US1431473A

US1431473A - Internal-combustion engine

Info

Publication number: US1431473A
Authority: US
Publication date: 1922-10-10
Anticipated expiration: 1939-10-10

Description

R. M. LovEIoY.

INTERNAL COMBUSTION ENGINE. APPLICATION FILED MAR- 29, IIl.'

R. M. LovEJoY.

INTERNAL GOMBUSTIGN ENGINE.

APPLICATION FILED MAR. 29, IBI?.

1,431,473. Patented oef. 10,1922.

2. SHEETS-SHEET 2.

Fig. 2.

Invenfor. Q FICIIph- M. Lovejoy byaw MQW Ays.

Patented Oct. l0, 1922.

UNITED STATES RALIPH M. LOVEJOY, OF MEREDITH, NEW HAMPSHIRE.

INCLERNAL-COIlVIIBlll'S'lIONl ENGINE.

Application filed March 29, 1917. Serial No. 158,378.

To all Iwhom may concern:

Be it known that l, RALPH M. LovEJoY, a citizen of the United States, and resident of Meredith, county of Belknap, State vof New Hampshire, have inventedan Improvement in Internal-Combustion Engines, of

which the following` description, in connec-` cient in operation and lighter-in construction than those heretofore used for the purpose of providing an engine which will be especially adapted for use in aeroplanes, light automobiles and for similar purposes.

With these ends in view one of the principal objects of the invention is to provide an improved means for vaporizing the fuel in an engine of the Diesel type in which the liquid fuel is forced into the combustion chamber during the compression stroke of the piston when the latter is compressing a charge of air taken in during the suction stroke of the piston.

ln engines of this type the fuel is usually supplied to the fuel chamber by a pump which forces it in under great pressure and the amount of fuel which is intermittently supplied 4by the pump to the fuel chamber is regulated by adjusting the stroke of the pump. ln the usual construction the pump draws in a charge of liquidfuel by suction against the action of gravity. If any consideral'ilequantity of air happens to be drawn into the pump it will by reason of its elasticity prevent proper action of the pump.

`More especially diiculty may be encountered in starting up the engine if there is no fluid between the pump and the fuel delivery chamber.

Another objectof the present invention is to provide means for preventing ,air from entering the pump and passing through the saine into the passages leading to -the'fuel delivery' chamber. This is accomplished in the present invention by providing a pump having a fluid chamber with a piston reciprocable therein, the inlet port of said chamber extending upwardly to receive fuel fed to it by gravity alone, means being provided for so operating the valve in the admission port as to open the same during a portion of the suction'stroke of the piston and to retain the same open during a part of the compression stroke thereof, so that any air bubbles or debris which may be drawn into the Huid chamber ofthe pump will be forced from it before the compression stroke of the pump becomes effective to deliver fuel through its delivery port to the engine. The delivery port as is usual in engines of this type is provided with a check valve for preventing the return of fuel to the pump.

A further feature of the invention conslsts in providing means for regulating the action of the admission Valve to control the amount of fuel delivered to the engine instead of regulating the stroke of the pump piston as is usual in devices of this character.

\ Another object of the invention is to provide means for intermittently supplying a measured amount of compressed air to the fluid delivery chamber of an engine of the type above described so as to correlate more effectively the air supplied to the fuel delivery chamber to the demands of the engine and to prevent wastage of the compressed air. It is well known that in operating engines of the Diesel type there is a great wastage of the compressed air which is used to force the fuel into the cylinder, for in practice it is necessary to force the fuel into the cylinder against a pressure of six hun-- dred pounds or more per square inch and to do this air under a pressure of from 1000 to 1200 pounds is maintained in the fuel delivery chamber. Where the air is used under lsuch high pressure any looseness of the valve or sticking of the valve in its operation causes an enormous, wastage of compressed air. As a consequence of this wastage it is often necessary to employ unusually large compressors or to work the usual compressors harder, thus consuming a considerable amount of energy. tion contemplates overcoming these defects by providing means for controlling the amount of air supplied to the fuel delivery chamber in co-ordination with the action of apump which delivers fuel to the fluid delivery chamber. ln the preferred embodiment of the invention disclosed herein such' a control is effected by providing a valve in The present inven-v4 the conduit leading. from the compressed air tank to the fuel delivery chamber and actuating said valve by, or in synchronism with, the reciprocation of the pump piston upon its compression stroke.

