which is installed at the ,halle ,municipal ,electricity ,works1 ,halle1 ,germany4 ,it is of the double acting type with twin-tandem cylinders giving four working impulses per revolution4 ,this engine was installed in addition to the six producer gas engines already in place to take the peak load of the station at different times during the day1 the gas engines meeting the normal steady demand4 ,this firm has built many thousands of the vertical type of ,diesel engine of all sizes1 and has recently installed #ac engines of #d1ejj brake horse-power for operating the ,kreff tramways4 ,the company is now building cylinders giving outputs of from #a1bjj to #a1ejj brake horse-power per cylinder1 giving outputs of from #e1jjj to #f1jjj horse-power in tandem twin type engines4 ,as will be seen from the cut1 the horizontal ,diesel engine is remarkably free from complicated valve gear4 7#fe7 ,mirlees-,diesel ,engines4 ,the ,mirlees-,diesel engine is built by the ,english firm1 ,mirlees1 ,bickerton and ,day both for stationary and marine service4 ,a generating plant consisting of two1 #bjj horse-power ,mirlees engines direct connected to ,siemens generators has been installed in the municipal plant at ,dundalk as shown by ,fig4 #ga4 ,on test these units consumed #j4fdg pounds of oil per horse-power at full load and #j4gjd pounds per horse-power at half load with a regulation of #c4bd per cent from full load to no load4 ,all of the engines built by this firm are of the four stroke cycle type4 ,illustration3 ,fig4 #ga4 ,mirlees-,diesels at ,dundalk4 7#ff7 ,willans-,diesel ,engines4 ,the ,willans-,diesel engines built by the ,willans and ,robinson ,company of ,rugby1 ,england1 are in sizes up to #djj brake horsepower1 and run at speeds up to #bej revolutions per minute4 ,they are all of the four stroke cycle type and are applied principally to the driving of electric generators4 ,the cut shows one of the four1 #bhj horse-power units supplied to the ,alranza ,company and the ,rosario ,nitrate ,works in ,south ,america4 ,illustration3 ,fig4 #gb4 ,willans ,vertical ,diesel ,engine4 ,unlike the ,mirlees engine1 the ,willans has an individual frame for each cylinder as in steam engine practice4 ,like the steam engine frame1 the bottom is left open for the inspection of the connecting rod ends and the main bearings which is a most desirable feature4 ,the air compressor and pumps are arranged in a most compact form at the left end of the crank-shaft from which the pipes may be seen issuing to the four cylinders4 ,the valves and over head gear are of the conventional type1 which1 with the exception of a few minor details are the same as those on the recently developed ,sulzer-,diesel4 ,the individual grouping of the cylinder units has many desirable features and should1 we believe1 be more extensively copied4 7#fg7 ,installation and ,consumption of ,diesel ,plant4 ,an ,english gas-electric station was completed at ,egham1 ,england1 that is a good example of the changes that have been made recently in the electricity supply abroad1 with ,diesel power4 ,the generating plant comprises two #id ,k4 ,w4 ,diesel engines built by ,mirrlees1 ,bickerton and ,day1 direct connected to single phase alternators generating at #b1jjj volts4 ,the exciters are direct connected to the main shaft1 and the plant is capable of generating an overload of #aj per cent for two hours4 ,space has been left for the installation of two more units of a larger size4 ,the following fuel consumption was guaranteed for a load of unity power factor1 and the official tests show slightly better figures than the guarantee4 ,full load #j4fh lb4 oil per ,k4 ,w4 ,h4 ,three-quarter load #j4gb lb4 oil per ,k4 ,w4 ,h4 ,half load #j4gi lb4 oil per ,k4 ,w4 ,h4 ,quarter load #a4ae lb4 oil per ,k4 ,w4 ,h4 ,illustration3 ,cross-,section ,through ,egham1 ,england ,municipal ,plant4 ,particular attention has been given to the water supply for the jackets of the engines2 the circulation being by two electrically driven1 direct connected centrifugal pumps1 one of which is a spare4 ,a ,little ,company's cooler has been installed1 which consists of a horizontal cylindrical chamber1 the lower part of which contains water4 ,in the tank are arranged a number of concentric metal cylinders spaced about -inch apart1 and in several sections1 that are carried on a slowly revolving shaft1 driven from the fan shaft4 ,the cylinders are all of the same length1 and are open at both ends4 ,the lower half of the cylinders dips into the water in the casing1 and as they revolve1 a thin film of water on each side of the plate is carried into the upper portion of the casing where it meets a blast of cold air from the fan4 ,the fan is driven from the circulating pumps1 and passes the air through the chamber in a direction opposite to that of the water1 baffles being placed so that correct circulation is maintained4 ,the small loss is made up by connecting the ball cock in the tanks with another tank charged from the works well by means of a self-starting rotary pump1 electrically driven4 ,very little power is required for the pumps and cooler4 ,fuel oil is stored in a tank outside the building1 the oil being supplied to the tanks from an oil wagon by means of a small hand pump4 ,oil is taken from the tanks and forced into the engine room by a rotary pump1 from which it enters two graduated tanks located in the roof of the station4 ,the graduations on the tanks allow the consumption of oil to be carefully recorded by alternately filling and emptying the two auxiliary fuel tanks4 ,the entire building is electrically heated1 and the kitchen of the flat above the station is equipped with an electric cooking-stove for the use of one of the engineers who make it his residence4 ,,diesel ,,horse-,,power ,,formula ,p4 ,a4 ,holliday1 in the ,engineer1 derives a new formula for computing the horse-power of the four stroke cycle1 single-acting engine4 ,for each horse-power developed by these engines about #ba1jjj cubic inches of displacement is necessary1 per minute4 ,d ,cylinder bore in inches4 ,s ,stroke in inches4 ,m4,p4,s4 ,mean piston speed in feet per minute4 ,r ,ratio of stroke to bore4 ,n ,revolutions per minute1 then 7,b4,h4,p4 #bbbj7 ,d -------------------------------- ,m4,p4,s4 #f ,m4,p4,s4 ,knowing the value of ,d1 ,n ---------------- ,s ,for high speed1 low ratio 7,r71 four stroke cycle engines1 approximately #bb1jjj cubic inches displacement per minute is required4 7#b1ccj ,b4,h4,p47 ,d ------------------------------ ,m4,p4,s4 ,in both formulae1 the air compressor for fuel injection is included4 7#cb7 ,semi-,diesel ,type ,engine4 ,in the 8,semi-,diesel0 ,type ,engine the oil is injected into the cylinder at the point of greatest compression in the same manner as in the ,diesel engine1 and like the ,diesel it compresses only pure air4 ,in regard to the compression pressure1 however1 it stands midway between the pressure of the ,diesel engine and that of the ordinary 8aspirating0 type oil engine1 as the compression averages about #aej pounds per square inch4 ,while this is a much higher pressure than that carried by the ordinary kerosene engine which compresses a mixture of kerosene vapor and air1 it is not sufficiently high to ignite the oil spray by the increase in temperature due to the compression1 but ignites the charge by means of a red hot bulb or plate placed in the combustion chamber4 ,this type of engine is built both in the two stroke and four stroke cycle types1 the events occurring in the same order as in the two stroke and four stroke ,diesel types1 that is1 pure air is drawn into the cylinder on the suction stroke 7four stroke cycle7 or is forced in at the beginning of the compression stroke 7two stroke cycle71 and is compressed in the combustion chamber4 ,at the end of the compression stroke1 the fuel is injected against the red hot bulb or plate by which the charge is ignited4 ,expansion follows on the working stroke after the fuel is cut off1 and release occurs at the end of the stroke4 ,fuel oil is supplied to the spray nozzles by a governor controlled pump having a variable stroke or by compressed air as in the ,diesel engine1 making the supply of fire proportional to the load4 ,a separate pump is generally supplied for each cylinder1 which is capable of developing a pressure of about #djj pounds per square inch4 ,several of the ,semi-,diesel type engines have water sprayed into the cylinder for the purpose of cooling the cylinder and piston1 and as an aid in the combustion4 ,this water spray increases the output of a given size cylinder by the amount of the steam formed by the heat of the cylinder and piston walls1 and by the increased rate of combustion4 ,the amount of water supplied to the cylinder is equal1 approximately to the amount of fuel oil4 ,the water connection is made in the air intake pipe so that the water spray and the intake air are drawn into the cylinder at the same time4 ,there is very little difference in the efficiency of the ,diesel and ,semi-,diesel in favor of the true ,diesel type for both have accomplished records of a brake horse-power hour on 4#de pound of crude oil in units of the same capacity4 ,neglecting the question of efficiency the ,semi-,diesel has many advantages which are due principally to the differences in compression pressures4 ,valve and piston perfection in regard to leakage is not as essential with the semi-type as with the ,diesel1 as the former is not dependent on compression for its ignition4 ,this means that the ,semi-,diesel has a lower first cost and a lower maintenance expense4 ,its low compression pressure makes starting possible without the use of compressed air with engines of a considerable horse-power4 ,as the explosion pressure is much lower than with the ,diesel type there is less strain on the working parts and lubrication is much more easily performed4 ,compared with the ordinary type of kerosene engine the ,semi-,diesel is much more positive in its action as the oil is sure to ignite when sprayed on the hot surface of the bulb or plate when under the comparatively high compression4 ,in the engine where the air is mixed with the vaporized fuel before it is drawn into the cylinder1 it is difficult to obtain perfect combustion because of the uncertain mixtures obtained on varying loads by the throttling method of governing4 ,at light loads the only difficulty encountered with the ,semi-,diesel type is that of keeping the igniting surface hot enough to fire all of the charges4 ,in the majority of cases the two stroke cycle type of ,semi-,diesel engines compress the scavenging air in the crank chamber in the same way that a two stroke cycle gasoline motor performs the initial compression1 although there are several makes that compress the air in an enlarged portion of the cylinder bore by what is known as a 8trunk0 piston4 ,this initial compression determines the speed of the engine1 the pressure limiting the time in which the air traverses the cylinder bore and sweeps out the burnt gases of the previous explosion4 7#fh7 ,de ,la ,vergne ,oil ,engines4 ,two types of four stroke cycle oil engines are built by the ,de ,la ,vergne ,machine ,company1 which differ principally in the method and period of injecting the fuel into the cylinder4 ,while both types compress only pure air in the working cylinder1 the oil is injected in a heated vaporizer during the suction stroke in the smaller engine 7type ,,ha71 and is injected directly into the combustion chamber of the larger engine 7type ,,fh7 at the point of greatest compression4 ,this fuel timing classifies the type ,,fh as a semi-,diesel1 while type ,,ha comes under the head of that class of engines known as aspirators4 ,illustration3 #gf-;a4 ,elevation of ,de ,la ,vergne ,oil ,engine1 ,semi-,diesel ,type4 ,class ,f ,h4 ,semi-,diesel 7,type ,,fh7 ,during the suction stroke1 air is drawn into the cylinder through the inlet valve located on the top of the cylinder head1 and on the return1 or compression stroke1 the air is compressed to about #cjj pounds per square inch in the combustion chamber4 ,the compression heats the air to a high temperature which is still further increased by contact with the hot walls of a cast iron vaporizer ,d1 shown by ,fig4 #gf-;b4 ,at the completion of the compression1 the fuel is injected in a highly atomized state by compressed air through the spray nozzle ,f1 the spray being thrown into the vaporizer4 ,illustration3 #gf-;b4 ,cross-,section of ,type ,f ,h1 ,de ,la ,vergne ,oil ,engine4 ,the vapor formed by the contact of the spray with the walls of the vaporizer mixes with the compressed air in the combustion chamber and is ignited at the instant of fuel admission by the combined temperatures of the vaporizer and compression pressure4 ,as the fuel is not injected until the proper instant for ignition1 it is possible to obtain a relatively high compression without danger of the charge preigniting4 ,the oil is supplied to the nozzle by a fuel pump under pressure4 ,the atomizing air takes the oil at pump pressure and performs the actual injection4 ,details of the spray valve are shown by ,fig4 #gf1 in which the oil and air are entered at a pressure of about #fjj pounds per square inch4 ,illustration3 ,fig4 #gf4 ,de ,la ,vergne ,spray ,nozzle4 ,the air and oil enter the nozzle at opposite sides of the cylinder ,b which fits snugly into the valve body ,a4 ,as the air and oil proceed side by side along the outside of ,b1 they are forced to pass through a series of chambers connected by a system of fine diagonal channels on the surface of ,b which results in a very fine subdivision and intimate mixture4 ,the charge is admitted to the cylinder by a sort of needle valve about one-half inch in diameter which is provided with a spring that holds it closed on its seat as shown by ,c1 in ,fig4 #gf4 ,the needle is so constructed that it may be readily removed at any time for inspection4 ,the spray valve is located on the right hand side of the valve chamber directly opposite the vaporizer and is operated by an independent cam on the camshaft4 ,illustration3 ,fig4 #gf-;c4 ,de ,la ,vergne ,governor and ,fuel ,pump4 ,the vaporizer consists of an iron thimble having ribs on the inside to increase the radiating surface4 ,in starting1 the vaporizer is heated for a few moments until it reaches the temperature necessary for vaporizing the fuel1 but after the engine is running1 the blast lamp is removed and the temperature is maintained by the heat generated by the combustion of the successive charges4 ,since the fuel is ignited at the instant that it makes contact with the vaporizer1 it is possible to accurately adjust the point of ignition by adjusting the position of the fuel cam on the camshaft4 ,air for spraying the fuel is supplied by a two stage air compressor that is driven from the crankshaft by an eccentric4 ,the air compressed by the first stage is stored in tanks at about #aej pounds pressure for starting the engine4 ,the second stage compresses the air to about #fjj pounds pressure1 but is correspondingly small in volumetric capacity since it handles only enough air to spray the oil which amounts to about #b per cent of the cylinder volume4 ,a governor controlled butterfly valve in the air intake pipe regulates the amount of air taken in on the second stage to suit the varying charges of oil injected at each load4 ,in starting by compressed air1 a quick opening lever operated valve on the cylinder head is used to admit air from the tanks to turn the engine over until the first explosion takes place4 ,if the vaporizer is sufficiently heated by the torch1 the explosion occurs during the first revolution of the crank shaft4 ,at a point about #he per cent of the expansion stroke1 the exhaust valve is opened1 and the products of combustion are expelled into the atmosphere4 ,when starting1 the compression may be relieved by shifting the starting lever from the exhaust cam to the auxiliary starting cam provided for that purpose4 ,speed regulation is affected by a ,hartung governor1 driven from the camshaft1 which actuates the oil supply pump through levers by shifting the point of contact between the pump levers and its actuating cam4 ,this lengthens or shortens the stroke of the pump in accordance with the requirements of the load4 ,the type ,,fh engines are built in both single and twin cylinders ranging from #ij to #ahj horse-power in the single cylinder type to #cfj horse-power in the twin4 ,since the fuel injection of the smaller engine type ,,ha differs from that just described1 it will be described separately in the following section4 ,the ,de ,la ,vergne ,oil ,engine 7,type ,,ha7 ,in the small four stroke cycle ,de ,la ,vergne ,oil ,engine1 the fuel is injected into a heated vaporizer during the suction stroke in such a way that the vapor and intake air do not form a mixture in the cylinder proper4 ,on the return stroke of the piston1 the compression of the pure air takes place which forces the air into the vaporizer and into intimate contact with the oil vapor4 ,this forms an explosive mixture which ignites and forces the piston outwardly on the working stroke4 ,the release and scavenging are performed in a similar manner to that of a four stroke cycle gas engine4 ,both the inlet and exhaust valves are of the mechanically operated poppet type1 and as both the inlet and exhaust gases pass through the same passage1 the entering air is heated to a comparatively high temperature4 ,the injection pump receives the fuel from a constant level stand pipe or tank1 located near the engine and injects the fuel into the vaporizer through a spray nozzle4 ,the vaporizer is a bulb shaped vessel that is connected with the cylinder through a short post and really forms a part of the combustion chamber4 ,since no water jacket surrounds the vaporizer1 it remains at a high temperature and vaporizes the oil at the instant of its injection4 ,because of the residual gases remaining in the chamber1 ignition does not occur until air is forced through the passage by the compression4 ,the air inlet valve and the fuel injection valve are opened at the same instant by a cam lever that also operates the pump4 ,on the compression stroke1 the air which is at a pressure of approximately #ge pounds per square inch enters the vaporizer1 and ignition occurs1 partly because of the increased heat due to the compression and partly because of the supply of additional oxygen4 ,internal ribs provided in the vaporizer greatly increase the heat radiating surface and add to the thoroughness with which the atomized oil is vaporized4 ,since no mixture of air and fuel takes place in the cylinder proper1 sudden changes in the load do not affect the ignition of the charge as the heated surfaces are surrounded with comparatively rich gas under all conditions4 ,before the engine is started1 the vaporizing chamber is heated to a dull red heat by means of a blast torch in order to vaporize the oil for the first stroke4 ,as soon as the engine is running1 the lamp is cut out and the temperature is maintained by the heat of the successive explosions4 ,the combustion attained by this method is very complete even with the heaviest fuels1 and whatever carbon deposit is formed occurs in the vaporizer from which it is easily removed4 ,the contracted opening of the vaporizer passage effectually prevents the solid matter from working in the bore or valves4 ,a ,porter-type fly ball governor maintains a constant speed at varying loads by regulating the quantity of fuel supply to the vaporizer1 the air intake remaining constant4 ,a by-pass valve1 controlled by the governor divides the oil supplied by the pump1 into two branches1 one of which leads to the spray nozzle and the other to the supply tank4 ,in the case where all of the oil is not supplied to the vaporizer because of a light load1 the by-pass valve will return the surplus to the tank1 thus maintaining a constant pressure at the spray nozzle4 ,when operating under ordinary loads1 the governor opens only the small inside valve which regulates the amount of oil injected into the vaporizer4 ,but should the engine speed up1 due to a sudden change in the load1 the governor will not only open the small valve but also the large concentric valve1 in which case all of the oil will return to the tank4 ,the makers guarantee the following speed variation limits under the different loads4 ,ordinary ,variation #b per cent4 ,full load to one-quarter load #d per cent4 ,full load to no load #e per cent4 7#fi7 ,operating ,costs of the ,semi-,diesel ,type4 ,as the semi-,diesel type engine will operate successfully on the lowest grades of crude oils1 with an efficiency that compares favorably with the true ,diesel type1 the operating expenses are very much lower than with the gas or gasoline engine4 ,with the same fuels1 the semi-,diesel will show greater net saving than the ,diesel with a low load factor1 as the fuel saving is not eaten up by the high first cost1 and overhead charges of the true ,diesel4 ,western crude oils with a specific gravity of 4#ifj 7#af ,beaum7 are being used daily with this type of engine while nearly every builder of the semi-,diesel type will guarantee results with oils up to #ah ,beaum 74#idh ,specific ,gravity74 ,fuel of this grade will cost anywhere from #a cents to #c cents per gallon in tank car lots1 depending on the distance of the engine from the wells or refinery4 ,with fuel oil weighing #g pounds per gallon1 an engine consuming 4#fe pounds per horse-power hour 7a usual guarantee7 at full load1 the cost of a horse-power hour delivered at the shaft will be 4#bf cent with fuel at #c cents per gallon4 ,this the lowest fuel expense of any prime mover even with steam or gas units of great power4 ,in a twenty-four hour test of a ,de ,la ,vergne oil engine running on #ai ,beaum oil1 the consumption was considerably below the figure assumed above1 being 4#ejh pounds per horse-power hour4 ,even the engine was exceeded in a test made on a #age horse-power engine by ,dr4 ,waldo1 which gave a consumption of 4#cdg pounds of oil per horse-power hour with oil of 4#hf ,specific ,gravity4 ,the following is a tabulation of reports received by the ,de ,la ,vergne ,machine ,company from the ,snead ,iron ,works1 giving the cost of power at their plant under actual working conditions extending over a period of twenty-four months4 ,the plant consisted of a #ag #bg inch ,de ,la ,vergne semi-,diesel type engine of #ahj horse-power rated capacity1 the load factor being #ed4b per cent4 ,the total power produced during the record was #eeb1bag horse-power hours1 with a working period of #ehh days4 ,fuel #bh4h ,beaum #g4ce pounds per gallon4 ,,tabulation ,items ,total ,cost ,cost per ,cost per ,k4,w4 ,hour ,h4,p4 ,hour ,fuel ,oil1 #ch1baa gallons #hei4ge 4#jjbcb 4#jjaee ,lubricating ,oil #bbh4gb 4#jjjfa 4#jjjda ,miscellaneous ,stores and ,repairs #abc4bj 4#jjjcb 4#jjjbb ,labor and ,attendance #acfa4db 4#jjcfh 4#jjbdf -------------- -------------- -------------- ,total 4#jjfic 4#jjdfd ,fuel oil used 4#gfa pounds per ,k4 ,w4 hour 4#ejh pounds per horse-power hour4 ,computing from the load factor of #ed4b per cent1 the cost of power produced under the above conditions would be #i4cj per horse-power year1 or #ac4ih per kilowatt year4 ,this result is obtained by assuming that the horse-power hours would be increased from #eeb1bag to #a1jgg1ced1 or in proportion to the actual load factor1 the period1 of course being the same in both cases4 7#gj7 ,elyria ,semi-,diesel ,type4 ,a type of semi-,diesel type oil engine has been recently developed by the ,elyria ,gas ,power ,co41 ,elyria1 ,o41 that presents many features of interest4 ,it operates on the two stroke cycle principle1 and with the exception of the spray nozzle has no valves in the working cylinder4 ,the principle of the semi-,diesel type cycle as distinguished from the true ,diesel engine1 was described in ,chapter ,,iii1 as having the following characteristics4 7#a7 ,fuel injection4 7#b7 ,medium compression pressure4 7#c7 ,hot plate ignition4 7#d7 ,an efficiency approximating that of the true ,diesel type4 ,illustration3 ,fig4 #gg4 ,working ,cylinder of ,elyria ,oil ,engine4 ,it is claimed that the change from the ordinary four stroke cycle ,diesel cycle has been accomplished with practically no loss of thermal efficiency1 and that the elimination of the many moving parts of that type has done away with many of the operating difficulties4 ,by the introduction of a false piston end and an unjacketed cylinder head1 the loss of efficiency due to the lower compression is compensated by the reduction of heat loss to the jacket water4 ,because of the high temperature it is possible to burn the heaviest fuels with a maximum pressure not exceeding #djj pounds per square inch1 and without trouble due to missed ignition at light loads4 ,with a given cylinder capacity this heating effect has increased the output about #ge per cent4 ,the loss due to the friction of the scavenging apparatus causes a fuel consumption of approximately #aj percent more than a standard four stroke ,diesel4 ,unlike the ,diesel1 this engine automatically controls the quantity of injection air admitted to the cylinder at different loads1 the air corresponding with the amount of fuel injected4 ,this is in marked contrast with the ,diesel engine which admits a constant volume of air at all loads4 ,in place of the usual crank-case compression of the scavenging air met with in the ordinary two stroke cycle engine1 the initial compression in the ,elyria engine is performed by a 8differential piston0 which acts in an enlarged portion of the cylinder bore4 ,this construction increases the volumetric efficiency from #gj percent1 in the case of the marine type1 to well over #ij percent1 and it also does away with the bad effect of the compression on the lubrication of the main crank shaft bearings4 ,illustration3 ,fig4 #gh4 ,compressor ,cylinder of ,elyria ,oil ,engine4 ,the working piston and differential piston as shown by ,fig4 #gg is separate castings fastened together by four studs1 and the piston pin is carried by the differential piston which acts as a cross-head1 taking all of the side thrust from the main piston4 ,the working piston is easily taken from the cylinder by removing the cylinder head and the four nuts that fasten it to the differential piston casting4 ,the displacement of the differential piston is approximately #a4i times the displacement of the working piston which is more than enough for thoroughly scavenging the cylinder and supplying air for combustion4 ,the air suction is controlled by a piston valve which eliminates much of the loss encountered in the marine type of two stroke cycle4 ,in the figure may be seen the separate or auxiliary piston head which is bolted to the piston proper1 a construction that greatly increases the working temperature1 and allows a symmetrical form of piston4 ,by removing the cap over the inlet port1 it is possible to inspect the condition of the six piston rings with removing the piston from the cylinder4 ,because of the clean burning of the fuel lubrication is easily effected by the force pump which supplies oil at three points around the cylinder wall4 ,three stages of compression are employed for providing the air for fuel injection1 the first stage being accomplished by the differential piston1 and the remaining two stages by a separate air pump driven by an eccentric from the crankshaft4 ,this cylinder also supplies the air for starting the engine1 the air being taken from the second stage and piped to the storage tank4 ,the suction of the second stage pump which receives its air from the differential pump 7first stage7 is controlled automatically so that it is possible to keep the supply tank at any desired pressure regardless of the pressure or amount of air used for the fuel injection4 ,air from the tank 7at approximately #bjj pounds pressure7 is piped to the suction side of the third stage air pump4 ,in this suction line is a valve1 controlled by the governor1 which regulates the amount of air admitted to the injection nozzle1 and also the amount4 ,this pressure at the nozzle will vary from #ejj pounds per square inch to #ajjj pounds depending on the load and the nature of the fuel4 ,the high pressure air travels directly from the pump to the fuel valve casing1 and is equipped with a safety valve and pressure gauge4 ,the fuel pump is driven by a ,rites ,inertia ,governor located in the fly-wheel which varies the stroke of the pump plunger and gives a correct proportion of fuel to the load4 ,this type of governor has been extensively used on high speed engines and is exceeding accurate4 ,the fuel pump may be disconnected from the governor drive1 and operated by hand when it is necessary to provide fuel for starting4 ,the spray or injection valve is operated by a cam1 which lifts the valve at the proper moment in a very simple manner4 ,the valve proper is made of a single piece of steel with openings of ample size1 so that there is no danger of clogging with the heaviest fuels4 ,as the valve only lifts #a_/af of an inch1 the amount of work required to operate the valve is very small4 ,starting is accomplished by spraying cold gasoline into the cylinder through the fuel valve in the same manner that the heavier oil is fed during operation1 and the ignition is performed by a high tension coil and batteries4 ,no spark time device is used1 so that a continuous shower of sparks is thrown into the mixture during the starting period4 ,within a minute after the engine is started1 the ignition switch may be opened1 the gasoline cut off1 and the heavy oil turned on for continuous running on full load4 ,starting by an electric spark avoids the inconvenience and danger of torch starting with a retort4 ,cooling water is admitted around the compressor cylinder from which point it goes to the working cylinder1 and is there discharged4 ,less water is required for this type of engine than for the ordinary gasoline engine1 for with the water entering at #fj;,f1 only #c gallons per horse-power hour is used4 ,with fuel oil weighing #g4cc pounds per gallon the makers claim a fuel consumption of 4#fe pounds per horse-power at the rated load4 ,the amount of cylinder oil used does not exceed #a pint per #ajj horse-power hours1 while the loss of the bearing oil is extremely small because of the return system4 7#ga7 ,remington ,oil ,engine4 ,the ,remington ,oil ,engine is a vertical oil engine operating on the three port1 two stroke cycle1 and is an oil engine in the strict meaning of the word1 the oil consumed being introduced into the combustion chamber as a liquid and gasified within this chamber4 ,the method of gasifying and igniting the charge of oil in the ,remington ,oil ,engine is unique4 ,only clean air unmixed with any charge1 is taken into the crankcase4 ,this air is afterwards passed up into the cylinder and compressed until its temperature has raised to a point high enough to vaporize the oil which is injected into it4 ,the charge of oil is then atomized into this hot compressed air and turns immediately into a vapor1 which finds itself well mixed with the charge of air1 comes in contact with a firing pin recessed in the head1 ignite and burns4 ,this method of having the oil well gasified and mixed with air before ignition begins1 prevents the formation of carbon which is formed when oil not well gasified and mixed with air comes suddenly in contact with very hot surfaces4 ,this perfect system of gasifying the oil has the effect not only of preventing the formation of carbon in the cylinder1 but also of increasing the mean effective pressure and therefore decreasing the amount of fuel necessary for doing a certain amount of work4 ,the engine passes through its cycle of operations smoothly1 and does not have to be constructed with excessive weight4 ,illustration3 ,fig4 #gi4 ,cross-,section of ,remington ,oil ,engine4 ,the ,remington ,engine is of the valveless type1 delivering a power impulse in each cylinder for each revolution of flywheel4 ,the gases are moved in and out of the cylinder through ports uncovered by the movement of the piston1 which itself performs also the function of a pump4 ,on the up stroke of the piston a partial vacuum is created in the enclosed crankcase1 causing air to rush in when the bottom of the piston uncovers the inlet port seen directly under the exhaust port 7#bc71 ,fig4 #gi4 ,on the next down stroke this air is compressed in the crankcase to about four or five pounds pressure per square inch4 ,meanwhile the mixture of oil vapor and air already in the cylinder is burning and expanding4 ,when the piston approaches the end of its down stroke1 it uncovers the exhaust port 7#bc71 permitting the burnt charge to escape1 until its pressure reaches that of the atmosphere4 ,directly afterward the transfer port on the opposite side of the cylinder is uncovered by the piston1 thereby allowing a portion of the air compressed in the crankcase to rush into the cylinder1 where it is deflected upwards by the shape of the top of the piston and caused to fill the cylinder1 thereby expelling the remainder of the burnt charge4 ,the piston now starts upward1 compressing the fresh charge of air into the hot cylinder head4 ,near the end of the stroke1 a small oil pump1 mounted on the crankcase and controlled by the governor1 injects the proper amount of oil through the nozzle 7#ac71 into the compressed and heated air4 ,illustration3 ,fig4 #hj4 ,remington ,spray ,nozzle4 ,this oil is atomized in a vertical direction through a hole near the end of the nozzle4 ,it is therefore vaporized and gasified before there is a possibility of its reaching the cylinder walls4 ,the spray of oil is ignited by the nickel steel plug 7#ab71 which is kept red hot by the explosions because the iron walls surrounding it are protected from radiation by the hood 7#aa74 ,by the burning of the oil spray in the air the pressure is gradually increased and the piston forced downward1 this being the power or impulse stroke4 ,near the end of the down stroke1 the exhaust port is again uncovered and the burnt gases discharged4 ,illustration3 ,fig4 #ha4 ,fuel ,pump and ,mechanism of ,remington ,oil ,engine4 ,the operations above described take place in the cylinder and crankcase with every revolution4 ,each upstroke of the piston draws fresh air into the crankcase and compresses the air transferred to the cylinder4 ,each down stroke is a power stroke1 and at the same time compresses the air in the crankcase preparatory to transferring it to the cylinder by its own pressure at the end of the stroke4 ,the same volume of air enters the cylinder under all conditions1 and the power is regulated by modifying the stroke of the oil pump1 which may be done by hand or automatically by the governor in the flywheel4 ,a separate fuel pump is provided for each cylinder when multiple cylinders are used1 making it absolutely certain that each cylinder shall receive the same amount of fuel for a position of the control lever4 ,when starting the engine1 the hollow cast iron prong rising from the cylinder head is heated by a kerosene torch1 and when hot1 a single charge of oil is admitted to the cylinder by working the hand pump4 ,the flywheel is now turned backward1 thereby compressing the charge which ignites the fuel before the piston reaches the highest position4 ,after being started the engine1 the torch may be extinguished4 ,illustration3 ,fig4 #hb4 ,two ,cylinder ,remington ,oil ,engine ,direct ,connected to ,dynamo4 ,the governor is of the centrifugal type4 ,it has an ,l-shaped weight1 pivoted to the piece attached to the flywheel4 ,as the engine speed increases1 the weight tends to swing outward toward the flywheel rim1 and thereby moves the arm attached to it so as to shift the cam along the crankshaft toward the left4 ,this cam turns with the shaft1 and operates the kerosene oil pump4 ,according to the position of the cam on the shaft1 it will impart to the pump plunger a long or a short stroke1 thereby injecting more or less oil into the cylinder4 ,the lever pivoted on the bracket moves with the cam and is used for controlling the engine's speed by hand4 ,to stop the engine the handle of the lever is pulled towards the flywheel1 thereby interrupting the pump action altogether4 ,the handle of the control lever can be fitted with an adjustable speed regulator when required4 ,this device is for use on marine engines to enable the operator to slow down the engine4 ,the speed regulator does not interfere with the action of the governor but acts in conjunction with it4 ,whatever the speed of the engine may be1 it is under the control of the governor4 ,the engine can be controlled from the pilot house if such an arrangement is desirable4 ,the fuel pump is made of bronze4 ,the valves are made of bronze and are designed with very large areas4 ,the plunger is made of tool steel4 ,a bronze cup strainer is attached to the lower end of the pump to prevent sediment or foreign matter from reaching the pump valves4 ,as a result of the care used in its construction1 the fuel pump is not only very sensitive in measuring the oil required by the governor1 but is also very strong and durable4 ,the nozzle through which the fuel is atomized into the cylinder is thoroughly water jacketed to prevent the formation of carbon within the nozzle4 ,it is so constructed that the water jacket spaces and fuel spaces can be opened for inspection4 ,lubrication of all the important bearing joints is effected by a mechanical force feed oiler1 pressure feed oiler or by gravity sight feed oilers1 depending upon the service for which the engine is designed4 ,oil is fed in this manner to the piston1 the main bearings and the crankpin bearings4 ,the oil for the crankpin is dropped from a tube into an internally flanged ring attached to the crank by which it is carried by centrifugal force to a hole drilled diagonally through the crank and crankpin to the centre of the bearing4 ,this insures that all the oil intended for the crankpin shall reach it4 ,this feature1 as well as the use of the sight feed oiler itself1 is in line with the best modern high speed engine practice1 and is an important factor in the reliability of the engine4 ,,chapter ,,viii ,,ignition ,,systems 7#gc7 ,principles of ,ignition4 ,it is the purpose of the ignition system to raise a small portion of the mixture to the combustion temperature1 or the temperature at which the air and fuel will start to enter into chemical combination4 ,when combustion is once started in a compressed combustible gas it will spread throughout the mass no matter how small the original portion inflamed4 ,the rate at which the flame spreads through the combustion chamber depends upon the compression pressure1 the richness of the mixture1 the nature of the fuel and upon the number of points at which it is ignited4 ,in practice perfect ignition is seldom realized4 ,this is due not only to the ignition system itself but to poor mixture proportions1 imperfect vaporizing of the fuel1 and low compression2 all of which tend to a slow burning mixture with the attendant losses4 ,the best ignition system will be that which will cause the ignition to occur invariably at the point of highest compression and which will supply ample heat to start the process of combustion with a cold cylinder1 imperfect mixtures1 and low compressions4 ,an efficient and reliable ignition system is without a doubt the most important unit in the construction of a gas engine4 ,as ignition systems have improved and become more reliable1 so has the gas engine become more widely used and appreciated1 and in almost a direct proportion to these improvements4 ,many ingenious ignition systems have been proposed1 but only two of these have met with any degree of success in practice2 i4 e41 electrical ignition and ignition by means of the hot tube4 ,sponge platinum has the peculiar property of igniting jets of hydrogen gas1 or hydrocarbons1 without the aid of heat2 this is due to the condensing effect of the platinum on these gases4 ,it was proposed to ignite the gaseous charge of the gas engine by means of the platinum sponge 7catalytic ignition7 but the system proved a failure because of the clogging of the pores in the sponge by fine particles of soot4 ,dr4 ,otto employed an open flame which was introduced into the mixture by means of a slide valve4 ,this met with only a fair measure of success4 ,cerium1 ,lanthum and several other rare metals cause a considerable spark when brought into contact with iron or steel4 ,the objection to this method was the expense of the ,cerium plugs which required frequent renewal4 ,the writer remembers a quaint attempt at firing the charge by means of a piece of flint and steel2 the failure of this is obvious4 ,the ,diesel ,engine1 a great success from a thermodynamic standpoint1 is fired by means of the heat produced by the compression of air1 the fuel being sprayed into air which is compressed to several hundred pounds pressure4 ,mr4 ,victor ,lougheed proposes ignition by means of a platinum wire rendered incandescent by a current of electricity4 ,the plan sounds feasible1 but we are still waiting to be shown4 ,electric ignition is applicable to all classes of engines2 in fact this system made the variable speed engine as used on automobiles1 etc41 a possibility1 as accurate timing with the electric spark covers the range from the lowest possible speed to speeds of #d1ejj revolutions per minute and over4 7#gd7 ,advance and ,retard4 ,while the combustion of the mixture is extremely rapid under favorable conditions1 there is1 nevertheless1 a perceptible lapse between the instant of ignition and the final pressure established by the heat of the combustion4 ,for this reason it is necessary that ignition should be started a certain length of time before the pressure is required if we are to expect a maximum pressure at a definite point in the stroke of the piston4 ,the amount by which the time of ignition precedes that of combustion is called the ,,advance1 and is usually given in terms of angular degrees made by the crank in traveling from the time of ignition to time of maximum pressure4 ,since the pressure is always required at the extreme end of the compression stroke1 the degree of advance is given as the angle made by the center line of the cylinder with the center line of the crank at the instant of ignition4 ,should the advance be given as #aj1 for example1 it is meant that the crank is still #aj from completing the compression when ignition occurs4 ,owing to variations in the richness of the mixture1 and changes in the compression pressure1 due to throttling the incoming charge1 the rate of inflammation varies from time to time under varying loads4 ,to keep the maximum pressure at a given point under these conditions it is necessary to vary the point of ignition to correspond with the increase or decrease of inflammation4 ,this variation of advance to meet varying loads is approximated by the governor in some engines1 and manually in others4 ,the advance of an automobile is an example of manual ignition control4 ,should the point of ignition vary from the theoretical point it will result in a loss of fuel and power1 and for this reason the ignition should be under at least an approximate control4 ,a wide variation in engine speed has a very considerable effect on the ignition point as there is less time in which to burn the mixture at high piston speeds1 and consequently the ignition must be further advanced to insure complete combustion at the end of the stroke4 ,this fact is evident to those who have driven automobiles4 ,should the ignition occur too early1 so that combustion is complete before the piston reaches the end of the stroke1 there will be a loss of power due to the tendency of the pressure to reverse the rotation of the engine4 ,when starting an engine1 over-advanced ignition will throw the crank over in the reverse direction from which it is intended to go1 and will not only prevent the engine from coming up to speed but will prove dangerous to the operator4 ,due to the effects of inertia and self induction in several types of ignition apparatus1 a greater advance will be required than that demanded by the combustion rate of the mixture4 ,this sluggishness of the apparatus in responding to the piston position is called ignition ,,lag4 ,the total advance required to have the combustion complete at the end of the stroke is equal to the advance required by the burning speed plus the ignition lag4 ,since lag is principally due to inertia effects1 it is much greater at high speeds than at low1 and it therefore causes an additional advance at high speeds4 ,causing the ignition to occur before the crank reaches the upper dead center is called ,,advanced ,,ignition1 causing it to occur after the piston has reached the upper dead center1 or when on the outward stroke1 is called ,,retarded ,,ignition4 ,ignition is retarded when starting an engine to prevent it from taking its initial turn in the wrong direction4 ,as the combustion takes place after the compression1 with the piston moving on the working stroke1 in retard1 it is impossible for the pressure to force the piston in any direction but the right one4 ,excessively retarded ignition will cause a power loss and will also cause overheating of the cylinder and valves as the combustion is slower4 7#ge7 ,preignition4 ,preignition which is in effect the same as over-advanced ignition as due to causes within the cylinder such as incandescent carbon deposits or thin sharp edges in the cylinder that have become incandescent through the heat of the successive explosions4 ,preignition is very objectionable since it causes heavy strains on the engine parts and causes a loss of power in the same way as over-advanced ignition4 ,any condition that causes the preigniting of the charge should be removed immediately4 7#gf7 ,misfiring4 ,the failure of the ignition apparatus to ignite every charge is called ,,misfiring4 ,this missing not only causes a waste of fuel and a loss of power but it also causes an increased strain on the engine parts because of the violence of the explosion following the missed stroke4 ,the heavy explosion is due to the fact that the stroke following the 8miss0 is more thoroughly scavenged by the two admissions of the mixture than the ordinary working stroke1 and consequently contains a more active charge4 7#gg7 ,hot ,tube ,ignition4 ,a combustible gas may be ignited by bringing it into contact with surface heated to1 or above the ignition temperature4 ,it is upon this principle that hot tube ignition is based4 ,in practice this surface is provided by the bore of a tube which is in communication with the charge in the cylinder1 the outer end of the tube being closed or stopped up4 ,around this tube is an asbestos-lined chimney which causes the flame from the ,bunsen burner to come into contact with the tube and also prevents draughts of air from chilling it4 ,a ,bunsen burner is located near the base of the tube and maintains it at bright red heat4 ,the gas for the burner is supplied from a source external to the engine4 ,when the fuel used is gasoline1 a gasoline burner is used1 which is fed from a small supply tank located five or six feet above the burner4 ,during the admission stroke1 the hot tube is filled with the non-combustible gases remaining from the previous explosion1 therefore1 the fresh entering gases cannot come into contact with the hot walls of the tube and cause a premature explosion1 before the charge is compressed4 ,as the compression of the new charge proceeds1 the fresh gas is forced farther and farther into the tube and at the highest point of compression it has penetrated far enough to come into contact with the hot portion4 ,at this point the explosion occurs4 ,the tube being of small bore1 does not allow of the burnt gases mingling with the fresh within the tube2 the waste gases in the tube acting as a regulating cushion4 ,the distance of travel of the new mixture is proportional to the compression1 hence the explosion does not occur until a certain degree of compression is attained4 ,the length of the tube required for a given engine is a matter of experiment1 as is also the location of the heated portion4 ,high compression naturally forces the mixture farther into the tube than low1 therefore the flame should come into contact with the tube at a point nearer the outer end with high compression than with a low compression4 ,shortening the tube causes advanced ignition1 as the mixture reaches the heated portion sooner1 or earlier in the stroke1 because of the decreased cushioning effect of the residue gases in the tube4 ,the length of tube and location of maximum heat zone should be so proportioned that combustion will take place at the highest compression4 ,moving flame to outer end of the tube retards ignition4 ,moving the flame toward the cylinder advances it4 ,while the hot tube is the acme of simplicity in construction1 it is not the easiest thing to properly adjust1 as the adjustment depends on compression1 temperature of the tube1 and the quality of the mixture4 ,any of these variables may cause improper firing4 ,the hot tube is rather an expensive type of ignition with high priced fuel1 as the burner consumes a considerable amount of gas1 and is burning continuously during the idle strokes as well as during the time of firing4 ,it is practically impossible to obtain satisfactory results from a hot tube on an engine that regulates its speed by varying the mixture or compression1 as engines running on a light load will not have sufficient compression to cause the mixture to come into contact with the hot surface1 the engine misfiring on light loads4 ,the tubes are made of porcelain1 nickel steel alloy1 or common gas pipe1 and are of various diameters and lengths4 ,all of these materials have their faults4 ,porcelain being very brittle1 is liable to breakage4 ,gas pipe burns out and corrodes rapidly4 ,nickel alloy is not liable to breakage1 is not so susceptible to corrosion as iron1 but is far from being a permanent fixture4 ,timing valves are a feature of some systems of hot tube ignition1 which correct to a certain extent the irregularity of firing of the plain type of tube4 ,the timing valve is introduced in the passage connecting the cylinder and tube1 and prevents the gas in the