A preferred embodiment of my invention is illustrated in the accompanying drawings in which,

Figure 1 is a view, partly in vertical section, of the cylinder and cylinder head, the pump for supplying the fuel to the cylinder and the means for supplying compressed air to force ythe fuel into the air which is compressed within the cylinder,

thereby to form an explosive mixture, and,

Fig. 2 .is a vertical sectional view, on an enlarged scale, of the upper portion of the cylinder and piston, and the delivery chamber and valve mechanism for supplying fuel to the cylinder. y

In the engine shown in the accompanying drawings the cylinder 1 is mounted upon a base 2 which may form the upper part of the crank case, the base 2 being` supported upon suitable bed pieces The usual crank shaftA L1? is mounted in suitable bearings not shown and has a crank 5 connected to a piston rod G which is connected at its opposite end to a piston 7 of the usual type. rlhe cylinder 1 is provided at its upper end with a flanger 8 having a series of parallel preferably concentric ribs 9 to receive complementary ribs upon the cylinder head.

The cylinder 1 may also conveniently be provided with a flange 10 to form a wall of a jacket. A sleeve 11 inclosing the flanges 8 and 10, secured thereto by

suitable collars

12, 13, may be employed to form a water jacket for the cylinder. The cylinder head 14, which preferably is constructed of aluminum, may be cored to provide a water chamber or acket 15 which may communicate with the acket surrounding the cylinder by suitable ports 16. The lower face of the cylinder head is provided with a series of parallel .preferably concentric ribs 17 complementary to the ribs 9 on the flange 8 of the cylinder and adapted to be forced tightly therein by hydraulic pressure or otherwise, the parts being secured together by suitable bolts, not shown.

In the embodiment of the invention disclosed herein the fuel delivery chamber 18 comprises an elongated cylindrical chamber formed in a block 19 which is provided at its lower end with a reduced cylindrical portion 2O having screw threads 21 engaging complementary screw threads in the walls of a central aperture in the cylinder head 14. The lower end of the chamber 18 is provided with a tapered, preferably conoidal wall 22, the apex of which communicates with a cylindrical aperture 23 forming an inlet opening leading from the delivery chamber 18 to the combustion chamber 24 of the cylinder 1.

The inlet port 23 is normally closed by a valve 25 having a conoidal portion 26 to engage the conoidal wall 22 at the bottom of the fuel delivery chamber and which forms a valve seat. The valve 25 is also provided with a cylindrical extension 27 which eX- tends preferably centrally into the inlet aperture 23 and desirably projects nearly through said aperture. The body 28 of the valve 25 desirably is cylindrical in form and has an annular rib 29 located within the lower end of the cylindrical portion of said delivery chamber adapted to engage the inner wall of the delivery chamber 18 and guide lthe lower end of the valve in its recip- 'rocation, said rib being provided with apertures 30 to permit the compressed airto flow freely past said rib.

In order that a pocket 31 may be provided beneath the rib 29 of sufficient capacity to receive more than the maximum charge of fuel delivered to the cylinder the lower end 32 of the body 28 of the valve is reduced to a smaller diameter than the main body of the valve but sufficiently larger than the aperture to form the valve 25. The upper end of the valve body 28 is reduced and screw threaded to receive a cap 33 which is provided at its upper end with an extension forming a journal for the stem of a supplementary valve.

A spring 35 seated at its lower end upon the cap 33 and bearing at its upper end against a head 36 screwed into the upper end of the block 19 serves normally to hold the valve 25 in closed position.

The valve thus described is substantially like those used in the usual Diesel engine, in which the fuel is introduced into the fuel delivery chamber .through a conduit 37 leading to the lower portion of the fuel delivery chamber, while compressed air, under a pressure of one thousand to twelve hundred pounds per square inch, is introduced into the upper portion of the chamber through the conduit 38.

Any suitable means may be provided for cansino' a jet of air or other gaseous fluid under pressure to impinge upon the fuel as it passes into the cylinder. This jet may be caused to strike the fuel directly tangentially, or otherwise, but desirably is so arranged as to discharge axially through vthe inlet aperture 23, suitable means preferably being provided to produce the jet of compressed air an instant before the fuel is released and to continue an instant after the valve controlling the admission port is closed.

In the preferred embodiment of the invention illustrated herein this is accomplished by providing a jet aperture or port 40 lead ing centrally through the extension 27 of the valve 25 and communicating with a supplemental chamber 41 within the body 28 of the valve 25. The port 40 is controlled by a supplemental valve 42 which has a stem 43 extending through the journal 34 `in the cap 83 of the main valve and also through the head 86 of the block 19. In order to render the journal of the valve stem 43 tight a stuiiing box may be provided and as shown herein comprises a cap `44 screwed upon an extension 45 of the head 86 and inclosing suitable stuliing 46. rThe valve stem 43 is provided with an enlarged portion, or collar, 47 located within the cap 33 of the main valve and adapted to have a slight reciprocating movement therein, the upper face of said enlarged portion or collar 47 being adapted to engage the under face 48 of the inner wall of said cap.

Suitable ports 49 lead from the chamber 18 through the cap 33, and the body of the valve 42 may also desirably be provided with grooves 50 to :permit `the compressed air to flow freely from the delivery chamber 18 into the supplemental chamber 41, so that, when the supplementary valve 42 is open, a jet of compressed air or other gaseous fluid under pressure will be projected throughthe port 40'centra-lly of the inlet aperture 23'.

The supplemental valve 41 may be operatedby the usual mechanism for operating the fuel controlling valve of a Diesel engine. As illustrated herein a head 51 is screwed upon the upper end of the valve stem and is engaged by a helical'spring 52 which surrounds at its upper end a boss 58 upon the offset end 54 of a bracket 55 which is secured to the side of the block 19 by screws 5G.

By reason of this construction the valve 41 is normally held seated by the spring 42 While the main valve 25 is forced against its seat by the joint action of the springs and 52. Any suitable means may Vbe provided for raising the valves 41 and 25 in timed relation to the reciprocation of the piston to deliver` fuel to the cylinder. its illustrated herein the valves are actuated by a lever 57 which is pivotally mounted upon stand 58 supported by the cylinder head and extends at one end beneath the collar 51 on the,y valve stem 43 and at its other end is connected to suitable actuating mechanism, `which is conventionally lllustrated herein as a linlr 59 having an l.- shaped foot 60 extending beneath a suitable cam 61 upon the usual cam shaft '82 which is driven from the main cranl shaft by

gears

63, 64 having relative diameters of one to two, the cam 60 being so located that fuel will be delivered to the cylinder at the end of the compression stroke.

In the operation of the device the actu" ation of the vlever 57 raises the valve stem 43 and the valve 41 thus permitting compressed air to flow through the port 40 into the cylinder. Immediately however, after the valve 41 is unseated the upper end of the collar engages the underface of the cap and further upward movement of the valve stem raises the valve 25 from its seat and permits the fuel which has accumulated in the fuel chamber 32 to flow through the inlet aperture i By reason however, of the fact that the et of compressed air is already established he liquid fuel is instantly vaporized as it passes into lthe iield of said jet of compressed air.

is soon as Ythe cam 61 releases its engagement with the foot 29 of the link 59 the

springs

52 and 85 force the valves 41 and 25 against their seats. rThe action of these springs is almost simultaneous but that of the spring` 35,' which desirably is a, stronger spring, will cause the valve 25 to seat slightly before the valve 41 is forced to its seat so that the central jet of compressed air is maintained from a period slightly before the opening of the valve 25 until an instant after it is closed, thus effectively v porizing all of the liquid which through the inlet opening 28.

Heretofore charges of fuel have been supplied intermittently to the fuel delivery chamber 18 by a pump, the piston of which is reciprocated intermediate of the reciprocations of the valve which controls the inlet passage leading from the fuel delivery chamber totho cylinder, and in order lto vary the amount of fuel supplied to the en gine under different ruiming conditions it has been customary to vary the length of ytrol-nz of 'the pump piston.

Ainasmuch as the amount of fuel delivered to the auxiliary fuel chamber at each stroke is a very small quantity, a very delicate adju 'lent of the str l. a of the piston is rehe present invention contemplates le p `ovision of a pump in which the piston i p ii'en uniform reciprocation, means bein.' provided to o ntrol the fuel supplied to th pump. said ontrolling means being adjuuable either manually or automatically to accord with the demands of the engine under different ruiming conditions.

ln the illustrative embodiment of the in- 4 vention herein disclosed the pump is shown comprising a vertical casing 65 having 'an upwardly extending inlet 66 and a preferably downwardly ei'tending outlet 67 from which the conduit 84 leads to the lower portion of the fuel delivery chamber 18. A spring` actuated cheek valve 68 is provided in the outlet port to prevent fluid being forced baclr through the conduit 87 into the pump casing 65. The casing G5 is provided with an extension G9 forming a journal for the pump piston 70, a suitable stuffing box 71 being provided to prevent leakage.