cylinder from coming into contact with the heated surface until ignition is desired4 ,the valve is operated by means of mechanism connecting it with the crank shaft4 ,it is evident that with sufficient compression in the cylinder1 the time of ignition can be obtained with certainty4 ,this mechanism is rather complicated1 and subject to wear1 and the advantage gained by the fixed point of ignition is offset by mechanical complication and consequent trouble4 ,the action of hot tube igniters is erratic and their use is not advisable unless under unusual conditions4 ,the open flame used in heating the tube is a constant menace1 as it is surrounded by inflammable vapors4 ,this feature alone condemns it in the eyes of the insurance underwriters2 in many places the use of the hot tube is prohibited both by the underwriters and city ordinances4 ,the above inherent defects of hot tubes are supplemented by breakage1 8blowing10 and clogging of the tube or passage with soot and products of corrosion1 each factor of which will cause misfiring4 ,in case of misfiring1 after determining that the tube is not broken or clogged with soot or dirt1 see that the engine is being supplied with the proper mixture2 that you are obtaining the proper compression2 and that the ,bunsen burner is delivering a bright blue flame on the tube at the proper point4 ,never allow the burner to develop a yellow sooty flame4 ,a yellow flame indicates that insufficient air is being admitted to the burner4 ,remember that an overheated tube is quickly destroyed1 and will cause misfiring as surely as an underheated tube4 ,regulate the gas supply to the burner4 ,a small leak near the outer end of the tube will destroy the cushioning effect of the burnt gas1 and hence will cause premature firing of the charge4 ,procure a new tube4 ,many engines are provided with a sliding burner and chimney which allows of some adjustment of the flame on the tube4 ,in cases of persistent misfiring1 move the chimney one way or the other4 ,it may improve the ignition4 7#gh7 ,electrical ,ignition4 ,ignition by means of an electric spark is by far the most satisfactory method as it makes accurate timing and prompt starting possible4 ,it is the most reliable of all systems and is easily inspected and adjusted by anyone having even a rudimentary idea of electricity or the gas engine4 ,for this reason electric ignition is used on practically all modern engines 7with the exception of the ,diesel types74 ,the spark is caused by the current jumping an opening or gap in the conducting path of the current1 and the ignition of the charge is obtained by placing this cap in the midst of the combustible mixture to which the spark communicates its heat4 ,the method of producing the spark gap1 and the method by which the current is forced to jump the gap1 divides the electrical ignition system into two principal classes3 7#a7 ,the ,,make ,,and ,,break1 or ,,low ,,tension system4 7#b7 ,the ,,jump ,,spark or ,,high ,,tension system4 ,in either system the spark is produced by the electrical friction of the current passing through the high resistance of the gas in the spark gap4 ,the incandescent vapor in the gap formed by this increase of temperatures causes the flash that is known as the spark4 ,the temperature of the gap depends principally upon the current flowing through it1 the amount of heat developed being proportional to the square of the current4 ,there is of course a practical limit to the amount of current used in the ignition apparatus to produce spark heat4 ,the limit is generally set by considerations of the life of the battery furnishing the current1 expense of generating the current1 and the life of the contact points between which the spark occurs4 ,the heat developed by an electric current is proportional to the amount of resistance offered to its flow and the strength of the current employed4 ,the greater the resistance1 the more heat developed4 ,the resistance of copper wire 7the usual conducting path71 being very low causes little rise in temperature1 but the air in the opening or break has a resistance of many thousands of times the resistance of the copper2 hence the current passing across the opening spark or gap raises the air to an exceedingly high temperature4 ,with a comparatively heavy current flowing across the break1 the temperature developed is high enough to boil or vaporize any metal in contact with the spark or flame1 rendering the metallic vapors incandescent4 ,with sufficient current1 the ends of the wires which constitute the break may be melted away4 ,for the successful and continuous operation of the engine it is imperative that ends of the conducting path or terminals be made of a metal of a high fusing point in order to withstand the heat of the spark and also that the current be kept to as low a value as possible4 ,in actual construction the spark gap terminals are generally made of platinum or platino-iridium1 or an alloy of high fusing point4 ,iron is sometimes used1 but deteriorates rapidly4 ,nickel steel lasts longer than common iron or steel but is not as durable as platinum or its alloys4 ,as the temperature of the electric spark or arc is approximately #g1ejj ,f41 and the ignition temperature of an ordinary rich gas at #gj lbs4 compression is #a1ajj ,f41 it is evident that the quantity of current for ignition may be kept to an exceedingly low value4 ,high compression increases the resistance of the spark gap1 and requires higher electrical pressure to force a given current across a gap of given length4 7#gi7 ,sources of ,current4 ,the electric current that causes the ignition spark is usually generated or supplied by one of the three following methods3-- #a4 ,by the primary battery which converts the chemical energy of metal1 and some corroding fluid1 into electrical energy1 by chemical means4 #b4 ,by the magneto or dynamo that converts mechanical work or energy into electrical energy through the method of magnetic induction4 #c4 ,by the storage or secondary battery which acts as a reservoir or storage tank for current that has been generated by either of the two above methods4 ,a storage battery simply returns electrical energy that has been expended on it by an external generator4 ,a storage battery does not really generate electricity but as it is often used as a source of current for an ignition system1 we will consider it as a generator4 ,current producers that convert chemical or mechanical energy into electrical energy are called primary generators1 and are represented by the primary battery and dynamo4 ,the above methods are used for generating current for either the high or low tension systems4 ,electricity may also be produced by friction1 but as such current is without heat value it is not used for ignition purposes4 ,electricity produced by friction is called static electricity4 ,primary and storage batteries always deliver a direct or continuous current of electricity1 that is a current which flows continually in one direction4 ,dynamos are usually made to furnish a direct current1 but can be built to deliver either direct or alternating4 ,alternating current1 unlike the continuous current1 changes the direction of its flow periodically2 flowing first in one direction and then in the other1 the flow alternating in equal periods of time4 ,magnetos being a special form of dynamo can furnish either class of current1 but with few exceptions are built for generating alternating current4 ,either current may be used for ignition purposes for either high or low tension systems4 ,alternating current has several advantages not possessed by the continuous current1 when used for ignition purposes4 ,the principal advantages are3 #a4 ,alternating current does not transfer the electrode metal of contact points1 and consequently causes less trouble with vibrators and 8make0 and 8break0 ignitors4 #b4 ,magnetos generating alternating current are less complicated1 have fewer parts to get out of order1 and are cheaper to keep in repair4 #c4 ,alternating current is not liable to burn out spark coils or overheat with an excessive voltage4 #d4 ,alternating current generators can be used at any speed without the use of governors4 ,illustration3 #dc-;a4 ,the ,esselb ,rotary ,aero ,motor4 ,four ,pistons are ,contained in the ,ring ,shaped ,cylinder at the ,left ,which are so ,connected with ,cranks and ,gears in the ,gear ,box that the ,pistons and the ,cylinder ,rotate in ,opposite ,directions4 ,as the ,pistons ,rotate they also ,oscillate ,back and ,forth in ,regard to ,one ,another1 so that the ,working and ,compression ,strokes are ,performed4 ,from ,aero ,london4 ,when installing an ignition system give due consideration to the reliability of the source of current4 ,the gas engine is no more reliable than its source of current4 ,failure of the current means the failure of the engine4 7#hj7 ,primary ,batteries4 ,current is produced in a primary battery by the chemical action of a fluid known as an ,,electrolyte upon two dissimilar metals or solids known as the electrodes4 ,one of the electrodes1 the negative1 is usually made of zinc which is more readily attacked by the electrolyte than the positive electrode4 ,as the metal of the negative electrode is dissolved and passes into the solution during the process of current generation1 the electrolyte is also exhausted4 ,the production of current is accompanied by the liberation of hydrogen gas from the electrolyte from which it is displaced by the zinc taken into solution4 ,when the electrodes are immersed in the electrolyte1 and the outer ends of the electrodes are connected with a wire1 a current will flow from the positive electrode to the negative through the wire1 and from the negative to the positive electrode through the fluid4 ,it will be seen that to complete the circuit between the electrodes it is necessary that the current flows through the electrolyte4 ,electrical energy is actually generated in the primary battery by the chemical combustion of the negative electrode in the same way that heat energy is developed by the burning of a fuel4 ,by connecting the binding posts of the electrodes to the two wires of the external circuit1 a current will flow through the circuit as long as the electrodes remain undissolved1 or until the positive electrode is covered with hydrogen gas bubbles4 ,the bubbles of gas tend to insulate the positive electrode from the electrolyte or fluid1 thus breaking the circuit through the fluid1 and stopping the flow of current4 ,this action is known as polarization4 ,when a battery is polarized1 the only remedy is to disconnect it from the circuit and allow it to rest or recuperate4 ,the greater the current drawn from a battery1 the more rapid the polarization1 and it is evident that if the battery is to be used for long periods1 polarization must be eliminated1 or the current must be considerably reduced in volume4 ,a battery that delivers a small current has a much greater capacity in ampere hours than a battery that has a higher rate of discharge4 ,the greater the discharge rate the longer must be the rest periods4 ,a battery that is designed for continuous service1 or for delivering heavy currents of long duration1 is called a closed-circuit battery4 ,polarization is eliminated in closed circuit batteries by various methods1 the usual methods being to place some substance in the electrolyte that will destroy the hydrogen film2 or by packing some solid oxidizing material around the positive electrode that will absorb the hydrogen2 or by making the positive electrode of some material that will destroy the hydrogen as soon as it is developed4 ,batteries that are capable of being operated only for short periods1 on account of polarization1 are called open circuit batteries4 ,open circuit batteries are cheaper and more simple than closed circuit batteries4 ,for ignition purposes1 a battery is made that is a compromise between the closed and open circuit cells1 this being a battery in which the polarization is only partially suppressed4 ,as the demand for current on an ignition battery is small with comparatively long rests between contacts1 the compromise battery answers the purpose and is fairly cheap4 ,all primary batteries are in reality wet batteries1 for the reason that it would be impossible to cause a chemical reaction and a current with a dry electrolyte4 ,the action of dry and wet batteries is identical4 ,there are many types of wet battery in use for various purposes1 but few of them are adapted for gas engine ignition because of a tendency to polarize or because of the cost of maintenance4 ,all wet batteries are not suitable for portable or automobile engines because of the slopping of the liquid electrolyte and the danger of breaking the containing jars4 ,their weight and bulk is also a drawback4 ,if the electrolyte or the electrodes be made of impure material local currents will be generated4 ,these currents decrease the life of the cell without producing any useful current in the ignition circuit4 ,due to the deteriorating effects of the local currents1 batteries standing idle for several months will often be found to be completely discharged and worthless without having done any useful work4 ,in the better grade of cells this loss is reduced to a minimum4 ,a type of wet battery using a solution of caustic soda for an electrolyte1 and having zinc and copper oxide electrodes1 is extensively used for stationary ignition purposes1 and is the most satisfactory type of wet cell for continuous work with this class of engine4 ,the caustic soda battery is of the ,,closed circuit type1 and is capable of furnishing a strong uniform current without danger of polarization4 ,the hydrogen bubbles which cause polarization are oxidized or eliminated by the copper oxide electrode as soon as they are formed4 ,the hydrogen combines with the oxygen of the copper oxide forming water4 ,the copper oxide is gradually reduced to metallic copper by the reaction with the hydrogen1 and in the course of time requires renewal4 ,the copper oxide element is rather expensive and cannot be obtained as readily as the electrodes used in other cells4 ,it will be noted that both electrodes are consumed in the caustic battery1 the consumption of the zinc furnishing the current1 and the reducing of the oxide furnishing the chemical energy for depolarizing the cell4 7#ha7 ,dry ,batteries4 ,dry batteries are by far1 the most convenient and economical form of primary battery to use1 for there is no fluid to slop and leak1 the first cost is low1 the output is large for the weight1 and last but not least1 the cell can be thrown away when exhausted without great monetary loss4 ,this does away with the expense and annoyance of changing wet cells1 a factor that will be appreciated by those that are far from a source of chemical supplies4 ,since the advent of the automobile the use of dry cells has extended so that they may be obtained in almost any country town or village4 ,while the cell is not dry1 strictly speaking1 the solution is held in such a way that it cannot slop around in the cell nor leak out of the seal4 ,the only fault of a dry cell is its tendency to deteriorate with age because of the constant contact of the electrolyte with the electrodes4 ,the negative electrode of the dry cell 7zinc7 is in the form of a cup which serves as a containing vessel for the electrolyte and the depolarizer4 ,the electrolyte is usually composed of a solution of ammonium chloride1 with a small percentage of zinc sulphate1 this fluid being held by some absorbent material such as blotting paper1 or paper pulp4 ,the electrolyte is applied to the electrodes by means of the saturated blotting paper1 which is also used to line the zinc container1 thus providing insulation between the electrodes4 ,a rod of solid carbon which forms the positive electrode is placed in the center of the container1 and the space between the rod and the zinc is packed solidly with granulated carbon1 the blotting paper lining preventing contact of the zinc with the carbon4 ,pulverized manganese dioxide is mixed with the granulated carbon for a depolarizer4 ,illustration3 ,brookes ,four ,cylinder ,gasoline ,engine ,direct ,connected to ,dynamo4 ,after the zinc container is filled with the electrolyte and pulverized carbon1 the top of the container is closed hermetically by means of sealing wax4 ,granulated carbon is used for it presents a large surface to the electrolyte1 reduces the internal resistance of the cell1 and therefore increases the current output of the battery4 ,as soon as the battery starts generating current1 polarization begins1 with the liberation of hydrogen gas4 ,if the cell is discharged at a high rate1 the manganese dioxide will be unable to absorb all of the gas1 and consequently pressure will be erected within the cell4 ,the greater the rate of discharge1 the greater will be the amount of hydrogen set free1 and the higher the pressure4 ,if a short circuit exists for any length of time1 the pressure of the excess hydrogen will speedily ruin it1 as the cell will puff up1 or even burst under the pressure4 ,if the rate of discharge be kept so low that all of the gas will be absorbed by the manganese1 as soon as generated1 the cell will furnish a steady current until the elements of the cell or the electrolyte are exhausted4 ,the steady current limit1 or non-polarizing limit is about one-half ampere and if long life of the cell is expected1 the current drain should be less than this amount4 ,a good spark coil will develop a satisfactory spark on a quarter to one-half ampere1 so that the demand of a good coil is well within the safe limits of battery capacity4 ,the voltage of the average dry cell when in good condition is #a4e volts on open circuit4 ,when the cell is old or exhausted1 the voltage falls rapidly when any demand for current is made on the cell1 and the voltage also varies with the rate of current flow1 the voltage decreasing with an increase of current4 ,as there is not much difference in voltage between a new and old cell when on open circuit1 it will be seen that the ammeter giving the current output will give a more accurate determination of the condition of the battery4 ,the voltage is independent of the size of cell4 ,the battery showing the greatest amperage is not necessarily the best for general use1 as cells having an unusually high current capacity are generally short lived4 ,the strong electrolyte used in high ampere batteries causes them to burn out or deteriorate rapidly when not in use4 ,under ordinary conditions1 a correctly proportioned ,no4 #f ignition cell should show a current of from fifteen to twenty amperes on short circuit when the cell is new1 although higher results may be obtained safely with some makes of cells4 ,while the voltage is the same for all sizes of batteries1 and depends on the material used in the construction1 the amperes increase with the size of the cell1 and the area of the electrodes4 ,if a cell does not show more than ten amperes on short circuit1 it should be thrown out and another substituted for it1 as the cell is liable to go out of commission at any minute when reaching this point of exhaustion4 ,a small battery testing voltmeter or ammeter should be in the kit of every gas engine operator using a battery for ignition1 as the exact condition of a vital part of the power plant can be determined quickly and with accuracy4 ,for dry batteries an ammeter is preferable2 for storage batteries a voltmeter must be used4 ,when buying dry batteries insist on having new1 fresh cells1 as any battery depreciates in value with age4 ,never take a cell without testing it1 as it is the practice of dealers to work off their old stock on unsuspecting customers4 ,examine the battery closely for the makers' dates1 and if the battery is several months old1 it is probable that the electrolyte is dried up or that the electrodes are wasted through long continued local action4 ,as heat stimulates chemical action in the cell1 they should be stored in a cool place to retard the wasting action as much as possible4 ,under all conditions1 the cell should be kept dry1 since the moisture that is deposited on the cell forms a closed circuit for the current which soon exhausts the battery4 ,cold retards chemical action in the cell and consequently reduces the output in zero weather to such an extent that starting is frequently impossible4 ,multiple cylinder engines exhaust a battery quicker than those with a single cylinder1 as there are more current impulses in a given time and consequently more current is used4 ,a battery may be compared with a bottle that holds a certain quantity of fluid4 ,if the water is allowed to drip out slowly it will last for a long time1 but if allowed to flow in a continuous stream will soon be exhausted4 ,with badly designed or poorly adjusted spark coil1 the demand on the batteries is greater than with one that is in proper condition4 ,an engine that runs continuously exhausts a battery faster than one that is run at long intervals4 ,always open the battery switch when the engine is to be idle for any length of time1 as the engine may have stopped with the igniter in contact1 allowing the battery to expend its energy uselessly4 ,test batteries immediately after a run1 as the batteries will recover after standing a while1 and will show a fictitious value4 ,a weak1 partially exhausted battery will cause a poor spark that will result in misfiring or a loss of power4 ,it is poor economy to attempt running an engine on a weak battery4 ,an engine may run on a weak battery for a short time1 and then gradually decrease in speed until it comes to a full stop4 ,misfiring is generally in evidence as the engine dies down4 ,in case of an emergency1 weak batteries may be made to run an engine of an automobile or boat to its destination1 by stopping the engine frequently and allowing the batteries to recuperate during the idle periods4 ,a battery that is temporarily weakened by hard service or by a temporary short circuit will usually revive or partially recover its strength if allowed to 8rest0 for a short time until the hydrogen is absorbed by the depolarizing material4 ,the life of a dry cell can be extended for a few hours by punching a hole in the sealing wax on the top of the battery1 and pouring water1 or a solution of water and sal-ammoniac into the cell4 ,this will reduce the internal resistance and increase the current4 ,the batteries will run under these conditions for a short time only1 and new cells should be procured at the earliest possible moment4 ,no old cell can be made as good as new by any method4 ,never drop the cells on the floor nor subject them to hard usage mechanically1 for if the active material is loosened1 the current output will be reduced4 ,a short circuit through a closed switch with the engine stopped or a loose dangling wire will put the cells beyond repair4 ,if the binding screw on the carbon electrode does not make good contact with the carbon1 tighten it to decrease the resistance4 ,fasten the connecting wires firmly under the binding screws and keep the connections clean4 ,in the absence of an ammeter1 a rough estimate of the condition of the cell may be made by fastening a short wire tightly in the zinc binding post1 and touching the carbon surface lightly and intermittently with the free end of the wire4 ,when contact is made with the free end of the wire1 a small puff of smoke will arise and a red spark will be seen if the cell is in good condition4 ,sometimes the contact made on the carbon will produce only a small black ring on the surface of the electrode4 ,this indicates a battery that is nearly exhausted1 and one which is good for only a few more hours of service4 ,when a number of cells are connected together in such a way that they collectively form a single source of current1 the group is called a battery1 and the resulting voltage and amperes of the group depends on the way in which the cells are interconnected4 ,it is possible to connect the cells of a battery in such a way that total voltage of the group or battery is equal to the sum of the voltages of the individual cells4 ,a battery connected in this manner is said to be connected in series4 ,while the voltage of a battery is increased1 by series connection1 the number of amperes is the same as that given by a single cell1 the same current flowing through the set4 7#hb7 ,series and ,multiple ,connections4 ,fig4 #hf shows the cells connected in series1 the carbon terminal of one cell being connected to the zinc terminal of the second4 ,the carbon of the second cell is connected to the zinc of the third1 and so on throughout the series1 the two remaining terminals of the battery being connected with the ignition circuit4 ,the number of watts or power developed by the group is equal to the sum of the outputs of the separate cells4 ,if the voltage of each cell shown in diagram is #a4e volts1 the total voltage of the group of five cells will be #a4e #e #g4e volts1 and if the current of a single cell is #ae amperes1 the current output of the group will be #ae amperes1 or the same as that of a single cell4 ,almost all ignition apparatus now on the market requires six volts for its operation1 so with cells having a voltage of #a4e volts such apparatus would call for four cells in series1 as #f #a4e #d4 ,illustration3 ,fig4 #hf4 ,five ,cells in ,series4 ,owing to the increase of internal resistance caused by series connections it is usual to add one more cell than is theoretically required1 making a group of five cells to supply the six volts required4 ,a large number of cells will give a hotter spark than a smaller1 but the excessive current causes the contact points of the igniter or vibrator to burn off rapidly and also hastens the destruction of the cells themselves4 ,batteries connected in such a way that the total amperes of the group is increased without increased voltage are said to be connected in multiple or parallel4 ,when batteries are connected in multiple1 the total current in amperes is equal to the sum of the amperes delivered by the separate cells2 and1 while the current in amperes is increased by multiple connection1 the voltage of the group remains equal to that of a single cell4 ,if each cell connected in multiple has an electromotive force of #a4e volts1 and can deliver #ae amperes1 the total current delivered by this system of connection will be #ae #e #ge amperes with five cells1 and the electromotive force will be #a4e volts as in the case of the single cell4 ,by connecting batteries in multiple1 the resistance is reduced1 allowing a maximum flow of current4 ,the demand on the individual cells is reduced by multiple connection1 as each cell only furnishes a small part of the total current4 ,the greater the number of cells1 the less will be the current required per cell1 with a given total current4 ,as the life of a battery depends entirely upon the rate at which it is discharged1 it is necessary1 for economical reasons1 to keep the current per cell as small as possible1 therefore the multiple system would prove of value as it reduces the load to the smallest possible limit4 ,enough cells should be placed in multiple to reduce the current to less than a quarter of an ampere per cell4 ,the cells shown will not have sufficient voltage to operate ordinary ignition apparatus requiring a potential of six volts1 hence the multiple system must be modified in order to have an increased voltage1 and at the same time secure the advantages of multiple connections4 7#hc7 ,multiple-,series ,connections4 ,a compromise is affected by the multiple series system of connections in which are combined the advantages of both the series and multiple systems of connection4 ,this arrangement allows sufficient voltage to operate #f volt apparatus and at the same time reduces the rate of discharge on the individual cells4 ,the series-multiple battery shown in the diagram #hh consists of four groups of batteries connected in multiple1 each group of which consists of five cells that are connected in series4 ,the current and voltage in the various branches is shown in the diagram4 ,the series-multiple system is adapted for use with multiple cylinder engines1 as engines with more than one cylinder cause a severe drain on the ignition system4 ,arranging the series groups in parallel increases the life and efficiency of the cells4 ,if an efficient coil is used1 the drain of a single cylinder is not too great to be met with a single set of series cells4 ,if possible the set should be provided with a duplicate1 so that the load could be transferred from one set to the other at proper intervals by means of a double throw switch4 ,with a single set of batteries in series the working life of the cells will be approximately twenty hours under ordinary conditions4 ,with four groups of four cells in series1 the life of the cell will be approximately #afj hours1 or eight times the life of the single set under similar conditions4 ,while the cost of the cells will be only four times that of the single set1 it will be seen that the cost of battery upkeep is halved by reducing the demand on the cells4 ,sometimes duplicate sets of series multiple connected batteries are used for heavy duty engines1 the engine running on one set for a while and then on the other1 allowing the first set to thoroughly recuperate before it is again thrown in service1 by means of the double throw switch4 ,when batteries are multiple or series-multiple connected they should be of the same size and make and of the same voltage4 ,if the cells are of different voltages useless local currents will circulate among the cross-connections1 shortening the life of the battery and reducing the output4 ,illustration3 ,fig4 #hh4 ,cells in ,multiple ,series4 ,in connecting a dry cell use a good grade of rubber insulated wire1 preferably wire with a stranded conductor1 as it is less liable to break or loosen at the binding screw of the battery4 ,carefully remove the insulation from the end of the wire that is to be fastened under the binding screw of the battery4 ,scrape it until it is bright and perfectly free from dirt before fastening it in the battery terminal4 ,never allow a dirty or corroded connection or a loose wire to exist4 ,an open battery circuit or loose connection will stop engine suddenly1 or will prevent starting4 ,the battery connections should be screwed down tight with the pliers1 care being taken that the screws are not broken by the tightening process4 ,see that frayed ends of the wire do not project beyond the binding screw to which they are connected and make contact with other cells or metal objects4 ,be sure that no insulation gets between the contact braces of the binding screw4 7#hd7 ,operation of ,dry ,cells4 ,the following hints should be observed to obtain the best results with dry cells4 7#a7 ,never remove the paper jackets from the cells4 7#b7 ,never lay tools or other metallic objects on top of the cells for this will cause a 8short0 that will quickly exhaust them4 7#c7 ,do not connect old and new cells together1 especially with the multiple-series system of connections1 for the old cells will limit the output of the new1 or else will cause cross-currents that will exhaust all of them4 7#d7 ,when trouble develops in the battery1 test each cell separately and remove the faulty cells4 ,do not reject all of the battery because of one or two dead cells4 7#e7 ,place the cells in a wooden box that will protect them from dirt or moisture1 and if possible divide the box off into pigeon holes with a cell in each hole4 ,for the best protection against moisture1 the box should be boiled in paraffine4 7#f7 ,provide a battery switch on the box that will cut both leads from the cells completely out of circuit when the engine is stopped4 7#g7 ,never place a dry cell in a box that has contained storage cells unless the box has been thoroughly washed out1 for the residual acid of the battery will destroy the zinc elements4 7#h7 ,make all connections firmly with well insulated wire and take care that the wire does not make contact with any part of the battery except that to which it is connected4 7#i7 ,keep the battery dry4 7#he7 ,storage ,batteries4 ,the purpose of the storage battery is to store or accumulate the current generated by a dynamo until so that the current will be available when the dynamo is not running4 ,a storage cell does not 8store0 current in the same way that water is held in a tank1 but returns the energy expended on it through the chemical changes caused in the cell by the current4 ,when the charging current passes through the storage battery chemical changes are produced in the electrodes and electrolyte1 and the energy expended on the cell is in the form of latent chemical energy1 in which state it remains until the electrodes are connected with one another by a wire or some other conducting medium4 ,when the electrodes are connected through an external circuit1 the electrolyte acts on the electrodes causing them to assume their original composition4 ,as they pass into their previous chemical condition the latent chemical energy is converted into electrical energy4 ,the current thus produced may be used in the same way as in a primary cell4 ,when discharging1 the action of a storage battery is similar to that of a primary battery1 the current being produced by the action of a fluid on two dissimilar electrodes4 ,instead of supplying new elements when the battery is discharged1 as in the case of the primary cell1 the elements are brought back to their original state by passing a current through the cell in the opposite direction to that of the discharge4 ,there are several combinations of materials which may be used in the making of storage battery electrodes and electrolytes1 but with the exception of the lead sulphuric battery and the new ,edison battery none have proven a commercial success4 ,the most common type of storage or secondary cell is the lead-sulphuric type in which the electrolyte is dilute sulphuric acid and the electrodes are lead plates1 covered with a chemical composition known as the active material4 ,these plates usually consist of a lead grid1 or lattice frame in the pockets of which is pasted the active material4 ,the pockets or lattice bars of the plates are for the purpose of supporting the active material which is of a weak and spongy nature4 ,the active material on the positive plate is usually litharge1 while that on the negative plate is red lead4 ,after charging1 the active material on the positive plate is changed to lead peroxide by the action of the current1 and the active material on the negative plate is changed into spongy metallic peroxide4 ,the composition of the active material on the plates determines the direction of flow of the discharge1 or secondary current4 ,the current flows from the positive plate to the negative through the external circuit4 ,when fully charged1 and in good condition1 the positive and negative plates may be readily distinguished by their colors1 the positive plate being a dark brown or chocolate color1 and the negative a slate or grey color4 ,the positive active material is hard1 while the negative may be easily cut into by the finger nail4 ,the density of the material changes slightly with the charge1 as the material expands during the discharge4 ,the problem of holding the active material securely to the plates during expansion and contraction has been a hard one to solve1 each manufacturer having some favorite form of grid or material plug to which he pins his faith4 ,while great improvements have been made in this direction1 it is certain that we have not yet reached perfection4 ,loose active material will cause short circuits and will reduce the output of the cell2 loose active material frequently ruins a cell4 ,the current capacity of a storage battery depends on the area of the plates or electrodes1 and in order to increase the capacity of a battery1 and consequently the area1 it is usual to use a number of plates connected in parallel4 ,a number of small plates of a given area are to be preferred to two large plates of the same area1 as the battery will be of a more convenient size4 ,customarily there is one more negative plate than positive1 so that the extreme end plates in a cell are negative1 as the positive and negative plates alternate with each other when assembled4 ,an ignition battery usually consists of two negative plates and one positive4 ,cells used for power purposes have as high as sixty plates4 ,a single cell of storage battery should show about two volts when fairly well charged4 ,if more than two volts are desired more cells should be connected in series4 ,the total voltage will be equal to the number of cells1 in series1 multiplied by the voltage per cell4 ,the voltage per cell should never be allowed to drop below #a4g volts1 as the cell is likely to be destroyed when operated with a low voltage4 ,recharge as soon as the voltage drops to #a4h volts4 ,the ordinary six volt ignition battery consists of three separate cells connected in series1 which are encased in one protecting box4 ,the plates are prevented from touching each other within the cell by means of a perforated sheet of hard rubber that is inserted in the space between the plates4 ,the perforations allow the liquid to circulate between the plates4 ,the storage battery is furnished as standard equipment with several well known gas engine builders1 and its use is advocated by nearly all4 ,when used in connection with a low tension direct current magneto two independent sources of current are at hand1 either of which will ignite the engine in an emergency4 ,with the magneto-storage battery combination1 it is possible to obtain a few small lights at any time1 whether the engine is running or not1 and the engine is always ready to start on the first 8over0 with the storage battery and a good mixture4 ,if a magneto is not used1 difficulty is sometimes experienced in obtaining a suitable source of charging current1 as many localities do not possess direct current plants4 ,batteries may be charged from the direct current exciter in an alternating current station1 or may be charged by an alternating current rectifier such as is used by automobile garages4 ,the principal objections to the storage cell are3 inconvenience of charging2 sulphating of cell when standing without a charge2 ease with which the cell is ruined by short circuits2 the damage caused by the spilling of the electrolyte2 and the fact that the cell gives no warning of failing or discharged condition4 ,since the composition of the plates depends on the direction in which the current flows through the cell1 it is obvious1 that an alternating current which periodically changes its direction of flow will first charge the plates and then discharge them alternately4 ,the result of an attempt at charging with alternating current would be that the plates would be in the same or a worse condition in a short space of time than they were at the beginning4 ,in charging a storage cell care should be taken to determine the character of the current1 especially when the cell is to be charged from a magneto4 ,when under charge1 the cell is connected to the charging circuit in such a way that the current flows backwards through the cell or in a direction opposite to that when the cell is discharging4 7#hf7 ,care of the ,storage ,cell4 ,the storage battery should never be left in an uncharged condition with the acid electrolyte in the cell1 for the solution will quickly attack the uncharged plates and combine with them to form lead sulphate4 ,as lead sulphate has a high electrical resistance and is insoluble in the electrolyte the sulphate coating will reduce the output or if present in excess1 ruin the cell4 ,the sulphate appears as a white coating on the surface of the plates4 ,the only remedy for this condition at the hands of the average engine operator is a prolonged charge1 or over charge1 at a slow rate4 ,there are several chemical processes but they are too complicated for the average man4 ,as sediment collects on the bottom of the battery jars1 and is liable to cause a short circuit1 the plates should be held about half an inch from the bottom of the jar4 ,care should be taken that the cells of the stationary type of battery are kept dry and clean4 ,do not allow dirt to drop into the solution as it is liable to destroy the cell4 ,a volt meter should be used to determine the condition of the battery1 and should be used frequently4 ,an ammeter should never be used on a storage battery1 as it is of very low resistance1 and would probably cause a rush of current that would destroy both the battery and the instrument4 ,never short circuit a storage battery1 even for an instant1 as excessive current will cause the plates to buckle1 or will loosen the active material on the plates4 ,the plates are immersed in the electrolyte1 which should cover the entire plate or active surface4 ,if the solution does not cover the plate1 the capacity of the cell will be reduced4 ,plates that are partially covered with solution deteriorate rapidly from 8sulphating40 ,this is caused by the air and acid acting on the damp inactive portion of the plate4 ,usually the electrolyte consists of a dilute solution of sulphuric acid and water1 but in some ignition cells the solution is 8solidified0 by some substance to about the consistency of table jelly4 ,the object of this thickened solution is to prevent the solution from slopping and leaking when the battery is being transported4 ,the solution used in a storage battery is exceedingly corrosive in its action1 and if spilled on metal or wood will destroy it immediately4 ,care should be taken in handling the electrolyte4 ,a cell should never be discharged below #a4g volts for below this point1 the plates are likely sulphate4 ,when the solution is replaced by fresh1 or water is added for the purpose of restoring the electrolyte to its original level1 use only distilled water1 free from metallic salts and suspended matter4 ,many people 8test0 their cells by snapping a wire across the terminals to 8see if there is a good spark40 ,nothing could be more injurious to the battery1 and as this test indicates nothing1 the practice should be discontinued4 ,make all your tests either with a hydrometer or a voltmeter1 the latter is preferable in the average case4 ,the electrolyte is a solution containing approximately #aj of chemically pure sulphuric acid and #ij of distilled water4 ,the specific gravity of the fluid should be from #a1baj to #a1bab in all cases4 ,a standard battery hydrometer should be used by all storage battery users to ascertain the exact density of the solution as the specific gravity is a direct index to the condition of the cell4 ,a gasoline hydrometer is useless for a storage battery4 ,when mixing the electrolyte it should be placed in a glass or porcelain jar1 and the process should never be performed in the battery jar in the presence of the plates4 ,the solution is very active chemically and should not be brought into contact with metallic or organic substances because of the danger of contaminating the fluid4 ,the acid should always be poured into the water in a thin stream while the mixture is being stirred with a glass or porcelain rod4 ,pouring the water into the acid is likely to produce an explosion and should therefore be carefully avoided4 ,as the acid heats the water during the mixing the hydrometer reading should not be taken until the heat caused by the first addition of acid has been reduced to that of the room4 ,taking a reading with a hot solution will give inaccurate results1 unless1 of course1 the reading is reduced to normal by the method described in a previous chapter4 ,when the reading has been taken and found to be correct and the solution has been reduced to the temperature of the room1 the electrolyte may be poured into the cell through the filler openings in the top of the cell4 ,pour into each cell sufficient fluid to cover the plates but avoid filling the cell to the top1 or flooding it4 ,at the end of the charging time given by the maker1 withdraw a sample of the electrolyte by means of a syringe and test the specific gravity4 ,this should not be over #a1bij for a fully charged cell1 and if the solution exceeds this amount1 pure water should be added until the proper point is reached4 ,always correct the specific gravity in this way every time the battery is charged as evaporation and internal chemical changes cause the density to change from time to time4 ,the voltage of a good storage battery will be about #b4a volts when fully charged4 ,overcharging is wasteful and finally destroys the cell1 the effects being similar to those caused by excessive discharges1 that is1 buckled plates and loosened active material4 ,overcharging a sulphated battery may cure the trouble1 a little overcharging at intervals being better than a long continued overcharge4 ,an increase in the specific gravity of the electrolyte of from #cj to #ej degrees1 with a corresponding rise of voltage1 shows that the cell is fully charged4 ,after the charging is completed remove all of the solution spilled on the battery1 preferably by washing1 and wipe bone dry4 ,if the solution is higher in the air1 remove the excess with the syringe4 7#hg7 ,make and ,break ,system 7,low ,tension74 ,when a circuit carrying a current is opened or broken at any place in its length1 an electric spark will occur at the point at which the wires or contacts are separated4 ,this is due to what might be termed the 8momentum0 of the current which causes it to persist in its course even to the extent of jumping over a short distance of the highly resistant air in the gap4 ,the size and heat of the spark may be increased by placing a coil of copper wire in series with the circuit that has an iron core in the center of the turns4 ,this coil increases the tendency of the current to jump the gap1 or in other words increases the momentum of the circuit4 ,each separation of the terminals of the circuit causes but a single spark1 so that in order to obtain another the terminals must be again brought into contact and the current reestablished in the circuit before the circuit is again opened4 ,thus the function of the make and break igniter is to alternately make and break the circuit in the presence of the combustible mixture4 ,to obtain the greatest spark and most certain ignition1 the contact points should be opened with the greatest possible speed1 an action that is accomplished in the actual engine by springs and triggers4 ,a typical cylindrical make and break coil consisting of an iron wire core surrounded by a coarse copper wire core is shown by ,fig4 #ia4 ,at one end of the coil will be seen the two terminal screws by which it is connected with the circuit4 ,another make and break coil is shown by ,fig4 #ib1 which has the same type of winding1 but differs in having the core wire coil extended beyond the winding and heads4 ,by closely examining the cut1 the iron wires will be seen in the projecting core tube at the left end of the coil4 ,a flat base is also provided for fastening it to a stationary foundation4 ,a typical make and break igniter is shown by ,fig4 #ic1 together with the usual circuit consisting of a primary coil and battery4 ,in this figure1 ,a and ,c are the two electrodes provided with platinum contact points ,n and ,o respectively4 ,the electrode ,a is stationary and is insulated from the iron casing ,k by the insulating washer ,h1 and the insulating bushing or tube ,i4 ,the electrode ,c is oscillated intermittently by the engine through its shaft ,e1 and the trigger ,g1 the springs ,s serving to snap the platinum contact ,o away from ,n at the proper moment4 ,this electrode 7,c7 is in electrical connection with the shell ,k1 and the engine frame at all times1 and is provided with a brass bushing ,f for a bearing surface4 ,the outer containing casing ,k is bolted to the combustion chamber of the engine by the bolts ,,ll1 so that the electrodes ,a and ,c project into the combustion chamber4 ,illustration3 ,fig4 #ia4 ,kingston ,cylindrical ,make and ,break ,coil4 ,illustration3 ,fig4 #ib4 ,kingston ,make and ,break ,coil4 ,short ,type4 ,current from the battery ,r passes through the coil winding ,p to the coil terminal ,u from which it passes from ,v to the igniter binding post ,j4 ,from ,j it flows along the rod ,d to the stationary electrode ,a4 ,since the rod ,d is surrounded by the insulating washers and tube ,h1 ,t and ,i1 the current cannot escape directly to the casing ,k4 ,with the two platinum points ,n and ,o in contact1 the current flows through ,c to the shell ,k from which point it flows back to the battery ,r through the conducting path ,v1 completing the circuit4 ,the greater portion of the path ,v consists of the engine frame4 ,when the electrode is moved in the direction of arrow ,b1 the current is opened and a spark occurs at the point of separation ,m1 in contact with the gas in the combustion chamber4 ,the electrode ,c being connected with the engine frame is said to be 8grounded40 ,if the stationary electrode ,a were not insulated from the casting ,k1 the current would pass directly from the terminal ,j back to the battery ,r without passing through the contact points at all1 and consequently no spark would be produced on the separation of the points4 ,illustration3 ,fig4 #ic4 ,diagram of ,igniter and ,connections4 ,a push rod which is actuated by a cam on the engine1 engages with the trigger ,g1 and causes the spark to occur when the piston is on the end of the compression stroke4 ,in nearly all engines1 the relation between the time of the spark and the piston position can be regulated to suit the requirements for advance and retard4 ,this adjustment is necessary in order that the spark may be varied to meet the difference between the starting and running requirements4 ,while the ignition should be considerably advanced while running1 it is necessary to retard it when starting1 as the engine is liable to 8kick back0 with an advanced spark4 ,this advance and retard device should be accessible while the engine is running1 and the operator should be able to control the point of ignition at all times4 ,many men have been seriously injured by the lack of this device or by neglecting to use it4 ,the