The piston is provided on the outside of the casing with a block 7 2 which is pivotk ally connected to a pitman 7 3 which is reciproeated from a cam 7e; on the crank shaft 60. In the construction disclosed herein the inlet end 6G of the casing G5 is connected to a casting 7 which is provided with a conduit 7 6 connected by a pipe 77 with a fuel reservoir 7 8 which is located at a higher level and preferably directly over the conduit 7 6. The casting 7 5 is provided at the lower end of the conduit 76 with a valve seat 79. A. valve 80 is normally forced against the valve seat 79 by a spring 81, which is seated at its lower end upon the upper end of the casing 65. The valve 80 has a valve stem 82 ex:- tendingl through a suitable ournal 83 in said casing. a stufiing box Sil preferably surround ing the valve stem to prevent leakage through the journal.

rllhe valve 8O is operated through a lever, preferably a bell crank lever S57 pivotally mounted upon a bracket 86 which may be integral with, or secured to, the casing 75, one arm S7 of said lever engaging the end of the valve stem 82 and the other arm Sti of said lever depending into the path of an actuating means, preferably an arm 89 extending upwardly from the block 72 on the pump piston 70.

ln order to provide for the adjustment of the valve operating means the bell cran; lever preferably is pivotally mounted upon an eccentric 90 carried by a shaft 91 rotatably mounted in the bracket 2G, the shaft 91 having an arm 92 which may be oscillated to adjust said eccentric by a link 93, which may be connected to a lever for manual opera tion, or may be connected to suitable automatic regulating means such the governor of the engine.

By rotarily adjusting the shaft 91 the fulcrum of the bell crank lever 85 is changed so that the relation of its arm 88 to the arm S9 on the piston block may be varied to con trol the time during which the valve 8O open.

The arm 88 ofthe bell crank lever S5 desirably is so positioned that the arm 89 which projects from the block on the piston, will not engage said bell crank lever to actuate the valve 8O during the initial portion of its stroke but will open the valve during the latter portion of the suction stroke of said pump piston.

When the piston moves in the opposite direction, upon its compression stroke, the valve 81 will be prevented from closing until an equal portion of the compression stroke has been made. Obviously, until the valve 81 is closed the piston 70 will force the fluid which has entered the casing 65 back through the conduit 76 into the reservoir 78 but as soon as the valve is closed will force the fluid through the outlet valve 68 into the conduit 37 and thence to the fuel delivery chamber.

By regulating the position of the fulorum of the bell crank lever 85 the action of the valve 81 may be very delicately adjusted so that a predetermined portion of fuel will be forced into the fuel delivery chamber upon every compression stroke of the pump piston and a uniform operation of the engine thereby insured.

ln pumping the fuel into the fuel delivery chamber by reciprocating pumps which raise the fluid from the main reservoir against the action of gravity, air sometimes is drawn into the pump7 and,l because of its extreme compressibility interferes with the action of the pump. By the present invention these objections are entirely eliminated since in the first place the fuel is delivered to the pump by the action of gravity and any bubbles of air which may be present in the fuel will immediately rise to the surface.

or secondly if drawn into theV casing of the pump will be quickly expelled therefrom during the early part of the compression stroke before the valve 81 is seated, also any light dbris which may have been drawn into the pump will likewise be discharged and will not be forced into the engine.

@ne of the principal objects of the invention as heretofore pointed out is to pro-y vide means for supplying to the fuel delivery chamber a measured amount of air or other gaseous fluid under pressure, thereby avoiding vvastage of compressed air which occursI mainly during the operation of the engine at a slow speed when the valve which opens the inlet leading from the fuel delivery chamber to the cylinder is retained open for a much longer period of timethan when the engine is working at its normal high speed.