contact points make contact only for a short time before the spark is required in order to reduce the amount of current to the minimum1 and therefore increase the life of the batteries4 ,the duration of the 8make0 or contact should be as short as possible4 ,prolonged contact weakens the batteries and causes them to run down rapidly4 ,for the same reason the electrodes should remain separated until the make is actually required4 ,a certain period of contact is necessary1 however1 to allow the spark coil to 8build up10 but with a properly designed coil the time required is very short4 ,some engines provide a device that cuts out the ignition current altogether during the idle strokes4 ,this adds materially to the life of the batteries4 ,the igniter should be located near the inlet valve1 as the cold incoming gases tend to keep it cool and clean1 besides insuring the presence of combustible gas around the igniter electrodes4 ,improper placing of the igniter will greatly reduce the efficiency of the engine4 ,avoid placing the igniter in a pocket1 or in the path of the exhaust gases4 ,the make and break ignition system has many good features1 but cannot successfully be applied to engines running over #ejj revolutions per minute1 nor can it be applied to engines of less than #c ,h4 ,p4 as the parts would be too small and delicate to be durable4 ,the make and break igniter produces the largest and 8hottest0 spark of any type of ignition1 and is especially desirable for large or slow running engines4 ,being operated at a low voltage1 it is not as easily affected by moisture1 poor insulation1 or dirt as the high tension or jump spark system1 nor is it liable to give the operator such a violent 8shock40 ,engines governing by the 8hit and miss0 system have a device that cuts out the current during the 8missed0 power strokes4 ,this effects a considerable saving in battery current1 especially on light loads when the engine misses a great number of strokes4 ,while possessing many points of merit1 the make and break system is open to several serious objections3 #a4 ,due to the high combustion temperature there is excessive wear of the working parts in the cylinder1 this wear causes a change in the ignition timing4 #b4 ,the low voltage used in the make and break system calls for perfect contact of the electrodes in the cylinder4 ,this contact is often interfered with or entirely prevented by the accumulation of carbonized oil and soot deposited on the surfaces4 #c4 ,the wear of the operating spindle or shaft1 which passes through the cylinder wall causes leakage1 which in turn causes a loss of compression in the cylinder4 #d4 ,the wear of the external operating mechanism produces a change in the timing4 ,the edge of the fingers1 wiper blades1 etc41 tend to cause an advance in the ignition as a general rule1 with the attendant danger of broken crank shafts4 #e4 ,the system is mechanically complicated1 correct operation calling for constant care as to adjustment4 ,all ignition apparatus wears in the course of time and changes the timing of the engine4 ,the electrodes and push-rods wear and require readjustment4 ,generally the tendency of worn parts is to advance the ignition4 ,this change in timing occurs so gradually that the operator does not notice it until the engine begins to pound1 or until the efficiency has been considerably reduced4 ,when the engine is new it is well to mark the ignition mechanism in such a way that the relative positions of the crank and igniter will be shown at the time when the igniter trips4 ,it will then be possible for the operator to refer to the marks at any time to tell whether his ignition is occurring at the proper time4 ,always mark the half-time gears when taking the engine apart for the difference of one tooth when reassembling will be sufficient to throw the engine out of time4 ,the usual method of marking the gears1 is to center punch1 or scratch one tooth on the small gear1 and then mark the two teeth of the large gear that lie on either side of it4 ,with these marks it is possible to replace the gears in their original and proper positions4 ,the igniter should trip1 causing the electrodes to separate just before the end of the compression stroke is reached1 or just before the crank reaches the inner dead center4 ,the distance lacking the exact dead center represents the instant of time between the time of ignition and the actual pressure established by the combustion4 ,as most engines have the ignition considerably retarded when starting1 the igniter will trip later with the lever in the 8start0 position than when in the 8running0 position4 ,never fail to retard spark when starting nor forget to advance it when engine is up to speed4 ,the actual advance given to an engine depends on the character of the fuel and on the speed4 ,an engine is said to have an advance of #aj1 if the crank lacks #aj of having made the inner dead center at the time of ignition4 ,the most economical point of ignition is easily determined when the engine is running on a steady load1 by varying the point of ignition and noting the position assumed by the governor4 7#hh7 ,operation of the ,make and ,break ,igniter4 ,to keep the igniter in order1 and to obtain the best results with the least trouble1 the following hints should be observed3 7#a7 ,clean the igniter frequently1 and remove all deposits of oil and carbon4 ,for cleaning1 the igniter must be removed from the cylinder1 care being taken to avoid injury to the packing or gasket4 ,graphite dusted on the gasket will prevent it from sticking to either the igniter or cylinder4 7#b7 ,if the contact points are rough1 pitted1 or covered with a carbon deposit1 the scale should be removed1 and the points smoothed down with a fine file1 taking care that the two faces are filed parallel with one another4 7#c7 ,insulating washers and tubes should be removed and washed in gasoline4 ,the hole through which the igniter rod passes should be scraped free from any deposit for much trouble can be caused by a tight working shaft4 7#d7 ,examine the hole or bushing through which operating spindle passes1 for wear4 ,a worn spindle or bushing may cause a serious loss of compression2 replace worn bushing at once4 ,see that the insulation of the stationary electrode is not broken4 ,if it is injured in the slightest degree1 replace it with new4 7#e7 ,often the sparking points may be cleaned temporarily without removing the igniter from the cylinder by pulling upon the outside finger or trigger until the points come together1 and then pushing in towards the cylinder several times on the movable electrode1 which slides them one on the other1 scraping off the deposit4 ,this method is only a make shift4 7#f7 ,after removing igniter1 replace all wires1 screwing them firmly into place4 ,the ends of wires and connecting screws should be perfectly clean when the connection is made2 to insure perfect contact1 the surfaces should be scraped or sand-papered until bright and shining4 ,see that no foreign matter of any kind gets between the wires and the metal of the binding screws4 ,wherever possible connections should be soldered4 7#g7 ,a small coil of the wire should be made at the point of connection2 i4 e41 the wire should be a trifle longer than necessary to reach the binding screw1 the excess wire being coiled up on a pencil4 ,this coil allows of removing igniter1 allows for broken wire ends and reduces the tendency to loosen the connection4 7#h7 ,ground wires1 or wires connected with the frame of the engine should receive careful attention4 ,they are generally fastened under some screw or bolt on the engine which may become loose or fail to make contact1 thus opening the entire circuit and causing the engine to stop4 ,the ground wires are generally connected in inaccessible places1 and require all the more attention for this reason4 7#i7 ,for the primary of low tension wiring1 use only the best grade of stranded rubber covered wire4 ,a special wire for ignition purposes is on the market4 ,it is rather expensive but is just the thing for the service4 ,never use cotton covered or waxed wire4 ,this covering affords absolutely no protection against moisture or abrasion4 7#aj7 ,as the voltage of a primary circuit1 or circuit for make and break is very low1 and the current comparatively high1 it is well to have the copper as large as possible4 ,it should never be less than number #ad gauge4 ,don't use solid wire if you can obtain stranded conductor4 7,stranded wire is made up of a number of fine wires which are twisted into a cable or rope of the desired size47 7#aa7 ,oil destroys rubber insulation and should be kept off the wiring4 ,try to locate the conductors so that they will be out of range of oil thrown by the moving parts4 7#hi7 ,jump ,spark ,system 7,high ,tension ,system74 ,due to its simplicity and the light weight of its moving parts1 the high tension ignition system is applied to practically all small1 high speed engines running #ejj ,r4,p4,m4 or over4 ,the high tension system is also desirable from the fact that it has no moving parts in the cylinder of the engine4 ,the principal objection to the high tension system is the ease with which the high voltage current leaks or short circuits1 moisture being fatal to the operation of a jump spark engine4 ,instead of producing the spark by breaking the circuit of a low tension current1 the spark is produced by increasing the voltage to such a point that the current will jump directly across a fixed gap4 ,to cause the current to jump through the air requires an extremely high voltage1 and as the battery current is very low it is necessary to introduce a device known as a 8transformer0 to stop the current up to the required tension4 ,in addition to the voltage required at atmospheric pressure 7about #ej1jjj volt per inch of spark7 we must also furnish sufficient pressure to overcome the increased resistance due to the compression in the cylinder4 ,unlike the spark coil used on the low tension make and break system1 the induction coil or transformer coil has two separate and distinct coils1 that are thoroughly insulated from each other4 ,one coil has a few turns of heavy copper wire which is called the primary4 ,the other consists of many thousands of turns of very fine copper wire1 and is called the secondary4 ,both coils are wound around a bundle of soft iron wire called the core1 from which they are carefully insulated4 ,when a battery or magneto current flows through the primary coil1 the core is magnetized1 and throws its magnetic influence through the turns of the secondary coil4 ,in ,fig4 #id the primary coil and the low tension battery and magneto circuit are represented by heavy lines4 ,the secondary coil1 and high tension circuit are represented by light lines4 ,in order to obtain a continuous discharge of sparks it is necessary to make and break the current in the primary coil very rapidly4 ,this is done by means of the interrupter or vibrator1 which is indicated in the diagram by ,v4 ,the interrupter consists ordinarily of a spring ,a on which is fastened a soft iron disc ,d and a platinum contact point ,b4 ,when the core is magnetized it attracts the iron disc ,d which is pulled toward the core1 bending the spring ,a and breaking the contact between the platinum point ,b and ,c4 ,when the contact points are separated1 and the current broken1 the core loses its magnetism1 and the spring assumes its normal position1 which brings the platinum points ,b and ,c into contact once more1 and reestablishes the current through the primary4 ,the core is again magnetized and the primary current is again broken1 and so on4 ,this make and break of the current is thus accomplished automatically1 the current being broken many thousands of times per minute1 the vibrator moving so fast as to cause a continuous hum4 ,as soon as the current starts flowing1 the magnetic force spreads out through the secondary coil and threads through the turns of which it is composed4 ,the instant that the current ceases1 the magnetic force decreases and the turns are again threaded by the magnetic field on its return to the core4 ,thus two magnetic waves are sent through the secondary coil1 one when the circuit is 8made10 and one when the circuit is 8broken40 ,illustration3 ,fig4 #id4 ,diagram of ,high ,tension ,coil4 ,when a magnetic wave threads or spreads through the turns of a coil of wire1 a current of electricity is generated in the coil1 the quantity and pressure or voltage of which is proportional to the intensity of the magnetism1 and to the number of turns of wire in the secondary coil4 ,thus it will be seen that at every make and break of the low tension current in the primary coil1 a current is generated in the secondary4 ,as the voltage generated in the secondary is roughly proportional to the number of turns in the secondary1 and as there are many thousands of turns1 it is evident that the voltage in the secondary will be very high4 ,thus by the use of the induction coil1 the low tension battery current is transformed into a high tension current of sufficient voltage to break down the high resistance of the spark gap4 ,the condenser is shown at ,l which has one wire leading to the vibrator spring ,a1 and one wire to the contact screw ,m4 ,the function of the condenser is to absorb the spark produced at the vibrator points so that the break is made quickly1 producing a maximum spark4 ,the intensity of the spark depends upon the quickness with which the primary current is broken1 and if it were not for the condenser the length and intensity of the spark would be greatly reduced4 ,this device consists of alternate layers of paper and tin foil1 every other leaf of foil being alternately connected to the vibrator spring and to the contact screw4 ,a method of using two independent sets of battery is shown in the diagram1 so that either set may be thrown into circuit by means of the double throw switch ,o4 ,when handle ,j is in contact with ,e1 the current of battery set ,h flows through the coil as shown by the arrows4 ,when ,j is in contact with ,f1 the battery ,c is thrown into circuit4 ,the spark gap is shown by ,x1 which represents the spark plug in the cylinder4 ,in practice1 the portion of the circuit shown by ,i-,u is generally formed by the frame of the engine1 or is grounded4 ,the terminal ,p of the high tension circuit is always grounded through the threaded shell of the spark plug1 the grounded circuit being shown by the dotted lines4 ,grounding saves wire and many connections1 for with ,p and ,u connected to ground it follows that one binding post will serve the place of one high tension and one primary post1 making three coil connections instead of four4 ,in order that the spark will occur in the cylinder of the engine at the proper time1 a switch must be placed in the primary circuit of the coil1 that will open and close the circuit at proper intervals4 ,such a switch is called a timer1 and is always driven by the engine4 ,the timer is connected to the engine shaft in such a way that contact is made at1 or slightly before1 the time at which the explosion is required1 and as soon as possible after spark occurs the current is cut off4 ,for multiple cylinder engines it is usual to provide one coil for each cylinder1 the primaries of which are controlled by a single timer and battery4 ,a high tension wire from each coil runs to the corresponding cylinder4 ,instead of having a number of coils with a battery system1 there are two or three makes that operate with one coil in combination with a special device known as a distributor which controls the high tension current4 ,the high tension distributor directs the current to the proper cylinder that is in the order of firing1 the timing being performed by a timer similar to that used with multiple coils except that a single contact sequent is supplied4 7#ij7 ,vibrator ,construction4 ,since the efficiency of the high tension coil depends largely on the construction and efficiency of the vibrator1 the different coil makers have developed various types of vibrators that differ greatly from the simple device shown in the coil diagram in details4 ,illustration3 ,fig4 #ie4 ,kingston ,vibrator4 ,the main objects in view in the construction of a successful vibrator are3 #a4 ,to reduce the weight of the moving part as much as possible in order to increase the speed of vibration1 and to make the trembler instantly responsive to the timer4 #b4 ,to cause the contact points to separate as rapidly as possible in order to cause the maximum spark4 #c4 ,to have the contacts as hard and infusible as possible to resist wear and the action of the spark between the contacts4 #d4 ,to make any adjustments that may be required1 due to wear1 as simple and accessible as possible4 ,the types of vibrators are legion1 and we have not the space to go into the details of all the prominent makes1 but will illustrate and describe two well known types4 ,the ,kingston vibrator made by the ,kokomo ,electric ,company1 is a good example of a modern vibrator and is shown in detail by ,fig4 #ie4 ,all adjustments between the contact points are made by means of the contact screw ,a which carries a platinum point at its inner end4 ,the retaining spring ,d keeps the contact screw from being jarred out of place by the engine vibration1 without the use of lock nuts4 ,turning ,a against the vibrator1 the tension of the spring ,b is increased1 raising the screw decreases the tension4 ,increasing the tension screw increases the length and heat of the spark1 and also increases the current consumption4 ,at ,n is a separate thin iron plate which is acted on by the magnetized core1 a rivet fastening the plate to the main vibrator spring is shown at the end of the spring4 ,the current enters through the lug ,c1 and from this point the circuit is the same as shown in the coil diagram4 7#ia7 ,operation of the ,jump ,spark ,coil4 ,the spark produced by a coil in good condition should be blue-white with a small pinkish flame surrounding it1 when the gap is of an inch or less4 ,the sparks should pass in a continuous stream with this length of gap without irregular stopping and starting of the vibrator4 ,coils giving a sputtering1 weak discharge that causes sparks to fly in all directions are broken down and should be remedied4 ,the secondary windings of coils are often punctured or broken down by operating the coil with the high tension circuit open1 or by trying to cause long sparks by increasing the spark gap over of an inch in the open air4 ,coils are also broken down by allowing excessive currents to flow in the primary coil4 ,never cause a spark to jump over of an inch4 ,high compression in the cylinder shortens the jumping distance of a high tension spark4 ,coils that will cause a stream of sparks to flow across a gap of an inch in the open air are often unable to cause a single spark to jump a gap of #a_/cb of an inch under a compression of #hj pounds per square inch in the cylinder4 ,remember that a hot spark causes rapid combustion1 and will fire a greater range of mixtures and 8leaner0 charges1 than a straggling1 thin1 weak spark4 ,spark coils that give poor results with a long spark gap under high compression are often benefited by the shortening of the spark gap4 ,shortening the gap will increase the heat of the spark1 and will insure the passing of a spark each time that the timer makes contact4 ,a good coil should have no difficulty in igniting a piece of paper inserted between the wires forming the spark gap in the open air4 ,illustration3 ,fig4 #if4 ,kingston ,dash ,coil4 ,the adjusting screw affords a means of increasing or decreasing the tension of the vibrator spring1 and the amount of battery or magneto current flowing through the primary coil4 ,increasing the tension of the spring requires stronger magnetization of the core to break the circuit of the contact points4 ,this in turn calls for more current from the battery2 hence in order to lessen the demand for current on the battery1 the tension should be as little as possible to obtain the necessary spark4 ,an increased tension produces more spark as the magnetization of the core is increased1 but for the sake of your batteries decrease the tension as much as possible with a satisfactory spark4 ,almost all operators have a tendency to run with too stiff a vibrator1 and hence use too much current4 ,an efficient coil should develop a satisfactory spark with to of an ampere of current in the primary coil4 ,i have often found coils that would work well with ampere1 that were screwed up so tight that the coils were consuming #d to #e amperes or #h to #aj times as much as they should4 ,a battery ammeter used for testing the current consumed by coil will save its cost many times over in batteries and burnt points if used at frequent intervals in the primary circuit4 ,an automobile or marine engine should be tested for vibrator adjustment in the following way3 ,adjust vibrator so that spring is rather stiff4 ,start engine and get it thoroughly warmed up and running at full speed1 then slowly and gradually decrease the tension of the spring until misfiring starts in2 then slowly increase tension until misfiring stops4 ,increase the tension no farther2 this is the correct adjustment4 ,poor vibrator adjustment is the cause of much trouble and expense as it uses up the batteries and wastes fuel4 ,the principles of correct adjustment are simple1 the adjustment easily made1 and there is no possible excuse for the high current consumption and rapid battery deterioration met in every day practice4 ,the usual practice of the average operator is to tighten the vibrator until the spark 7observed in the open air7 is at its maximum4 ,this is commonly known as 8adjusting the coil20 shortly after you hear of him throwing out his batteries as no good4 ,after once getting the vibrator in proper trim the ear will give much information as to the adjustment4 ,a vibrator adjusted too lightly will cause 8skipping0 or misfiring with the consequent loss of power4 ,never attempt to operate a coil that is damp2 the coil will be ruined beyond repair4 ,above all1 do not place the coil in a hot oven to dry1 as the box is filled with wax1 and if this is melted it will run out and reduce the insulation of the coil4 ,dry coil gradually4 ,if the batteries are new or too strong the vibrator may be held against the core of the coil so that the vibrator will not buzz4 ,if this is the case loosen the screw until it works at the proper speed4 ,if the batteries are weak1 the coil may not be magnetized sufficiently to draw the vibrator and break the circuit4 ,if this is the case tighten the screw4 ,if the vibrator refuses to work with the battery and wiring in good condition1 and if you are sure that the current reaches the coil1 look for dirty or pitted contacts on the vibrator4 ,should the contact points be dirty1 clean them thoroughly by scraping with a knife or sandpaper4 ,water on the points will stop the vibrator1 as will oil or grease4 ,if contact points are of a uniform gray color on their contact surfaces1 and are smooth and flat without holes1 pits or raised points1 they are in good condition4 ,if pits1 discolorations or projections are noted1 the contact surfaces should be brought to a square1 even bearing by means of a small1 fine file4 ,the point should not come into contact on an edge1 but should bear on each other over their entire surface4 ,do not use sand paper to remove pitting1 as it is almost impossible to secure an even1 flat surface by this means4 ,it is best to remove the contact screw and vibrator blade for examination and cleaning1 as it is much easier to file the points square and straight when removed from the coil4 ,be careful not to bend the vibrator spring when cleaning1 as the adjustment will be impaired4 ,when replacing contact screw and vibrator blade in coil1 be careful that they are in exactly the same relative position as they were before removing4 ,also be sure that the contacts meet and bear uniformly on their surfaces4 7#ib7 ,primary ,timer4 ,the duty of the primary timer is to close the primary circuit of the spark coil at1 or a little before the time at which the explosive of the charge is required4 ,the exact time at which the timer closes the circuit depends on the load1 the speed1 and the nature of the fuel4 ,the lapse of time between the instant that the timer closes the circuit and the instant at which the piston reaches the end of the compression stroke is called the 8advance0 of the timer4 ,when the timer closes the circuit after the piston reaches the end of the stroke1 the timer is said to be 8retarded40 ,the timer is constructed so that the time of ignition or the advance and retard can be varied between wide limits4 ,advancing the spark too far will cause hammering and power loss as the piston will work against the pressure of the explosion4 ,retarding the spark will cause a loss of power1 as the compression will be less when the piston starts on the outward stroke2 and also for the reason that more of the heat will be given up to the cylinder walls as the combustion will be slower4 ,the pressure in the cylinder is less with retarded ignition4 ,greatly retarded ignition often causes overheating of the cylinder walls1 especially with air cooled engines1 and also overheats and destroys the seat and valve stem of the exhaust valve4 ,do not expect the engine to develop its rated horse-power or run efficiently with a late1 or retarded spark4 ,when the engine is installed1 and before the timer wears or has a chance to get out of adjustment1 look it over carefully and see whether the maker has left any marks relating to the timing of the spark4 ,if there are no marks1 it is well to determine the relation between the position of the piston and the timer1 as the efficiency of the engine depends to a great degree upon the firing point4 ,timers are advanced and retarded by partially rotating the housing either in one direction or the other4 ,when the timer is mounted directly on the cam shaft with the cam shaft traveling in a direction opposite to that of the crank shaft1 the timer will be retarded by moving it in the same direction as the cam shaft travels1 moving it against cam shaft rotation advances the spark4 ,timers for two stroke cycle engines rotate at crank shaft speed1 and the direction of advance and retard varies with the methods adopted for driving the timer4 7#ic7 ,timer ,construction4 ,fig4 #ig shows a typical timer and circuit arranged for a four cylinder engine4 ,the device can be arranged for any number of cylinders1 however1 by changing the number of sectors1 the sectors being equal to the number of cylinders4 ,there are timers on the market that differ from the one shown in the diagram but the principle of operation is the same with all4 ,the shaft ,e is usually connected to the cam shaft and is electrically grounded to the engine frame at ,l by means of the bearing in which the shaft rotates4 ,the lever ,f mounted on the shaft ,e carries the pivoted arm ,h which is free to move on the pivot to a limited extent to allow for wear on the walls ,w-,w-,w-,w4 ,at one extremity of ,h is the roller ,i which rotates on the pin ,j1 as the roller runs around ,w-,w-,w-,w4 ,at the other extremity of ,h is fastened the spring ,s1 which forces ,i into contact with the walls4 ,a-,b-,c-,d are metallic contact sectors whose connections lead to the four spark coils4 ,when the metal roller ,i comes into contact with one of the sectors as at ,b1 the sector is grounded to the engine frame by the roller1 the current traveling through the roller and its pin1 through lever ,h and its pin1 through the lever ,f and shaft ,e to ground at ,l1 the course of the current being indicated by the arrows4 ,illustration3 ,fig4 #ig4 ,timer ,diagram4 ,as the shaft ,e rotates and carries with it roller ,i1 the roller makes contact with the sectors in order ,b-,c-,d-,a1 if rotated in the direction shown by arrow1 which rotation grounds the primary coils of the spark coils ,r#c-,r#d-,r#a-,r#b in succession2 the connection from the timer to the primary being to the primary binding posts ,p#c-,p#d-,p#a-,p#b4 ,a high tension spark occurs at each contact of the roller with the sectors1 as the contact allows current to flow through the primary of the coils4 ,the high tension binding posts ,s#a-,s#b-,s#c-,s#d are connected with the spark plugs or spark gaps ,u#a-,u#b-,u#c-,u#d by means of high tension cables4 ,as soon as the timer grounds a coil1 the coil produces a high tension spark in its corresponding spark plug4 ,it is evident from the foregoing that the timer not only determines the time at which a spark will take place1 but it also determines the cylinder in which the spark will be produced1 providing of course that a spark coil is provided for each cylinder4 ,the contact sectors ,a-,b-,c-,d are insulated from each other by the insulating walls ,w-,w-,w-,w1 the inner surface of which provides a path on which the contact roller ,i revolves4 ,the contact sectors and insulating walls are encased by the protective housing ,z1 to which they are rigidly fastened4 ,the housing ,z can be moved back and forth on the shaft ,e for advance and retard1 by means of the lever ,k4 ,the current flows from the battery terminal ,v 7with the roller in the position shown7 through the switch ,m1 through coil ,r#c1 post ,p#c to sector ,b1 from which it passes through the roller ,i1 levers ,h and ,f to ground4 ,from the ground on the engine frame the current flows back to its source1 the battery ,o1 thus completing the circuit4 ,when the roller makes contact with sector ,c1 the coil ,r#d is energized1 contact with ,d energizes ,r#a1 and so on4 ,no two coils can be thrown on simultaneously as only one coil is grounded at a time4 ,the high tension current flows from each coil to its plug as soon as the current passes through the primary of that coil4 ,in some timers1 the current is taken from the revolving arm through a separate connection to ground instead of grounding the shaft through the bearings4 ,with these timers1 the connection is not affected by worn bearings or an oil film that tends to insulate the shaft from the bearings4 7#id7 ,operation of ,timers4 ,timers frequently cause misfiring which is generally due to dirt or oil getting between the contacts1 or to the wear of the insulating walls ,w-,w-,w-,w1 or to the wear of the moving parts4 ,dirt or gummy oil will prevent the contact coming together and completing the circuit1 or will clog up the rollers or levers so that they cannot perform their functions properly4 ,this will of course interfere with production of the spark4 ,the contacts and moving parts of the timer should be kept as clean as possible1 all dirt and heavy oil being removed by means of gasoline at regular periods4 ,make a practice of cleaning out the timer at intervals not greater than one month2 oftener if possible4 ,parts subject to wear1 such as the roller pin ,j and the bearings should be well lubricated1 none but the lightest oil being employed for this purpose4 ,heavy grease will gum the contacts and cause trouble4 ,there should be no rough places or shoulders on the contact sectors or on the walls ,w-,w-,w-,w as roughness will cause the roller to jump over the high places which in turn result in misfiring4 ,the remedy is to machine the surfaces of the sectors and walls by grinding or turning in the lathe4 ,care should be taken in this operation to have the interior perfectly smooth and the sectors perfectly flush with the walls4 ,repair black or burnt sectors immediately by grinding or sand paper4 ,burnt spots or blackened surface on the contact sectors prevent good contact between roller and sector1 sectors should show a bright1 shining metallic surface4 ,sometimes the insulation warps or swells above the contacts so that the roller jumps over the contacts without touching them1 or if for any reason that contact is made under these conditions1 it is of a short period and results in a poor spark4 ,timers often make good contact when starting1 or at low speed1 and misfire badly at high speed4 ,this will be caused generally by the contact sectors or insulation projecting beyond one another1 the roller has time to make good contact at low speed but jumps over the sector at high4 ,the roller ,i may become rough or develop a flat stop which will cause it to jump over the contact occasionally1 or it may become loose on its bearing pin ,j1 causing intermittent misfiring4 ,the wearing or loosening of pins ,j and ,x result in poor contact4 ,should pin ,j fall out of the lever ,h1 the roller would drop out of the fork and cause serious damage4 ,this has happened in two cases to my knowledge4 ,should the spring ,g weaken or break1 contact will be made intermittently at high speed1 and no contact at low4 ,in this case it would probably be impossible to start the engine4 ,in case the spring breaks1 a rubber band may be used temporarily4 ,wire connections to the timer should be examined frequently as the continual back and forth movement tends to twist and loosen the wire4 ,use stranded or flexible wire for these connections1 if possible4 ,before removing the timer mark the hub and the shaft so that the hub can be properly replaced4 ,if this is not done the engine will be out of time with the usual results of hammering or power loss4 ,should the gears which drive timer shaft be removed1 be sure and mark the teeth of both gears in such a manner that there will be no mistake possible in reassembling them4 ,mark a tooth on the small gear by scratching or with a center punch 7the tooth selected should be in mesh with the large gear74 ,then mark the two teeth of the large gear that lay on either side of the marked tooth of the small gear4 ,thus it will be easy to locate the proper relative position of the two gears at any time4 7#ie7 ,high ,tension ,spark ,plug4 ,the high tension spark plug is a device that introduces the spark gap and spark into the combustion chamber1 and at the same time insulates the current carrying conductor from the cylinder walls4 ,since the voltage of the jump spark current is very high it is evident that the insulation of the plugs must be of a very high order and that this insulation must be capable of withstanding the high temperature of the combustion chamber4 ,a cross-section of a typical plug is shown by ,fig4 #ih1 together with its connections and the course of the current1 the latter being shown by the arrow heads4 ,the electrode ,b through which the current enters the cylinder is thoroughly insulated from the walls by the porcelain rod ,c4 ,the porcelain forms a gas tight joint with the threaded metal bushing ,f at the point ,p1 the tension caused by the electrode ,b and the nut ,i holds the porcelain firmly on its seat at ,p4 ,the nut is supported by the porcelain shell ,h which rests in the top of the metal bushing ,f4 ,a washer ,l is inserted between ,h and ,f to insure against the leakage of gas from the plug should a leak develop at ,p4 ,l being a soft washer 7usually asbestos7 allows the porcelains ,c and ,h to expand and contract without breaking4 ,a packing washer or gasket is also placed at the point where the electrode ,b passes through the porcelain ,h4 ,this is the washer ,q1 held in position by the nut ,i4 ,this washer is elastic and reduces strain on porcelain caused by the expansion4 ,the cylinder wall ,g has a threaded opening ,r into which the plug is screwed1 the threads of the opening corresponding with the threads on the metal sleeve ,e4 ,the plug may be removed from the cylinder for examination without disturbing the adjustment of the electrode and porcelains by unscrewing it at ,r4 ,allowing the current to jump from the electrode to the cylinder wall via the metal sleeve saves one wire and connection1 the cylinder and the frame of the engine serving as a return path for the current4 ,this simplifies the wiring and minimizes the danger of high tension short circuits4 ,illustration3 ,fig4 #ih4 ,cross-,section of ,typical ,spark ,plug4 ,by unscrewing the threaded metal bushing ,f it is possible to examine the condition of the porcelain rod ,c at the point where it is exposed to the heat of the cylinder4 ,this inspection can be made without disturbing the packed joints at ,l or ,q4 ,in the high tension1 or jump spark system1 the spark gap ,d-,k is of fixed length1 hence there are no moving parts or contacts within the cylinder to wear1 to cause leakage of gas1 or to cause a change in the timing4 ,this advantage is offset to some degree by the difficulty experienced in maintaining the insulation of the high tension current4 ,the high tension current leaves the spark coil ,m at the binding screw ,n1 flows along the wire ,j1 and enters the spark plug at the binding screw ,a4 ,from the binding post the current follows the central electrode ,b to its terminal at ,d4 ,at ,d a break in the circuit occurs which is called the spark gap4 ,it is at this point that the spark occurs1 the current jumping from ,d to point ,k through the air4 ,point ,k is fastened in the threaded metal sleeve ,e which is in turn screwed into the cylinder wall ,g or ground4 ,from the ground the current returns to its source through binding post ,o to the coil4 ,the spark therefore occurs inside of the cylinder wall and in contact with the combustible charge1 at the point marked 8spark0 in the cut4 ,illustration3 ,fig4 #ii4 ,bosch ,spark ,plugs4 ,if the fuel1 lubricating oil1 and air are not supplied in proper proportions1 soot will be deposited on the lower surface of the porcelain1 and as soot is an excellent conductor of high tension current1 the current will follow the soot rather than the high resistance of the spark gap1 a condition that will result in misfiring or a complete stoppage of the motor4 ,carbonized lubricating oil or moisture have the same effect4 ,preventing the deposits of soot1 moisture and carbonized oil is the chief object of plug manufacturers1 many of whom have brought out designs of merit4 ,in fact the problem of elimination of soot is the principal cause of the many types of plugs now on the market4 ,while many plugs differ in minor refinement of detail from the typical plug shown1 the connections and general construction are the same in all types1 the spark being produced in a gap of fixed length which is insulated from the cylinder4 ,a well known form of plug1 the ,bosch1 is shown by ,fig4 #ii a-b4 ,in this plug a special material known as ,steatite is used instead of the usual porcelain4 ,the three external electrodes surrounding the center electrode is a particularly efficient arrangement1 especially for magnetos4 ,a peculiar form of pocket minimizes the soot problem4 ,as porcelain is brittle and is easily broken by the effects of heat or blows1 mica insulation is often used in place of the porcelain4 ,the central core of a mica plug is formed by a stack of mica washers1 which are held in place by the central electrode and the upper lock nuts4 ,a poorly constructed mica plug is easily destroyed by a weak1 stretching1 electrode1 or by an overheated cylinder4 ,the latter causing the washers to shrink and admit oil between the layers of mica washers causes a short circuit4 ,as soon as the mica washers loosen and separate1 they should be forced together by means of the mica lock nuts on the top of the plug4 ,if by any reason the mica core becomes saturated with oil1 it is best to obtain a new one1 as it is almost impossible to remove the oil by simple means open to the average operator4 ,the chief value of a mica plug lies in its toughness and mechanical strength1 a good mica plug being practically indestructible4 ,when heated1 porcelain does not expand at the same rate as the metal sleeves1 hence in poorly designed or imperfect plugs1 heavy strains are thrown on the delicate porcelains which causes them to crack4 ,when a crack develops it provides a lodging place for soot and carbon which of course causes a short circuit4 ,should a compression leak occur through faulty packing between the porcelain and sleeve1 it should be immediately tightened up for eventually it will leak enough to destroy the plug or reduce the output of the engine4 ,when ordering a plug be sure that you know the size and type required by your engine4 ,some engines require a longer plug to reach the combustion chamber than others4 ,never install a shorter plug than that originally furnished with the engine4 ,be sure that the plug is not too long as it may interfere with the action of the valves or may be damaged by them4 ,plugs are furnished with several threads and taps1 i4 e43 inch pipe thread 7,generally used on stationary engines74 ,metric ,thread 7,generally used on imported autos74 inch ,a4 ,l4 ,a4 ,m4 ,standard 7,used on ,domestic automobiles74 ,using a plug in a hole tapped with the wrong thread will destroy the thread in the cylinder casting and cause compression leaks4 7#if7 ,care of ,spark ,plug4 ,porcelains are often broken by screwing the plug too tightly in a cold cylinder1 as the cylinder expands when heated and crushes the frail plug4 ,a plug installed in this manner is difficult to remove as the expanded walls grip the thread4 ,the plug should be screwed in just enough to prevent the leakage of gas4 ,a short thin wrench should be used in screwing the plug home such as a bicycle wrench4 ,a wrench of this type is so short that it will be almost impossible to exert too much force1 and will be thin enough to avoid any possible injury to the packing nut4 ,bad leaks may be detected by a hissing sound that is in step with the speed of the engine1 small leaks may be detected by pouring a few drops of water around the joint4 ,if a leak exists bubbles will pass up through the water and show its location4 ,plugs are more easily removed from a cold cylinder than a hot4 ,if the plug sticks when the engine is cold and is impossible to remove with a moderate pressure on the wrench squirt a few drops of kerosene around the threads4 ,never exert any force on the porcelain or insulation4 ,the high tension cables should be connected to the plugs by means of some type of 8,snap ,terminal10 such terminals may be had from automobile dealers4 ,these terminals make a firm contact with the plug and do not jar loose from the plug by the vibration of the engine4 ,they are easily disconnected when the inspection of the plug becomes necessary1 and are generally a most desirable attachment4 ,the high tension cable should be firmly connected to the plug terminal under all circumstances4 ,a loose connection will cause misfiring or will bring the engine to an abrupt halt4 ,if snap terminals are not used the plug binding screw should be screwed down tightly on the wire4 ,when making connections see that the wire is bright and clean1 and that frayed ends of the wire do not project beyond the plug and make contact with other parts of the engine4 ,a large percentage of high tension ignition troubles are due to short circuits in the spark plug which are generally caused by deposits on the surface of the plug insulation4 ,soot or oil may be removed from the plug by scrubbing the porcelain and the interior of the chamber with gasoline applied by a tooth brush4 ,examine the plug for cracks1 and if any are found1 replace the porcelain or throw the plug away4 ,a cracked porcelain is always a cause of trouble4 ,to test a plug for short circuits1 remove it from the cylinder1 reconnect the wire1 and lay the sleeve of the plug on some bright metal part of the engine in such a way that only the threaded portion is in contact with the metal of the engine4 ,close the switch and see if sparks pass through the gap4 ,if no sparks appear1 and if the coil is operating properly1 clean the plug4 ,as an additional test for the condition of the coil1 hold the end of the high tension cable about inch from the metal of the engine while the coil is operating4 ,if a heavy discharge of sparks takes place between the end of the cable and the metal of the engine1 the coil is in good condition4 ,if a partial short circuit exists1 the spark at the gap will be weak and without heat2 the result will be intermittent1 or misfiring with a loss of power4 ,moisture in the cylinder is a common cause of plug short circuits1 the moisture coming from leaks in the water jacket or from the condensation of gases in a cold cylinder4 ,a drop of water may bridge the spark gap1 allowing the current to flow from one electrode to the other without causing a spark4 ,if a cloud of bluish white smoke has been issuing from the exhaust pipe before the misfiring started1 you will probably find that the trouble is due to sooted or short circuited plug4 ,the remedy is to decrease the amount of lubricating oil fed to the cylinder4 ,when a magneto is used the intense heat of the spark causes minute particles of metal to be torn from the electrodes and deposited on the insulation as a fine metallic dust4 ,this will of course cause a short circuit and must be removed4 ,short circuits are sometimes caused by the magneto current melting the electrodes and dropping small beads of the metal between the conductors4 ,all metallic particles should be removed from the plug4 ,while a spark plug may show a fair spark in the open air test1 it will not always produce a satisfactory spark in the cylinder on account of the increased resistance of the spark gap due to compression4 ,compression increases the resistance of the spark gap enormously and thin1 highly resisting carbon films that would cause very little leakage in the open air will entirely short circuit the gap under high pressure1 the current taking the easiest path which in the latter case is the carbon deposit4 ,in order to produce conditions in the open air test similar to those in the cylinder we must devise some method of increasing the resistance of the spark gap in the open air above any possible resistance that could be offered by the carbon film4 ,placing a sheet of mica or hard rubber between the electrodes1 or in the spark gap1 will increase the resistance to the required degree4 ,if the spark plug is in good condition the spark will jump from the insulated terminal to the shell when the mica is in the spark gap1 but if a short circuit exists the current will go through it without causing a spark4 ,it is assumed that the battery and coil are in good condition when making the above test4 ,if the electrodes or spark points are dirty they should be cleaned with fine sand paper1 special attention being paid to the surfaces from which the spark issues4 ,when reassembling the plug1 see that all of the washers and gaskets are replaced and that the length of the spark gap is unchanged4 ,a little change in the spark gap may make a great change in the spark4 ,a good spark is blue white with a faint reddish flame surrounding it4 ,when the discharge is intermittent or sputters in all directions1 either the coil or the plug are partially short circuited4 ,always have a spare plug on hand4 ,ordinarily the length of the gap or the distance between the electrodes should be about #a_/cb inch for batteries1 and a trifle less for magnetos4 ,a silver dime is a good gauge for the gap4 ,if the engine misfires with the coil and batteries in good condition1 try the effects of shortening the gap a trifle1 usually this will remedy the difficulty4 ,exhausted batteries may be made operative temporarily by closing up the plug gap to #a_/fd inch or even less4 ,shortening the gap increases the heat of the spark and nothing is gained by having it over #a_/cb inch4 ,almost all high tension magnetos have visible safety spark gaps that show instantly the presence of an open circuit in the secondary or high tension circuit4 ,if an open circuit exists1 a stream of sparks will flow across the safety spark gap at low speed4 ,to determine the cylinder that is misfiring in a four cylinder engine proceed as follows3 ,remove cover on spark coil1 and hold down one vibrator spring firmly against the core while the engine is running4 ,if the engine speed is not decreased by cutting this coil out of action1 it is probable that this is the coil connected to the misfiring cylinder4 ,now release this vibrator and proceed to the next coil1 and hold its vibrator down4 ,if this decreases the speed of the engine you may be sure that the first coil is in the defective circuit4 ,if the vibrator buzzes on the coil under inspection the trouble will be found in the plug4 ,cutting out a coil connected to an active cylinder decreases the speed of the engine4 ,cutting out the coil connected with a dead cylinder makes no difference4 7#ig7 ,magnetos4 ,a magneto is a device that converts the mechanical energy received from the engine into electrical energy1 the electricity thus produced being used to ignite the charge in the engine4 ,this appliance does away with all of the troubles incident to a rapidly deteriorating chemical battery and produces a much hotter and uniform spark4 ,a magneto is especially desirable with multiple cylinder engines where the demand for current is almost continuous1 as the amount of current delivered by the magneto has no effect on its life or upon the quality of the spark4 ,the principal parts of the generating system of the magneto are the magnets1 the armature1 the armature winding1 and the current collecting device1 of which the armature and its windings are the rotating parts4 ,the production of current in the magneto is the result of moving or rotating the armature coil in the magnetic field of force of the magnets4 ,when any conductor is moved in a space that is under the influence of a magnet a current is generated in the conductor which flows in a direction perpendicular to the direction of motion4 ,the value of the current thus generated depends on the strength of the magnetic field1 the speed with which it is cut1 and the number of conductors cutting it that are connected in series4 ,roughly1 the voltage is doubled1 with an increase of twice the former speed1 and with all other things equal1 the voltage is doubled by doubling the number of conductors connected in series4 ,by employing powerful magnets1 and a large number of conductors 7turns of wire7 on the armature it is possible to obtain sufficient voltage for the ignition system at a comparatively low speed4 ,the number of amperes delivered depends principally upon the internal resistance of the armature and the external circuit1 