rllhe means for supplying compressed air to 'he fuel delivery chamber which is conventionally illustrated in the accompanying drawing comprises a compressed air tank 94, which may be connected with a suitable com pressorj not shown, and which delivers the air through a conduit 95 to the conduit 38 which communicates with t-he upper portion of the fuel delivery chamber 18. In the present invention a valve actuated in synchronism with the reciprocation of the pump piston 7 0 is interposed between the

conduits

95 and 38 so that compressed air is allowed to pass into the fuel delivery chamber only during the compression stroke of the pump pistom and preferably during only a portion thereof the valve 101 being closed before the inlet valve 25 is raised from its seat, so that the amount of compressed air which can be delivered to the cylinder at each charge is that contained in the conduit 38 and the dome 104;. By reason of this construction, therefore, a measured charge of 'the same from its seat.

air is introduced into the cylinder at each stroke irrespective of the speed at which the piston moves.

In the construction illustrated in the accompanying drawing a valve casing' or union 96 is provided with nipples 97,v 98 connected respectively to the

conduits

95 and 38, said valve casing having a lateral extension 99 forming a journal for the stem 100 of a valve 101 adapted to engage a suitable valve seat 102. In the embodiment shown herein the valve stem 100 is shown as extending .into the path of the arm S9 which projects upwardly from the block 72 of the pump piston so that said arm during the movement of the piston on its compression stroke will engage said valve and force The valve is normally maintained upon its seat by a helical spring 103 engaging the under face of the valve 10]. and at its opposite end seated upon the opposite Wall of the union.

If the capacity of the conduit 38 and the fuel delivery chamber 18 is insuiiicient to contain enough air under pressure efhciently to force the fuel into the cylinder a dome 101i may be connected to the conduit 38 by a suitable T-connection 105.l It vvill be obvious that by reason of this construction a measured `amount'of compressed air is permitted to iiovv into the conduit 38 or fuel delivery chamber 18 and the dome 109 and that the compressed air will be thus introduced simultaneously with the forcing of the fuel into said chamber by the action of 41 are actuated to introduce liquid fuel into the cylinder and @hiring` its introduction to atomize the same.

Inasmuch as the effective pressure in the auxiliary chamber will be reduced during` the injection of Afuel into the cylinder the Wastage of air Will be greatly reduced since the pressure Within the fuel delivery chamber 18 will be at more nearly that in the combustion chamber'.

By the elimination of this Wastage a smaller compressor may be used for supplying the compressed air to the engine and consequently a considerable amount of power saved.

It Will be understood that the embodiment of the invention disclosed herein are of an illustrative character and are not restrictive and that various modifications in structure, form and arrangement of parts may be made Within the meaning and scope of the following' claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In an internal combustion engine comprising a combustion chamber and fuel supplying means, a reservoir containinga supply of air under substantially constant pressure, and means for causing` a measured charge of air therefrom to inject a charge of fuel from said fuel supplying` means into said combustion chamber. i

2. In an internal con'ibustion engine comi prising1 a cylinder and piston and fuel supplying means, reservoir containing a supply of air under substantially constant pres* sure, a conduit leadingtherefrom to said cylinder, means for transmitting` measured amount of air to said conduit intermediate of the compression strokes of the piston and means for causing' the con'iprcssed air in said conduit to inject fuel from said fuel supplying' means into said cylinder upon the compression strokes of said piston.

In combination with an internal combustion engine comprising a cylinder and piston and fuel supplying` means, a reservoir containingv a supply of air under substantially constant pressure, a conduit leading therefrom to the cylinder. means operable intermediate of the compression strokes of said piston to transmit a i ieasured charge of fuel and a measured amount of air to said conduit and means for causing the compressed air in said conduit to inject said fuel into the cylinder upon the compression strokes of the engine.

In an internal combustion engine comprising` a cylinder. a piston rcciprocable therein, a fuel delivery chamber located in p orrimity to said cylinder, an inlet passage leading' from said delirerv chamber to said cylinder, means for sup L,ing a charge of liquid fuel to said delivery chamber, reservoir containing` a supply of ai r under substantially constant pressure, means for introducing a measured ai'uount of air under pressure oui said reserroir into said delivery chamber, a valve in said inlet passage for controlling` the deli'.y y of fuel from said delivery chamber to said cylinder and means operable in conjunction with said valve for projecting; a jet of air under pressure centrally through the cha. i of fuel injected from the delivery chamber into the cylinder.

5. In an internal combustion engine com` prisingj a cylinder. a piston reciproca-ble therein, a f .el delivery chamber in proximity to said cylinder', an inlet rpassage for the fuel leading from the deliveryv chamber to said cylinder, means for supplying charge ofliquid fuel to said delivery chamber, a reservoir containing` a supply of air under Substantially constant pressure, means for introducing` a measured amount of air under pressure from said reservoir into said delivrery chamber, a spring-controlled main valve combustion chamber and means for actuating said valves to open the supplemental valve in advance of the opening of the main valve and to retain the supplemental valve open until after the main valve is closed.

6. ln an internal combustion engine comprising a cylinder', a piston reciprocable therein, a fuel delivery chamber in proximity to said cylinder, an inlet passage for the fuel leading from the delivery chamber to said cylinder, means for supplying fuel to said delivery chamber, a reservoir containing a supply of air under substantially constant pressure, means for introducing a measured amount of air under pressure from said reservoir into said delivery chamber, a main valve in said inlet passage, resilient means normally maintaining said valve seated, a supplemental valve telescopically arranged Within said valve, means for operating said supplemental valve and means operable by said supplemental valve to actuate the n ain valve whereby the supplemental valve will be open in advance of the main valve and Will be closed by said resilient means after the closing of the main valve to deliver a jet of gaseous fluid under pressure into the passving from the delivery chamber to the cylinder.

7 ln an internal combustion engine comprising a cylinder, a piston reciprocable therein, a fuel delivery chamber located in proximity to said cylinder, an inlet passage leading from said delivery chamber to said cylinder, a pump having a fuel chamber', a piston reciprocable therein, means for regulating the fuel chamber of said pump to cause a predetermined amount to be delivered to the delivery chamber upon cach compression stroke of the engine piston, means for adjusting the regulating means whereby the amount of fuel delivered to said fuel chamber may be controlled, means for introducing air under pressure into said delivery chamber, a valve in said inlet passage for controlling the delivery of fuel from said delivery chamber to said cylinder and means operable in conjunction with said valve for projecting a jet of gaseous fluid under pressure into said fuel during its passage fromvtlie delivery chamber into the cylinder.

8. In an internal combustion engine com prising a cylinder, a piston reciprocable therein, a fuel delivery chamber located in proximity to said cylinder, an inlet pas4 sage leading from said delivery chamber to said cylinder, means for supplying fuel to said fuel delivery chamber comprising a pump having a fuel chamber provided With an upwardly extended inlet port connecting with a fuel supply and an outlet port leading to said fuel delivery chamber, means for supplying fuel to the inlet port by the action of gravity, a check valve in said inlet port, means for opening said check valve during the suction stroke of the piston and for preventing the same from closing during a portion of the compression strolre of said piston whereby air bubbles and floating debris Will be expelled from said fuel chamber and a predetermined amount of fuel delivered to said delivery chan ber upon the compression stroke of the engine, means for introducing air under pressure into said delivery chamber, a valve in said inlet passage for controlling the delivery of fuel from the delivery chamber to said cylinoer and means operable in conjunction with said valve for projecting a jet of airunder pressure into the fuel during its passage from the delivery chamber to the cylinder.

9. In an internal combustion engine comprising a cylinder, a piston reciprocable therein, a fuel delivery chamber located in proximity to said cylinder, an' inlet passage leading from said delivery chamber to said cylinder, means for supplying a measured charge of liquid fuel to said delivery chamber, means for introducing air under pressure into said delivery chamber and a reservoir communicating with said fuel delivery chamber acting to maintain a constant presq sure upon the fuel in said fuel delivery chamber, a main valve in said inlet passage for controlling the delivery of fuel from said delivery chamber to said cylinder and a supplementary valve telescopically l0-. cated Within said main valve communicating with said fuel delivery chamber and operable in conjunction with said main valve to project a jet of air under pressure into the charge of fuel during its passage from the delivery chamber into the cylinder.

l0. ln an internal combustion engine comprising a cylinder, a piston reciprocable therein, a fuel delivery chamber located adjacent to said cylinder, an inlet passage leading from said delivery chamber t0 said cylinde 1, means including a pump having a reciprocating piston for supplying fuel to said fuel delivery chamber, an air tank for supplying air under pressure to said fuel delivery chamber and a valve operable by said pump piston to cause a measured amount of air to be supplied from said air tank to said fuel delivery chamber.

ln testimony whereof, I have signed my name to this specification.

RALPH M. LOVEJ OY.