and not on the number of conductors1 nor directly upon the strength of the field4 ,for this reason1 low voltage machines that are intended to deliver a great amperage have only a few conductors of large cross section1 while high tension machines have a great number of conductors of small size4 ,in all cases the magneto1 or ignition dynamo must be considered simply as a generator of current in the same way that a battery is a source of current since the current generated by them is utilized in precisely the same way4 ,the class of ignition system on which the magneto is used determines the class of the magneto4 ,the low tension magneto is used principally for the make and break system1 although it is sometimes used in connection with a high tension spark coil or transformed in the same way that a battery is used with a vibrator coil4 ,the high tension magneto is used exclusively with the jump spark system and high tension spark plug4 ,these classes are again subdivided into the direct and alternating current divisions1 depending on the character of the current furnished by the magneto4 ,briefly a continuous current is one that flows continually in one direction while an alternating current periodically reverses its direction of flow4 ,as the alternating current magneto is the most commonly used type1 we will confine our description to this class of magneto4 ,the alternating current magneto is much the simplest form of machine as it has no commutator1 complicated armature winding1 nor field magnet coils1 and in some types the brushes and revolving wire are eliminated4 ,as the magnetic flux of an alternating magneto is changed in value1 that is increased and decreased1 twice per revolution1 it follows that the current changes its direction twice for every revolution of the armature4 ,each change in the direction of current flow is called an alternation4 ,the voltage developed in each alternation or period of flow is not uniform1 the voltage being low at the start of the alternation1 rapidly increasing in voltage until it is a maximum at the middle1 and then rapidly decreasing to zero1 from which point the current reverses in direction4 ,as we have two such alternations1 in a shuttle type magneto1 per revolution we have two points at which the maximum voltage occurs2 that is in the center of each alternation4 ,these high voltage points are called the peak of the wave and consequently the sparking devices should operate at the peak of the wave or at the point of highest voltage4 ,the spark therefore should occur when the shuttle or inductors are at a certain fixed point in the revolution at which point the peak of the wave occurs4 ,the peak of the wave occurs when the shuttle is being pulled or turned away from the magnets4 ,in what is known as the 8shuttle type0 alternating current magneto1 the generating coil is wound in the opening of an 8,h0 type armature4 ,this iron armature core is fastened rigidly to the driving shaft and revolves with it4 ,as the armature revolves1 it is necessary to collect the current that is generated by means of a brush that slides on a contact button ,b1 the button being connected to one end of the winding4 7#ih7 ,low ,tension ,magneto4 ,the winding of the low tension magneto consists of a few turns of very heavy wire or copper strip1 one end of which is grounded to the armature shaft and the other passing through the hollow shaft from which it is insulated4 ,the end of the insulated wire is connected to the contact button 7,b7 on which the current collecting brush presses4 ,as one end of the winding is grounded1 one brush1 and one connecting wire is saved as the current returns to the magneto through the frame of the magneto4 ,as the shuttle revolves between the magnet poles the magnetism is caused to alternate through the iron of the armature1 thus causing the current to alternate in direction and fluctuate in value4 ,since there are only two points at which the maximum current can be collected during a revolution with the alternating current magneto1 it is necessary to drive it positively through gears1 or a direct connection to the shaft so that this maximum point of voltage will always occur at the same point in regard to the piston position4 ,if it is driven by belt without regard to the position of the piston1 it is likely that there will be many times that the voltage is zero or too low in value when the spark is required in the cylinder4 ,alternating current magnetos must be positively driven1 and the armature must be connected to the engine so that the peak of the wave occurs at1 or a little before the end of the compression stroke4 ,with this type of magneto the only point that is likely to give trouble is the point at which the brush makes contact with the contact button4 ,if the brush should stick or not make contact1 or if the button is dirty or rusty1 the current will not flow2 this point should always be given attention4 ,outside of this the only attention necessary is to keep the bearings oiled4 ,illustration3 ,fig4 #aja4 ,sumter ,magneto ,advanced4 ,illustration3 ,fig4 #ajb4 ,sumter ,magneto ,retarded4 ,illustration3 ,fig4 #ajc4 ,sumter ,magneto on ,horizontal ,engine4 ,fig4 #aja and ,fig4 #ajb show the ,sumter low tension magneto as arranged for make and break ignition4 ,the armature and its connections are of exactly the same type as that shown in the previous diagram4 ,the magnets and frame are arranged to tilt back and forth so that the peak of the wave will occur at the advanced and retarded positions of the igniter4 ,this arrangement allows the full voltage of the magneto to be obtained at any point within the range of the ignitor1 an important item when starting the engine or running at low speed4 ,when mounted on the engine1 as shown by ,fig4 #ajc1 the magnets are provided with an operating rod that is marked 8start0 and 8run40 ,when the pin on the engine bed is engaged under 8start10 the magneto is retarded1 when the pin is under 8run0 it is advanced4 ,a number of intermediate points are provided at which the operating arm is held fast by tooth engagements as shown in the slotted handle4 ,as shown in the illustration the magneto is fully advanced4 ,the gears by which the magneto is driven are clearly shown in the cut1 the ratio between the gear on the crank shaft and that on the magneto shaft being exactly #b to #a4 ,one lead is carried to the make and break igniter in the cylinder head1 the current being returned through the bed of the engine4 ,the same make of magneto is shown mounted on a vertical engine in ,fig4 #ajd4 ,in this case the magneto is positively driven from the crank shaft of the engine by a chain4 ,the single conductor running from the magneto to the cylinder heads is clearly shown4 ,to start the engine1 the igniter is set in the usual manner and the magneto tilted to starting position1 as shown in the illustration4 ,the engine is then started in the usual manner and1 when running1 the igniter is changed to running position1 and the magneto is tilted outwardly4 ,it is not important which is changed first1 the magneto or the igniter4 ,it is easy to remember the 8starting0 and running 8position0 of the magneto1 the running position always being that in which the magnetos are tilted in the direction opposite to that in which the engine runs4 7#ii7 ,care of ,low ,tension ,magnetos4 7#a7 ,avoid setting a magneto on an iron or steel plate1 unless stated otherwise in the manufacturer's directions1 as in some makes the magnetism will be short circuit by iron or steel and will reduce the output4 7#b7 ,do not jar magnets or magneto unnecessarily1 for this tends to weaken the magnets4 7#c7 ,never remove the magnets if it can possibly be avoided4 ,if this must be done1 mark the magnets and gears so that they may be replaced in exactly the same position4 ,if your magneto refuses to generate after reassembling it is probable that they are reversed in position or that the magnetism has been knocked out of them while off of the magneto4 7#d7 ,as soon as the magnets are removed1 or better before1 place a plate of iron or steel across both ends of the magnet4 ,don't leave the magnets without this keeper for any length of time or they will lose their magnetism4 ,the best plan is to leave the magnets alone4 7#e7 ,remember that the running clearance between the magnets and armature is very small1 only a few thousandths of an inch1 and that any error in replacing the bearings in their proper position will cause the armature to bind in the tunnel4 ,handle armature carefully and do not lay it in a dirty place as a bent shaft or grit in the armature tunnel will fix it permanently4 7#f7 ,most all magnetos are practically water proof1 but don't experiment with the hose4 7#g7 ,make all connections firmly and have the wire clean under the binding posts4 7#h7 ,only a few drops of oil are needed at long intervals1 don't neglect to oil them1 but above all do not drown them with oil4 7#i7 ,examine the brush occasionally and clean off all oil and dirt4 7#aj7 ,when replacing the magneto on the engine after its removal see that the gears are meshed in the former position4 ,best to mark the teeth before removal4 7#ajj7 ,high ,tension ,magnetos4 ,the 8true0 high tension type magneto is complete in itself1 requiring no jump spark coil nor timer1 the high tension current being generated directly in the coils carried by the armature4 ,this arrangement reduces the wiring problem to a minimum1 as the only wires required are those leading directly to the spark plugs1 and one low tension wire connecting the cutout switch used for stopping the engine4 ,illustration3 ,fig4 #aje4 ,single ,cylinder ,high ,tension ,bosch ,magneto4 ,the armature of this type of magneto carries two independent windings1 one of a few turns of coarse wire called the primary coil1 and the other consisting of thousands of turns of extremely fine wire called the secondary coil4 ,it is in the latter coil that the high tension current is generated4 ,the timer is connected directly to the armature shaft1 and is an integral part of the magneto4 ,all primary connections are therefore made within the magneto4 ,belts or friction drives cannot be used with this type of magneto4 ,as there are no vibrators or independent coils used1 the spark occurs exactly at the instant that the timer operates or breaks the primary circuit4 ,it will be noted that the spark is produced with this magneto when the primary circuit is broken by the timer1 instead of made as is the case with battery coils1 or coils used with low tension magnetos4 ,there is no lag and consequently the time of ignition is not affected by variations in the engine speed1 which requires an advance and retard of the spark with batteries and vibrator coils4 ,when used with multiple cylinder engines the high tension magneto is provided with a distributor1 which connects the high tension current with the different cylinders in their proper firing order4 ,the timer determines the time at which the spark is to occur and the distributor determines the cylinder in which the spark is to take place4 ,illustration3 ,fig4 #ajf4 ,connecticut ,high ,tension ,magneto4 ,the sparks delivered by the high tension magneto are true flames or arcs of intense heat1 and exist in the spark gap for an appreciable length of time4 ,it is evident that such flames possess a much greater igniting value than instantaneous static spark delivered by the high tension spark coil used with the battery or operated by the low tension magneto1 and are capable of firing much weaker mixtures4 ,like low tension magnetos1 the true high tension type may be of either the inductor or shuttle wound class4 ,all high tension magnetos are positively connected or geared to the engine in such a manner that there is a fixed relation between time of the current impulse produced by the magneto and the firing position of the engine piston4 ,the current is generated on the same principle as in the low tension shuttle type2 that is1 by a coil of wire revolving in the magnetic field established by permanent magnets4 ,during each revolution of the armature1 two sparks are produced at an angle of #ahj from each other4 ,the advance and retard of the spark is obtained by means of the timing lever which shifts the timer housing back and forth which results in the primary current being interrupted earlier or later in the revolution of the armature4 ,illustration3 ,fig4 #ajg4 ,longitudinal ,section ,through ,bosch ,high ,tension ,magneto4 ,the timing lever can turn through an angle of #dj measured on the armature spindle1 and the angle of advance for multiple engines is as follows3 ,advance for #a cylinder #dj ,advance for #b cylinders #dj ,advance for #c cylinders #ej ,advance for #d cylinders #dj ,advance for #f cylinders #bg ,a timer is used with the magneto on a 8jump spark0 system in the same way as with a battery1 providing a vibrating coil is used4 ,in one type of magneto the ,connecticut1 the coil is part of the magneto1 and is fastened to the magneto frame4 ,this type of magneto uses a non-vibrating coil1 and produces but a single spark each time the primary circuit is broken by the magneto timer4 ,as the timer on this type is driven by the magneto shaft1 it is evident that the magneto must be 8timed0 with the engine1 or must have its armature shaft connected to the shaft of the engine in such a manner that the timer contact is broken1 and the single spark produced at the instant that ignition is required in the cylinder4 ,unlike the dynamo1 the alternating current magneto cannot be used with a storage battery1 the alternating current producing no chemical change in the electrodes of the battery4 ,illustration3 ,four ,cylinder 8,d#d0 ,high ,tension ,bosch ,magneto ,showing ,distributor4 ,the ,bosch high tension magneto is a typical high tension magneto having the primary and secondary windings wound directly on the armature shaft1 there being no external secondary coil4 ,the end of the primary winding is connected to the plate 7#a7 ,fig4 #ajg1 which conducts the current to the platinum screw of the circuit breaker 7#c74 ,parts 7#b7 and 7#c7 are insulated from the breaker disc 7#d71 which is in electrical contact with the armature core and frame4 ,when the circuit breaker contacts are together the primary winding is short circuited1 and when they are separated the current is broken and the spark occurs4 ,the breaker contacts are simply two platinum pointed levers that are separated and brought together by the action of a cam as they revolve4 ,a condenser 7#h7 is provided for the circuit breaker to suppress the spark and to increase the rapidity of the 8break40 ,the secondary winding of fine wire is a continuation of the primary winding1 and the secondary is wound directly over the primary4 ,the outer end of the secondary connects with the slip ring 7#i7 on which slides the carbon brush 7#aj71 which conducts the high tension current from the armature4 ,this brush is insulated from the frame by the insulation 7#aa74 ,from 7#aj7 the current is led through the bridge 7#ab7 through the carbon brush 7#ac7 to the distributor brush 7#ae74 ,metal segments are imbedded in the distributor 7#af71 the number of which corresponds to the number of cylinders4 ,as the brush rotates1 it makes consecutive contact with each of the segments in turn and therefore leads the current to the cylinders in their firing order4 ,wires from the cylinders are connected to sockets that in turn connect with the segments4 ,the disc driving the distributor brush 7#ae7 is geared from the armature shaft in such a way that the armature turns twice for every revolution of the distributor1 when four cylinders are fired1 and three times for the distributors once when six cylinders are fired4 ,illustration3 ,fig4 #ajh4 ,bosch ,high ,tension ,circuit4 ,the voltage of the current generated in the secondary coil by the rotation of the armature is increased by the interruption of the primary circuit caused by the opening of the contact breaker4 ,at the instant of interruption of the primary circuit the high tension spark is produced at the spark plug4 ,as the spark must occur in the cylinder of the engine at a certain position of the piston1 it is necessary that the interrupter act at a point corresponding to a definite position of the piston1 consequently this type of magneto must be driven positively from the motor by means of gears1 or directly from the shaft4 ,these magnetos run in only one direction4 ,this running direction should be given when magneto is ordered1 as being 8clockwise0 or 8counter-clockwise0 when looking at the driving end of the magneto4 ,the magneto for the single and double cylinder engines has no distributor1 the high tension current being led directly from the armature4 ,the circuit diagram of the ,bosch four cylinder magneto is shown by ,fig4 #ajh1 the winding and plug connections being clearly shown4 ,when connecting the magneto care should be taken to have the distributor and plug connections arranged so that the cylinders will fire in the proper order4 7#aja7 ,bosch ,oscillating ,high ,tension ,magneto4 ,the oscillating type of magneto is used on slow speed heavy duty engines that move too slowly for the ordinary type of magneto4 ,in the oscillating type the armature is given a short angular swing by the action of a tripping device operated by the engine which results in an intense spark at the lowest speeds4 ,magneto type 8#bi0 is constructed with two powerful steel magnets1 while magneto type 8#cj0 is provided with three2 an armature of the shuttle type is arranged to oscillate between their pole-shoes4 ,the magneto is actuated by a rotating cam or other suitable device1 which moves the armature #cj from its normal position whenever ignition is required4 ,to permit this movement1 a trip lever is mounted upon the tapered end of the armature shaft1 this trip lever being held in a definite position by the tension of the spring or springs #a4 ,the trip lever is only supplied when specially ordered1 but each magneto is provided with the necessary springs and spring bolts4 ,when the trip lever is moved from its normal position by the operating mechanism1 the springs are extended1 and when the operating mechanism releases the trip lever1 the later returns the trip lever and armature to their normal position1 this movement resulting in the production of a sparking current in the armature winding4 ,the winding of the armature is composed of two parts1 one being the primary winding1 which consists of a few turns of heavy wire1 and the other the secondary winding1 which consists of many turns of fine wire4 ,the tension of the current produced by the oscillation of the armature is increased by closing the primary circuit at a certain position in its movement1 and then interrupting it by means of the breaker4 ,at the moment of the interruption1 an arc-like spark is formed at the spark plug and ignition occurs4 ,illustration3 ,fig4 #aji4 ,elevation of ,bosch ,oscillating ,magneto for ,slow ,speed ,engines4 ,high ,tension ,type4 ,on cam shaft 7c7 two cams are mounted side by side4 ,one of these cams 7a7 is to be used for starting the motor1 or for the retarded spark position1 while the second 7b7 is to be used for operation1 or for the full advance position4 ,these cams are mounted on a sleeve1 which may be moved longitudinally on the shaft1 so that the trip lever may be operated by cam 7a7 or cam 7b7 as desired4 ,the sleeve is caused to rotate with the shaft by a key4 ,between the cam 7b7 and a fixed collar 7f7 a spiral spring is arranged1 which tends to maintain the sleeves in the position when the cam 7b7 is in operation4 ,a stop collar is also provided to limit the movement of the sleeve beyond this full advance position4 ,over this collar is fitted a hand wheel1 which1 in the position illustrated in the diagram1 acts together with the collar as a stop4 ,around the collar is a circular key-way1 and a brass bolt is located in the hand wheel to lock into this key-way when the hand wheel is pushed into the position indicated by the dotted lines4 ,this movement of the wheel forces the cam sleeve forward1 and brings the retarded cam 7a7 into the operating position to permit the engine to be started4 7#ajb7 ,the ,mea ,high ,tension ,magneto4 ,illustration3 ,fig4 #aaj4 ,diagram of ,oscillating ,magneto1 ,showing ,cam and ,trigger ,arrangement4 ,the low tension winding of the ordinary type of magneto is short-circuited by a breaker which opens at certain points of each revolution with the result that a high voltage is generated across the high tension winding at the moment of the break1 and a spark produced across the spark gap in the cylinder to which it is connected4 ,the quality of this spark1 or in other words the heat value1 depends among other factors upon the particular position of the armature in relation to the magnetic field at the moment the spark is produced4 ,as the armature in this type of magneto is in a favorable position for obtaining a spark twice every revolution1 two sparks can be obtained per revolution4 ,the timing of the spark is accomplished by opening the breaker earlier or later1 by shifting the breaker housing naturally with the unavoidable result that if the position of the magnetic field remains stationary1 the relative position between armature and field at the moment of the break must vary4 ,since1 however1 as explained above1 the quality of the spark depends upon this relative position1 it is apparent that a good spark1 can1 with a stationary magnetic field1 be produced only at one particular timing4 ,illustration3 ,fig4 #aaa4 ,side ,elevation of 8,mea0 ,magneto1 ,showing the ,magnets1 and ,cradle in ,which the ,magneto ,swings ,when ,advanced and ,retarded4 ,illustration3 ,fig4 #aab4 ,longitudinal ,section of 8,mea0 ,high ,tension ,magneto4 ,the result of these conditions are known to everybody familiar with automobiles4 ,they are the difficulty of cranking a motor on one of the average high tension magnetos1 if the spark is fully retarded1 and of operating the motor on the magneto at very low speed1 particularly when it is overloaded1 as for example1 in hill climbing4 ,attempts have therefore been made to obtain the spark1 independent of the timing1 always at the same favorable position of the armature4 ,the distinct innovation and improvement incorporated in the ,mea magneto consists in bell shaped magnets 7,fig4 #aaa7 placed horizontally and in the same axis with the armature1 instead of the customary horse-shoe magnets placed at right angle to the armature4 ,this at once makes possible and practicable the simultaneous advance and retard of magnets and breaker instead of the advance and retard of the breaker alone as the magnets may be moved to and fro with the breaker housing4 ,it will be seen that as a result of this new departure the relative position of armature and field at the moment of sparking is absolutely maintained1 and the same quality of spark is therefore produced1 no matter what the timing may be4 ,furthermore1 the range of timing1 which with the horse-shoe type of magneto is limited to #aj or #ae at low speeds 7i4 e4 at speeds at which a retarded spark is of value7 becomes limited only by the necessity of supplying a suitable support for the magnets4 ,with the standard types of ,mea magnetos described in the following1 this range varies from about #de to #gj1 but if necessary this range can be increased to any amount desired4 ,the bell-shaped magnets are fixed to the casing which is mounted on a base supplied with the magneto4 ,the timing is altered by turning the casing and magnets together on the base4 ,fig4 #aab shows a longitudinal section of a four cylinder ,mea magneto4 ,the armature ,f with the ball bearings #ag-ah rotates in the bell-shaped magnets #ajj1 the poles of the magnets being on a horizontal line opposite the armature #a4 ,the armature is of the ordinary ,h type iron core wound with a double winding of heavy primary and fine secondary wire4 ,on the armature are mounted the condenser #ab1 the high tension collector ring #d1 and the low tension circuit breaker #bf-ci4 ,the circuit breaker consists of a disc #bg on which are mounted the short platinum #cc1 the other contact point #cd is movable and is supported by a spring #cj which is fastened to the insulated plate #bh mounted on disc #bg4 ,fiber roller #ca in connection with cam disc #dj which is provided with two cams is located inside the breaker4 ,revolving with the armature the roller presses against the spring supported part of the breaker whenever it rolls over the two cams which of course is twice per revolution4 ,illustration3 ,magneto of ,roberts ,motor in ,advanced ,position4 ,illustration3 #aab-;a4 ,advance and ,retard ,mechanism ,used in the ,roberts ,motors4 ,the ,magneto is ,driven by a ,helical ,gear from the ,small ,pinion4 ,by ,shifting the ,gear ,back and ,forth on the ,pinion1 the ,armature of the ,magneto is ,advanced or ,retarded in ,regard to the ,piston ,position4 ,the ,reason for this ,change ,will be ,seen from the ,cuts by ,noting the ,position of the ,lower ,helix4 ,inspection of the breaker points is made easy by an opening in the side of the breaker box4 ,the box is closed by a cover #gd supporting at its centre the carbon holder #dg by means of which the carbon #df is pressed against screw #bd4 ,this latter screw connects with one end of the low tension winding while the other end is connected to the core of the armature4 ,it will1 therefore1 be seen that the breaker ordinarily short-circuits the low tension winding and that this short-circuit is broken only when the breaker opens2 it will also be apparent that when the screw #bd is grounded through terminal #ej and the low-tension switch to which it is connected1 the low-tension winding remains permanently short-circuited1 so that the magneto will not spark4 ,the entire breaker can be removed by loosening screw #bd4 ,the high tension current is collected from collector ring #d by means of brush #gg and brush holder #gf1 which are supported by a removable cover #ia which also supports the low tension grounding brush #gh provided to relieve the ball bearings of all current which might be injurious4 ,cover #ia also carries the safety gap #hi which protects the armature from excessive voltages in case the magneto becomes disconnected from the spark plugs4 ,the distributor consists of the stationary part #gj and the rotating part #fj which is driven from the armature shaft through steel and bronze gears #g and #gb4 ,the current reaches this distributor from carbon #gg through bridge #hd and carbon #fi4 ,it is conducted to brushes #fh placed at right angles to each other and making contact alternately with four contact plates embedded in part #gj4 ,these plates are connected to contact holes in the top of the distributor1 into which the terminals of cables leading to the different cylinders are placed4 ,in the front plate of the magneto is provided a small window1 behind which appear numbers engraved on the distributor gear which correspond to the number of the cylinder the magneto is firing4 ,this indicator is of great value as it allows a setting or resetting after taking out1 without the necessity of opening up the magneto to find out where the distributor makes contact4 ,the magneto proper is mounted in the base #ec which is bolted to the motor frame and the arrangement is such that the magneto can be removed from its base by removing the top parts #fj;a and #fj;b of the two bearings4 ,the variation in timing is affected by turning the magneto proper in the stationary base which is accomplished by the spark lever connections attached to one of the side lugs #hh4 ,the spark is advanced by turning the magneto opposite to rotation and is retarded by turning it with rotation4 ,one cylinder magnetos are similar to the four cylinder except that the distributor and gears are omitted4 7#ajc7 ,the ,wico ,high ,tension ,igniter4 ,the ,wico igniter produces a spark similar to that of the conventional high tension magneto except that the heat of the spark is independent of the engine speed4 ,in other respects it is very different from the types described in the preceding pages for its motion is reciprocating instead of being rotary1 and because all of the wire is stationary1 the only movement being that of the iron core that passes through the center of the fields4 ,the fact that the spark is of the same intensity at all speeds makes this device particularly desirable in starting the engine at which time the mixture is always of the poorest quality4 ,illustration3 ,fig4 #aac4 ,wico ,igniter4 ,high ,tension ,reciprocating ,type4 ,it is very simple1 and is without condensers1 contact points or primary windings1 and has no parts that require adjustment4 ,the current is generated by the reciprocating movement of two soft iron armatures shown as a bar across the bottom of the two coils1 which move alternately into and out of contact with the ends of the soft iron cores4 ,the movement of these armatures in the upward direction is produced by the motion of the engine and the speed of this movement is1 of course1 proportional to the speed of the engine4 ,the downward movement1 which produces the spark1 is caused by the action of a spring1 is much more rapid than the upward movement and entirely independent of the speed of the engine4 ,the magnets are made of tungsten steel1 shown as two bars across the top of the coils1 hardened and magnetized and are fastened by machine screws to the cast iron pole pieces1 which serve to carry the magnetic lines of force from the poles of the magnets to the soft iron cores4 ,the cores1 which fit into slots milled in the pole pieces1 are laminated or built up of thin sheets of soft iron1 each sheet being a continuous piece1 the full length of the core4 ,each core1 extends from just below the top armature1 down through the pole piece1 and coil to just above the bottom armature4 ,each armature consists of a number of laminations or sheets of soft iron mounted on a spool shaped bushing1 which1 in turn1 is loosely fitted onto the squared end of the armature bar4 ,the armature bar is supported with a sliding fit in a box shaped guide which is fastened in the case4 ,on the outer ends of the armature bar are spiral springs held in place by cup shaped washers and retaining pins1 the combination making a self-locking fastening similar to the familiar valve spring fastening used almost universally on gas engines4 ,these springs bear against the armatures and tend to force them against the shoulders of the armature bar4 ,the coils each have a simple high tension winding of many turns1 thoroughly insulated and protected against mechanical injury4 ,they are connected together in series by means of a metal strip1 thus making one continuous winding4 ,in the single cylinder igniter1 one end of the winding is grounded to the case of the igniter1 while the other end is connected to the heavily insulated lead wire4 ,this lead wire passes out through a stuffing box1 packed with wicking and thoroughly water tight1 direct to the spark plug in the cylinder4 ,in the two cylinder machine no ground connection is used1 but both ends of the winding are connected to lead wires passing out of the case to the spark plugs4 ,the action of the igniter is as follows3--,as the driving bar1 through its connection with the engine1 is moved downward to its limit of travel1 carrying the latch with it1 the shoulder on the side of the latch snaps under the head of the latch block4 ,as the motion reverses the latch carries the latch block and armature bar upward4 ,the lower armature1 being in contact with the stationary cores1 cannot rise with the armature bar1 but the lower armature spring is compressed between its retaining washer and the armature1 while the bar rises and carries with it the upper armature1 which bears against the upper shoulders on the bar4 ,as the driving bar continues its upward motion the upper end of the latch meets the lower end of the timing wedge and1 as the wedge is held stationary by the timing quadrant1 a further movement of the latch causes it to be pushed aside until the shoulder on the latch clears the latch block and releases it4 ,as the lower armature spring is at this time exerting a pressure between the armature bar and cores through the medium of the lower armature1 the instant the latch block is released1 the armature bar is quickly pulled downward1 carrying the upper armature with it4 ,just before the motion of the upper armature is stopped by its coming in contact with the cores1 the lower shoulders on the armature bar come in contact with the lower armature1 and1 as the bar has acquired considerable velocity1 its momentum carries the lower armature away from the cores against the pressure of the upper armature spring1 which thus acts as a buffer to gradually stop the movement of the armature bar4 ,the armature bar finally settles in a central position4 ,the timing of the spark is accomplished by releasing the armature bar earlier or later in the stroke4 ,this is done by shifting the position of the eccentric timing quadrant1 which in turn varies the position of the wedge so that the latch strikes it earlier or later in the stroke4 ,the timing quadrant is furnished with several notches into one of which the top of the wedge rests1 thus holding the quadrant in the desired position4 ,the motion should preferably be taken from an eccentric on the cam shaft of a single cylinder four cycle engine1 or the crank shaft of a single cylinder two cycle or a two cylinder four cycle engine4 ,on a two cylinder four cycle engine1 it is sometimes more convenient to drive the igniter from the cam shaft1 using a two throw cam to produce the required number of sparks4 ,in this case the shape of the cam should be such as to duplicate the motion of the eccentric4 ,that is1 it should start the driving bar slowly from its lower position1 move it most rapidly at mid stroke and bring it to rest gradually at the upper end of the stroke1 exactly as is done by the eccentric motion4 ,when an eccentric is already on the engine the motion may be taken from it to an igniter with a driving bar through a properly proportioned lever that will give the required length of stroke4 ,where a plunger pump is used on the engine the motion can usually be taken from the pump rod4 ,where an eccentric has to be provided especially for the igniter1 the driving bar is generally used with its roller running on the eccentric4 7#ajd7 ,starting ,on ,magneto ,spark4 ,a four-cylinder engine in good condition will come to rest with the pistons approximately midway on the stroke and balanced between the compression of the compressing cylinder and of the power cylinder4 ,when the cylinders of such an engine are charged with a proper mixture1 the engine will start by the ignition of the mixture contained in the compressing cylinder1 for the pressure produced by the ignited gas will be sufficient to rotate the crankshaft4 ,illustration3 ,fig4 #aad4 ,bosch ,dual ,system4 ,it is essential1 for the ignition system to be so arranged that a spark can be produced at any point in the piston travel1 and in this the ,bosch dual1 duplex and two independent systems are successful4 ,the ,bosch dual system1 ,fig4 #aad1 is part of the equipment of many of the cars and engines marketed1 and is composed of two separate and distinct ignition systems1 one supplying ignition by direct high-tension magneto1 and the other by a battery and high-tension coil4 ,these two systems consist in reality of but two main parts2 the dual magneto1 incorporating a separate battery timer1 and the single unit dual coil with its battery4 ,the sparking current from either battery or magneto is brought to the magneto distributor1 so that the only parts used in common are the distributor and the spark plugs2 the common use of the latter for both magneto and battery systems is cause for the popularity of the dual system for motors having provision for only one set of plugs4 ,in both the magneto and the battery sides the spark is produced on the breaking of the circuit1 and the coil is so arranged that by pressing a button when the switch is in the battery position1 an intense vibrator spark is produced in the cylinder during that period when the circuit breaker is open1 which will be the case during the first three-fourths of the power stroke4 ,the current is transmitted to the distributor and passes through the spark plug of the cylinder that is on the power stroke4 ,illustration3 ,fig4 #aae4 ,bosch ,duplex ,breaker4 ,should the engine come to a stop in such a position that the battery timer is closed1 it will not be possible to produce a vibrator spark by the pressing of the button1 but the releasing of the button will produce a single contact spark that will ignite the mixture and thus start the engine4 ,thus if the engine should stop in some odd position1 and the spark is produced when the piston is slightly before top center1 for instance1 there will be a slight reverse impulse which will bring another cylinder on the power stroke and into the ignition circuit4 ,the engine will thereupon take up its cycle in the proper direction4 ,in the ,bosch duplex system the coil is in series with the magneto armature1 but the spark is produced under the same condition1 that is1 on the breaking of the circuit4 ,in consequence the ,bosch duplex system will permit the production of a spark during the first three-quarters of the power stroke by the pressing of the push button set on the switch plate4 ,illustration3 ,the ,herz ,high ,tension ,magneto in ,which the ,magnets are ,built up of ,thin ,steel ,plates ,without ,pole ,pieces 7,four ,cylinder ,type74 ,the ,bosch two independent system is composed of a separate ,bosch battery system and a separate ,bosch magneto4 ,although the operation of the coil is somewhat similar to that of the dual system1 the nature of the battery system is such as to require arrangements for two separate sets of spark plugs4 ,the coil is not unlike that supplied with the dual system in that by pressing a button located on the switch plate a series of intense sparks may be produced in the cylinder at all advantageous points of the power stroke4 ,,chapter ,,ix ,,carburetors 7#aje7 ,principles of ,carburetion4 ,the carburetor is a device for converting volatile liquid fuels1 such as gasoline1 alcohol1 kerosene1 etc41 into an explosive vapor4 ,besides vaporizing the liquid1 the carburetor also controls the proportion of the fuel to the air required for its combustion4 ,the mixture produced by the carburetor must be a uniform gas and not a simple spray to accomplish the best results for complete and instantaneous combustion4 ,proper combustion cannot be attained with any of the fuel in a liquid state as all of the fuel contained in a liquid particle cannot come into contact with the consuming air4 ,it is of the utmost importance to have the air and fuel in correct proportions so that the fuel may be completely consumed without danger of interfering with the ignition by an excess of air4 ,with few exceptions modern gasoline carburetors are of the nozzle type in which the liquid is broken up into an extremely fine subdivided state by the suction of the engine piston4 ,this fine spray is then fully vaporized or gasified by the heat drawn from the surrounding intake air that is drawn through the carburetor and into the cylinder on the suction stroke4 ,owing to the low grade fuels now on the market and to the constantly varying atmospheric conditions it is seldom possible to obtain a perfect vapor in the correct proportions1 and for this reason much heat is lost that would be available were the mixture perfect4 ,carburetors for automobiles and boats vary in detail from those used on stationary engines due principally to the difference in matters of speed4 ,a stationary engine runs at a constant speed which makes adjustment comparatively easy1 while automobile engines have a wide range of speeds and loads making it very difficult to maintain the correct mixture at all points in the range4 ,the difference in the fuel and air adjustments for varying of speeds marks the principal difference between stationary and automobile carburetors4 ,there are many types of successful carburetors on the market1 so many in fact that we have room for the description of only three or four of the most prominent1 but we will say that the well known carburetors are based on the same principles and differ only in matters of detail4 ,a cross-sectional view of the well known ,schebler ,type ,d carburetor is shown by ,fig4 #aaf1 and is of the type commonly used on automobile motors and boats4 ,illustration3 ,,model 8,d0 ,fig4 #aaf4 ,cross-,section ,through ,type 8,d0 ,schebler ,carburetor4 7#ajf7 ,schebler ,carburetor4 ,the carburetor is connected to the intake of the engine by pipe screwed into the opening ,r1 the gas passing from the carburetor to the engine through this opening4 ,d is the spray nozzle which opens into the float chamber ,b1 the opening of the nozzle being regulated by needle valve ,e which controls the quantity of gasoline flowing into the mixing chamber ,c4 ,on the suction stroke of the engine1 air is drawn through the upper left hand opening1 past the partially open auxiliary air valve ,a1 past the needle valve ,d1 through the mixing chamber ,c1 and into the engine through ,r4 ,the suction of the engine produces a partial vacuum in the mixing chamber ,c which causes the gasoline to issue from the nozzle ,d1 in the form of a fine spray which is taken up by the air passing through the passage ,h1 and is taken into the engine through ,r1 thoroughly mixed4 ,the amount of mixture entering the engine1 and consequently the engine speed is regulated by the throttle valve ,k1 operated by the lever ,p4 ,in order that the amount of spray given by the nozzle ,d be constant it is necessary that the level1 or height of the gasoline in the nozzle be constant4 ,the level is maintained by means of the float ,f1 which opens1 or closes the gasoline supply valve ,h1 opening it and allowing gasoline to enter when the level is low1 and closing the valve when the level is high4 ,the carburetor is connected to the gasoline supply tank1 by pipe connected to the inlet ,g1 through which the gasoline flows into the float chamber ,b4 ,the float chamber carries a small amount of gasoline on which the float ,f rests4 ,the richness of the mixture is controlled by opening or closing the nozzle needle valve ,e1 which passes through the center of the nozzle ,d4 ,the float ,f surrounds the nozzle in order to keep the level of the liquid constant when the carburetor is tilted out of the horizontal by climbing hills1 or by the rocking of the boat when used on a marine engine4 ,a drain cock ,t is placed at the bottom of the float chamber for the purpose of removing any water1 or sediment that may collect in the bottom of the float chamber4 ,at low speeds1 the auxiliary air valve ,a lies tight on its seat1 allowing a constant opening for the incoming air through the space shown at the bottom of the valve4 ,when the speed of the engine is much increased1 the vacuum is increased in the mixing chamber ,c1 which overcomes the tension of the air valve spring ,o and allows the valve to open and admit more air to the mixing chamber4 ,the action of the auxiliary air valve keeps the mixture uniform at different engine speeds1 as it tends to keep the vacuum constant in the mixing chamber4 ,when the engine speed increases1 the flow of gasoline is greater1 and consequently more air will be required to burn it2 this additional air is furnished by the automatic action of the valve1 and when once adjusted1 compensates accurately for the different engine speeds4 ,the gasoline is generally supplied by a tank elevated at least six inches above the level of the fluid in the float chamber2 although in some cases the gasoline is supplied by air pressure on a tank situated below the level of the carburetor4 ,in some types of ,schebler carburetors1 the float chamber ,b is surrounded by a water jacket that is supplied with hot water from the cylinder jackets of the engine4 ,this keeps the gasoline warm so that it evaporates readily under any atmospheric conditions4 ,the quantity of air admitted to the carburetor is controlled by an air valve shown in the air intake by the dotted lines4 ,this is adjusted by hand for a particular engine and is seldom touched afterward4 ,when starting the engine it is necessary to have a very rich mixture for the first few revolutions1 this mixture being obtained by 8flooding0 the carburetor4 ,on the ,schebler carburetor the mixing chamber is flooded by depressing the 8tickler0 or flushing pin ,v4 7#ajg7 ,two ,cycle ,carburetors4 ,nearly any type of carburetor can be used on a two port1 two stroke1 cycle engine providing a check valve is placed between the crank case and carburetor to prevent the crank-case compression from forcing its contents back through the inlet passages4 ,a great many manufacturers make special carburetors for two stroke motors that have the check valve built into the carburetor itself4 ,with three port two stroke cycle engines a check valve is not necessary as the piston in this type of engine performs this duty4 ,in that class of vaporizers known as mixing valves1 the valve that controls the flow of gasoline blocks the air passage in such a way that an additional check valve is not necessary4 7#ajh7 ,kingston ,carburetors4 ,the ,kingston ,carburetor shown by ,fig4 #aag differs from the ,schebler in many details1 the principal difference being in the construction of the spray nozzle and the construction of the auxiliary air valve4 ,the throttle valve ,e controls the exit of the mixture through the engine connection ,c which is an extension of the mixing chamber4 ,the spray nozzle ,j which is surrounded by a hood or tube is controlled by the needle valve ,a which is threaded into the top of the mixing chamber1 this latter adjustment being locked into place by a button head screw and a slot in the casting4 ,illustration3 ,fig4 #aag4 ,cross-,section ,through ,kingston ,carburetor ,showing ,balls ,used for ,auxiliary ,air ,valves4 ,surrounding the nozzle tube or hood is a curved restriction in the air intake passage1 is known as a ,venturi tube1 which insures a constant relation between the air and fuel supplies4 ,as the action of the ,venturi tube is rather complicated1 it will not be taken up in detail4 ,air is supplied to the ,venturi passage through the intake 7,d74 ,an annular float 7,k7 surrounds the mixing chamber that acts on the gasoline supply valve 7,i7 through a short lever arm4 ,this valve is accessible for cleaning on the removal of the cap ,h that covers the valve chamber4 ,gasoline enters the float chamber through the fuel pipe ,g1 and enters the spray nozzle through the two ports in the base of the mixing chamber4 ,the auxiliary air valve is a particularly novel feature of this carburetor1 as no springs nor disc valves are used in its construction4 ,five balls 7,m7 of different weights and sizes act as air valves1 the balls covering the inlet ports 7,l7 under normal operation4 ,as the speed increases1 the balls are lifted off their seats in order of their weight or size by the increase in suction4 ,with a slight increase of suction1 the lightest ball covering the smallest hole is lifted first1 a further increase in suction lifts the next largest ball which still further increases the auxiliary air intake1 and so on until at the highest speed all of the balls are off their seats4 ,access to the ball valves is had through the valve caps 7,n74 ,the constant supply inlet is circular and may be set at any desired angle1 as can the float chamber and gasoline supply connection4 ,control and adjustment are entirely by the needle valve4 7#aji7 ,the ,feps ,carburetor4 ,the ,feps carburetor has the main needle valve surrounded by a ,venturi chamber as in the preceding case1 the needle valve adjustment being made through a lever on the left of the mixing chamber4 ,an auxiliary nozzle directly under the auxiliary air valve at the right1 connects with the float chamber and furnishes an additional mixture of gasoline and air for hill climbing and high speed work when the leather faced auxiliary air valve lifts from its seat4 ,the adjustment for this auxiliary jet is shown at the right of the air valve chamber4 ,for intermediate speeds1 the air valve alone is in action4 ,no controlling springs are used on the air valve which insures positive action and sensitive control of the air4 ,a float surrounding the ,venturi tube controls the fuel valve through the usual lever arm4 ,a wire gauze strainer placed in the fuel chamber to the left prevents dirt and water from being drawn into the nozzle1 and as this strainer easily removed it is a simple matter to clean and prevent the troubles due to dirty fuel4 ,by closing the upper valve in the vertical engine connection the vacuum is increased in the manifold when starting the engine4 ,this increase of vacuum draws gasoline from the float chamber and primes the engine making the engine easy to start in cold weather4 ,the tube through which the gasoline is drawn for priming is the small crooked tube bending over the float and terminating above the starting valve4 ,below this valve is the throttle valve which controls the mixture in the ordinary manner4 ,the adjustment for intermediate speeds is made by the center knurled thumb-screw shown over the air valve chamber which controls the travel of auxiliary air valve4 ,in effect this is a double carburetor1 one jet for high speed and one for low4 7#aaa7 ,gasoline ,strainers4 ,much trouble is caused in carburetors by dirt1 water and sediment1 collecting in the small passages and obstructing the flow of the gasoline4 ,illustration3 ,fig4 #aai4 ,the ,excelsior ,carburetor in ,which the ,air is ,regulated by a ,ball which ,lies in the ,tapering ,venturi ,tube4 ,an ,increase of ,suction ,lifts the ,ball and ,allows ,more ,air to ,pass4 ,the purpose of the gasoline strainer is to prevent any water or foreign matter from being carried into the carburetor1 and this device should be used on every engine if the owner wishes to be free from carburetor troubles4 7#aab7 ,installing ,gasoline ,carburetors4 7#a7 ,use brass or copper pipe from the tank to carburetor if possible to avoid trouble from dirt and flakes of rust4 7#b7 ,when installing a gasoline tank be sure that the bottom of the tank is at least six inches above the carburetor to insure a good flow4 7#c7 ,the tank should be provided with an air vent hole1 or the gasoline will not flow because of the vacuum in the top of the tank4 7#d7 ,all tanks should be provided with a drain cock at the lowest point so that water and dirt may be easily removed4 7#e7 ,clean out the tank thoroughly before filling with gasoline to avoid clogged carburetors4 7#f7 ,pipes from the tank to carburetor should never be placed near exhaust pipes or hot surfaces for the gasoline vapor may prevent the feeding of gasoline4 7#g7 ,clean out pipes before using4 7#h7 ,if common threaded pipe joints are used on the gasoline piping1 use common soap in place of red lead4 7#aac7 ,installing the ,carburetor4 ,the carburetor should be placed as near to the cylinder as possible1 the shorter the pipe1 the less the amount of vapor condensed in the manifold4 ,with multi-cylinder engines the carburetor should be so situated1 that is1 an equal distance from each cylinder1 so that each cylinder will inhale an equal amount of vapor4 ,the intake opening of the pipe should be placed near one of the cylinders1 or draw warm air off the surface of the exhaust pipe in order that gasoline will evaporate readily in cold weather1 and form a uniform mixture at varying temperatures4 ,great care should be taken to prevent any air leaks in the carburetor1 or intake manifold connections1 as a small leak will greatly reduce the strength of the mixture and cause irregular running4 ,always use a gasket between the valves of a flanged connection and keep the bolts tight4 ,if a brazed sheet brass manifold is used1 look out for cracks in the brazing4 ,leaks may be detected in the connections by spurting a little water on the joints1 and turning the engine over on the suction stroke4 ,if the water is sucked in the leaks should be repaired at once4 ,make sure when placing gaskets1 that the gasket does not obstruct the opening in the pipe1 and that it is securely fastened so that it is not drawn in by the suction4 ,never allow the carburetor to support any weight1 as the shell is easily sprung which will result in leaking needle valves4 ,,carburetor ,,adjustment4 ,when adjusting the carburetor of multiple cylinder engine1 it is advisable to open the muffler cutout in order that the character of the exhaust may be seen or heard4 ,with the muffler open1 the color of the exhaust should be noted4 ,with a ,,purple flame you may be sure that the adjustment is nearly correct for that load and speed2 a yellow flame indicates too much air2 a thin blue flame too much gasoline1 and is not the best for power4 ,before starting for the adjustment test1 try the compression1 and the spark4 ,if the compression is poor1 try the effects of a little oil on the piston1 which may be introduced into the cylinder through the priming cup4 ,it will be well to dilute the oil to about one-half with kerosene4 ,after all trouble with all the parts are clear1 you may start the engine4 ,turn on the gasoline at the tank1 and after standing a moment see whether there is any dripping at the carburetor1 if there is1 the trouble will probably be due to a leaky float1 dirt in the float valve1 or to poor float adjustment4 ,locate the leak and remedy it before proceeding further4 ,dirt on the seat of the needle valve may sometimes be removed by 8flooding0 the carburetor1 which is done by holding down the 8tickler0 lever for a few seconds1 causing the gasoline to overflow1 and wash out the dirt4 ,if the motor has been standing for a time it would be well to 8prime0 the motor by admitting a little gasoline into the cylinder through the priming cup1 or by pushing the tickler a couple of times so as to slightly flood the carburetor4 ,now turn on the spark and turn over the engine for the start1 taking care that the throttle is just a little farther open than its fully closed position4 ,if the engine takes a few explosions and stops1 you will find the nozzle1 or that some part of the fuel piping is clogged which will stop the engine4 ,if the motor gradually slows down1 and stops1 with ,,black ,,smoke issuing from the end of the exhaust pipe1 or ,,misfires badly1 the mixture is ,,too ,,rich1 and should be reduced by cutting down the gasoline supply by means of the needle valve adjusting screw4 ,if it stops quickly1 with a ,,backfire1 or explosion at the supply of gasoline should be ,,increased by adjusting the mouth of the carburetor1 the mixture is ,,too ,,lean1 and the needle valve4 ,in all cases be sure that the auxiliary valves are closed when the engine is running slowly1 with the throttle closed1 as in the above test4 ,if they are open at low speed1 the mixture will be weakened and the test will be of no avail4 ,after adjusting the needle valve as above until the engine is running 7with throttle in the same partially closed position71 turn the valve slowly in one direction or the other until the motor seems to be running at its best4 ,during the above tests the spark should be left retarded throughout the adjustment1 and the throttle should not be moved4 ,the carburetor should now be tested for high speed adjustment1 by opening the throttle wide 7spark advanced71 and observing the action of the motor4 ,if the engine back-fires through the carburetor at high speed1 it indicates that the mixture is too weak which may be due to the auxiliary air valve spring tension being too weak and allowing an excess of air to be admitted4 ,increase the tension of the spring1 and if this does not remedy matters1 admit a little more fuel to strengthen the mixture by means of the needle valve adjustment4 ,do not touch the needle valve if you can possibly avoid it1 or the high-speed adjustment1 as the fuel adjustment will be disturbed for low speed4 ,if the engine misfires1 with loud reports at the exhaust1 does not run smoothly1 or emits clouds of black smoke at high speed1 the engine is not receiving enough air in the auxiliary air valve1 consequently the tension of the spring should be reduced4 ,back firing through the carburetor denotes a weak mixture4 ,trouble in cold weather may be caused either by slow evaporation of the gasoline1 or by water in the fuel that freezes and obstructs the piping or nozzle4 ,in cold weather a higher gravity of gasoline should be used than in summer1 as it evaporates more readily1 and therefore forms a combustible gas the rate at lower temperatures4 ,to increase the rate of evaporation of the gasoline1 it should be placed in a bottle and held in hot water for a time before pouring it into the carburetor or tank1 or the air inlet warmed with a torch4 ,the cylinder water jacket should always be filled with hot water before trying to start the engine1 and will prevent the gas from condensing on the cold walls of the cylinder4 ,often good results may be had by wrapping a cloth or towel around the carburetor1 that has been dipped in hot water4 ,the cylinder of an air-cooled engine may be warmed by gently applying the heat of a torch to the ribs1 or by wrapping hot cloths about it4 ,the tank1 piping1 and carburetor should be drained more frequently in cold weather than in hot1 to prevent any accumulation of water from freezing1 and stopping the fuel supply4 ,a gasoline strainer should always be supplied on the fuel line1 and should be regularly drained4 ,the motor may often be made to start in cold weather by cutting out the spark1 and cranking the engine two or three revolutions with the throttle wide open4 ,the throttle should now be closed within of its fully closed position1 the ignition current turned on1 and the engine cranked for starting4 ,this system will very seldom fail of success at the first attempt4 ,carburetor flooding is shown by the dripping of gasoline from the carburetor1 and which results in too much gasoline in the mixture4 ,flooding may be caused by dirt accumulating under float valve1 by a leaking float 7,copper ,float71 by ,water ,logged ,float 7,shellac worn off ,cork ,float71 by float adjustment causing too high a level of gasoline1 by leaking float valve1 by cutting out ignition when engine is running full speed1 by rust or corrosion sticking float valve lever1 by float binding in chamber1 by float being out of the horizontal1 by float valve binding in guide1 by excessive pressure on gasoline1 or by tickler lever held against float continuously4 ,dirt accumulated under float valve may sometimes be flushed out by depressing tickler lever several times2 if this does not suffice1 the cap over the valve must be removed1 and the orifice cleaned by wiping with a cloth4 ,,leaking ,,float ,,valves should be reground with ground glass or very fine sand2 never use emery as the particles will become imbedded in the metal1 which will be the cause of worse leaks4 ,should the shellac be worn off of a cork float allowing the gasoline to penetrate the pores of the cork1 a new float should be installed1 as it is a doubtful policy for owner to give the float an additional coat of shellac4 ,,misfiring ,,at ,,low ,,speed4 ,if the carburetor cannot be adjusted to run evenly on low speed after making all possible adjustments with the needle valve1 the trouble is probably due to air leaks between the carburetor and engine1 caused by broken gaskets1 cracked brazing in the intake manifold1 or by leaks around the valve stem diluting the mixture4 ,,incorrect ,,valve ,,timing will cause missing1 especially on multiple cylinder engines1 as the carburetor cannot furnish mixture to several cylinders that have different individual timing4 ,look for air leaks around the spark edge openings1 and be sure that all valves seat gas tight4 ,always be sure that the auxiliary air valve remains closed at low speeds1 as a valve that opens at too low a speed will surely cause misfiring as it dilutes the mixture4 ,,missing in one cylinder may be caused by an air leak in that cylinder4 ,,water in gasoline will cause misfiring1 especially in freezing weather1 as it obstructs the flow of fuel to the carburetor4 ,the carburetor and tank should be drained at regular intervals1 and if possible1 a strainer should be introduced in the gasoline line4 ,,clogged ,,nozzle4 ,particles of loose dirt in the nozzle will occasion an intermittent flow of gasoline that will result in misfiring4 ,the nozzle should be cleaned with a small wire run back and forth throughout the opening4 ,,clogged ,,air ,,vent in the float chamber will change the level of the fuel1 and will either 8starve0 the engine1 or flood the carburetor4 ,the air in the float chamber is a very small hole1 and is likely to clog4 ,,hot ,,fuel ,,pipe4 ,if the fuel pipe that connects the tank with the carburetor1 becomes hot1 due to its proximity to the exhaust pipe of cylinders1 vapor will be formed in the pipe that will interfere with the flow of fuel4 ,,dirt ,,under ,,auxiliary ,,air ,,valve will prevent the valve from seating properly1 causing the engine to misfire at low speed4 ,,cracks ,,or ,,leaks in intake pipe or gaskets will cause intermittent leaks of air and spasms of misfiring4 ,old cracks that have been brazed will sometimes open and close alternately causing baffling cases of spasmodic misfiring4 ,,dirt ,,in ,,air ,,intake will change the air ratio1 and the increased suction will cause a greater flow of gasoline4 ,do not place the end of the inlet pipe in a dusty place1 nor where oil can be splashed into it by the engine4 ,clean out periodically4 8,,loading ,,up0 of the inlet piping in cold weather on light load is caused by the mixture condensing in the intake pipe4 ,the only remedy is to keep the piping warm1 or to heat the inlet air4 ,,clogged ,,overflow ,,pipe1 with engines equipped with pump supply will cause flooding1 as the fuel does not return rapidly enough to the tank4 7#aad7 ,kerosene ,vaporizer for ,motorcycles4 ,an ingenious vaporizing device has been designed for the use of kerosene as a fuel for motorcycle engines1 by the ,m4 ,g4 and ,g4 ,motor ,patents ,syndicate1 ,ltd41 ,england1 is described in ,motor ,cycling4 ,the device consists of a comminuter1 or vaporizer1 which screws into the sparkling-plug hole in the cylinder1 the plug being transferred to an aperture in the vaporizer1 a feeder for regulating the supply of fuel to the vaporizer1 and a throttle and air barrel1 or mixing chamber1 for the purpose of proportioning the amount of air and gas supplied to the engine1 and for controlling the speed of the machine as in an ordinary carburetor4 ,the feeder receives the fuel--in this case kerosene--although any heavy oil can be used with almost equally good results4 ,the feeder answers a purpose similar to the ordinary float chamber of the carburetor1 i4 e41 to regulate the amount of kerosene it is required to pass through the vaporizer4 ,it consists of a small chamber mounted upon the end of a pipe leading to the vaporizer4 ,kerosene is fed to this device by a copper pipe from the tank1 and enters at the lowest point through a #c_/af-;inch hole or jet4 ,this is covered by a small valve1 operated by engine suction4 ,the lift of this valve can be adjusted by the insertion of washers to suit any particular size of engine1 just as one would use various size jets to suit either a large or small engine4 ,one of the greatest advantages of the device lies in the size of this aperture or jet1 inasmuch as it cannot possibly choke up with grit1 and even water will pass through and not stop the operation of the carburetor4 ,at the top of the feeder is an air hole1 which admits just sufficient air to pass the kerosene through the vaporizer1 the reason for this being that the heat of the vaporizer shall only act upon the fuel1 the mixture afterwards being balanced by air being admitted through the mixing chamber4 ,after the kerosene leaves the feeder it passes through a pipe to the vaporizer4 ,this consists of a gunmetal body with cooling ribs cast on the outside1 whilst through the center runs a thin copper tube of -inch diameter and only #bj gauge1 which would really melt during the heat of combustion were it not for the fact of the fuel passing through it4 ,the heat derived from this formation of vaporizer is approximately #a1jjj degrees ,fahr4 ,inside the central tube is a strip-steel spiral1 which serves the double purpose of giving a centrifugal motion to the fuel1 and at the same time forming a supporter for the tube1 preventing it crushing under the force of the explosions4 ,it is1 of course1 understood that the inside of the feeding tube is entirely isolated from the combustion chamber4 ,the sparking plug is screwed into the wall of the vaporizer1 which is now really an extension of the combustion chamber4 ,obviously this slightly reduces the compression of the engine1 which1 however1 is a necessary feature when kerosene is used as a fuel4 ,after passing through this device the kerosene is thoroughly vaporized1 and the vapor is led through a flexible pipe to the throttle chamber2 this taking the place of an ordinary carburetor and being fitted to the induction pipe4 ,there are two slides1 operated by ,bowden levers from the handle-bar1 one being for the main air intake and the other for the gas4 ,illustration3 ,fig4 #aba-;a4 ,the ,english ,aster ,electric ,lighting ,unit4 ,undoubtedly the greatest claim for this vaporizer is the fact that practically no carbon deposit forms upon the inside of the cylinder or on the piston4 ,what little deposit is formed takes the shape of small1 soft flakes1 which1 instead of adhering to the cylinder walls1 break away before they have attained any size and are blown through the exhaust valve4 ,altogether1 this device seems to have finally solved the problem of using kerosene as a fuel on air-cooled engines1 especially if the carbon deposit difficulty has been finally overcome4 ,the device was fitted to a #c h4p4 ,matchless with a ,white and ,poppe engine4 ,in order to start up1 a small gasoline tank1 holding about one half-pint of gasoline1 is fitted under the main tank and communicates with the feeder4 ,half a minute is all that is necessary running on gasoline1 when the kerosene can be turned on4 ,the machine would fire at a walking pace1 and could also be accelerated up to #ee m4p4h4 ,,chapter ,x ,,lubrication 7#aaf7 ,general ,notes on ,lubrication4 ,no matter how carefully the surface of a shaft or bearing may be finished1 there always remains a slight roughness or burr of metal1 which although of microscopic proportions is productive of friction or wear4 ,each minute projection of metal on a dry shaft acts exactly as a lathe tool1 when the shaft revolves in cutting a groove in the stationary bearing4 ,since there are a multitude of these projections in a journal1 the wear would be very rapid1 and would in a short time completely destroy either the shaft or bearing1 no matter how highly finished in the beginning4 ,when lubricating oil is introduced into a bearing it immediately covers the rubbing surface1 and as the oil has a considerable resistance to being deformed1 or is 8stiff10 it separates the surface of the shaft from that of the bearing for a distance equal to the thickness of the oil film4 ,with ordinary lubricants this distance is more than enough to raise the irregularities of the shaft out of engagement with those of the bearing4 ,this property of 8stiffness0 in the oil is known as 8viscosity40 ,the value of viscosity varies greatly with different grades of oil1 and also with the temperature with the result that the allowable pressure on the oil per square inch also varies4 ,with oils of low viscosity a small pressure per square inch on the bearing will squeeze it out1 and allow the two metallic surfaces to come against into contact1 causing wear and friction1 while an oil of greater viscosity will successfully resist the pressure4 ,the life and satisfactory operation of the engine depends almost entirely upon the lubricant and the devices that apply it to the bearings4 ,excessive wear and change in the adjustments are nearly always the result of defective lubricating devices or a poor lubricant4 ,the principal lubricants are3 7#a7 ,solid lubricants such as graphite1 soapstone1 or mica4 7#b7 ,semi-solid lubricants such as vaseline1 tallow1 and soap emulsions1 or greases compounded of animal fats1 vegetable and mineral oils2 and 7#c7 ,liquid lubricants1 such as sperm oil1 or one of the products of petroleum1 the latter medium being the class of lubricant most suitable for internal combustion engines1 owing to its combining the qualities of a high flash-point with a comparative freedom from either acidity or causticity4 ,oils of animal or vegetable origin should never be used with gas engine as the high temperatures encountered will char and render them useless4 ,tallow and lard oil are especially to be avoided1 at least in a pure state4 ,in the cylinder only the best grade of ,,gas ,,engine cylinder oil should be used1 which according to different makers has a flash point ranging from #ejj to #gjj degrees4 ,using cheap oil in the cylinder is an expensive luxury4 ,in general1 the oils having the highest flash points have also the objectionable tendency of causing carbon deposits in the combustion chamber and rings which is productive of preignition and compression leakage4 ,the lower flash oils have a tendency to vaporize and to carry off with the exhaust which will leave the walls insufficiently lubricated unless an excessive amount is fed to the cylinder4 ,by starting with samples of well known brands recommended by the builder of the engine it will be an easy matter to find which is the cheapest and gives the best results4 ,in figuring the cost of oil do not take the cost per gallon as a basis1 but the cost for so many hours of running1 or better yet the number of horse-power hours4 ,unless you are fond of buying replacements and new parts do not stint on the oil supply4 ,on the other hand1 an excess of oil should be avoided as this means not only a waste of oil through the exhaust pipe1 but trouble with carbon deposits and ignition troubles as well4 ,foul igniters1 misfiring1 and stuck piston rings are the inevitable result of a flood of lubricating oil4 ,when a whitish yellow cloud of smoke appears at the end of the exhaust pipe1 cut down the oil feed4 ,the exhaust should be colorless and practically odorless4 ,too much oil cannot be fed to the main bearings of the crank shaft if the waste oil is caught1 filtered and returned to the bearings by a circulating system1 for the flood of oil not only insures ample lubrication but removes the heat generated as well4 ,the bearings require a much lighter oil1 of a lower fire test than the cylinder oil4 ,it is evident that its viscosity is a most important element1 as it determines the allowable pressure on the shaft4 ,the viscosity of an oil varies with the temperature and is greatly reduced at cylinder heat4 ,a comparative test of the viscosity or load bearing qualities of an oil may be made by making bubbles with it by means of a clay pipe2 the larger the bubble1 the higher the viscosity of the oil4 ,different sizes of bearings1 and bearing pressures1 call for oils of different viscosities1 and consequently an oil that would be suitable for one engine would not answer for another2 heavy bodied oils being used for heavy bearing pressures1 and light thin oil for small high speed bearings4 ,the best way to determine the value of an oil for a particular shaft bearing is by experiment1 attention being paid to its adaptability for the feeding devices used4 ,the compression attained in a gas engine cylinder depends to a certain extent upon the body of the cylinder oil1 for many engines that leak compression past the rings with thin oil will work satisfactorily with a heavy viscous oil that clings tightly to the surfaces4 ,an engine will often lose compression when an oil of poor quality is used4 ,air cooled engine cylinders require an oil of heavier body than water cooled because of the higher temperature of the cylinder walls4 ,gum and sticky residue are usually formed by animal oils or adulterants added to the numeral oil base4 ,oils containing free acids should be avoided as they not only corrode and etch the bearing1 but also clog the oil pipes or feeds with the products of the corrosion4 ,free acid is left from the refining process1 and may be determined by means of litmus paper inserted into the oil4 ,if the litmus paper turns red after coming into contact with the oil1 acid is present1 and the oil should be rejected4 ,the following are the characteristics of an oil suitable for use on an engine3 7a7 ,the oil must be viscous enough to properly support the bearings or to prevent leakage past the piston rings4 7b7 ,it should be thin enough so that it can be properly handled by the oil pumps1 or drip freely in the oil cups4 7c7 ,it should not form heavy deposits of oil in the cylinder and cause the formation of 8gum40 7d7 ,it should contain no free acid4 ,ordinarily a good grade of fairly heavy machine oil will be suitable for use on the bearings of the average engine1 such as the cam-shaft and crank-shaft bearings4 ,only very light clean oil1 or vaseline should be used on ball-bearings1 as heavy greases and solid lubricants pack in the races and cause binding or breakages4 ,flake graphite is much used as lubricant1 and too much cannot be said in its favor1 as it furnishes a smooth1 even coat over the shaft1 fills up small scores and depressions1 and makes the use of light oil possible under heavy bearing pressures4 ,with graphite1 less oil is used1 as the graphite is practically permanent1 and should the oil fail for a time1 the graphite coat will provide the necessary lubrication until the feed is resumed without danger of a scoring or cutting4 ,in fact1 when graphite is used1 the oil simply acts as medium by which the graphite is carried to the bearings4 ,if graphite is injected into the cylinder in small quantities it greatly improves the compression1 as it fills up all small cuts and abrasions in the cylinder walls4 ,a good mixture to use for bearings is about #a teaspoonsful of graphite1 to a pint of light machine oil1 thoroughly mixed4 ,graphite can be placed in the crank chamber of a splash feed engine1 by means of an insect powder gun4 ,trouble with oil cups is always in evidence during cold weather1 as the oil congeals1 and does not drip properly into the bearings4 ,the fluidity of the oil can be increased in cold weather by the addition of about ten per cent of kerosene to the oil4 ,if too much oil is fed to the cylinders1 the piston rings will be clogged with gum1 and a loss of compression1 or a tight piston will be the result4 ,an excess of oil will short-circuit the igniter or sharp plugs1 and will form a thick deposit in the combustion chamber that will eventually result in preignition or back-firing4 ,deposits and gum formed in the cylinder will cause leaky valves and a loss of compression4 ,feed enough oil to insure perfect lubrication1 but not enough to cause light colored smoke at the exhaust4 ,lubricating systems may be divided into three principal classes3 ,sight-feed1 splash system1 and the force feed system4 ,sight feeding by means of dripping oil cups is too common to require description1 and is used on many stationary engines1 both large and small4 ,the splash system is in general use on small high speed engines both stationary1 and of the automobile type4 ,the force feed system in which oil is fed under pressure by a pump is by far the most desirable as the amount of oil fed is given in positive quantities proportional to the engine speed1 and with sufficient pressure to force it past any ordinary obstructions that may exist in the oil pipe4 ,another system that is half splash1 and half force feed1 is the pump circulated system much used in automobiles4 ,,the ,,splash ,,feed ,,system is the simplest of all1 as the bearings are lubricated by the oil spray caused by the connecting rod end splashing through an oil puddle located in the bottom of the closed crank case4 ,the piston and cylinder are lubricated by the spray1 as well as the bearings1 as the lower end of the piston projects into the crank chamber at the moment that the connecting rod end strikes the oil puddle4 ,to maintain constant lubrication1 it is necessary that the oil in the puddle be kept at a constant height1 or as in some cases be varied in such a way that the surface of the puddle is raised and lowered in proportion to the load on the engine4 ,in the average engine the oil level is maintained by overflow pipes or openings that allow any excess of oil over the fixed level to flow back to the pump4 ,in the ,knight engine the puddles are formed in movable cups which are connected with the throttle in such a way that the opening of the throttle raises the oil level and supplies more oil to the engine at the greater load1 or speed4 ,oil in splash systems is supplied by a low pressure pump1 usually of the rotary type1 in the base of the engine4 ,oil from the pump passes to the bearings1 drops into the puddle1 overflows through the overflow opening1 and returns to the pump through a filter1 the same oil being used over and over again until exhausted4 ,this strainer should be removed occasionally and the dirt removed1 for should it be allowed to collect it is likely to obstruct the oil supply4 ,the oil should be replaced before it becomes too black or foul1 the crank case and bearings thoroughly cleaned with kerosene1 and new oil replaced4 ,the supply may be interrupted by the failure of the pump1 caused by sheared keys or leakage of air in the suction line due to cracks4 ,it would be well to run the engine for a few minutes with the kerosene in the crank case1 in order that all of the oil may be removed4 ,see that the drain cock is closed at the bottom of the cylinder or all of the oil will be lost4 ,lock the valve handle carefully so that it cannot jar open4 ,if light colored smoke appears in intermittent puffs with a multiple cylinder engine1 it indicates that one cylinder is receiving too much oil4 7#aag7 ,force ,feed ,lubricating ,system4 ,the force feed system is by far the most reliable of all oiling systems1 as it feeds uniformly and continuously at almost any temperature1 and against the pressure of practically any obstruction in the pipe4 ,the oil is supplied by a small pump driven from the engine1 the pump being incased in the oil tank housing4 ,frequently a hand pump is used in combination with the power pump when starting the engine1 or at times when the power pump is out of service4 ,a single pump is used with any number of leads1 each lead1 or feed1 having an independent regulating valve and sight feed1 or a pump unit may be provided for each lead1 depending on the size of the engine4 7#aah7 ,bosch ,force ,feed ,oiler4 ,the force feed of the ,bosch ,oiler is so positive in character1 that the flow of oil is not affected by heavy back-pressure due to elbows and the diameter of the conducting pipes4 ,springs1 valves and other devices1 which would check the flow of oil1 are fundamentally eliminated4 ,the amount of oil fed may be accurately and permanently regulated4 ,glands and other packings and bushings are eliminated4 ,connecting rods and all links are eliminated by the direct application of the movements of the oscillating cam disks to the pump plungers and piston valves4 ,each feed of this oiler is provided with a separate pump element consisting of a pump body plunger and a piston valve1 the suction and feed ducts connecting directly with the pump body of their respective elements4 ,with this construction1 pump elements may be replaced or added4 ,the oiler requires no attention other than to be supplied with oil2 and the opening and closing of the valves1 pet cocks1 etc41 on starting and stopping the machine is rendered unnecessary4 ,the correct and regular operation of the elements may be verified by observation of the reciprocating movements of the regulating screws4 ,each pump plunger is provided with an adjusting screw through which the feed may be regulated from #j to #j4b cubic centimeters for each stroke4 ,the ,bosch ,oiler 7,fig4 #aba7 being positively driven by the machine that it supplies1 the oil fed is in all cases proportional to the engine speed2 overloads are thus automatically taken care of4 ,the circular arrangement of the elements of the ,bosch ,oiler permits the device to be driven by a single shaft1 and the oil is forced through the feeds from a single reservoir to the required points of application4 ,a pump element consists of a pump body #a1 a pump plunger #b and a piston valve #c1 and is supported on the base plate #ac4 ,the elements are arranged concentrically about the drive shaft in such a manner that the pump plungers form a circle around the circle formed by the piston valves4 ,illustration3 ,top ,view of ,bosch ,force ,feed ,oiler4 ,illustration3 ,fig4 #aba4 ,cross-,section ,bosch ,oiler4 ,the pump cam disk #bj and the valve cam disk #bb are set on the drive shaft at other than a right angle with its axis1 and the rims of the disks are gripped by slots formed in the heads of the pump plungers and piston valves4 ,the relation of these cam disks is such that the valve cam disk is #ij in advance of the plunger cam disk4 ,the valve cam disk is solid on the drive shaft1 but the pump cam shaft is loose and driven through a lug on the valve cam disk4 ,when the drive of the pump is reversed1 the lug on the valve cam disk frees itself and again takes up the drive of the pump cam disk1 after the drive shaft has made a half revolution4 ,regulating screws #d are set in the slotted heads of the pump plunger1 and by means of this the back-lash or play of the cam disk may be regulated4 ,the regulating screws are provided with lock nuts1 and project through the cover of the oil tank housing1 being exposed by the removal of the filler cover #db4 ,the filler opening is provided with a removable strainer to prevent the entrance of foreign particles into the oil tank4 ,pump shaft #ad is driven through worm gear #bc which meshes with worm #bd on drive shaft #be2 drive shaft #be projects from the oiler housing1 and is coupled with the driving shaft of the machine to be lubricated4 ,base plate #ac is attached to the oiler cover by three stud bolts1 thus permitting the removal of the entire oiler mechanism from the housing4 ,the quantity of oil in the oil tank is shown by gauge glass #dd4 ,on the starting of the machine to which the oiler is attached1 the pump shaft and the cam disks that it supports are set in motion through worm #bd and worm gear #bc4 ,a direct reciprocating motion is given to the pump plunger and to the piston valve by the rotation of the cam disks which have a movement similar to that of the 8wobble saw40 ,the relation of the cam disk is such that the piston valve movements are #ij in advance of the movements of the pump plungers4 ,the pump will run in either direction without alteration4 ,to secure this effect a play of #ij is provided between the cam disk4 ,when cam #bb is driven clockwise1 cam disk #bj is driven by the lug which meshes with a lug on disk #bb4 ,the cams are then in such a relation that the cam valve disk is #ij in advance of the pump cam disk4 ,when reversed1 cam #bj remains at rest until cam #bb catches the lug and cam #bj1 when the drive continues as before4 ,the cams are then in the same relation as previously for as the valve disk #bb has traveled through #ahj it is evident that it is #ij in advance of the pump disk4 7#aai7 ,castor ,oil for ,aero ,engines4 ,castor oil is used almost exclusively in the ,gnome and other rotary engines of the same type1 but has not been particularly successful on stationary cylinders4 ,chemically1 castor oil differs from all other vegetable or animal oils in containing neither palmitin or olein4 ,it is soluble in absolute alcohol1 but practically insoluble in gasoline4 ,on the other hand1 the castor oil is capable of dissolving small quantities of mineral oil1 the more fluid they are the less it absorbs of them4 ,but the insolubility of castor oil in mineral oil disappears completely when it is mixed with even a very small quantity of another vegetable or animal oil1 such as colza or lard oil4 ,an adulteration may thus result in a serious reversal of the oil's best qualities2 in fact1 in serious seizures1 ,castor oil does not attack rubber1 but it contains #a to #b per cent of acid fats2 sometimes more4 8,in my opinion says a writer in #8,autocar' castor oil can only be used in fixed cylinders with impunity for short distances and then with repeated cleanings between runs1 but on rotary engines of the ,gnome type cleaning is almost unnecessary4 ,the reason is that one cannot consistently use castor oil over and over again1 for the fact is indisputable that it has a far greater tendency than mineral oils to absorb oxygen1 and so gradually to increase in body and finally to gum4 ,when once it commences to gum the carbonization becomes more rapid1 because the thickened and pitch-like oil acts as an insulating covering on the top of the pistons and of the cylinder1 and cannot get away with sufficient rapidity to avoid decomposition and baking to a coke4 ,therefore if castor oil is to be used on the ordinary stationary cylinder type of engine1 it is necessary to wash out the crank chamber and to replace with fresh oil at frequent intervals4 ,on a rotary engine such as the ,gnome this cleaning is unnecessary1 because there is a continuous stream of fresh castor oil brought into the crank chamber and then thrown by centrifugal force past the pistons and through the cylinder into the exhaust4 ,thus the stream of oil never has sufficient time to oxidize fully1 gum or decompose4 ,this action of centrifugal force accounts for the large consumption of oil on the rotary engine1 and also for the fact that the pistons and cylinders keep comparatively clean4 8,in thus criticizing the use of castor oil ,i do not wish it to be inferred that it is not an excellent lubricant4 ,what ,i wish to suggest is that in the case of an internal combustion engine it must be made with discretion4 ,a point in favor of castor oil is the fact that it maintains its viscosity in a remarkable manner at high temperatures1 and that at those high temperatures it has a peculiar creeping or capillary action which enables it to spread uniformly over the whole of the metallic surfaces1 whereas under the same conditions a similarly bodied mineral oil would be unevenly distributed in patches4 ,another point is that the specific heat of castor oil is considerably higher than that of a pure mineral oil4 ,this is in its favor1 insomuch that it shows castor oil to be a better heat remover than a mineral oil4 8,motorists and aviators have from time to time informed me that they are using castor oil1 but have apparently been under some misapprehension4 ,i find that they have been using a brand of prepared oil under the impression that it is a specially refined castor oil1 or that it is a blend of castor oil40 ,illustration3 ,producer ,gas ,engine ,plant at ,gttingen1 ,germany1 ,consisting of ,four #c1ejj ,horse-,power ,units4 ,a simple method for testing the purity of castor oil is at the disposal of all4 ,it is known as the ,finkener test4 ,ten cubic centimeters of castor oil is placed in a graduate4 ,five times as much alcohol1 #ij per cent1 is added and stirred in4 ,the solution should remain clear and brilliant at #ae to #bj degrees ,c4 ,an admixture of foreign oils1 even if only #e per cent1 riles the solution at this temperature1 though not above it4 7#abj7 ,force ,feed ,troubles4 ,the most common trouble with force feed systems is the failure of the operator to remove the dirt collected by the strainer4 ,the oil piping should be cleaned out at least once every year by means of a wire and gasoline1 to remove any gum that may have been deposited4 ,driving belts should be kept tight to prevent slipping1 and belts that are soaked with oil should be cleaned with gasoline and readjusted4 ,leaking pump valves generally of the ball type are a common cause of failure4 ,they may leak because of wear or by an accumulation of grit and dirt on their seats1 which prevents the valves from seating properly4 ,if the valves leak1 the oil will be forced back into the tank1 or will not be drawn into the pump cylinder at all1 depending on whether the inlet or discharge valve is the offender4 ,plunger leakage which is rare will cause oil failure4 ,if the oil pipes that lead to the bearings rub against any moving part1 or against a sharp edge1 a hole will be worn in the pipe1 a leak caused which will prevent the oil from reaching the bearing4 ,a dented or 8squashed0 pipe will prevent the flow of oil4 ,the set screw or pin holding the pulley to the pump shaft may loosen and cause it to run idly on the shaft without turning the pump4 ,this will of course1 prevent the circulation of oil4 ,the worm and worm wheel may wear so that the pump is no longer driven by the pulley shaft1 or a poor pipe connection may leak all that the pump delivers4 ,the amount of oil required by each lead or bearing should be carefully determined by experiment1 and kept constantly at the right number of drops per minute4 ,the feed adjustments jar loose1 and should be inspected frequently4 7#aba7 ,oil ,cup ,failure4 ,oil cups should be cleaned out frequently with gasoline or kerosene1 as any gum or lint will interfere seriously with the feed4 ,they should be adjusted and filled frequently to prevent any possible chance of a hot bearing4 ,oil cups should be as large as possible in order that they may be left for considerable periods without danger of a hot box4 ,cold weather affects the oil feed to a considerable extent1 especially with small oil cups1 and they should be kept as warm as possible4 ,when heavy oils are used a cold draft will stop the feed4 ,oils may be made more fluid in cold weather by the addition of about ten per cent of kerosene4 7#abb7 ,hot ,bearings4 ,a hot bearing is almost a sure sign of insufficient oil1 and the trouble should be located and remedied immediately4 ,oil pumps stopping1 clogged oil pipes or holes1 frozen oil1 or oil leaks are common causes of hot bearings4 ,never allow an engine to run with a hot bearing for any length of time1 as the bearing or piston may seize tight and wreck the engine4 ,inspect the journals frequently to see if they are above normal temperature4 ,a hot1 binding bearing often causes the effect of an overload on the engine1 slowing it down1 and increasing the governor and fuel feed1 this is followed in a short time by the bearing seizing4 7#abc7 ,cold ,weather ,lubrication4 ,it is by no means uncommon trouble in cold weather to find excessive fluctuations in pressure as the engine speed and temperature of the oil varies4 ,thus1 if the pressure be set correctly with the engine running fast1 and when just started up1 it will be found1 after half-an-hour's running1 that1 with the engine turning slowly1 the pressure is far too low1 owing to the oil having become thin4 ,if the pressure be then reset1 it may be found on next starting up from cold that the gauge goes hard over1 and may very easily be burst if the engine is run fast4 ,the point is one to which many designers of engines pay far too little attention1 though the difficulty may be very easily gotten over4 ,the secret lies in having the by-pass outlet of most ample proportions1 so that the excess of oil1 however thick1 can get away quite easily4 ,if there is any throttling of the by-pass1 back pressure must result with consequent increase of the pressure at which the by-pass valve comes into operation4 ,in other words1 the pressure of the main supply to the bearings will be increased4 ,a writer to 8,the ,motor10 ,london solved this problem in the following manner3 8,originally1 the by-passage was somewhat small1 little larger than the oil delivery pipe to the engine1 which was about #c_/af inch bore1 and the result was that the pressure when starting with the oil cold rose to about #be pounds per square inch1 and fell to about one pound per square inch with the oil hot and the engine running slow4 ,it was possible1 however1 to bore out the by-pass passage and fit a larger pipe1 about three times the area of the main delivery pipe1 with the result that the oil1 when cold1 never rose above about #ae pounds per square inch1 however fast the engine run4 ,when thoroughly heated1 the normal running pressure was about #f pounds per square inch1 falling to #b pounds per square inch with the engine only just turning over1 which brings up the question of the correct working pressure4 ,this will vary very largely with the design of the engine1 but1 broadly speaking1 the higher the pressure the better for the bearings4 ,the limiting figure is determined by the tendency of the engine to throw out oil at the end of crankshaft bearings1 and by the amount that gets past the piston rings4 ,obviously1 an engine with new1 tight bearings and new piston rings will stand a higher pressure without undue waste of oil or excess deposit in the cylinder head than will an old engine with worn bearings and slack rings4 ,and1 again1 the question will be affected by the design of the pistons4 ,for instance1 where the trunk of the piston is bored for lightness1 much more oil will get past the rings than in cases where a #8solid' trunk is employed4 ,roughly speaking1 #h to #ae pounds per square inch is a good figure for a new1 high-speed engine4 ,an old and worn engine1 particularly if not of a high-speed type1 may require no more than #b to #f pounds per square inch40 ,illustration3 ,brookes ,gasoline-,electric ,generating ,units for ,operating ,search ,lights4 ,an ,independent ,unit is ,used for ,each ,light4 ,the writer recently encountered a rather curious difficulty in connection with obtaining a free by-pass4 ,the return pipe from the by-pass led into the case carrying the gearwheels of the camshaft and magneto drive1 and oil continually flooded out from the end of the camshaft and other bearings4 ,the waste and mess were sufficiently serious to warrant investigation1 and the cover plate over the gears was accordingly taken off4 ,it was then noticed that the oil delivered to the gearwheel case had only two small holes by which to drain away to the crankcase4 ,the flow from the by-pass was beyond the proper capacity of these holes1 and so the whole gearwheel case became filled with oil under considerable pressure1 quite possibly #b or #c pounds per square inch1 and it was not surprising that oil exuded from the ends of the bearing4 ,a few extra limber-holes1 if one may borrow a nautical expression1 were drilled through to the crankcase1 and no further trouble was experienced4 7#abd7 ,plug ,oil ,holes ,when ,painting4 ,when the chassis of the car is repainted it is well to see that all exposed oil holes are stuffed with waste to prevent them from being choked4 ,failure to observe this precaution may result in the holes being clogged with paint1 which if not removed before the car is started1 will prevent oil reaching the bearings4 7#abe7 ,oiling the ,magneto4 ,never oil the circuit breaker or circuit breaker mechanism1 unless for a drop of sperm oil that may be applied to the cam roller by means of a toothpick4 ,if oil gets on the circuit breaker contact points1 it will cause them to spark badly1 resulting in pitting or destruction of the points4 ,if the oil is occasionally applied to the cam roller or should oil accumulate on breaker points1 the breaker should be rinsed out with gasoline to remove the surplus4 ,pitted or carbonized contact points are capable of causing much trouble1 and gummy oil or dirt will develop this trouble quicker than any other cause4 ,use only the best grade of thin sperm oil on the ball bearings4 ,in the course of time the circuit breaker contact points will wear or burn1 causing imperfect contact1 and too great a separation between the points4 ,the contacts should be examined from time to time1 and if rough or pitted1 should be dressed down to a flat even bearing by means of a dead smooth file1 and the distance readjusted4 ,the contacts should not bear on a corner or edge1 but should bear evenly over their entire surface to insure a maximum primary current and spark4 ,,chapter ,,xi ,,cooling ,,systems ,the object of the cooling system is not to keep the cylinder cold1 but to prevent the heat of the successive explosions from heating the cylinder walls to a degree that would vaporize the lubricating oil and prevent satisfactory lubrication of the cylinder and piston4 ,the hotter the cylinder can be kept without interfering with the lubricating oil1 the higher will be the efficiency of the engine and the greater the output of power4 ,to obtain the greatest power from an engine1 the heat developed by the combustion should be confined to the gas in order that the pressure and expansion be at a maximum1 it is evident that the pressure and power will be reduced by over-cooling as the heat of the expanding gas will be taken from the cylinder and transferred to the cooling medium4 ,the temperature of the cylinder1 and therefore the efficiency of the engine is determined principally by the vaporizing point of the lubricating oil1 and consequently the higher the grade of the oil1 the higher the allowable temperature of the cylinder4 ,if cold water from a hydrant or well be forced around the water jacket rapidly1 the power will be greatly reduced owing to the chilling effect on the expanding gas4 ,there is not much danger in keeping the cylinder of an air cooled engine too cool1 in fact the great difficulty with this type of engine is to keep it cool enough to prevent an excessive loss of lubricating oil4 ,the valves1 particularly the exhaust valves1 should be surrounded with sufficient water to keep them cool as they are subjected to more heat than any other part of the engine1 and are liable to wrap or pit4 ,the water leaving the jacket of a gasoline engine should not exceed #afj ,f41 as temperatures in excess of this amount cause deposits of lime scale4 ,when possible1 a portion of the cooling water should be run into the exhaust pipe immediately after it has completed its flow around the valves and cylinders1 as the water cools the gas so suddenly that the exhaust to atmosphere is rendered almost noiseless1 and the exhaust pipe is kept much cooler and less liable to cause fire by coming into contact with combustible objects4 ,on some engines the exhaust pipe is water jacketed for some distance to prevent dirty rusty pipes in the vicinity of the engine mechanism and also to prevent injury to the operator should he come into contact with the pipe4 ,small engines and medium size vertical engines usually have the water jacket cast in one piece with the cylinder casting and others have a separate head that is bolted to the cylinder4 ,in the latter type the water flows from the cylinder to the head through ports or slots cut in the end of the cylinder water jacket that register with similar slots in the jacket of the head4 ,thus in this construction we have not only to pack the joint to prevent leakage of gas from the cylinder1 but also to prevent the leakage of cooling water from the jacket into the cylinder1 or outside4 ,thus there is always a chance of water leaking into the cylinder bore and causing trouble unless the packing is very carefully installed and looked after4 ,in large horizontal engines the gas and water joints are never made at the same point1 as it would be practically impossible to prevent leakage into the cylinders of such engines4 ,when the cylinder and cylinder water jackets are cast in one piece without a water joint at the junction of the cylinder and the head1 the water connection between the head and the cylinder being made by pipes external to the castings4 ,small1 portable1 stationary engines are sometimes 8,,hopper ,,cooled10 or cooled by means of the evaporation of the water contained in an open water jacket that surrounds the cylinder4 ,the hopper is merely an extension of the water jacket such as used on all water cooled engines1 the only difference being that the top of the hopper is open permitting the free escape of water vapor or steam to the atmosphere4 ,the water level should be carried within two inches from the top of the hopper4 ,water when converted into vapor or steam absorbs a great quantity of heat1 and of course the steam carries the heat of evaporization with it when it escapes to the atmosphere4 ,as the hopper is open to the air1 the temperature of the cylinder cannot exceed #bab ,f4 7temperature of boiling water7 as long as there is sufficient water left to cover the cylinder4 ,the hoppers contain sufficient water for runs of several hours' duration1 and as the water boils away or evaporates1 it may be replenished by simply pouring more water in the top of the hopper4 ,hopper cooling is used principally for small portable engines where the weight of a water tank or other cooling device would be objectionable and also where there is danger of freezing the pipes and connections of other systems4 ,the loss of water by evaporization is from 4#c to 4#f of a gallon per horsepower hour2 that is1 for a #e hp4 engine the loss would be from #a4e to #c gals4 for every hour that the engine was operated under full load4 ,the cylinder and the water jacket are cast in one integral piece1 with no joints of any kind in either the combustion chamber or in the water jacket4 ,illustration3 ,fig4 #abd4 ,air ,cooled 8,grey ,eagle0 ,aeronautical ,motor4 ,note the ,depth of ,cooling ,ribs4 ,a system of cooling by which the heat of the walls is radiated to the air directly without the medium of water is often used on small high speed engines1 and is known as 8,,air ,,cooling40 ,this type of cylinder is surrounded with radiating ribs or spires which increases the radiating surface of the cylinder to the extent that the required amount of heat is lost to allow of economical lubrication4 ,this system is desirable where the weight of radiators and water would be a drawback1 where it would be inconvenient to obtain water1 or where there would be trouble from freezing4 ,an air cooled motor generally is provided with a fan that increases the efficiency of the radiating surface by changing the air between the ribs4 ,with aeronautical motors such as the ,gnome1 and ,gray ,eagle1 shown by ,fig4 #abd1 the circulation of the air due to the propeller and the rush of the aeroplane is sufficient to thoroughly cool the machine4 ,as a rule1 the air cooled motor is made more efficient in fuel consumption than the water cooled type because of the high temperature of the cylinder walls4 ,in fact all engines are air cooled eventually1 whether the heat is radiated at a high temperature by the fires1 or at a lower temperature through the circulating water and radiator4 ,when the engines are of the portable type1 and likely to be used out of convenient reach of water1 the hopper or ,,evaporator ,,tank system is used1 the tank system being used for the larger engines4 ,in effect1 the tank system is the same as the hopper cooler1 the heat being dissipated principally by evaporation1 although some heat is radiated from the surface of the tank itself4 ,the difference between the two systems is merely one of size1 the tank offering a greater area for the emission of heat than the hopper4 ,a tank-cooled engine has one pipe running from the top of the cylinder to a point near the top of the tank1 the bottoms of the cylinder and tank being connected together by another pipe4 ,when the water becomes heated in the cylinder1 it expands and becomes lighter than the cold water in the tank and consequently rises to the surface of the water in the tank through the upper pipe4 ,as the warm water flows into the tank1 it is immediately replaced by the heavier cold water that flows into the cylinder from the bottom of the tank through the lower pipe4 ,this successive discharge of the heated water from the cylinder to the tank sets up a continuous flow of water through the water jacket of the cylinder1 which transfers the excess heat of the cylinder to the tank where it is dissipated to the atmosphere by evaporation and radiation4 ,the circulation of the cooling water set up by the action of heat or the expansion of the water is called ,natural or ,thermo ,syphon circulation4 ,cooling tanks may be used profitably with stationary engines if the tank can be located so that vapor and steam produced will not be objectionable4 ,if the tank is used inside of a building1 the vapor should be conveyed to the outside air by means of a stack or chimney1 or by means of a small ventilating fan driven by the engine4 ,the water consumption of a cooling tank is from 4#c to 4#f gallons per hour1 the exact quantity varying with the atmospheric conditions and temperature4 ,illustration3 ,fig4 #abd-;a4 ,de ,dion ,bonton 8,v0 ,type1 ,air ,cooled ,aero ,motor4 ,the ,cooling ,air is ,furnished by a ,blower ,mounted on the ,crank ,shaft at the ,rear of the ,motor4 ,the ,propeller is ,driven from the ,cam ,shaft4 ,courtesy of ,aero4 ,for engines of from #aj to #ej horsepower a battery of cooling tanks may be used1 the number depending on the size of the engine4 ,for natural circulation1 the tank should be installed so that bottom of the tank is above the bottom of the cylinder for maximum results1 if placed much lower the engine should be provided with a circulating pump4 ,if water is used from the city mains from #aj to #ae gallons will be required per horsepower hour1 the exact quantity varies with the temperature of the supply4 ,the water from very large stationary engines is cooled by allowing it to trickle down through a cooling tower1 which is built somewhat like the screen cooler only on a larger scale4 ,the object of the cooling tower is to present the greatest possible surface of water to the air1 this is accomplished by screens or baffles that turn the water over and over as it falls4 ,the water1 well cooled1 finally collects in a cistern at the base of the tower from which it is pumped back to the engine and thus is used over and over again4 ,this is an ideal system when water is expensive and when engines of considerable power are used4 7#abf7 ,cooling ,system ,troubles4 ,overheating caused by deposits of scale or lime in the jacket is one of the most common causes of an excessively hot cylinder4 ,when hard water containing much lime is heated1 the lime is deposited as a solid on the walls of the vessel forming a hard1 dense1 non-conducting sheet4 ,when scale is deposited on the outside of the cylinder walls it prevents the transfer of the heat from the cylinder to the cooling water and consequently is the cause of the cylinder overheating4 ,besides acting as an insulator or heat1 the deposit also causes trouble by obstructing the pipes and water passages1 diminishing the water supply and aggravating the trouble4 ,scale interferes with the action of the thermo syphon system more than with a pump1 as the pressure tending to circulate the water is much lower4 ,whatever system is used1 the scale should be removed as often as possible1 the number of removals depending1 of course1 on the 8hardness0 of the water4 ,large horizontal engines are usually provided with hand holes in the jacket1 through which access may be had to the interior surfaces on which the scale collects4 ,under these conditions the scale may be removed by means of a hammer and chisel4 ,the scale may be softened by emptying half the water from the jacket and pouring in a quantity of kerosene oil1 the inlet and outlet pipes being stopped to prevent the escape of the oil4 ,the engine should now be started and run for a few minutes with the mixture of kerosene and water in the jacket2 no fresh water being admitted during this time4 ,after the mixture has become boiling hot1 stop the engine and allow it to cool2 it will be found that the scale has softened to the consistency of mud1 and may easily be washed out of the jacket4 ,the work of removing the scale can be reduced to a minimum by filling the jacket with a solution of #a part of ,sulphuric ,acid and #aj parts of water1 allowing it to stand over night4 ,the scale will be precipitated to the bottom of the jacket in the form of a fine powder and may be easily washed out in the morning4 ,if the jacket water is kept at a temperature above #ahe ,f4 the amount of scale deposited will be nearly doubled over that deposited at #afj ,f4 ,wash out sand and dirt occasionally1 a strainer located in the pump line will help to keep the jacket clear and free from foreign matter4 ,if a solution of carbonate of soda1 or lye1 and water are allowed to stand in the cylinder over night1 the deposit will be softened and the work with the chisel will be made much easier4 ,if a radiator is used 7automobile or aero engine7 the deposit can be removed with soda1 never use acid1 lye1 or kerosene in a radiator or with an engine with a sheet metal water jacket4 ,obstructions in ,water ,pipes4 ,poor water circulation may be caused by sand1 particles of scale1 etc41 clogging the water pipes1 or by the deterioration of the inner walls of the rubber hose connections4 ,sometimes a layer of the rubber1 or fabric of the hose may loosen from the rest and the ragged end may obstruct the passage4 ,a sharp bend in a rubber hose may result in a 8kink0 and entirely close the opening4 ,the packing in a joint may swell1 or a washer may not have the opening cut large enough1 either case will result in a poor circulation4 ,sediment is particularly liable to collect or form in a pocket1 pipe elbow1 or in the jacket opposite the pipe opening4 ,oil should be kept off of rubber hose connections as it will cause them to deteriorate rapidly1 this may finally result in water circulation troubles4 ,rubber pipe joints between the engine and the radiator or tanks are advisable as they do not transmit the vibration of the engine1 and hence reduce the strain on the piping4 ,a strainer should be provided in order to reduce the amount of foreign material in the water4 ,radiators4 ,a clogged radiator will give the same results as a clogged jacket with the exception that steam will issue from the radiator if the circulation is not perfect4 ,if the radiator becomes warm over its entire surface it is evident that the water is circulating1 the temperature being a rough index of the freedom of the water1 or the interior condition of the surfaces4 ,a leaking radiator may be temporarily repaired with a piece of chewing gum4 ,should the radiator be hot and steaming at the top and remain cold at the bottom for a time1 it shows that the water is not circulating and that the jackets on the cylinders are full of steam4 ,such a condition usually is indicative of clogging between the bottom of the radiator and pump1 between the pump and bottom of cylinders1 or of a defective pump4 ,illustration3 ,natural ,gas ,plant at ,independence1 ,kansas4 ,used for ,pumping ,gas ,from the ,wells to ,various ,distributing ,points4 ,thermo-syphon radiators are more susceptible to the effects of sediment and clogging than those circulated by pumps4 ,a radiator may fail to cool an engine because of a slipping or broken belt driving the fan1 or on account of a loose pulley or defective belt tension adjuster4 ,keep the belt tight4 ,the fan may stick on account of defective bearings4 ,radiator may be ,,air ,,bound1 due to pockets or bends in the piping holding the air4 ,rotary ,pump ,defects4 ,a defective circulating pump will cause overheating1 as it will supply little if any water to the jackets4 ,examine the clutch or coupling that drives the pump and see that the key or pin that fastens it to the shaft is in place4 ,next see that the driving pinion and gear are in mesh and properly keyed to their respective shafts4 ,in some cases the shaft has been twisted off1 or the coupling pin sheared through by reason of the shaft rusting to the pump casing4 ,worn gears or impellers ,,in ,,the ,,pump reduce the output and cause heating1 as will a sheared driving pin in the impeller4 ,wear and bad impeller fits reduce the capacity of the pump4 ,scale or sediment collecting in the pump sometimes strips the pins or impeller teeth4 ,note the condition of the gaskets or whether the pump shaft is receiving the proper amount of grease4 ,put a strainer in pump intake4 ,see that no leak occurs on pump intake pipe4 ,to avoid the trouble and expense due to cracked water jackets1 never neglect to drain the cylinders and piping from all water in freezing weather4 ,drain cocks should be provided at the lowest points in the water circulating system for this purpose4 ,it would be well to provide an air cock at the highest point in the line in order that all of the water can drain out as soon as the drain cock is opened4 ,with automobile or portable engines it is not always convenient or possible to drain the engine every time that it is stopped and consequently we must resort to a 8non-freezing0 mixture or at least a solution that will not solidify under ordinary winter temperatures4 ,such a solution should be chosen with care1 as many will cause the corrosion and destruction of the jackets and piping2 ,,never ,,use ,,common ,,salt and water under any conditions4 ,wood alcohol and water in equal parts1 is often used for automobiles1 but is rather expensive for portable engines having a comparatively great amount of water in circulation4 ,unless the circulating system is absolutely air tight1 as it is when radiators are used1 alcohol will be lost by evaporation and must be replaced frequently4 ,the most practical solution for the average engine used1 is made up by dissolving about five pounds of ,,calcium ,,chloride in one gallon of water4 ,this mixture will stand a temperature of about #ae ,f below zero1 and if diluted to half the strength will not freeze above zero4 ,use ,,calcium ,,chloride1 not ordinary ,salt 7,sodium ,chloride74 ,,chapter ,,xii ,,governors ,,and ,,valve ,,gear 7#abg7 ,hit and ,miss ,governing4 ,when the speed of an engine is held constant for varying loads by missing explosions on the light loads and increasing the number for heavy loads1 the governing system is said to be of the 8hit and miss type40 ,the mixture remains constant in quantity and quality in this type of engine4 ,a hit and miss governor allows only enough charges to be fired to keep the speed constant4 ,when the load falls off1 with a natural tendency on the part of the engine to increase its speed1 the governor cuts out the next explosion by holding the exhaust valve open and the inlet closed1 thus preventing fresh mixture from being drawn into the cylinder4 ,with an increase in load1 the governor allows the valves to follow their regular cycle with the result that a greater or less number are fired in succession4 ,hit and miss governing is very economical for only full charges of the most perfect mixture are fired1 and with short exhaust pipes the scavenging is much better than with other forms of governing4 ,the principal difficulty with this system is that the regulation is not as perfect as with some other types4 7#abh7 ,the ,throttling ,system4 ,unlike the hit and miss system of governing1 the throttling type of governor allows the engine to take an explosion on every working stroke1 the speed being held constant by either regulating the quality or quantity of the mixture1 or both4 ,throttle governor permits of close speed regulation as the impulses are more frequent and not so violent as with the hit and miss system4 ,the governor acts directly on the throttle valve1 and at no time is the operating mechanism disengaged from the driving cam4 ,the throttle governor engine is particularly well adapted for driving dynamos1 supply electric light1 as the uniform speed gives a smooth1 steady light without the objectionable flickering so likely with the hit and miss engine4 ,to obtain the best fuel economy with a throttling engine1 it should be run close to its rated capacity1 as the poor and imperfect mixture admitted at light loads considerably increases the fuel consumption4 ,illustration3 ,fig4 #gf-;d4 ,de ,la ,vergne ,governor4 ,practically all motors of the variable speed type such as are used on automobiles and motor boats are controlled manually by the throttle2 although marine motors are often fitted with governors to prevent racing when the screw is lifted out of the water in a heavy sea4 7#abi7 ,the ,controlling ,governor4 ,the governor proper depends upon centrifugal force for its action1 and generally consists of two weights which are pivoted at one end to a rotating shaft driven by the engine4 ,when these weights are rotated rapidly the bottoms are thrown outwardly by the centrifugal force and tend to assume a horizontal position4 ,the faster the weights are rotated1 the greater will be the tendency for the bottoms of the weights to come into the horizontal1 and the greater will be the pressure exerted by them on the controlling levers connected to the throttle4 ,it is evident that the centrifugal pull on the weights varies directly with the speed of rotation and consequently with the speed of the engine4 ,the exact relation between the travel of the weights and the speed of the engine is controlled by a spring that acts between arms cast on the weights and the spindle4 ,if a heavy spring is used1 greater speed must be attained to move the weights a given distance than with a weak spring1 as the centrifugal force must be greater4 ,illustration3 ,fig4 #abd-;d4 ,governor and ,governor ,mechanism of ,fairbanks-,morse ,type 8,r ,e0 ,engine4 ,the ,fly-,balls1 ,springs1 and ,control ,rods ,are ,shown on the ,governor ,staff4 ,the ,upper ,end of the ,bell ,crank ,goes to the ,throttle4 ,the throttle valve of the engine is connected by a rod to the governor through a sliding collar in such a way that the movement of the governor weights due to an ,,increase of speed partially closes the valve until the speed of the engine is reduced4 ,should the speed of the engines ,,decrease1 owing to a heavy load coming on1 the spring will force the balls to occupy a lower position which will increase the valve opening until the engine again reaches the normal speed for which the tension of the spring is adjusted4 ,thus the speed of the engine is kept practically constant by the action of the governor in opening and closing the throttle1 which in turn1 varies the ,,quantity of mixture admitted to the cylinder4 ,the ,,quality of the mixture is varied by hand1 in the engine by means of cocks in both the air and gas pipes4 ,the ,,governor ,,proper is of practically the same construction in the hit and miss engine1 the difference of the two types lying in the method of connecting it to the controlling system4 ,in one case 7hit and miss7 the governor controls the exhaust valve1 and in the other 7throttling7 it controls the quantity of gas admitted by the throttle valve4 ,the speed of the engine may be varied within certain limits by a lever connected to the valve controlling rod4 7#acj7 ,types of ,governors4 ,the types of governors used on the leading makes of engines will be found described and illustrated in ,chapter ,v which treats of each engine in detail4 7#aca7 ,governor ,troubles4 ,hit and miss governor troubles may be due to the following defects3 ,,binding ,,governor ,,collar1 stuck with dirt or gummy oil1 will cause the engine to die under load1 and overspeed on light load4 ,,inlet ,,valve ,,lock may be worn in such a manner as to prevent the valve from seating during the idle strokes and lose fuel1 or cause overspeeding4 ,,detent ,,lever ,,knife ,,edge may be worn1 or rounded off1 so that the exhaust valve is not held open for the idle stroke4 ,this defect will cause overspeeding4 ,,speed ,,changing ,,lever may work loose and cause the speed to vary erratically4 ,,governor ,,weights may be stuck on pins with dirt or gummy oil causing engine to overspeed4 ,,lost ,,motion ,,in ,,governor ,,gear such as loose pins and bushings1 worn rollers1 or bearing surfaces will cause the speed to vary continuously4 ,,lost ,,motion on portable engines will cause the engine to run normally in one position1 and overspeed in another4 ,,weak ,,or ,,broken ,,springs ,,on ,,governor will cause engine to lose speed or die down altogether4 ,springs may be stiffened by pulling out the coils4 ,,dry ,,governor ,,bearings or joints will cause binding and cause governor to act sluggishly4 ,use plenty of lubricant4 ,,worn ,,rollers may cause a speed variation4 ,keep the governor well oiled1 clean1 and free from gum4 ,if the knife edges are allowed to slip over one another1 much wear is caused on the cams and if allowed to continue1 sooner or later the engine will run away4 ,springs will weaken with age and hard usage4 ,with belt driven governors see that the belt is tight and that the lacing is in good condition for a slack belt may allow the engine to overspeed4 ,i advise that every purchaser of an agricultural motor read his instruction book with care1 that is1 locate all oil holes and note the action and purpose of every part4 ,if in doubt as to any part of its use write the manufacturer of the motor4 7#acb7 ,throttling ,governor ,troubles4 ,,sticking ,,governor ,,valve will cause the engine to overspeed2 remove the gum and dirt4 ,,loose ,,pins ,,or ,,bushings1 or lost motion in any part of the governor mechanism will cause irregular motion or running2 be sure that the bearings and joints are well oiled4 ,,stuck ,,pins will cause the engine to overspeed on light loads1 and fall down on the normal load1 or cause racing4 ,,weak ,,or ,,broken ,,springs will cause the engine to lose speed or to lie down altogether even on light loads4 ,,stiff ,,governor ,,springs cause the engine to speed up4 ,,sliding ,,collar stuck will cause racing or a fluctuation in the speed4 ,keep the governor well oiled1 clean1 and free from gum4 ,the governing valve should be removed from its care frequently and thoroughly cleaned with kerosene4 ,deposits of carbon and gummed oil at this point are dangerous because of the likelihood of their causing overspeeding4 7#acc7 ,valve ,gear ,arrangement4 ,the valve operating mechanism lay-out depends upon the cylinder and valve arrangement1 and consequently varies in detail with different engines4 ,illustration3 ,overhead ,valve ,arrangement of the ,fairbanks-,morse 8,r ,e0 ,engine4 ,fig4 ,f-#ad-ae in ,chapter ,v1 shows the valve gear of an upright engine having the inlet and the exhaust valves located in pockets placed at one side of the cylinder4 ,the inlet valve is operated by a valve rod that is actuated by the cam4 ,the exhaust valve stem is raised and lowered1 directly1 through a cam on the same shaft4 ,the method of driving the valves in this engine is practically standard for all vertical engines having the valves located in pockets4 ,this system is used in a greater proportion of automobile engines4 ,the opposed engine has the cylinders arranged on opposite side of the crank case1 and makes an exceedingly well balanced and quiet running engine2 as there is no point in the revolution where either the crank throws or connecting rods have an unequal angularity1 or differ in velocity4 ,while this type of two cylinder engine is common in automobile practice1 it is not often met with in stationary work1 the cam-box and the cam being directly in the center of the crank case4 ,the opposed type of engine is particularly well adapted for aeroplane service as a steady1 quiet running engine is an absolute necessity because of the frail construction of the aeroplane frame4 7#acd7 ,cam ,shaft ,speeds4 ,the valves of the gas engine are opened and closed by means of cams or eccentrics1 that are geared to the crankshaft1 and which also control the timing4 ,as a four stroke cycle engine performs all of the events1 or a complete cycle in two revolutions of the crankshaft1 it is evident that the cam must go through the routine in one revolution or must revolve at ,,one-,,half ,,of ,,the ,,crankshaft ,,speed4 ,therefore the cam gear ratio must be as one is to two1 the smaller gear being placed on the crankshaft1 the gears being known as the 8half time gears40 ,as a two stroke cycle engine goes through the routine of events in every revolution1 the cam-shaft must run at crankshaft speed so that the cam outline makes one revolution in the same time as the crank4 ,the cam shaft speeds given here apply to all engines of the corresponding cycle no matter whether the valves are of the poppet1 rotary or slide-sleeve types4 7#ace7 ,valve ,gear ,troubles4 ,the valve gear mechanism causes trouble principally through the wear of the various parts which results in a change in the valve timing1 or in the lift of the valves4 ,loss of power1 ,,misfiring1 and overheating are the result of such derangements4 ,often trouble is caused in reassembling the valve mechanism after the engine has been torn down for repairs1 which trouble may generally be traced to incorrect gear meshing4 ,the following list will give the principal defects due to the wear of the valve mechanism4 7a7 ,,worn ,,cam ,,gears change timing because of play1 or 8back lash0 in the teeth1 or cause a howling or grinding noise1 that will cause the owner to believe that the end of the engine is near4 ,,misfiring and ,,loss of power are probable results of a change in the timing4 ,if any of the teeth are stripped from the gear you may be sure that the timing is changed4 ,replacement with a new gear is the only cure for a worn or broken gear4 7b7 ,,gears ,,not ,,in ,,proper ,,mesh due to an error in assembling the gears1 will prevent the engine from being started1 or cause misfiring and loss of power4 ,the maker of the engine generally marks the teeth that go together1 but if no such marks appear1 the owner should center punch or scratch them before taking down the engine4 7c7 ,a ,,gear ,,slipping ,,on ,,the ,,shaft1 due to a missing key in the gear1 or to a loose set-screw will cause all of the troubles due to a change in the timing4 ,examine the key carefully1 for dirt often collects in the key-way to such an extent that it is liable to be mistaken for the key4 ,keys and pins have sheared in two1 allowing the shaft to slip in the gear4 7d7 ,,worn ,,cam-,,shaft ,,bearings are the cause of trouble1 as they will change both the timing and the lift of the valves4 ,if much play exists in the bearing1 it will prevent the valves from lifting at the proper time1 and will also reduce the lift by the amount of the play1 which sometimes has a considerable effect on the free passage of the gases4 ,if the cam-shaft bearings are of the bushing type they should be replaced with new paying attention at the same time to the condition of the shaft4 ,if rough or shouldered the shaft should be machined to a dead smooth surface4 ,if on a large engine and of the adjustable type1 the shims should be removed as required or the wedges adjusted4 7e7 ,,loose ,,cams ,,or ,,eccentrics will change the timing because of lost or sheared keys4 ,if your cams are not integral with the shaft1 look them over occasionally and be sure that the keys are tight4 ,loose cams will produce thumping and grinding and may often be located by the sound4 ,see that the key-way is not worn when fitting keys4 ,if the cams are fitted with taper pins it would be well to ream the hole before placing new pins1 as there is a liability of the hole being worn oval4 7f7 ,a ,,twisted ,,or ,,sprung ,,cam-,,shaft will change the positions of the cams relative to one another1 and not only will change the time of all cylinders1 but will change their time relatively causing the engine to run out of balance1 or produce an unusual vibration4 7g7 ,,worn ,,cams are causes of a change of timing on all types of engines1 and are the most frequent cause of reduced valve lift with its consequent trouble of overheating4 ,if the outline or contour of a cam is changed with wear it should be replaced1 if keyed to the shaft1 as it will be a constant source of trouble4 ,if the cams and cam-shaft are in one integral piece1 it will be necessary to replace the entire shaft4 7h7 ,,worn ,,cam ,,rollers ,,and ,,roller ,,pins will reduce the lift of the valves1 and in the case of a broken or sheared pin will prevent the valve from lifting at all4 ,always replace loose pins or loose rattling roller4 7i7 ,,push ,,rod ,,defects4 ,too much clearance between the push rod and valve stem will reduce the lift of the valves and change the timing4 ,the clearance for small engines should be equal to the thickness of a visiting card1 and for large engines is somewhat larger1 say #a-af4 ,the increase of clearance is due principally to wear4 ,too small a clearance should be avoided for the reason that the valve stems expand with the heat and will lift the valves too soon1 or even permanently until readjusted4 ,broken valve springs will cause trouble1 or lost keys that retain the valve spring washers4 ,loose adjusting screws on the push rods or stripped threads will delay the valve opening4 7j7 ,,tappet ,,lever ,,defects are generally caused by wear or poor adjustment4 ,loose pins or bushings1 too much clearance between the tappet and valve stem or broken valve springs1 or loose adjusting screws will produce changes in the timing or valve lift4 7k7 ,,bent ,,valve ,,rod4 ,a bent valve rod will shorten the travel of the valves1 and change the timing4 7l7 ,,cam ,,lever ,,or ,,pin will cause timing troubles if the pin or bushing are loose or worn1 by reducing the travel of the valves4 ,when occasion arises for the removal of valves1 the opportunity should be taken to clean the stems and guides1 which may be more or less gummed with ancient oil4 ,freedom of valve movement is of extreme importance1 and for this reason neither the cleaning nor the lubrication of the stems and guides should be neglected4 ,the occasional use of a little kerosene will prevent gummy accumulations1 but care should be taken not to allow the kerosene to wash out all of the oil and thereby leave the surfaces dry4 ,a broken valve spring1 though not a common occurrence1 is not an unknown possibility4 ,if no spare spring is at hand1 a plan that can be recommended is to turn the broken spring end for end1 thus bringing the finished ends up together2 this will prevent the spring from shortening by overlapping1 and winding itself together4 7#acf7 ,valve ,timing4 ,the exact time at which the valves of a four stroke cycle engine open and close depends to a great extent upon the speed of the engine1 the fuel used1 the compression pressure1 and the relation of the bore to the stroke4 ,as these items vary in nearly every make of engine there has appeared in the technical press1 a great mass of seemingly conflicting data4 ,engine speed is the principal factor in determining the timing4 ,correct valve timing plays a considerable part in the output and efficiency of an engine1 for if the inlet valve1 for example1 opens too late1 the cylinder will not receive a full charge4 ,if it opens too early the hot gases in the cylinder will ignite the gas in the carburetor and cause back-firing4 ,should the exhaust open too late1 the retention of the hot gas in the cylinder is likely to cause overheating4 ,the timing of the valves is usually expressed in degrees of the circle described by the crank-pin1 or the angle formed by the crank with the center line of the cylinder at the time the valve is to open or close4 7#acg7 ,valve ,setting on ,stationary ,engines4 ,the exhaust should open when the crank lacks #cj of completing the outer end of the power stroke1 that is1 the crank should make an angle of #cj with the center line of the cylinder when the exhaust valve begins to open1 and should be inclined ,,away from the cylinder4 ,some makers have the exhaust open a little later in the stroke1 but little is to be gained with a later opening as the retention of the charge beyond #cj heats the cylinder and does very little towards developing power4 ,the only advantage of the late opening is that the valve opens against a lower pressure and causes slightly less wear on the parts4 ,the exhaust valve should close #e ,,after the crank has passed the ,,inner dead center on the exhaust or scavenging stroke1 although some makers close the valve exactly on the dead center4 ,the #e should be given to allow the gas all possible chance of escape4 ,the piston is said to be on the inner dead center when it is in the cylinder as far as it will go1 and on the outer dead center when it is on the center nearest the crankshaft4 ,the ,,intake valve should open about #e ,,after the exhaust valve closes1 or #aj after the crank passes the inner dead center4 ,the inlet valve should ,,never open before the exhaust valve closes on a low speed engine4 ,the above timing is for engines running #aej-fjj ,r4,p4,m4 ,the automatic type of inlet valve1 of course1 cannot be timed1 but attention should be paid to the strength and tension of the spring and the condition of the valve stem guides4 ,the inlet valve should close #aj ,,after the crank passes the outer dead center in order that the cylinder be filled to the fullest possible extent4 ,if the valve closed exactly on the dead center a partial vacuum will exist and the charge retained in the cylinder will be comparatively small1 but if the valve remains open past this point the air would have time to completely fill the cylinder and develop the capacity of the engine4 ,the longer the inlet pipe1 the longer the inlet valve opening4 7#ach7 ,high ,speed ,engine ,valve ,timing4 ,the faster a motor turns1 all other things being equal1 the greater the amount of advance necessary with the valves1 as the higher the speed the less the time required to fill or empty the cylinder4 ,in a short stroke high speed motor the exhaust should close and the intake open as early as possible in order to admit the full charge4 ,the exhaust should open early to allow of the full escape of the gases1 as the time allowed for expulsion is extremely short when an engine runs #a1jjj ,r4,p4,m4 and the back pressure is liable to be considerable4 ,the inlet valve of high speed engines should remain open for a considerable period after the crank passes the outer dead center on the suction stroke1 owing to the inertia of the gases which tends to fill the cylinder4 ,lengthening the period of opening of the inlet valve in multiple cylinder engines produces better carbureting conditions and reduces the variations of pressure in the manifold4 ,,exhaust ,,valves4 ,the exhaust valve should begin to open #dj ,,before the crank reaches the ,,outer dead center on the working stroke1 and should close #aj ,,after the crank has passed the inner dead center4 ,,inlet ,,valves4 ,the inlet valve should open #ae ,,after the crank passes the inner dead center on the suction stroke1 and should close #ce after the crank passes the outer dead center4 ,the inlet valve should never open before the exhaust valve closes1 although this is done on several types of high speed aeronautical engines4 ,the makers of these engines claim that this practice scavenges the combustion chamber more thoroughly and makes the mixture more effective owing to the inertia of the burnt gases forming a partial vacuum in the combustion chamber4 ,the writer has never been able to get satisfactory results with this timing and doubts whether it can be accomplished successfully4 ,in timing an engine great care should be taken to get the crank exactly on the dead center4 7#aci7 ,timing ,offset ,cylinders4 ,the only difference in timing engines with offset cylinders and timing those with the center line of the cylinder in direct line with the crank shaft1 is in the locating of the dead center4 ,with no offset1 the center of the cylinder1 the crank pin and the crank shaft are all in one direct line when the engine is on the dead center4 ,with offset cylinders the crank pin lies to one side of the cylinder center line when on the dead center1 on either the inner1 or the outer center4 ,to find the center on an offset engine proceed as follows3 ,turn the engine over slowly until the crank-pin reaches either the extreme top or bottom point of the crank circle1 depending on which center is to be determined1 and then turn very slowly until the centers of the piston-pin1 crank-pin1 and crank-shaft are in line4 ,with the average engine this will be found a difficult and tedious job1 and it will be well to mark the dead center on the flywheel or other convenient point to prevent a repetition of the job4 ,the quickest method of accomplishing the feat is to remove the spark plug or relief cock to gain access to the piston1 and insert a rod or pointer in the opening thus provided4 ,draw the piston back a short distance from the end of the stroke with the pointer resting on the head of the piston1 and mark this position of the piston both on the pointer1 and on the flywheel1 using some stationary part of the engine as a reference point4 ,now turn the crank over the center line until the piston is moving in the opposite direction1 and is the same distance from the end of the stroke as shown by the mark on the pointer4 ,mark this position on the flywheel using the same reference mark as before4 ,we now have two marks on the flywheel1 and will bisect the distance between them1 using the dividing mark to obtain the center4 ,place the bisection mark even with the reference point used for obtaining the two previous marks on the flywheel1 and the engine will be on the true dead center1 as the flywheel is now midway between two points of equal stroke4 7#adj7 ,auxiliary ,exhaust ,ports4 ,to decrease the amount of hot gas and flame passing over the exhaust valve some makers provide their engines with auxiliary exhaust ports1 which are similar to the exhaust ports used on two stroke cycle engines4 ,the auxiliary exhaust consists of a series of holes drilled or cored through a rib on the cylinder wall1 the holes being so situated that they are covered by the piston until it is at the extreme end of its outward stroke4 ,the holes are not uncovered until the burning charge has been expanded and cooled to the greatest extent possible in the cylinder4 ,as soon as the piston uncovers the ports the greater portion of the dead gas escapes instantly to the atmosphere1 carrying with them the greater percentage of the heat and flame4 ,the small amount of residual gas that remains is forced out through the exhaust valve in the usual manner1 thus no flame ever reaches the exhaust valve4 ,the use of auxiliary exhaust ports produces a cooler cylinder as the gas passes over the cylinder wall only once1 and consequently is in contact with the walls only one-half of the time usual with the ordinary system4 ,the cool cylinder lessens the liability of ,,preignition and decreases the consumption of cooling water and lubricating oil4 ,auxiliary exhaust ports are particularly desirable on air cooled engines4 7#ada7 ,valves and ,compression ,leaks--,misfiring4 ,owing to the intense heat in the cylinder1 and the action of the gases on the valves the seating surfaces become ,,rough and ,,pitted which causes leakage and loss of compression4 ,exhaust valves cause the most trouble in this respect as they are surrounded by the hot gases during the exhaust stroke and are much hotter than the inlet valves4 ,to determine the value of the compression1 turn the engine over slowly by hand4 ,leaking inlet valves usually are productive of ,,back ,,firing or ,,explosions ,,in ,,the ,,carburetor intake passages1 or in the mixing valves1 as flame from the cylinder leaks through the valve and fires the fresh gas in the intake4 ,,misfiring ,,or ,,loud ,,explosions at the end of the ,,exhaust ,,pipe are indicative of leaky exhaust valves1 if the mixture is correct and the ignition system above suspicion4 ,misfiring caused by leaky exhaust valves is due to combustible mixture escaping from the cylinder to the exhaust pipe and being ignited by the succeeding exhaust of the engine4 ,if the engine has more than one cylinder1 test one cylinder at a time1 opening the relief valves on the other cylinders4 ,now take a wrench and ,,rotate the inlet valve on its seat1 for it may be that some particles of carbon or dirt have been deposited on surface of the valve seat which prevents the valve from closing properly4 ,rotating the valve will usually dislodge the deposit4 ,try the compression again2 if there is no improvement1 rotate the exhaust valve on its seat in the same manner1 and repeat the test for compression4 ,,rotating ,,the ,,valves ,,in ,,this ,,manner ,,will ,,often ,,make ,,the ,,removal ,,of ,,the ,,valves ,,unnecessary4 ,when the valves are closed the end of the valve stem should ,,not be in contact with the ,,push ,,rod1 or cam lever4 ,suitable ,,clearance should be allowed between the end of the valve stem and the operating mechanism when the valve is closed2 this clearance varies from the thickness of a visiting card on small engines to of an inch on the large4 ,if the valve stem is continually in contact with the push rod it cannot seat properly and consequently will leak4 ,wear on the valve seats and regrinding reduces this clearance1 wear on the ends of valve stems and push rods from continuous thumping increases it4 ,keep the clearance constant and equal to that when the engine was new4 ,on many engines this clearance is adjustable to allow for wear by lock nuts on the ends of the valve stems or push rods4 ,if the above attempts have proved unsuccessful remove the exhaust valve from the cylinder1 if the valve is in a cage1 remove the entire cage2 this may easily be done on most types of engines4 ,always remove the exhaust valve first as the inlet valve rarely requires attention4 ,with small engines1 and engines having the valves mounted directly in the cylinder head it will be necessary to remove the cylinder head to gain access to the valves4 ,in such a case use care when opening the packed joint between the cylinder and head1 to avoid damaging the gasket4 ,the exhaust valves should be lubricated with ,gas ,engine ,cylinder ,oil1 never with common machine oil on account of gumming and sticking1 or with gas engine cylinder oil thickened with ,,flake ,,graphite4 ,powdered graphite may be used with success without the addition of oil1 but oil makes the application of the graphite much easier4 ,a cracked valve seat1 due to expansion strains or to the hammering of the valve1 is a common cause of compression leakage1 and is rather difficult to locate as the leakage only occurs under comparatively high pressure4 ,leakage may also occur between the valve cage and the cylinder casting unless pains are taken to thoroughly clean the cage and the bore before fastening into place4 ,warped valves are caused by overheating1 the head of pallet of the valve becoming out of square with the stem1 or by twisting on the valve seat4 ,if warped valves are suspected the high point of the seat may be determined by means of the following test and should be carefully filed down until it is close to a bearing after which it may be ground down as described under pitted valves4 ,if the stems are now in good condition examine the seating surfaces of the valve pallets and cage or rings4 ,the seats should be bright and free from pits1 depressions1 or streaky blue discolorations4 ,if the seats are deeply grooved from long continued leaks it is best to discard them and replace with new4 ,pitted valves1 and those slightly grooved or streaked should be reground by the use of a little emery flour and tripoli which operation is performed as follows3 ,lift the valve from its seat and apply lubricating oil to the seating surface1 then sprinkle a little flour or emery on the oiled surface and drop the valve back on the seat4 ,do not use coarse emery nor too much of the abrasive1 a pinch is enough and will grind as rapidly as a pound4 ,take care to drop the emery only where required1 do not sprinkle it over the engine or working parts as it will cause cutting and the destruction of the bearings4 ,now turn the valve around in one direction for about a half dozen turns and then in the other direction for the same length of time1 alternately1 at the same time applying a moderate pressure on the valve4 ,small valves may be rotated with a large screw driver entered in the slot found on the valve plate1 but the handiest method is with a carpenter's brace in which is inserted a screw-driver bit4 ,never turn the valve around and around in one direction continuously as this movement is liable to cause grooving1 alternate the direction of rotation frequently with occasional back and forth movements made in a semi-circle4 ,do not press heavily on the valve1 use only enough pressure to insure contact between the two seating surfaces4 ,the valve should be lifted occasionally from the seat to prevent grooving1 and to redistribute the abrasive1 and then dropped back1 after which the grinding should proceed as before4 ,remove the valve after it turns without friction1 wipe it clean1 apply fresh oil and emery and grind once more4 ,when the grinding has removed all pits and ridges1 and presents a smooth even surface1 the grinding is complete4 ,to test for accuracy of grinding place a little ,prussian ,blue on the seat1 if the valve is ground to a perfect surface the blue will show uniformly spread over the seat1 if the grinding is incomplete bare places showing high spots will be seen4 ,it is a good plan to finish the grinding by using a little ,tripoli with oil after the emery has removed the pits and high spots1 as ,tripoli is finer than emery and will smooth down scratches made by the emery4 ,after the grinding has been performed to your satisfaction1 wash the valve1 valve stem1 and guides thoroughly with gasoline and kerosene to remove the smaller traces of emery1 to prevent wear and cutting4 ,when the valves are ground in place on the engine stuff up all openings or parts of the cylinder to prevent the emery from gaining access to the bore4 ,after grinding is complete wipe off surfaces thoroughly and remove waste used for stuffing4 ,,chapter ,,xiii ,,tractors ,,and ,,farm ,,power ,because of our increased population1 which results in a greater planted acreage1 and the scarcity and increased cost of farm labor1 farming has rapidly developed into an industrial science4 ,where formerly the farmer was content to perform certain parts of his work by hand1 he today employs machinery for the same task1 and is far more particular as to the working of his soil and the cost of production per acre4 ,by the use of machinery his crop is marketed at less expense1 in a shorter time1 and he has more time in which to enjoy life than ever before4 ,the modern gasoline and oil engine has been the greatest factor contributing to the farmer's ease and prosperity for it has eliminated the terrors and drudgery of plowing1 churning1 watering stock1 sawing wood1 threshing1 and has besides given him many of the conveniences of city life1 such as running water and electric light4 ,the benefits of power are not only conferred on the farmer but his wife as well for the small domestic engines have saved the back of the house wife during the strenuous period of harvest time4 ,one of the difficulties of farming is the necessity of doing certain work in a limited time or else suffering a heavy loss4 ,the breaking1 the plowing1 the harvesting1 and the threshing each must be done at a certain time1 often within a few days of each other in order to obtain the benefits of the best weather conditions4 ,threshing starts as soon as the grain is ready1 and if rain interferes with the threshing1 the farmer can start plowing immediately if provided with a tractor and thereby gain the undoubted benefits of fall plowing4 ,plowing at harvest time has much to do with eliminating weed seeds for the weeds are turned under while green1 the seeds sprout and commence their growth and are winter killed before they reach maturity4 ,in this way the field is practically freed from weeds in the spring4 ,when the weather again becomes suitable1 the threshing may be resumed and when completed he can again turn to his plowing4 ,illustration3 ,operator's ,view of the 8,big ,four0 ,tractor1 ,showing the ,four ,cylinder ,engine in ,place4 ,gas power is not to be considered merely as a substitute for animal power for the engine not only performs the work of the horses but also performs work that no horse can do1 and does it with far less expense4 ,in the hottest weather when horses are dropping in the broiling sun1 the tractor moves tirelessly through the fields4 ,every farmer knows the expense attached to keeping a horse in the idle winter period for it must be fed1 watered1 and cared for1 work or no work4 ,when the engine is idle it costs nothing except for the interest on the investment1 while animals grow old and are subject to disease whether they work or not4 ,the time of plowing and harvest is short and requires quick work1 and continuous work4 ,horses cannot be driven at plow faster than one mile per hour1 and cannot be worked more than #aj hours per day1 while the tractor under suitable conditions can travel #b to #c miles per hour1 and keep at it twenty-four hours per day4 ,an ordinary tractor can break from #bj to #dj acres of ordinary loam per day and will plow in cultivated land from #dj to #ej acres per day4 ,the same factors govern the fuel consumption of a tractor that govern the rate of plowing1 that is1 the character of the soil and the depth of plowing4 ,on an average1 #a to #b gallons of gasoline will be used in breaking an acre of sod1 and #a to #a gallons of gasoline in plowing stubble4 ,as kerosene contains about #ah per cent more heat per gallon than gasoline1 the quantity of fuel used by an oil tractor is correspondingly less4 ,when used for pulling wagons on the road at about #c miles per hour the fuel consumption will approximate #d gallons per hour1 this consumption varying of course with grades1 etc4 ,thirty horse-power1 at the speed given above represents a draw bar pull of about #i1jjj pounds1 which is equivalent to the tractive effort of from #cj to #dj horses1 were it possible to concentrate the pull of so many horses at a single point1 at one time4 ,it would of course be impossible for the horses to maintain this effort for as long a time as the tractor4 ,on a level road it will take about #ajj pounds tractive effort for each #b1jjj pounds of weight in the form of road wagons 7including the weight of the wagon74 ,the number of wagons that can be drawn with a given draw bar pull can be easily figured4 ,when pulling on a grade1 the effective draw bar pull will be reduced in proportion to the extent of the grade4 ,while no fixed rule can be given regarding the number of plows that can be handled by a tractor1 the average machine can pull six to eight breaking plows and from eight to twelve stubble plows1 depending on the character of the soil and the depth of plowing4 ,when the conditions permit the use of a greater number of plows1 than specified above the amount of work done will of course be greater4 ,a tractor can haul four ten foot seeders and two twenty foot harrows and cover #g or #h acres per hour at a cost of from #ab to #ae cents per acre4 ,at harvest time the tractor will also effect a great saving in time and expense for the average machine will handle five or six eight foot binders1 making a cut of nearly #ej feet wide1 and this can be kept up for #bd hours at a stretch4 ,a tractor of the average output can handle any separator1 and with a #dd cylinder machine can turn out from #b1jjj to #c1jjj bushels of wheat and #e1jjj bushels of oats in a ten hour run4 ,it will also handle any of the largest shredders4 ,for irrigation work1 silo filling1 and wood cutting it is equally efficient4 7#adb7 ,the ,gas ,tractor4 ,the tractor of the internal combustion type using gasoline or oil as a fuel is much more successful than the steam machine1 both from the standpoints of convenience and cost of operation4 ,there is absolutely no danger of fire whatever around a gas tractor for this reason the engine can be placed in any position regardless of the direction of the wind1 which would be impracticable with a steam engine4 ,this is a great advantage for if the wind is allowed to blow directly from the engine to the separator1 it will be of great assistance to the pitchers who feed the separator4 ,when threshing or plowing in a remote field considerable difficulty is always experienced in supplying the steam tractor with the enormous amount of water that it consumes4 ,to supply the water requires a team1 tank wagon and drivers which is a considerable item in the running expense4 ,the small amount of water used for cooling the gas engine is renewed once1 or at the most1 twice a day4 ,steam coal is bulky and requires the continuous service of a man and team to keep things moving1 and this expense is greatly increased by the expense of the coal4 ,a gas tractor can be started in a very few moments while the engineer of a steam rig has to start in an hour or more before the crew to get steam up1 etc4 ,in addition to this there is the usual tedious routine of 8oiling up10 cleaning the flues1 etc4 ,there is absolutely no danger of explosions with the gas engine which have proved so disastrous in the past with steam threshing engines4 ,with the gasoline1 the operator is left free to work on the separator as he has no firing to do and does not have to concentrate his attention on keeping the water level at the correct point in the gauge glass4 ,the engine is automatically lubricated in all cases so no attention is demanded on this score for it will run smoothly hour after hour without the least attention4 ,this feature eliminates one high priced man from the job4 ,on heavy loads the problem of keeping up the steam pressure is often a vexatious one1 especially if a poor grade of coal is used4 ,with a lower priced man as operator tending both the separator and the gas engine the crew need only consist of two pitchers to feed the machine1 with a man and team for each pitcher4 ,this small crew is easily accommodated at the farmers house1 and does not require the services of a separate cook and camp equipment4 ,with a gasoline rig the expenses will be approximately as follows3 ,engineer1 wages and expenses #e4jj ,two pitchers1 at #c4jj #f4jj ,four men and teams #bj4jj #fj gallons of gasoline at #ae;c #i4jj ,lubricating oil #a4jj ------------ ,cost per day #da4jj ,taking #a1ejj bushels 7wheat7 as a day's work1 the cost of threshing figures out at #b cents per bushel4 ,according to data furnished by the ,m4 ,rumely ,company1 which is based on an actual test1 the total cost of plowing1 seeding1 cutting and threshing1 including ground rental and depreciation1 amounted to #h4fe with horses and #f4ee with their oil tractor4 ,these figures will of course vary in individual cases1 but are principally of interest in showing the comparative cost of horse and tractor operation4 ,with a gasoline or oil tractor equipped with engine plows one man can tend to both the plows and the engine1 although some operators prefer to have two men1 one relieving the other consequently plowing more acres per day and reducing the cost per acre4 ,in some cases one man is placed on the plows and the other on the engine4 ,by running the tractor twenty-four hours per day1 with two shifts of men1 a much better showing is made by the tractor when compared with horse plowing1 for with the latter method it would be necessary to supply twice the number of horses4 ,to show the relative merits of various grades of fuel we will print the data kindly furnished by ,fairbanks ,morse for a ten hour day4 ,,item ,fuel ,oil,kerosene,gasoline #c;c #f;c #ae;c #fj ,gallons ,fuel #a4hj #c4ij #i4jj ,lubricants 4#dj 4#dj 4#dj ,engineer #c4ej #c4ej #c4ej ,plowman #b4jj #b4jj #b4jj ,repairs 4#ab 4#ab 4#ab ,cost to ,plow #bd ,acres #g4hb #i4ib #ae4jb ,cost per ,acre 4#cb 4#da 4#fc ,plowing at the rate of #bj acres per day1 and kerosene at #f cents per gallon1 the ,rumely ,company obtain the cost of plowing one acre as #j4ff4 ,in the latter figure the interest and depreciation are included which will increase the figures over those given by ,fairbanks ,morse4 ,it should be understood that these costs are approximate and will vary considerably in different localities and under various conditions4 ,oil ,injection ,engines4 ,engines using low grade fuels such as kerosene1 usually experience much trouble in obtaining a proper mixture when the fuel is vaporized in an external carbureter even when the carbureter is specially designed for the heavy oil4 ,this leads to fuel waste1 starting troubles and cylinder carbonization1 to say nothing of the objections of an odorous1 dirty exhaust4 ,to overcome the objections of carbureting the heavy oils it has been common practice to inject or aspirate a small amount of water1 the water vapor tending to prevent the fuel from cracking and to distribute the temperature more uniformly through the stroke4 ,the injection of water is not a particularly desirable feature1 since its use involves one more adjustment and possible source of trouble when running on variable loads4 ,in the semi-,diesel engine the fuel is sprayed directly into the combustion chamber by mechanical means1 thus making the fuel supply to a certain extent independent of atmospheric and temperature conditions4 ,after the injection the spray is vaporized both by the hot walls of the combustion chamber and the heat of compression1 the latter being principally instrumental in causing the ignition of the gas4 ,in this case no electrical ignition devices are required1 thus at one stroke overcoming one of the principal objections to a gas engine4 ,until recently the semi-,diesel engines were confined to units of rather large size1 the smallest being much larger than the engines usually used on the farm4 ,it is now possible1 however1 to obtain oil engines of the fuel injection type in very small sizes1 built especially for portable or semi-portable service4 ,not only is it possible to use a cheaper grade of fuel with this type of engine1 but the fuel consumption is also less than with the carbureting type4 ,to this may be added the advantages of an engine free from the troubles incident to the ignition and carbureting systems4 ,good results may be obtained with small injection engines on oils running from kerosene 7#dh gravity7 down to #bh gravity1 the combustion in all cases being complete and without excessive carbon deposits4 ,little trouble is caused by variable loads as long as the speed is kept constant4 ,compared with gasoline1 the heavier fuels are much safer to store and handle1 owing to their high flash points4 ,the compression of the injection engine is much higher than the old carbureting kerosene engine as the compression heat is used in a great part to ignite the oil vapor4 ,usually the pressure is in excess of #aej pounds per square inch1 the exact value being determined by the form of the combustion chamber1 whether a hot bulb is used1 etc4 ,the high compression assists in increasing the economy of the engine4 ,usually the piston either draws in a complete volume of pure air or draws in pure air through the greater part of the induction stroke1 the spray either starting near the end of the suction stroke or during the early part of the compression4 ,when a hot bulb is used the oil spray strikes the bulb forming vapor1 the increasing compression caused by the advancing piston furnishing the air for combustion and forces the mixture into contact with the hot walls4 ,another type has no hot bulb1 the lighter constituents of the fuel being vaporized and ignited by the compression alone1 their inflammation serving to kindle the main1 heavy body of the oil4 ,in some engines1 the combustion of the light constituents serves to spray the heavy oil through the valve and into the combustion chamber4 ,details of several of the most prominent makes of oil engines are described in an early chapter of this book4 ,as a rule1 this class of oil engine does not run well when the speed is varied through any great range1 nor when governed by a throttling type governor1 since both of these conditions affect the compression4 ,they may be either of the two or four stroke cycle type1 and when of the latter they are much more successful than a two stroke cycle engine using a carbureter4 ,on small engines the fuel consumption will run about #j4g pint per brake horsepower hour1 this consumption decreasing on large engines to about #j4f pint per brake horsepower hour or even less4 ,illustration3 ,oil ,injection ,type4 ,injection pump ,p driven by eccentric ,e through rods ,g-,h draws oil from tank ,k through ,m-,n and sprays it into combustion chamber ,r through ,o-,q4 ,amount of oil sprayed is controlled by fly-wheel governor ,w-,w shifting ,e on shaft ,s1 thus varying stroke of ,p4 ,engine is started by heating ,r with torch ,u and injecting first oil with hand lever ,i4 ,a second pump supplies constant level of oil to ,k1 level being observed in glass ,l4 ,c-,c is the cylinder1 and ,f is the fly-wheel4 ,the accompanying diagram shows a diagram of a typical oil engine of the injection type1 a pump ,p supplying the oil from auxiliary tank to the hot1 extended combustion chamber ,r1 this chamber being an extension of the cylinder ,c-,c4 ,oil is kept at a constant level in ,k by an overflow pipe1 the oil entering from the supply pump through pipe ,j1 and entering the pump through ,m at ,n4 ,by gauge glass ,l1 the operator can tell whether he has a sufficient supply of oil4 ,the injection pump ,p is driven from the eccentric ,e 7mounted on the main shaft ,s7 through the eccentric rod ,g and the rod ,h4 ,the governor weights ,w-,w alter the amount of fuel supplied by changing the stroke of the pump1 thus keeping the speed constant under varying loads4 ,the governor acts by shifting ,e in relation to the shaft ,s1 a spring ,t controlling the throw of the governor4 ,the entire governor mechanism is contained in the fly-wheel ,f4 ,to start1 the combustion chamber ,r is heated by the torch ,u1 and after thoroughly heated1 the starting fuel is injected by means of the hand lever ,i4 ,this engine is of the two cycle type with scavenging air furnished by crank-case compression4 7#adc7 ,construction of ,gas ,tractors4 ,a gas tractor may be considered as being simply a special application of the gasoline or oil engine in which the engine drives the road wheels through a train of gearing instead of driving its load by a belt from the pulley4 ,four intermediate mechanisms must be provided between the engine and the road wheels in order that the tractor may properly perform its work4 ,these devices are known as the 8clutch10 the driving gears1 reverse gear and the 8differential0 gear4 ,it should be understood that these mechanisms do not change the construction or operation of the engine in the slightest1 and that the principles that apply to the engines described in the previous chapters apply also to the engine of the tractor4 ,the following will briefly describe the functions of the intermediate trains in their proper order1 starting at the engine4 ,the ,clutch4 ,a tractor is arranged to pull its load in two different ways1 first by the draw bar1 as when pulling plows1 and secondly by a belt from the engine pulley as in driving a threshing machine or circular saw4 ,in the first case it is necessary to drive the road wheels through the gear train1 and in the second case it is necessary to disconnect the road wheels while driving the thresher or saw4 ,as the engine cannot be started while under load it is also necessary to disconnect the road wheels to free the engine while turning it over to get the first explosion4 ,the device that connects and disconnects the engine from the road wheels is known as the ,,clutch4 ,this usually consists of two or more friction surfaces that form a part of the driving gear1 which may be brought into frictional contact with the engine pulley1 when it is necessary to drive the road wheels4 ,when the two members of the clutch are brought into contact they revolve together1 thus connecting the engine with the driving gear4 ,reverse ,gears4 ,illustration3 ,the ,reverse ,gear of the 8,big ,four0 ,tractor4 ,as it is not practicable to reverse the direction of rotation of the gas engine1 the rotation of the road wheels is reversed by means of gears contained in the driving train4 ,in some tractors the reverse gears are similar to those in an automobile1 being located in the transmission4 ,in other tractors two bevel pinions are provided that fit loosely on the engine shaft and engage with a large bevel wheel that forms part of the driving gear4 ,a sliding jaw clutch that revolves on the engine shaft is arranged so that it can connect with either of the bevel pinions causing them to rotate with the engine shaft and drive the main wheel4 ,as the two pinions are on opposite sides of the large bevel wheel1 they run in opposite directions in regard to it1 so that it is possible to reverse the large wheel by engaging the clutch with either one or the other of the bevel pinions4 ,the ,differential ,gear4 ,the differential gear makes it possible to apply the same amount of power to each of the road wheels1 and also allows one wheel to rotate faster than the other when turning around a corner4 ,if both road wheels were rigidly fastened to a single rotating axle it would be practically impossible to turn a corner for it would be necessary for the engine to slip one or the other of the wheels because of their difference in speed1 as the outer wheels turn faster than the inner4 ,illustration3 ,differential ,gear of the 8,big ,four0 ,tractor4 ,the ,driving ,gear4 ,the driving gear consists of a series of spur gears arranged for the purpose of reducing the high speed and small 8pull0 of the motor into the low speed and heavy pull of the road wheels4 ,this reduction in speed is generally brought about by a double system of shafts1 the second shaft from the motor carrying the differential gear and meshes directly with the master gear on the bull wheel4 ,the first shaft is an idler4 ,illustration3 ,fig4 #abe4 ,fairbanks-,morse ,oil ,tractor1 ,showing ,general ,layout4 ,illustration3 ,fig4 #abf4 ,two ,cylinder ,engine of ,fairbanks-,morse ,oil ,tractor4 7#add7 ,fairbanks-,morse ,oil ,tractor4 ,the ,fairbanks-,morse #cj-fj ,horse-power ,oil ,tractor gives an effective draw bar pull of #i1jjj pounds and develops over #fj horse-power at the belt pulley which is more than sufficient to drive any farm machinery4 ,it will operate equally well on kerosene1 distillate oils1 and gasoline1 any of which will develop the rated horse-power4 ,two forward speeds and one reverse are obtained by a gear transmission of the automobile type1 the forward speeds being #a and #b miles per hour and the reverse #a miles4 ,combined with the governor variation1 it is possible to get the proper speed for any kind of work4 ,the fuel is sprayed directly into the cylinder with a spray of water1 the proportion of water to oil being nearly equal at full load4 ,as explained in ,chapter ,,vii1 the water spray aids in the combustion of the heavier oils1 eliminates soot and tarry deposits1 and makes the engine run more smoothly because of the reduction of the explosion pressure4 ,the spray also reduces the temperature of the cylinder and minimizes the dangers of preignition4 ,the engine is of the slow speed type running at a normal speed of #cge revolutions per minute1 and the two cylinders have a bore and stroke of #aj #ab inches4 ,the speed regulator supplied with the engine gives an extreme variation of #cjj to #cge ,r4,p4,m4 ,illustration3 ,fig4 #abg4 ,fairbanks-,morse ,tractor ,transmission with ,two ,forward ,speeds and ,one ,reverse4 ,the cylinders are cast two in a block which arrangement permits of the bores being brought close together and gives an easy circulation of cooling water4 ,the value of this practice has been proved in automobile work where a simple and rigid structure is absolutely necessary4 ,all of the valves are in the heads of the cylinder which eliminates heat radiating pockets in the combustion chamber4 ,both the inlet and exhaust valve are mechanically operated through substantial push rods and valve rockers1 and are completely surrounded by water4 ,large clean out holes are provided in the separately cast cylinder head making it accessible for the removal of scale and sediment4 ,a single cylinder head serves for both cylinders which contributes to easy cooling passages and a single arrangement of exhaust and inlet piping4 ,the valves are in cages bolted to the cylinder head in such a way that they are easily removed for inspection without disturbing the piping or connections4 ,the pistons are easily removed without taking the heads out of the cylinder or taking down any shafting4 ,the valve rocker arms are provided with easily renewed bushings and grease cups4 ,as the engine is of the four stroke cycle type with both cylinders on the same side of the crank-shaft1 only a single throw crank shaft is used1 which is without intermediate bearings4 ,dual ignition is used1 the high tension magneto and the two unit spark coils shown in ,fig4 #abf being independent of one another so that either the magneto or battery can be used for starting or for continuous operation4 ,the magneto is mounted directly on the engine bed and is gear driven from the crank shaft4 ,the ignition advance and retard lever and ignition switch are mounted on the engine in an accessible position4 ,as the coil is mounted on the engine the leads are short and the vibrators are directly under the supervision of the operator4 ,close speed regulation is maintained by a throttling type governor4 ,the voluntary speed variation used to slow the engine down to meet certain conditions encountered in plowing is accomplished by a small lever located at the end of the cylinders4 ,the cooling water is circulated through the cylinders by a gear driven centrifugal pump4 ,from the cylinders the water enters a closed radiator of the automobile type located at the front of the traction where it is cooled without loss4 ,a nine feed1 forced type oiler is used which supplies oil to the cylinders and bearings1 and also to the transmission gears4 ,external bearings which are subjected to dust are equipped with grease cups4 ,the fuel pump which takes its supply from an #hj gallon tank is in an accessible position near the operator and is provided with a handle by which it is operated when starting the engine4 ,the clutch which is located in the flywheel at the right of the engine is operated by a lever on the footboard4 ,all of the friction faces and levers are arranged inside of the pulley so that they are not only protected from injury but are prevented from tearing the belt should it slip from the pulley face4 ,a powerful foot with a drum on the differential gear will hold the outfit on a grade independent of the engine4 ,the transmission is of the shifting gear type with hardened steel gears4 ,the transmission gears are enclosed in a practically dust proof case1 this being connected with enclosed crank case and better providing for air displacement of the pistons4 ,power is transmitted to the truck through the clutch on the left hand side of the engine1 which is operated by combined clutch and shifting lever on the footboard4 ,this lever has an interlocking device1 arranged so that it is impossible for the operator to shift the gears before the clutch is disengaged1 or to engage the clutch until the gears are completely in mesh4 ,it is also impossible to get two sets of gearing in mesh at one time and prevents any possibility of stripping gears by applying the load on the corners of the teeth4 ,the drive wheels are #gh diameter1 #cj face4 ,these give a very large bearing on the ground which is particularly desirable when using the engine for cultivating or seeding on plowed ground4 ,the front wheels are #dh in diameter1 #ad face4 ,the wheel base is long and engine is easy to guide4 ,the drive wheels are covered by a metal housing which protects the operator and the working parts of the engine from dust and mud4 ,this engine gives a drawbar pull on low gear of #i1jjj lbs41 which will haul from #h to #ab-ad plows1 according to the character of the plowing4 ,the hitch is placed about #ah above the ground and consists of a heavy bar extending approximately to the middle of the bull wheels on each side1 thus providing for hitching the load most satisfactorily4 7#ade7 ,the ,rumely 8,oil ,pull0 ,tractor4 ,the ,rumely oil-pull tractor is driven by a two cylinder1 four stroke cycle oil engine1 having a bore and stroke of #aj #ab inches giving #cj tractive horse-power and #fj horse-power at the pulley4 ,the cylinders are cast single and are provided with independent heads4 ,the pistons are easily removed by unbolting the cylinder heads and the crank end of the connecting rod1 after which operation they may be pulled out upon the platform4 ,the exhaust and inlet valves are in easily removable cages placed on either side of the cylinder4 ,the stems of the valves are at right angles to the bore of the cylinder and open directly into the combustion chamber without pockets or extensions to the chamber4 ,a bell crank rocker arm acts on the valve stems which in turn is actuated through a push rod that extends from the cam-shaft in the crank chamber4 ,the cam-shaft1 rocker arms1 valves1 and half time gears are clearly shown by ,fig4 #abh4 ,the housings of the inlet valves connect directly with the special kerosene carburetor made by the ,rumely ,company4 ,the ,higgins carburetor used on these engines is very simple and effective in vaporizing the heavier fuels and has no springs nor internal mechanism to get out of order4 ,the carburetor is controlled directly from the governor which regulates the air1 water and kerosene required for the combustion1 and has no manual adjustments that need attention from the operator4 ,a constant flow of kerosene and water is maintained through the carburetor by means of force pumps1 the level in the device being kept constant by overflow pipes through which the excess returns to the supply tanks4 ,illustration3 ,fig4 #abh4 ,phantom ,view of the ,rumely 8,oil ,pull0 ,engine4 ,as in nearly all types of low compression1 or carbureting oil engines1 the ,rumely engine receives an injection of water in the cylinder to aid the combustion and cooling1 and to reduce the initial pressure of the explosion4 ,while the initial pressure is reduced by the water vapor1 and with it the strain on the engine1 the mean effective pressure is increased because of the absorption of heat from the walls and the more perfect combustion4 ,the only moving part in the carburetor is a single plate controlled by the governor which is produced with one or more air passages4 ,the governor that operates this valve is driven by gears and regulates the speed by throttling the charge4 ,the speed of the engine can be varied from #cjj to #djj revolutions per minute while the engine is running4 ,illustration3 ,fig4 #abi4 ,higgins ,oil ,carburetor4 ,in this engine it is a very simple matter to remove the crank-case cover and the cylinder heads and expose the whole of the working mechanism of the engine4 ,after removing the cylinder heads and without changing his position1 the operator can examine1 clean1 and1 if necessary1 regrind the valves4 ,also without changing position the operator can control his reverse transmission gears1 friction clutch for starting the tractor4 ,he is also in reach of the ignition apparatus1 governor carburetor and oiler4 ,the crank case is cast in one piece4 ,the bearings are cast integral with the crank case1 and are fitted with interchangeable1 adjustable1 babbitted shells4 ,binder caps hold the bearings together and keep the babbitted shells securely in position4 ,the design permits removal of binder caps for examination of crank shaft bearings without distributing the adjustment4 ,the crank case is secured to tractor frame by well fitted bolts1 thereby avoiding annoyance from loose bolts and nuts4 ,the crank case is covered with a sheet steel lid that shuts out all dust and dirt4 ,this cover can easily be removed at any time by simply unscrewing the bolts that hold it in place4 ,it is constructed with this cover on top instead of on the side or end1 which permits of easy access to any working parts in the crank case4 ,illustration3 ,fig4 #acj4 ,rumely ,oil ,pull ,tractor4 ,to further facilitate the accessibility to working parts in the crank case1 a secondary cover is provided which can be removed in a couple of minutes4 ,this opening is large enough to allow the operator to reach any point within the crank case4 ,all cams are key-seated upon the cam shaft with double key-seats1 which absolutely prevent any possibility of slipping or alteration in the timing of the engine4 ,the exhaust and intake valves are mechanically operated4 ,the valves are constructed with steel stem1 nickel-steel heads1 the whole being highly finished4 ,valve cages are oil cooled1 thereby eliminating all possibility of the valves overheating or warping4 ,the valves themselves can be removed by simply unscrewing the connection4 ,the engine is provided with a set of relief cams by which the compression can be relieved--this greatly facilitates the starting of the engine4 ,the piston is equipped with five self-expanding rings4 ,connecting rod is of drop-forged steel construction4 ,crank-pin bearings are made in halves and lined with shells of special metal4 ,a combination of mechanical force feed and splash lubrication is employed4 ,six force feed tubes enter the crank case1 on to each bearing1 and two tubes force oil into the cylinder4 ,the crank case contains two gallons of oil and is arranged so that any surplus may be drawn off immediately4 ,the lubricator has a gauge glass that shows the quantity of oil supplied at all times1 and which is always in view of the operator4 ,a make and break system 7low tension7 furnishes the ignition spark1 which is supplied with current by a ,bosch low tension magneto under normal running conditions1 and a battery for starting and for use when the magneto fails4 ,the magneto is of course gear driven so that its armature has a fixed relation with the piston position4 ,the igniters of either cylinder may be easily removed for examination by simply unscrewing two nuts4 ,oil is used as a medium for carrying heat from the cylinder walls to the radiator4 ,in the construction of the cooler the company have followed new principles1 thus accomplishing the desired result with a minimum amount of metal and liquid4 ,there is no surplus of liquid1 just enough oil being used to fill the cylinder jackets1 radiator and circulation pipes4 ,the oil is kept in a constant flow from the cylinders to the radiator and back to the cylinders by a large pump which is driven by a chain direct from the crank shaft4 ,the radiator is self-contained and will hold the oil for an indefinite period4 ,the radiator is composed of a number of sections of pressed galvanized steel4 ,oil circulates freely within the sections and the air is drawn round the outside4 ,there is a constant flow of oil inside and a constant current of air outside4 ,the engine is provided with a smooth-working1 efficient friction clutch1 which is easily handled by a platform lever and with little exertion on the part of the operator4 ,the toggle bolts are adjustable so that any wear in the blocks can be taken up4 ,the clutch and brake are so connected that when the clutch is thrown out the brake is immediately applied and when thrown in the brake is released4 ,the various movements of the valves and the ignition mechanism on the face of the flywheel1 are marked so that one can check up the timing of the engine4 ,by bringing any one of these marks to coincide with the stationary pointer attached to the side of the crank case1 one can easily ascertain whether the adjustments and the timing are exact4 ,the crank shaft is supported by two end1 and one intermediate bearing1 the latter bearing being placed between the two throws of the crank shaft4 ,as the two cylinders are placed on the same side of the crank shaft1 the two throws are also on the same side of the shaft and to balance these throws cast iron counter weights are bolted on the bottom of the crank arms4 ,the bearings are exceptionally long1 the total length of the three bearings amounting to more than half the length between the outer ends of the bearings4 ,the frame of the tractor consists of four twelve inch 8,i0 beams securely riveted together with intermediate channel stiffeners4 ,the cast steel bearings are riveted to the frame so that the whole construction is one unyielding mass4 ,the bearings are in halves which makes the removal of the shafts an easy task4 ,with the exception of the differential and master gears all of the gears are cut out of semi steel blanks4 ,the fly wheel has a face of #aa inches1 and a diameter of #cf inches4 7#adf7 ,the 8,big ,four0 ,tractor4 ,the ,big ,four tractor differs from the majority of tractors in having a four cylinder vertical type motor of #cj tractive and #fj brake horse-power capacity4 ,the cylinders have a bore of #f inches and a stroke of #h inches4 ,the engine runs at the comparatively high speed of #dej revolutions per minute4 ,gasoline is used for fuel1 and is vaporized in a conventional type of jet carburetor4 ,both the inlet and the exhaust valves are placed in a pocket at one side of the cylinder making what is known as an 8,l0 engine4 ,the cylinders and the heads are cast in one piece1 doing away with points between the cylinders and heads4 ,the pistons and connecting rods may be removed without disturbing the cylinders or their connections by pulling them out through hand holes in the base of the crank case4 ,the four throw crank shaft is provided with five bearings1 these intermediate bearings between the throws and two end bearings in the case4 ,the interior working parts of the motor are lubricated by the splash system with a positive forced feed oiler4 ,the splash pools can be adjusted at a minute's notice so that any desired oil level can be obtained4 ,grease cups provide the lubrication for all bearings outside of the motor4 ,water is circulated by a direct driven centrifugal pump1 and as the cooling water is in a closed system the same water is used over and over again without much loss1 a bucketful or so a day being an ample supply4 ,the tubular radiator situated in the front of the tractor is provided with a cooling fan that is driven from the engine in a manner similar to automobile practice4 ,a high tension magneto is gear driven from the cam shaft1 and is mounted on a rocking bracket so that the armature is advanced and retarded as well as the circuit breaker4 ,illustration3 ,fig4 #aca4 ,views of the ,four ,cylinder ,motor of the 8,big ,four0 ,tractor4 ,note the ,massive ,construction ,compared with ,automobile ,practice4 ,an internal expanding clutch connects the motor with the driving gear by operating on the inner run of the fly-wheel4 ,the motion of the engine is transmitted to an intermediate reversing device through bevel gears1 this being necessary for the reason that the crank-shaft runs 8fore and aft10 or parallel to the length of the tractor4 ,a double acting jaw clutch engages with either one or the other of a pair of bevel pinions that run in opposite directions4 ,motion from the reverse gear is transmitted directly to the different shaft1 and from there it is transmitted to the master gears on the bull wheels4 ,the differential shaft is in one piece4 ,illustration3 8,big ,four10 ,four ,cylinder ,tractor ,motor4 ,illustration3 ,showing the ,position of ,engine on 8,big ,four0 ,tractor4 ,the main driving wheels are very large when compared with the wheels of an ordinary tractor1 for they are eight feet in diameter and are proportionately broad4 ,this no doubt gives splendid tractive effect in soft and uneven fields and must save the machine from 8stalling0 under adverse conditions4 ,another unusual feature is the automatic steering device used in plowing4 ,this device consists of a long tubular boom that is fastened to the swiveled front axle of the tractor and a small wheel fastened to the outer end of the boom4 ,the small wheel rolls in the next furrow and compels the tractor to plow in a line parallel to it4 ,this steers the tractor more accurately than would be possible by hand and at the same time enables one man to operate both the engine and the plows4 ,illustration3 ,the 8,case0 ,gas ,tractor4 ,cost of ,gas ,engine ,operation 7,american74 ,,gas ,,producer ,,plant4 ,,natural-,,gas ,,engine4 ,three- ,half ,three- ,half ,load4 quarter ,load4 ,load4 quarter ,load4 ,load4 ,load4 #a ,fuel per hp-hour #a4be #a4e #a4h #aj cu4 #ab cu4 #ae cu lb4 lb4 ft4 ft4 ft4 #b ,fuel per hp-year 7#d1ejj #b4e #c4f #de1jjj #ed1jjj #fg1ejj hours7 tons #c tons tons cu4 cu4 ft4 cu4 ft4 ft4 #c ,cost of fuel #d4jj per ton #cj cents per #a1jjj cu4 ft4 #d ,cost of fuel per year #aj4jj #ab4jj #ad4djac4ej #af4bf #bj4be #e ,cost of attendance per #j4dj cent #j4be cent hp-hour #f ,cost of attendance per #ah4jj #aa4be year #g ,lubricating oil per #j4jjf pint #j4jjf pint hp-hour #h ,cost of oil per year at #j4hd #j4hd #be cents per gal4 #i ,scrubber and cooling #h gals4 #e gals4 water per hp-hour #aj ,cost of water per year at #cj cents per #a1jjj #a4dd #j4ij cubic feet #aa ,operating expenses2 #cj4bh #cb4bh #cd4fhbf4di #bi4ai #cd4bd items1 #d1 #f1 #h and #aj #ab ,saving by ,diesel engine #e4dc #f4dg #g4ij #a4fd #c4ci #f4ef #ac ,interest1 depreciation and maintenance #f #g #b #ae #f #g #b #ae respectively in per cent of investment #ad ,assuming #hj initial cost per hp4 the #ab4jj #ab4jj yearly fixed charges will be ,,low-,,pressure ,,oil ,,diesel ,,engine4 ,,engine4 ,three- ,half ,three- ,half ,load4 quarter ,load4 ,load4 quarter ,load4 ,load4 ,load4 #a ,fuel per hp-hour #a lb4 #a4be #a4fj #j4ej #j4ee #j4fj lb4 lb4 lb4 lb4 lb4 #b ,fuel per hp-year 7#d1ejj #fdc #hjc4e #ajbh4ecba4e #cec4e #chf hours7 gals4 gals4 gals4 gals4 gals4 gals4 #c ,cost of fuel #c cents per gallon #c cents per gallon #d ,cost of fuel per year #ai4cj #bd4aj #cj4hei4fe #aj4fj #aa4eh #e ,cost of attendance per #j4be cent #j4cj cent hp-hour #f ,cost of attendance per #aa4be #ac4ej year #g ,lubricating oil per #j4jjf pint #j4jjg pint hp-hour #h ,cost of oil per year at #j4hd #j4ih #be cents per gal4 #i ,scrubber and cooling #e gals4 #d gals4 water per hp-hour #aj ,cost of water per year at #cj cents per #a1jjj #j4ij #j4gb cubic feet #aa ,operating expenses2 #cb4bi #cg4ji #dc4hdbd4he #be4hj #bf4gh items1 #d1 #f1 #h and #aj #ab ,saving by ,diesel engine #g4dd #aa4bi #ag4jf 444 444 444 #ac ,interest1 depreciation and maintenance #f #g #b #ae #f #aj #c #ai respectively in per cent of investment #ad ,assuming #hj initial cost per hp4 the #ab4jj #ae4jj yearly fixed charges will be ,from a ,paper ,read ,before the ,american ,institute of ,electrical ,engineers4 ,,chapter ,,xiv ,,the ,,steam ,,tractor 7#adg7 ,the ,steam ,tractor4 ,the steam tractor consists of the following elements1 which will take up in detail under separate headings4 7#a7 ,engine proper1 consisting of the cylinder1 piston1 valve motion1 guides1 crank1 fly wheel1 etc4 7#b7 ,boiler--with the grates1 burners1 etc4 7#c7 ,feed pump or injector4 7#d7 ,feed water heater4 7#e7 ,driving gear1 differential1 clutch1 etc4 ,as in the case of the gas tractor1 the machine consists simply of a steam engine and its boiler that drive the road wheels of the tractor through a gear train4 ,with the steam tractor the gearing is simplified as the reverse is performed by the engine's valve motion1 and not through gearing4 ,there is no need of speed changing transmission gears in the steam tractor as the engine is sufficiently flexible to provide an innumerable number of speeds by simple throttle control4 ,while the fuel most commonly used is coal1 straw and wood1 crude oil is often used1 the fuel being determined principally by the location of the engine1 and by its cost on the job4 ,the matter of fuel should be taken into consideration when the engine is purchased as the different grades demand different fire box and boiler construction4 ,when it is possible to obtain crude oil at a reasonable figure1 it certainly should be used in preference to all others as liquid fuel is the most compact1 most easily controlled1 and efficient of any4 ,the subject of oil burners is taken up later in this chapter1 a number of types of which are clearly illustrated4 7#adh7 ,the ,cylinder and ,slide ,valve4 ,the steam engine cylinder consists essentially of a smoothly bored iron casting in which a plunger called the 8piston0 slides to and fro1 the cylinder acting not only as a container for the steam acting on the piston but as a guide and support as well4 ,needless to say1 the contact or fit between the piston and cylinder walls must be as perfect as possible1 tight enough to prevent steam passing the piston1 and free enough to allow the piston to slide without unnecessary friction4 ,the reciprocating piston is connected to the crank through a connecting rod by which the pressure on the piston is communicated to the crank arm4 ,the pressure exerted on the crank pin by the piston depends on the area of the piston 7in square inches7 and the pressure of the steam on each square inch of the area4 ,with a given steam pressure1 the greater the area1 the greater the force tending to turn the crank4 ,as power is the rate or distance through which the force acts in a unit of time it is obvious that the power developed by the engine is equal 7in foot pounds7 to the force in pounds multiplied by the velocity of the piston in feet per minute4 ,since there are #cc1jjj foot pound minutes in a horse-power1 the power developed by such a cylinder is equal to the force multiplied by the piston velocity1 divided by #cc1jjj4 ,illustration ,as the cylinder is necessarily limited in length it is evident that the piston cannot travel in one direction continuously but must be reversed in direction when it travels the length of the cylinder bore thereby traveling the next distance in the opposite direction4 ,this reversal of the piston is accomplished by admitting the steam in one end of the cylinder and then into the other1 this causing the steam to act on the opposite sides of the piston alternately4 ,to establish a difference of pressure on the two piston forces1 the steam pressure is relieved on one side while the steam acts on the other4 ,a typical cylinder furnished with the ordinary steam tractor is shown by ,fig4 #acc1 in which ,t is the cylinder1 ,p the piston and ,r is the piston rod4 ,when the steam in the cylinder end ,e acts in the direction shown by arrow ,e1 the piston pulls the rod ,r in the direction shown by arrow ,s1 the pressure in the cylinder end ,d being relieved to atmospheric at this time4 ,the steam is admitted and relieved by the valve ,l which slides back and forth on its seat actuated by the valve rod ,,vr4 ,in the position shown1 the valve ,l is moving to the left as shown by arrow ,o4 ,the edge of the valve ,n is just opening the steam port ,g through which the cylinder end ,f is placed in communication with the steam filled valve chest ,a4 ,steam at boiler pressure fills the space ,a1 which flows into ,e past ,n and through ,g when the valve opens and establishes pressure against ,p1 which1 through the piston and connecting rods turns the crank4 ,the steam is exhausted from the cylinder end ,d1 through the port ,f1 through the exhaust port ,u1 and out of the exhaust pipe ,x4 ,as will be seen from the figure1 the inside valve edge ,y has moved to the left so that the port ,f is fully opened4 ,when the piston reaches the left hand end of the cylinder1 the valve ,l moves to the right so that the end of the cylinder ,e is connected to the exhaust port ,v through the cylinder port ,g1 thus allowing the steam in the space ,e to pass out of the exhaust pipe ,x4 ,a further movement of the valve to the right causes the left edge ,z of the valve to uncover the cylinder port ,f which allows the steam to flow into the cylinder space ,d and push the piston to the right4 ,this motion is carried on continuously1 the valve moving in a fixed relation to the piston1 and admits the steam and releases it first on one side of the piston and then on the other4 ,the valve shown is known as a 8,d0 valve and is one of a variety of valves furnished with steam engines1 which1 however perform exactly the same functions as the valve shown4 ,an 8eccentric0 which is really a form of crank1 drives the valve to and fro1 the eccentric being fastened to the crankshaft4 ,the full pressure of the steam forces the ,d valve down on its seat1 and as the valve is of considerable size1 this pressure causes much friction and power loss4 ,in some engines a 8balanced0 valve is used in which the pressure on the valve is balanced by an equal pressure that acts on the under side of the valve face4 ,balanced or unbalanced1 the function of the slide is to alternate the flow of steam in the two ends of the cylinder4 ,steam is prevented from passing the piston into the opposite end of the cylinder by elastic rings placed in grooves on the piston which are known as 8piston rings40 ,being thin and elastic these rings instantly conform with any irregularity of the piston bore and effectually stop the flow of steam past them4 ,at the point where the reciprocating piston rod ,r passes through the cylinder1 a steam tight joint is made by the 8stuffing box0 or gland ,h4 ,the space between the inner walls of the stuffing box and the piston rod are either filled with some description of fibrous packing or a metallic packing that fits around the rod in the same manner that the piston rings fit in the bore of the cylinder4 ,the packing is arranged around the valve rod ,,vr in the same manner4 ,as the piston1 piston rod1 and valve slide on their respective surfaces with considerable pressure it is absolutely necessary that these parts receive ample lubrication4 ,in practically all engines the oil is taken into the cylinder with the steam in the form of drops1 the oil being measured out by a sight feed lubricator that is tapped into the steam supply pipe4 ,in this device1 the oil from the lubricator reservoir is fed through a regulating needle valve1 drop by drop1 up through a gauge glass so that the engineer can tell the amount of oil that he is feeding4 ,the body of the lubricator is filled with condensed water up to the level of the outlet through which the oil passes into the cylinder1 and the entire lubricator1 reservoir and all is under boiler pressure at all points4 ,the oil regulating valve is placed at the bottom of the lubricator1 and as oil is lighter than water1 it floats up from the valve to the level of the outlet1 through the gauge glass1 and from the outlet level floats out into the steam pipe and mixes with the steam4 ,by floating the oil in this manner1 the engineer can see every drop that is fed4 7#adi7 ,expansion of ,steam4 ,in order to reduce the amount of steam used1 the valve does not allow the steam to follow the piston at full boiler pressure through the entire stroke1 but cuts it off at a certain point after the piston has started on its travel4 ,as the volume of the steam is increased by the further travel of the piston after the point of cut-off1 the steam expands in volume until the end of the stroke is reached1 at which point the pressure is naturally much below the initial or boiler pressure4 ,this reduction in temperature and pressure results in a wider working temperature range than would be the case with the steam following the piston throughout the stroke1 and as the steam is exhausted to atmosphere at a temperature much lower than that of the boiler steam1 much less heat is carried out through the exhaust4 ,as a general rule1 the most economical point of cut-off is at of the stroke4 ,engines requiring more steam than is supplied at cut-off in order to carry the load1 are too highly taxed for efficient results4 ,since the most efficient point of cut-off is only of the possible steam travel it is evident that an engine can carry a load much greater than that for which it is rated1 but it is also evident that this increased capacity is gained at the expense operating economy4 ,wear and tear on the engine parts are also duly increased4 ,illustration3 ,fig4 #acd4 ,case ,steam ,tractor4 7#aej7 ,speed ,regulation4 ,on steam tractors a constant speed is maintained by 8throttling0 the steam1 to meet the demands of the load by partially restricting the flow of steam at light loads and opening the inlet at full load4 ,the valve that controls the steam for the different loads is controlled by a 8governor0 which depends on the centrifugal force exerted by two fly-balls4 ,the balls1 or weights are hinged to a revolving spindle1 driven by the engine1 in such manner that an increase of speed tends to straighten out and revolve in a more nearly horizontal plane4 ,the amount of travel of the balls for a given speed increase1 is governed by a spring1 which returns them to a vertical position when the speed decreases4 ,by means of a simple system of levers1 the valve is closed when the balls fly out1 due to an increase of speed1 and is opened when the speed decreases1 so that the engine will receive the steam at a higher pressure and again build up its speed to normal4 ,as the load fluctuates1 the balls are constantly moving up and down1 seeking a valve position that will keep the engine at a constant speed4 ,speed variation is generally accomplished by increasing or decreasing the tension of the spring that controls the travel of the governor fly balls1 and in the majority of engines this may be done without stopping the engine4 ,another form of governor used extensively on stationary engines controls the speed by increasing or decreasing the cut-off4 ,thus with a heavy load the cut-off may occur at the stroke while with a very light load it may be at #a_/aj stroke4 ,this is by far the most sensitive and economical form of governor1 but on account of the reverse gear it is difficult to apply it on a tractor4 7#aea7 ,reverse ,gear4 ,as explained under 8,cylinders0 the travel of the valve bears a definite relation to the piston position so that the ports may be opened and closed at the proper times4 ,it may be shown by a rather complicated diagram that this relation of the valve together with that of the eccentric that drives it is only correct for one direction of rotation4 ,for any other direction of rotation the relation of the valve and piston position must be changed4 ,this may be done in several ways but the most common types are the ,stevenson ,link and the ,wolff slotted yoke4 ,the ,stevenson link motion used on the majority of engines1 consists of two independent eccentrics1 one being fixed in the relation for forward motion and the other for the reverse direction4 ,the ends of the eccentric rods leading from these eccentrics are connected by a slotted bar or link1 in which a block is placed that is connected with the valve rod4 ,the block is free to slide in the slot of the links1 that is1 it may be moved from one end of the slot to the other4 ,when it is desired to have the engine rotate in a right handed direction1 for example1 the link is lowered so that the rod from the forward eccentric is brought directly in line with the block so that this eccentric alone acts directly on the valve through the valve stem4 ,when the reverse is desired the link is raised until the rod from the reverse eccentric is brought in line with the block and valve stem1 drive being by the reverse eccentric4 ,when the block is on the link in a position between the two points mentioned1 the valve has less travel and it cuts off earlier in the stroke than when driven directly by one eccentric1 for the motion at an intermediate point on the link is much different than at the ends of the slots4 ,this fact is taken advantage of in operating engines with the idea of economy in view1 and is known commonly as 8hooking up0 the engine4 ,the best point at which to 8hook up0 the engine is best determined by experiment1 and is equivalent in many respects to the problem of advancing and retarding the spark of a gas engine4 ,we earnestly advise an engineer of a traction engine to take up this subject and determine the best point of cut-off for different loads as he will find that different positions make a considerable difference in his coal bill4 ,of course the proper way is to determine this point with a steam engine indicator1 but as few engineers have such an appliance1 the work is generally of the cut and try order4 ,wear and varying adjustment soon change the points marked on the reverse sector1 and for economy's sake these points should be checked occasionally4 ,in the ,wolff motion1 a single eccentric is used for both directions of rotation1 in connection with a slotted link4 ,a single eccentric is securely keyed to the crank shaft4 ,the eccentric strap has an extended arm which is pivoted to a block that slides back and forth in a curved guide4 ,the angle at which the guide stands with the horizontal determines the direction of rotation1 the angle being changed by the reverse lever4 ,the degree of the angle made by the block also determines the point of cut-off4 ,this is a very efficient and simple valve gear4 ,guides and ,cross-,head4 ,the outer end of the piston rod is supported by a sliding block known as the 8cross-head0 which in turn is supported by the guides4 ,an oscillating rod called the 8connecting rod0 connects the reciprocating cross-head with the crank pin1 this rod is used in the same way as the connecting rod of the gas engine except that it is connected to the cross-head instead of the piston4 ,clutch4 ,the clutch affords a means of connecting and disconnecting the driving wheels and engine shaft4 ,it is usually of the friction type described under 8,gas ,tractors40 ,by releasing the clutch the engine is disconnected from the driving gear so that the tractor remains stationary while the engine is driving a load through the belt4 ,use of the ,exhaust ,steam4 ,the exhaust from the cylinders is used in two ways1 first to create a draft for the fire1 and second to heat the feed water pumped into the boiler4 ,the draft is increased by exhausting a portion of the steam into a nozzle placed directly under the stack4 ,the friction of the steam on the surrounding air1 draws the air with it1 forming a partial vacuum over the grate at each puff1 and in this way it causes additional air to rush through the fuel and increases the temperature of the combustion4 ,as the load increases the 8puffs0 increase in intensity due to the greater terminal pressure and the fire is accelerated in proportion4 ,this is a simple but rather expensive way of increasing the draft4 ,a considerable proportion of the heat in the exhaust steam is saved by using it to heat the feed water supplied to the boiler4 ,besides the saving in fuel1 affected by heating the water from steam that would otherwise be thrown away1 the strains on the boiler due to the injection of cold water are greatly decreased as the difference between the temperatures of the boiling water in the boiler and the hot feed water are much less than in the former case4 ,the feed water heater consists essentially of a series of tubes in a cylindrical shell4 ,the tubes are surrounded on the outside by the feed water1 and are filled with the exhaust steam which passes from end to end through the tubes4 ,the hot water is pumped from the heater into the boiler4 ,an efficient feed water heater adds greatly to the steaming capacity of the boiler4 7#aeb7 ,feed ,pump4 ,a small steam pump is furnished for pumping the water into the boiler4 ,this device consists of a small steam cylinder connected directly with the pump plunger and is absolutely independent of the main engine so that it can be used whether the engine is running or not4 ,the exhaust of the pump should be turned into the feed water heater when the engine is not running so as to heat the water1 but should be directed to atmosphere when the main exhaust is passing through the heater4 ,an injector is usually supplied with the engine for feeding the boiler in emergencies4 ,the injector forces water into the boiler by means of a steam jet which is arranged so that a high velocity is imparted to the water in the injector nozzle by the condensation of the steam furnished by the jet4 ,in this way water is pumped into the boiler against a pressure that is equal to the pressure of the steam acting on the water4 ,except for a check valve there are no moving parts4 ,no feed water heater connection is made with the injector for this device raises the temperature of the feed to a considerable temperature4 ,the temperature is not as high1 however1 as the temperature of the water from the feed water heater and pump1 and because of the comparatively low temperature coupled with the fact that live steam is used in heating the injector water1 it is not an economical method of pumping4 7#aec7 ,the ,boiler4 ,as the boilers of traction engines sustain the pull and vibration of the engine as well as the stresses due to traveling over rough roads in addition to the steam pressure strains1 they must be made very substantially and of the best materials4 ,the service of the boiler on a traction engine is very different from that met with in stationary or locomotive practice for the tractor seldom receives the attention that is given to the other types and as it goes bumping over the fields with the water whacking at every joint and the engine rushing and surging at every little grade1 it receives an 8endurance0 test every moment of its existence4 ,a boiler should show an inspection pressure considerably in excess of that which it is intended to carry4 ,it should be well stayed and braced1 and should be suspended from the road wheels in such a way as to be relieved from as much strain as possible4 ,no transverse seams should be permitted1 and the barrel should be well reinforced at the point where the front bolster is attached as well as at points where pipe connections are tapped into the shell4 ,no large bolts should be tapped into the steam or water space4 ,the tubes should be placed so that they may be easily withdrawn or cleaned4 ,the location of the hand holes and washout holes is also an important item1 for inaccessible hand-holes are an abomination4 ,boiler lagging or covering is intended to reduce the heat loss by radiation1 and for this reason it should be of a good insulating material and should be thick enough to be effective4 ,the cost of jacketing is more than covered by the saving in coal1 especially in cold weather4 ,a straw-burning fire box differs from a coal burner in having a fire brick arch and a shorter grate1 and in having a special chute on the fire door for feeding the straw into the furnace4 ,after a short time1 the fire brick arch becomes incandescent1 keeping the firebox temperature constant and producing perfect combustion of the tarry vapors distilled from the straw4 ,a trap door is provided on the straw chute which automatically keeps the outside air from chilling the fire4 7#aed7 ,oil-,burning ,steam ,tractors4 ,as with the straw-burning furnace1 a brick arch is used in burning oil for the purpose of preventing fractional distillation of the oil during the combustion4 ,in some forms of oil furnaces a brick checker-work is used that provides a much greater surface to the gases than the ordinary firebrick arch and therefore keeps a steadier temperature and pressure4 ,broken firebrick in the furnace placed in heaps with a rather porous formation is also an aid to combustion4 ,with very heavy oils a jet of steam in the firebox is of great assistance in consuming the free carbon of the fuel 7soot74 ,the oil in practically all cases is atomized or is broken up into a very finely subdivided state by the action of a jet of steam4 ,the finer this subdivision the better will be the combustion for the oil particles will be brought into more intimate contact with the air4 ,provision is also made in the burner for either whirling or stirring the oil vapor with the air so that a rapidly burning mixture is formed4 ,in other respects the oil burning engine is the same as the coal or wood burner4 7#aee7 ,care of the ,steam ,tractor4 ,during the idle season1 the engine should be well housed1 all bright parts slushed with grease and the whole engine carefully covered with tarpaulins4 ,a tractor is an expensive machine and should be given care1 or it will rapidly depreciate and start giving trouble4 ,when one considers the abuse and neglect given farm machinery it is remarkable that it will work at all1 let alone give efficient service4 ,illustration3 ,small ,fairbanks-,morse ,motor ,driving ,binder4 ,before starting a new engine or one that has been idle for a considerable time1 all of the bearings and lubricating should be thoroughly cleaned with kerosene oil1 removing all grit or gum4 ,after cleaning1 they should be thoroughly oiled with the proper grade of lubricant and then adjusted for the correct running fit1 taking care that the bearings and wedges are not taken up too tight1 nor too many shims are taken out4 ,be sure that the openings in the lubricating cups and oil pipes are not clogged and that oil holes in the bearing bushings register with those in the bearing caps4 ,at points where there are sight feed gauge glasses1 the glasses should be cleaned with gasoline and all of the joints repacked with new packing4 ,careful attention should be paid to the piston rod and valve rod packing taking care that it is only tight enough to prevent the leakage of steam and no greater4 ,excessively tight packing burns out rapidly1 scores and shoulders the piston rod1 making it impossible to keep the joint tight4 ,when rods are badly scored they should be trued up in the lathe taking care not to take off too much metal on the finishing cut4 ,when renewing fibrous packing be sure that all of the old packing is removed before placing the new packing in the box4 ,keep the packing well lubricated at all times to prevent wear1 and in some cases it will be advisable to add an oil cup to the stuffing box to insure sufficient lubrication4 ,go over the valve gear and make sure that there is no looseness or play in the eccentrics or pins1 and that all of the bolts and keys are tight and in place4 ,loose connections in the valve gear are not only productive of knocks and wear but also tend to increase the fuel consumption of the engine4 ,when possible1 indicator cards should be taken at intervals to make sure that the valves are correctly set4 ,in a test recently made by the author1 the indicator cards showed a defective setting due to wear1 that when corrected saved the owner of the engine about #fjj pounds of coal per day1 and as the coal cost #i4ej per ton delivered in the field1 the saving soon paid for the expense of the test4 ,points of adjustment are provided on all valve gears1 and as they differ in detail for each engine we cannot give explicit directions for settling the valves1 but will leave this point for the direction book of the maker4 ,the governor and governor belt should now receive attention making sure that there are no loose points or nuts in the mechanism and that the governor belt is in good condition4 ,defective governor belts are dangerous through the possibility of over speeding4 ,slipping or oily belts not only increase the chances of fly-wheel explosions1 but also cause a fluctuation in the speed which is not desirable especially in threshing1 where good results are obtained only by a constant speed4 ,make sure that the safety lever works properly and shuts off the steam with a loose or broken belt4 ,test the governor valve stem for sticking or for rough shots that are likely to cause uneven running4 ,keep the governor well lubricated with light oil1 and keep the oil off the belt as much as possible4 ,governor valve should be carefully tested for tightness and freedom4 ,the throttle valve must be absolutely steam tight for a leaking valve is a dangerous proposition especially in stopping the engine4 ,it is generally arranged so that it can be reground with pumice stone or crocus powder and oil4 ,if the valve is of bronze or brass do not use emery or carborundum for the particles will become imbedded in the soft metal and put it in a worse condition than ever4 ,pack the valve stem4 ,a leaking slide valve is the cause of much loss of power1 and waste of coal1 and as the leakage mingles directly with the exhaust1 it often remains unknown until it has thrown away a considerable quantity of fuel4 ,it is best detected by blocking the engine with the piston at mid-stroke and opening the throttle valve slightly4 ,if the cylinder drain cocks are now opened1 the leaking steam that escapes into the cylinder will be seen issuing from the drains4 ,the leakage that passes into the exhaust will be seen escaping from the stack while it is practically impossible to have the valves absolutely tight at all times1 the steam should not escape so rapidly that it roars through the openings4 ,leakage past the piston is another source of loss that can be detected by blocking the engine so that the piston is very near1 one end of the stroke1 with the valve opening one of the cylinder ports4 ,any steam that passes the piston will pass out of the exhaust4 ,with an old engine it is likely that the cylinder is worn oval1 or that the valve seat is grooved or uneven1 in which case it will be necessary to rebore the cylinder and fit new piston rings or reface the valve seat4 ,broken piston rings are often the source of leakage1 and if not replaced with new at an early date1 are likely to destroy the cylinder bore as well4 ,broken rings generally make themselves known by a wheezing click when the engine is running4 ,the steam feed pump should be well lubricated with a good grade of cylinder oil and should be well packed around the piston rod especially at the water end4 ,to guard against pump troubles a good strainer should be provided on the water suction line to prevent the entrance of sticks and dirt into the cylinder4 ,great care should be exercised in keeping the suction line air tight1 for if any air escapes into this line no water will be lifted4 ,dirt under the valves is the cause of much pump trouble1 as a very small particle of dirt will allow the water to pass in both directions through the valves4 ,leaking packing will also destroy the vacuum in one end of the cylinder4 ,for the best results the pump should be run slowly but continuously1 feeding a small amount of water at one time4 ,this method of feeding allows the feed water heater to bring the water up to the highest possible temperature which reduces the fuel consumption and reduces the strains on the boiler4 ,it is a bad policy to let the water get low in the boiler and then 8ram0 full of cold water in a couple of minutes4 ,attention should be paid to the check valve that is located between the pump and boiler4 ,it should be kept clean and the valve kept tight and in good condition4 ,when the feed water is hard a boiler compound should be used to reduce the amount of scale in the boiler or soften it and make its removal easier4 ,scale of #a_/af inch thickness will decrease the efficiency of the boiler by #ab1 and this loss increases rapidly with a further increase in the thickness of the scale because of its insulating effect on the tubes4 ,soft sludges such as mud and clay may be removed by-blowing off or by the filtration of the water before it is pumped into the boiled4 ,lime and magnesia which form flint-hard deposits1 require chemical treatment such as the addition of sodium phosphate1 etc4 ,in any case1 the deposits waste heat and increase the liability of burning out tubes or bagging the sheets4 ,illustration3 ,buffalo ,marine ,motor4 ,a solution that has given good results with waters containing lime1 consists of #ej pounds of ,sal ,soda and #ce pounds of japonica1 dissolved in #ej gallons of boiling water4 ,about #a_/dj quart is fed into the boiler for every horse-power in #aj hours1 the solution being mixed with the feed water4 ,kerosene has been used a great deal to soften scale1 and gives good results if not fed in quantities to exceed #j4ja quart per horse-power day of #aj hours4 ,an excess of kerosene is to be guarded against for it is likely to accumulate in spots and cause bagged sheets or burn outs4 ,,chapter ,,xv4 ,,oil ,,burners4 7#aef7 ,combustion4 ,to obtain the full heat value of a liquid fuel it must be provided with sufficient air to complete the combustion1 it must be in a very finely subdivided state1 or in the form of a vapor at the time of ignition1 and it must be thoroughly mixed with the air so that every part of the oil is in contact which its chemical equivalent of oxygen4 ,failure to comply with any of these conditions will not only result in a waste of fuel but will also be the cause of troublesome carbon deposits and soot1 which eventually will interfere with the operation of the burner4 ,complete combustion is much more easily attained with the lighter hydrocarbons such as gasoline or naptha than with crude oil or the heavier distillates1 for they are more readily vaporized and mix more thoroughly with the oxygen4 ,only a slight degree of heat and pressure is required with gasoline while with crude oil a high atomizing pressure and high temperature are required to obtain a satisfactory flame4 ,in the majority of cases where heavy oils are used the fuel is not even completely vaporized but enters the combustion chamber in the form of a more or less finely atomized spray4 ,the methods by which the liquid fuel is broken up divides the burners into three primary classes4 7#a7 ,,low ,,pressure ,,burners in which the fuel is atomized by a blast of low pressure air which also supplies a considerable percentage of the air required for combustion4 7#b7 ,,high ,,pressure ,,burner in which a small jet of high pressure air or steam is used to atomize the oil1 the air for combustion being supplied from a source external to the burner4 7#c7 ,,combined ,,high ,,and ,,low ,,pressure ,,burner in which the fuel is atomized by high pressure air or steam1 and the greater part of the air for combustion is furnished by a blower at a comparatively low pressure4 ,in class 7#a7 the oil is supplied to the burner under pressure and by means of a specially designed jet is thrown against hot baffle plates or gauze screens where the partially broken up liquid is caught by the high velocity air and reduced to a still finer spray by its impact against other screens or baffles further on in the burner4 ,this system is applicable only to the light and intermediate grades of oils1 such as gasoline1 naptha or kerosene1 unless heat is applied to the external casing to aid in the vaporization4 ,in some cases the projection of the burner into the furnace gives satisfactory results1 but with such an arrangement there is a tendency to deposit carbon in the burner and for the flame to 8strike back0 should the velocity of the air fall below a certain critical point4 ,better results were had with this type of burner1 by the author when the air blast was preheated by passing several long lengths of the intake air pipe over a hot part of the furnace1 instead of entering the burner nozzle into the combustion chamber proper4 ,a well known modification of this type is the gasoline torch used by electricians and plumbers in which the gasoline is sprayed into a perforated hot tube by air pressure in the tank4 ,when the spray formed at the needle valve strikes the surrounding hot tube it is instantly vaporized and is mixed with the air passing through the perforations in the tube4 ,while the air entering the tube is not forced through the openings by external pressure it attains sufficient velocity to aid in the vaporization because of the vacuum established by the jet4 ,this however is only enough for the more volatile fuels--such as gasoline or benzine4 ,the high pressure which is by far the most commonly used with low grade fuels may be divided into five principal types 7a7 ,,atomizer burner1 7b7 ,the ,,injector burner1 7c7 ,,drip feed burner1 7d7 ,,chamber ,,or ,,internal burner1 7e7 ,,external ,,blast burner4 ,all of these burners break up the fuel by high pressure air or steam1 the types given being different only in the way that the pressure is applied to the fuel4 ,the atomizer acts on the same principle as the medical or perfumery atomizer1 the high pressure jet playing directly across the open end of the oil passage as shown by ,fig4 ,a4 ,as the vacuum created by the blast is very low1 and has little effect in lifting the fuel to the burner1 the oil either is made to flow by gravity or by a pump4 ,in the figure the oil in the upper passage is shown pouring down in front of the air or steam jet issuing from the lower port4 ,both ports are supplied by the pipes shown by the circular openings at the right4 ,the steam and oil are controlled by independent valves placed in the two passages4 ,in practice the oil and steam openings at the end of the burner may be either single or multiple round openings or long thin slots1 the former style being the most common4 ,since only a small amount of air is admitted through the blast nozzle1 far too little to completely consume the oil1 the air for the combustion is admitted through openings in the combustion chamber proper1 this air being supplied by natural draft or by blower4 ,in some cases the burner is entered into the furnace through an opening that is much larger than the burner itself4 ,the atmospheric air enters through baffle plates in this opening which impart a whirling motion to the air that passes over the burner4 ,this is of considerable aid in maintaining complete combustion in the furnace1 and also tends to prevent deposits in the burner4 ,illustration3 ,fig4 #ace4 ,showing the ,different ,classes of ,oil ,burners4 ,illustration3 ,fig4 ,f4 ,mixed ,pressure ,burner1 ,using ,both ,steam and ,low ,pressure ,air4 ,illustration3 ,fig4 ,g4 ,burner ,used by the ,pennsylvania ,railroad ,under ,locomotives4 ,in the injector type of burner shown by ,fig4 ,b the air or steam nozzle terminates inside of a shell and is completely surrounded by the oil4 ,a mixture of air and oil issues from main nozzle shown by 7#b74 ,when the air or steam blows through the inner opening1 a partial vacuum is formed in the space 7#a7 which draws the oil into the burner from the supply pipe4 ,on entering this vacuous space the oil comes into contact with the jet and is blown out through the opening 7#b7 in the form of a spray4 ,this vacuum is high enough to lift the fuel for a considerable distance without the aid of a pump and for this reason is the type most commonly met with in practice4 ,a boiler or furnace equipped with this burner will lift the oil directly to the furnace from the reservoir in the same way that a feed water injector will lift water into the boiler4 ,with the commercial injector1 the position of the steam jet is made adjustable in relation to the main jet to meet different feed conditions4 ,the steam enters the inner port through the end of the pipe shown at the right4 ,the oil enters the outer port at the right through a port not shown4 ,illustration3 ,fig4 ,h4 ,lassoe-,lovelsin ,burner4 ,fig4 ,c shows a drip feed or 8dribbling0 burner in which the oil pours out of the upper port and over the lower port through which the steam or air issues4 ,as would be expected1 the atomization is not as perfect with this burner as with the atomizer or injector type4 ,illustration3 ,fig4 ,i4 ,sheedy ,oil ,burner1 ,used for ,locomotives4 ,a burner in which the oil and steam mix before passing out into the furnace through the final opening is known as a 8,chamber burner10 and is shown by ,fig4 ,d4 ,in some respects1 at least in construction1 it is similar to the injector burner1 but it does not possess the lifting abilities of the latter because of the open space in front of the steam nozzle4 ,the atomization takes place largely within the burner because of the eddy currents of air and oil vapor created both by the vapor striking the walls of the outer tube and by the large space in which it has to circulate before passing out of the orifice4 ,an external blast burner as shown by ,fig4 ,e1 in which the oil is forced out of the openings 7#c-c7 at the extreme end of the burner atomizes by blowing the oil off of the tube by jets of steam directed by a series of annular openings in a disc4 ,this is really a type of atomizer burner as will be seen by close inspection4 ,this type must be very carefully constructed and the steam jets must be kept very clean in order to have good results for a little variation in the pressure or a small particle of dirt in the openings will deflect the steam and prevent a perfect oil spray4 ,it's one advantage lies in the fact that the oil and air are always separate and therefore minimize the danger of carbonization4 ,illustration ,it should be noted that the figures just shown in the illustration of the various classes of burners are diagrammatic only1 and that many modifications in detail are made in the practical burner such as regulating valves1 sliding steam nozzles1 etc4 ,a burner much used in stationary engine practice and with heating furnaces1 where air at two or three ounces pressure is available1 is the mixed pressure burner shown by ,fig4 ,f4 ,in this burned steam or air compressed1 to say #hj pounds per square inch is used for breaking up the fuel oil4 ,a blast of air at low pressure but with considerable volume is used to support combustion in the furnace4 ,the steam or compressed air enters the burner at 7#e7 and meets the oil at the nozzle 7#h7 where it is sprayed into the chamber 7#i74 ,the oil enters the burner by the pipe 7#d71 flows into the annular passage around the steam nozzle and meets the steam at 7#h74 ,it will be noted that the steam nozzle 7#e7 is free to slide back and forth in its casing so that the relation between the steam nozzle and spray nozzle may be adjusted to meet different operating conditions4 ,this adjustment is affected by the levers 7#aj7 at the end of the burner4 ,the low pressure air entering through opening 7#f7 from the blower passes around the chamber 7#i7 and mixes with the oil spray from 7#h7 in the mixing chamber 7#g74 ,this causes a violent swirl in 7#g7 with the result that a comparatively intimate mixture of oil vapor and air is formed before they issue into the furnace4 ,in many burners of this type a gauze screen 7#aa7 is placed over the mouth of the final orifice so that back fires are prevented and a still better mixture is formed4 ,many burners of this type have been built by the author with very satisfactory results1 and he knows of only one weak point in the type4 ,this is due to the fact that if a sufficient volume of air is not kept flowing through the low pressure pipe 7#f71 the oil vapor may collect in the piping with the result a back fire will wreck all of the low pressure connections4 ,to prevent this trouble a light galvanized iron weighted damper was placed beneath 7#f7 which closed the pipe when the pressure fell below a certain amount4 ,since this check valve was placed there were no more pipe fires4 ,in all cases a sliding damper should be placed in the opening so that the blast can be regulated to suit the amount of oil injected4 ,as these burners were used in a closed building continuously without smoke or smell and with indifferent grade of oil it will be seen that the combustion was as nearly perfect as could be expected with any type of oil burner4 ,several of these burners were made from ordinary steam pipe fittings without steam nozzle adjustment4 ,while the burners shown are arranged to give a flat flame 7with the exception of burner ,f7 they may all be built for a circular flame by surrounding the injection nozzle with a suitable nozzle4 ,a ,,rose or circular flame is particularly desirable for a vertical boiler where it can be made to conform with the circular shell and apply the heat directly to the tube sheet through suitable fire brick baffles4 ,a burner of the injector type shown by ,fig4 ,g1 has been used by the ,pennsylvania ,railroad with a considerable degree of success4 ,the steam enters the steam nozzle at 7#ab7 through the circular openings from which point it passes through the nozzle 7#ac7 and carries the oil from the air port 7#ad74 ,the mixture or spray of steam and oil passes out of the nozzle 7#ae7 into the furnace4 ,the steam nozzle is threaded into the casing at 7#af71 and is keyed to the bevel gear 7#ag74 ,meshing with 7#ag7 is the bevel mounted on the vertical stem which terminates in a hand-wheel in the engineer's cab4 ,by turning the bevels1 the nozzle turns in the casing threads causing it to move back and forth for the adjustment4 ,in many types of burners having a nozzle similar to 7#ae7 a twisted form of rifling is placed in the bore that gives the escaping gas a rotary motion4 ,this is very effective in mixing the air and oil vapor and spreads the flame very close to the orifice4 ,in burners of the chamber type a spiral vane is sometimes used to gain the same effect1 and in one make a rotating fan1 is placed near the opening of the outer nozzle which gives a sudden whirl to the gases4 ,while this latter attachment does all that is claimed for it while it is in good repair1 it is very likely to stick and put the burner out of commission4 ,the ,lassoe-,lovelsin locomotive burner is shown by ,fig4 ,h in which the gas exits through a series of holes in the end of the nozzle 7#bb74 ,the steam enters the outside casing1 and unlike the burners just described1 entirely surrounds the central oil nozzle1 7#bj74 ,the steam in passing through the openings #ba-bb draws the oil through the central opening 7#bc71 this oil nozzle being controlled by the needle valve 7#bd7 which terminates in the handle 7#be74 ,oil enters the oil nozzle through the inlet pipe 7#bf74 ,the ,sheedy oil burner shown by ,fig4 ,i has a rectangular nozzle for a flat flame1 and has no steam nozzle adjustment4 ,oil surrounds the steam nozzle and enters the casing through the upper connection4 ,air enters the lower port through the lower opening as shown in the cross-section of the burner4 ,as the oil flows over the trough formed by the steam nozzle it meets the jet of steam at 7#cj7 and is atomized4 ,the air from the lower port aids in bringing the combustion near the tip of the nozzle and therefore prevents carbon deposits from being formed in the burner as well as spreading the flame at a wide angle4 ---------------------------------------- -------------------------------- ,,up-,,to-,,date ,,practical ,,hand ,,books ,fine paper1 profusely illustrated1 silk cloth stiff covers1 leather style limp1 all titles in gold1 size #ex#h inches4 ,cloth styles #a4jj1 leather #a4ej4 ,questions and ,answers for ,automobile ,students and ,mechanics4 ,by ,thomas ,h4 ,russell1 ,a4 ,m4 ,m4 ,e4 #fjj ,questions and ,answers4 ,automobile ,troubles and ,how to ,remedy ,them4 ,by ,charles ,p4 ,root1 ,ex-,editor of ,motor ,age4 #bej pages4 ,practical ,hand ,book of ,gas1 ,oil and ,steam ,engines4 ,by ,john ,b4 ,rathbun1 ,m4 ,e4 ,all styles engines1 all fuels4 #cgj pages4 ,automobile ,driving ,self ,taught4 ,by ,thomas ,h4 ,russell1 ,a4 ,m4 ,m4 ,e4 #bej pages4 ,automobile ,motors and ,mechanism4 ,by ,thomas ,h4 ,russell1 ,a4 ,m4 ,m4 ,e4 #bhj pages4 ,ignition1 ,timing and ,valve ,setting4 ,by ,thomas ,h4 ,russell1 ,a4 ,m4 ,m4 ,e4 #bdj pages4 ,gas ,engine ,troubles and ,installation4 ,by ,john ,b4 ,rathbun1 ,m4 ,e4 #ddj pages4 ,flying ,machines3 ,construction and ,operation4 ,by ,w4 ,j4 ,jackman1 ,m4 ,e41 and ,thomas ,h4 ,russell1 ,a4 ,m4 ,m4 ,e4 #bef pages4 ,a ,b ,c of the ,motorcycle4 ,by ,w4 ,j4 ,jackman1 ,m4 ,e4 #bef pages4 ,motor ,boats3 ,construction and ,operation4 ,by ,thomas ,h4 ,russell1 ,a4 ,m4 ,m4 ,e4 #bhh pages4 ,moving ,picture ,making and ,exhibiting4 ,by ,john ,b4 ,rathbun1 ,m4 ,e4 ,construction of ,dwelling ,houses and ,bungalows4 ,by ,u4 ,m4 ,dustman4 ,estimates and specifications for modern low priced homes4 ,cloth only4 ,dustman's ,book of ,plans and ,building ,construction4 ,by ,u4 ,m4 ,dustman1 ,licensed ,architect4 ,plans1 specifications and estimates complete of #aej buildings4 #bdj large #iac pages4 ,cloth styles only4 ,price #b4jj4 ,,ignition1 ,,timing and ,,valve ,,setting ,illustration ,by ,,thomas ,h4 ,,russell1 ,a4 ,m4 ,m4 ,e4 ,revised and extended by ,,john ,b4 ,,rathbun1 former editor of 8,ignition and ,accessories40 ,pocket size1 #bdj pages1 fully illustrated4 ,a comprehensive illustrated ,manual of self-instruction for the use of ,automobile ,owners1 ,chauffeurs1 ,aviators1 ,stationary ,engine ,operators1 and ,repair ,men4 ,especially adapted for the use of driving schools and students4 ,,contents ,common ,battery ,systems describing the battery1 spark coil1 and timer4 ,many circuit diagrams and systems4 ,master ,vibrators1 etc4 ,primary and ,storage ,cells--,description1 systems of connection1 charging circuits1 care and repair1 etc4 ,modern ,battery ,systems--,including ,delco1 ,remy1 ,atwater-,kent1 etc4 ,application of ignition apparatus to self-starting circuit4 ,low ,tension ,magnetos--,low tension magnetos as applied to the make and break system4 ,fundamental principles of the magneto and its circuits4 ,high ,tension ,magnetos--,general circuits of ,single1 ,duplex1 ,dual and ,two ,point4 ,shuttle and inductor types4 ,timing1 ,mounting1 ,repair and operation4 ,drive speeds for multi-cylinders4 ,ignition ,timing--,battery spark1 magneto1 and the four stroke cycle principle4 ,firing order of multiple cylinder engines4 ,firing order of the ,gnome ,rotary ,motor4 ,ford ,car ,ignition ,system1 etc4 ,valve ,setting and ,timing--,valve lap4 ,cause of variations in the valve setting of different motors4 ,table of ,valve ,setting and ,timing for ,prominent ,modern ,automobiles1 also of leading ,aero ,motors4 ,valve repairs and adjustments4 ,timing ,ford ,cars1 etc4 ,self-,starting and ,lighting--,circuit diagrams and elements of prominent self-starting and lighting systems4 ,motor and generator principles1 construction and repair4 ,common causes of trouble in the wiring1 batteries1 and electrical appliances of the self-starting system4 ,car wiring diagrams for modern automobiles4 ,,silk ,,cloth1 ,,gold ,,stamping #a4jj ,,flexible ,,leather1 ,,gold ,,stamping #a4ej ,,automobile ,,troubles and ,how to ,remedy ,them ,illustration ,including ,electric ,self-,starting and ,lighting ,systems with ,wiring ,diagrams ,by ,,charles ,p4 ,,root ,former ,editor 8,motor ,age0 ,pocket size1 #bef pages1 well illustrated4 ,it not only tells you how to locate troubles1 and make repairs1 but shows you4 ,,contents ,trouble ,charts of ,symptoms and ,causes1 followed by detailed ,remedies written in plain comprehensive language1 with many illustrative diagrams under the following chapter heads3 ,back ,firing1 ,causes and ,remedy--,blow ,backs--,carburetion ,troubles--,compression ,cylinder ,troubles--,ignition ,troubles and ,diagrams--,storage ,batteries--,high ,tension ,magneto--,knocks in ,cylinder or ,gearings--,lubrication--,muffler ,troubles--,piston ,troubles--,loss of ,power--,starting ,troubles--,tire ,troubles--,valve ,troubles--,water ,circulation--,non-,freezing ,mixtures--,starting on the ,switch--,noise from ,transmission ,gears--,timer ,trouble and ,remedy--,trouble with ,valve ,tappets--,engine ,hard to ,start--,electric ,starting and ,lighting ,troubles--,overhaul and ,repair of ,car--,self-,starting and ,lighting ,systems1 etc4 ,,silk ,,cloth1 ,,gold ,,stamping #a4jj ,,flexible ,,leather1 ,,gold ,,stamping #a4ej ,,automobile ,,driving ,,self-,,taught ,illustration ,by ,,thomas ,h4 ,,russell1 ,m4 ,e41 ,,ll4 ,b4 ,author of 8,ignition1 ,timing and ,valve ,setting40 8,automobile ,motors and ,mechanism0 8,motor ,boats3 ,construction and ,operation40 ,an exhaustive treatise on the ,management1 ,care and ,operation of ,motor ,cars4 ,pocket size1 #bcj pages1 liberally illustrated1 handsomely bound in black seal flexible leather1 round corners1 red edges4 ,,contents ,automobile ,driving--,general ,instructions--,starting the engine--,advancing the spark--,how to change speeds--,use of the ,clutch--,the ,control levers--,principles of gear changing--,the engine as a factor--,use of brakes--,causes of irregular firing--,to avoid side-slip--,the tire bill--,gear missing in speed changes--,engine thumping--,driving on the brake--,how to get the best work out of a motor--,skidding or side-slip4 ,self-tuition ,in driving ,continued--,the initial trip--,charging tanks--,starting the engine--,manipulating the control--,correct mixture--,changing gear--,on the top speed--,withdrawing the clutch--,coasting slopes--,picking up the ,drive--,driving on the reverse--,entering and leaving the garage--,after the drive--,road risks4 ,another lesson in driving--,learning the steering and ,control--,preliminary attention to car--,starting--,changing ,speed--,coasting1 braking and reversing--,sources of side-slip--,to avoid skidding--,non-slip devices--,choice of ,track--,speed limits--,conduct in emergencies--,driving through city traffic--,meeting horses1 cattle and cyclists4 ,difficulty in starting--,symptoms1 causes and remedies4 ,involuntary stops--,causes and remedies4 ,loss of power--,causes and remedies4 ,care and maintenance of motor cars--,private housing--,the garage--,cleaning--,lubricating--,care of tires4 ,care of a car on a tour--,engine treatment--,overhauling the ignition apparatus--,accessories and tools for the tour--,stabling the car4 ,laying up a car--,cleaning the engine--,the transmission gear--,connections and chains--,the lubricators--,tire treatment--,laying up for the winter4 ,gasolene--,its properties and ,economical ,use--,production of ,gasolene--,its distillation--,specific gravity--,vaporization experiments--,proper design and function of the carbureter--,the ton mileage ,method of arriving at economy--,quality of the fuel4 ,gasolene hints and tips4 ,operating mechanism of a modern car4 ,choice of a car1 ,etc4--,considerations of price and cost of maintenance--,small and large cars--,new and tried types--,second hand cars4 ,change speed gear--,various forms--,selective sliding gears--,the ,panhard and ,mercedes systems--,gate control mechanism1 etc4 ,don'ts for motor car drivers and tire owners4 ,price1 ,,flexible ,,leather #a4ej ,,cloth ,,binding #a4jj ,gas ,engine ,troubles and ,installation ,illustration ,by ,j4 ,b4 ,,rathbun4 ,b4 ,s4 ,c4 ,e4 ,author of 8,commercial ,vehicles for ,all ,purposes10 8,oxygen--,acetylene ,welding10 etc4 #dbj ,pages1 #aej ,detailed ,line ,drawings and ,illustrations4 ,a book that shows you ,,how ,,to ,,install--,,how ,,to ,,operate--,,how ,,to ,,make ,,immediate ,,repairs and ,,how ,,to ,,keep ,a ,,gasolene ,,engine ,,running4 ,the language is simple--,the illustrations are clear4 ,the book is authentic--complete--up-to-the-minute1 written by an expert who is employed daily as a ,consulting and ,demonstrating ,engineer and ,instructor4 ,nothing has been omitted--,it contains no useless matter--,just the cream of daily experience4 ,two ,folding ,trouble ,charts4 ,,contents ,elementary mechanics--,units of heat and mechanics defined--,fuels--,behavior of gases under the influence of heat and pressure--,combustion--,work done by the expansion of gases--,composition of the charge--,the elementary gas engine--,functions of the cylinder1 piston connections1 rod and crank--,cycle defined--,four stroke cycle1 two stroke cycle1 six ,stroke cycle defined--,functions of ports1 valves1 and cams as applied to foregoing types--,events in cycles--,periods of ignition1 compression1 etc41 outlined--,multiple cylinder engines--,crank relations--,ignition--,flame1 catalytic1 hot tube1 electric 7high and low tension7--,make and break ignition--,batteries--,spark coils1 dynamos--,magnetos--,wiring systems--,timing--discussion of prominent makes of ignition apparatus--,valve gears--,practical construction of valves and valve operating mechanism--,valve timing charts--,location of ports in two stroke cycle engines--,three port1 two-stroke cycle engines--,mixing valves--,carburetors--,manifolds for multi-cylinder engines--,mufflers--,exhaust pots1 etc4--,cooling systems--,purpose of cooling systems--,the radiator--,air cooling--,tank1 hopper and trays--,circulating pumps--,thermo--,syphon--,water vs4 oil--,anti-freezing solutions--,lubrication--,splash1 force feed1 exhaust feed1 properties of lubricating oils1 grease1 pumps1 strainers1 filters1 cups1 connections1 etc4--,details of approved systems--,construction details--,engines for various purposes--,electric lighting engines--,dynamos--,storage batteries--,wiring--,switch ,board--,installation--,engine room arrangement--,foundations--,piping--,sha fting--,hangers1 etc4--,operation--,trouble ,chart for location of troubles--,remedies for trouble--,shop rules--,formulas--,automobile1 motor boat and aero motors1 ,trouble ,chart--,accessories--,operation1 etc41 etc4 ,price1 ,,flexible ,,leather #a4ej ,,cloth ,,binding #a4jj ,,the ,,practical ,,handbook ,,of ,,gas1 ,,oil1 ,,and ,,steam ,,engines ,illustration ,,by ,,john ,b4 ,,rathbun4 ,author of 8,gas ,engine ,troubles and ,installation10 ,editor 8,ignition0--,instructor ,chicago ,technical ,college4 #cgj ,pages1 #aej ,line ,drawings and ,illustrations4 ,this book is the most complete and up-to-the-minute book for the practical man on the subjects of gas1 gasoline1 oil1 and steam engines4 ,oil burners for use in steam engines in a useful feature4 ,special emphasis is placed on farm tractors and their operation1 both oil and steam driven4 ,the engines described are the latest types1 and include the ,diesel1 ,semi-,diesel ,gnome1 ,low and ,turbine types4 ,,contents ,heat and ,power4--,fuels--,calorific ,values of ,fuels--,solid1 ,liquid and ,gaseous ,fuels--,kerosene--,gasoline--,crude ,oil--,producer ,gas--,illuminating ,gas--,coal--,benzol4 ,working ,cycles--,definitions of ,cycles ,indicator ,diagrams--,practical ,use of the ,indicator--,typical ,four ,stroke ,cycle ,engines--,single ,cylinder--,four ,cylinder--,automobile--,opposed ,type--,v ,type--,tandem--,twin ,tandem--,rotary ,cylinder--,radial--,diesel--,knight--,a rgyle--,rotary ,valve4 ,typical ,two ,stroke ,cycle ,engines--,two ,port--,three ,port--,marine--,controlled ,port--,aeronautic--,oechehauser--,gnome ,rotary ,two ,stroke4 ,oil ,engines--,elyria--,marine ,diesel--,installation--,aspiration ,types--,fairbanks ,morse--,kerosene--,carburetion--,semi-, diesel--,combustion of ,heavy ,oils4 ,ignition ,systems--,hot ,tube ,system--,low ,tension ,system--,high ,tension ,system--,details of ,make-and-,break ,batteries--,low ,tension ,magnetos--,high ,tension ,magnetos--,coils--,adjustment--,trouble s4 ,carburetors--,principles of ,carburetion--,jet ,carburetors--,water ,jacketing--,fuel ,supply--,different ,types of ,auto ,carburetors--,adjustment--,carburetor ,troubles4 ,lubrication--,forced ,speed--,splash ,system--,oil ,pumps--,lubrication ,troubles4 ,cooling ,systems--,evaporation ,systems--,radiators--,air ,cooling4 ,speed ,governors--,automobiles--,stationary--, adjustment--,mixture--,control ,hit and ,miss--,mixed ,systems4 ,tractors and ,various ,farm ,engines--,gasoline and ,oil ,tractors--,mechanism of ,various ,types--,steam ,tractors--,plowing and ,threshing ,costs--,plowing ,contests ,data--,two ,speed ,mechanisms--,draw ,bar ,pole--,oil ,carburetors1 etc4 ,oil ,burners--,combustion--,high ,pressure ,system--,low ,pressure ,system--,mixed ,system--,burners for ,furnaces1 ,locomotives1 ,pennsylvania ,type1 ,sheedy ,burner1 ,kirchoff ,burner1 etc4 ,price1 ,,flexible ,,leather #a4ej ,,silk ,,cloth #a4jj ,questions and ,answers ,for ,automobile ,students and ,mechanics ,illustration --,by-- ,thomas ,h4 ,russell1 ,a4,m41 ,m4,e4 ,author of 8,automobile ,driving ,self-,taught10 8,automobile ,motors and ,mechanism40 8,ignition1 ,timing and ,valve ,setting10 8,motor ,boats3 ,construction and ,operation10 etc41 etc4 ,a book of #fjj ,questions and ,answers1 adapted for teaching ,school1 the ,machine-shop or before the ,board of ,examining ,engineers4 ,this is the largest1 the latest and most authentic book of its kind upon the market4 ,prepared especially for ,home ,study4 #aej pages4 ,bound in ,cloth1 ,stiff ,covers--,in fact it is a regular text book4 ,the ,questions and ,answers in this book will be found useful by every ,student and ,mechanic of ,motor ,cars and ,motoring1 as a handy means of reviewing systematic study or in daily work4 ,it has long been recognized that the ,question and ,answer method is most effective in fixing in the memory facts gained by study or problems that confront the ,mechanic in his daily work2 hence it is adapted for the purpose4 ,the more important subjects connected with ,motor ,cars1 are treated individually1 there being a separate set of ,questions and ,answers for each4 ,for the greater convenience of the reader1 the ,questions and the ,answers in each set appear on separate pages2 the ,questions can thus be used alone for self-instruction1 while the ,answers if needed are close at hand for reference4 ,minor subjects are covered in a special ,catechism1 which deals with all the factors which go to make up the power plant of a ,modern ,motor ,car4 ,price1 ,,cloth #a4jj ,,leather #a4ej ,,automobile ,,motors ,,and ,,mechanism4 ,illustration ,by ,,thomas ,h4 ,,russell1 ,m4 ,e41 ,,ll4 ,b4 ,author of 8,automobile ,driving ,self-,taught40 8,ignition1 ,timing and ,valve ,setting40 8,motor ,boats3 ,construction and ,operation10 etc ,pocket size1 #bfe pages1 ,blue flexible leather1 round corners1 red edges1 fully illustrated ,,contents ,the ,internal ,combustion ,engine--,principles and ,construction--,production of the fuel mixture--,function of the carbureter--,the cycle of operations--,cylinders1 piston and rings--,shafts and bearings--,ignition apparatus--,single and multi-cylinder engines--,the two cycle engine--,valves and their functions--,silencing the exhaust--,engine hints and tips--,a ,typical ,modern ,motor--,detailed description of construction--,governing and ,governors--,the centrifugal governor--,throttle valves--,governing and control--,the hit-or-miss governor--,carbureters--,the float-feed principle--,the float chamber and jet--,various types of modern construction--,quality of mixture--,flooding the carbureter--,carbureter troubles and adjustments1 etc4--,transmission ,mechanism--,the ,clutch--,various forms in use--,positive and friction clutches--,plate or disk clutches--,the combined disk and cone type--,expanding clutches--,clutch troubles1 etc4--,gear or ,gearing--,belt and chain gearing--,friction gear--,spur or tooth gearing--,spiral1 helical1 worm and bevel gearing--,epicyclic gear--,infinitely variable gear--,differential or ,balance ,gear--,its functions--,shafts and their ,functions--,the crankshaft1 half-speed shaft1 countershaft1 etc4--,lubrication and ,lubricators--,pumps and their ,purposes--,motor ,misfiring1 ,causes and ,remedies--,noises in the ,motor1 ,causes and ,remedies--,motor ,overheating1 ,causes and ,remedies--,electric ,motors--,principles and operation--,steam ,cars--,the engine1 generator1 reverse gear1 etc4 ,price1 ,,flexible ,,leather #a4ej ,,cloth ,,binding #a4jj ,a ,b ,c of the ,,motorcycle ,illustration ,by ,w4 ,j4 ,,jackman4 ,m4 ,e4 ,author of 8,facts for ,motorist10 8,crushed ,stone and ,its ,uses10 and ,similar ,books4 ,pocket ,size1 #bej pages1 fully ,illustrated1 ,leather and ,cloth1 ,round ,corners1 ,red ,edges4 ,a 8,show ,how0 ,book for ,owners and ,operators of ,motorcycles4 ,,contents ,inception and ,evolution of the ,motorcycle--,modern ,machines and their ,vital ,parts--,how to ,master the ,mechanism--,production and ,application of ,motive ,power--,construction and ,operation of the ,carbureter--,what the ,carbureter ,does--,ignition ,systems--,batteries and ,magnetos--,practical ,methods of ,handling--,various ,types of ,motors--,theory and ,effect of ,internal ,combustion--,troubles of all ,kinds and ,how to ,avoid or ,overcome ,them--,lubrication ,methods--,transmission or ,drive ,systems--,how to ,compute ,horse ,power--,relation of ,power and ,speed--,weather ,effects on ,gasolene ,engines--,cost of ,maintenance on ,basis of ,mileage--,some ,dont's that will save ,time and ,money--,selecting a ,motorcycle--,hints for the ,buyer--,what an ,owner should do on receiving a ,new ,machine--,the ,first ,ride4 ,price1 ,,flexible ,,leather #a4ej ,,cloth ,,binding #a4jj ,,dustman',s ,,plan ,,book and ,,complete ,,modern ,,estimator of ,,general ,,building ,,construction ,by ,u4 ,m4 ,dustman1 ,licensed ,architect1 ,editor of 8,the ,progressive ,builder40 #bej pages1 #iac inches1 ,several ,books ,combined in ,one4 ,invaluable to the ,contractor1 ,builder or ,layman4 ,illustration ,cloth ,binding1 ,white ,foil ,stamping1 ,price #b4jj ,,contents ,designs and ,suggestions--,geometrical ,problems ,illustrated--,roof ,trusses ,illustrated--,rafter ,diagrams--,construction ,diagrams--,stair ,work ,diagrams--,stair and ,handrailing ,tables--,window ,frame ,work and ,diagrams--,store ,front ,problems ,illustrated--,brick ,work ,construction and ,tables--,window ,frames for ,brick ,walls--,general ,construction ,problems1 ,concrete ,work1 ,arches1 ,brick ,work1 ,mill ,construction1 ,beams1 ,columns and ,splices1 ,framing1 ,drafting1 ,properties of ,woods and ,metals--,plastering--,painting--,roofs- -,tables of ,mensuration--,engineering ,tables of ,beams1 ,columns1 ,channels1 etc4--,tables of ,rafters--,building ,terms--,builders' ,arithmetic--,how to ,read ,plans--,detailed ,estimates of various mechanical departments--,complete ,detailed ,specifications ,form--,concrete ,mixing1 ,construction of ,houses1 ,barns1 ,garages1 ,silos1 ,sidewalks1 etc4--,photographs1 ,plans and ,elevations of ,many ,houses1 ,barns4 ,public ,buildings1 ,out-buildings1 etc4 ---------------------------------------- -------------------------------- ,,transcriber',s ,,notes #a4 8,baum0 was consistently misspelled as 8,beaum04 ,did not correct4 #b4 ,the spelling of words such as 8distributor_/distributer0 and 8carburetor_/carbureter0 was inconsistent4 #c4 ,the section and paragraph numbers are not always sequential4 #d4 ,changed 8may read0 to 8may be read0 on p4 #bb4 #e4 ,changed 8engine is instrument0 to 8engine is an instrument0 on p4 #bg4 #f4 ,changed 8use in temperature0 to 8rise in temperature0 on p4 #cb4 #g4 ,changed 8air the same temperature0 to 8air at the same temperature0 on p4 #eb4 #h4 ,changed 8alcohol than for in the neighborhood0 to 8alcohol in the neighborhood0 on p4 #ee4 #i4 ,changed 8fuel heated0 to 8fuel is heated0 on p4 #ef4 #aj4 ,changed 8moving ports40 to8moving parts40 on p4 #fd4 #aa4 ,changed 8reading for the succeeding suction stroke0 to 8ready for the succeeding suction stroke0 on p4 #gf4 #ab4 ,changed 8inlet shots0 to 8inlet slots0 on p4 #abd4 #ac4 ,silently corrected typographical errors4 #ad4 ,retained anachronistic and non-standard spellings as printed4 #ae4 ,enclosed italics font in underscores4 #af4 ,enclosed bold font in equals4 #ag4 ,superscripts are denoted by a caret before a single superscript character or a series of superscripted characters enclosed in curly braces1 e4g4 ,mr4 or ,mister4 #ah4 ,subscripts are denoted by an underscore before a series of subscripted characters enclosed in curly braces1 e4g4 ,h#b,o4