US1839792A - Combustible mixture supply for internal combustion engines - Google Patents

Description

Jan. 5, 1932.

G. LAWRENCE 1,839,792

COMBUSTIBLE MIXTURE SUPPLY FOR INTERNAL COMBUSTION ENGINE S Filed July 2, 1928 3 Sheets-Sheet 1 'l 'it I 4; H 27 1 V: v H 23 .Ll E 74 4? 74 P Jan. 5, 1932. V G. R. LAWRENCE 1,339,792

COMBUSTIBLE MIXTURE SUPPLY FOR INTERNAL COMBUSTION ENGINES Filed July 2, 1928 3 Sheets-Sheet 2 G. R. LAWRENCE 1,839,792

Filed July 2, 1928 3 Sheets-Sheet 3 m z z W W TF m Jan. 5, 1932.

'COMBUSTIBLE MIXTURE SUPPLY FOR INTERNAL COMBUSTION ENGINES Patented Jan. 5, 1932 UNITED STATES PATENT OFFICE GEORGE R. LAWRENCE, OF CHICAGO, ILLINOIS Application filed July 2, 1928. Serial No. 289,959.

This invention has reference to certain improvements in means for supplying combustible mixture to internal combustion engines, and also has reference to the mode of operation thereof. Briefly stated the invenplicity and reliability,

tion relates to the foregoing features as applied to internal combustion engines generally. The structure and mode of operation herein disclosed are particularly intended for use with two stroke cycle engines; and more particularly the features of the invention have been devised for use in connectionwith that type of engine illustrated and described in Letters Patent of the United States No. 1,160,419 which was issued to me on N ovember 16, 1915. Inasmuch as, however, the features of the present invention may be advantageously used in connection with many other forms of internal combustion en ines, either two or four stroke cycle, wish it understood that I do not intend to limit the usefulness or scope of my invention to engines of the type particularly illustrated and described in the said earlier patent, except as I may do so in the claims.

The'present invention relates primarily to improvements in the means for introducing the individualized charges of fuel into the different cylinders-together with the relationship w ich such means bears to the general construction and operation of the engine as a whole, as well as to the construction and mode of operation of the fuel umping device per se, and when considere as an independent element.

Generally stated one of the objects of the invention is to provide a fuel pumping and charge delivering mechanism of great simand one-which is adjustable under control of the operator and does not require any lubrication as it operates on the diaphragm principle. Also a device which will meter the fuel charges very accurately as to amount of fuel delivered per cycle.

One of the features of the present invention relates to the provision of an arrangement whereby the actual force for delivering the metered charge of fuel into position for movement to the cylinders is the same as that for subsequently driving the fuel charges into the cylinders.

Other objects of the invention are to provide a very simple construction of device, one which can be very cheaply built in quantities, and especially one which will be extremely rugged and durable, and not liable to get out of order after long intervals of continuous service. Also to provide a very compact arrangement, and one which can be readily incorporated into the general design and arran ement of the engine for which it is intended.

Other objects and uses will appear from a detailed description of the invention which consists in the features of construction and combinations of parts hereinafter described and claimed.

In the drawings:

' Figure 1 shows a vertical section through a construction of engine of the two stroke cycle type, having applied thereto a fuel pump incorporating the features of the present invention, the engine therein illustrated being of the general type of my aforesaid Patent, No. 1,160,419;

Fig. 2 shows a vertical section throu h a fuel pump incorporating the features 0 the present invention, the same being attached to the engine which is shown in fragmentary form, and the drawing being on enlarged scale as compared to Fig. 1;

Fig. 3 shows a horizontal section on the line 3-3 of Fig. 2, looking in the direction of (fhe arrows, and being on enlarged scale; an

Fig. 4 shows a vertical section on the line 4- 1 of Fig. 3 looking in the direction of the arrows.

Referring first to Fig. 1, I have therein illustrated the features of my invention as incorporated in a fuel pump for supplying the needs of a two stroke cycle engine 0 the general type of my aforesaid Patent, No. 1,160,419. This is the engine having the working cylinder 6 which I have shown as being air cooled, and as therefore being pro vided with the cooling fins 7. At its upper end this cylinder has the main air valve 8 which is a rotary valve working in the head portion of the cylinder structure, said valve 8 having a port 9 for the cylinder shown. This air valve 8 is rotated in timed relationship with respect to the rotations of the crankshaft 10. Means maybe provided, as in the arrangement of my aforesaid Patent No. 1,160,419, for changing the timing of the valve 8 with res ect to the crankshaft, such means being optional as far as the features of the present invention are concerned. The engine is also provided with the customary piston 12 and connecting rod 13.

Around the belt of the cylinder there is provided the spent gas or delivery passage 14, which communicates with the interior of the cylinder by means of the exhaust ports 15 when the latter are uncovered by the full downward movement of the piston. The uncovering of the ports 15 takes place just before theLlower limit of piston movement is reached, so that the scavenging operation is performed at the proper time. Immediately after the upward movement of the piston commences the ports 15 are covered or closed, so that the compression stroke may be properl performed.

he fuel pump of the present invention is designated in its entirety by the numeral 16. It includes a body member 17 of generally circular form as shown in Fig. 3, and having at one side of its to a flattened portion which is attached to a Eracket l8 projecting out sidewise from the engine cylinder.

The body member 17 has a downwardly depending flange 19 which is internally threaded to receive a spanner nut 20. This spanner nut 20 when drawn up tight serves to clamp a flange like bottom plate 21 in place,

and the edge portion of this plate 21 serves in conjunction with a shoulder 22 of the body member 17 to clamp the edge of a diaphragm 23 in firm and gas 'tight manner. The top face of the plate 21 is dished out into a concave form as shown in Fig. 2 in particular so as to allow for the needed amount of diaphragm deflection without interference. The bottom face of the body member 17 is dished upwardly and serves to freely accommodate the stop member against whichthe diaphragm rests during the intake or suction stroke 0 the pump, and allows for free circulation of air over the entire top surface of the diaphragm.

The diaphragm 23 is preferably of hard brass about .002".004" thick, and it bows or deflects about in the case of a diaphragm 1 1%" diameter, which diaphragm will have a free clearance of about 1 diameter. The above amount of deflection of the diaphragm may occur without exertion of such an amount of tension thereon as will either require an excessive amount of deflecting force or permanent distortion or injury to the material of the diaphragm itself.

The diaphragm restores itself to its upper limit of returning movement by reason of its elasticity, and without the need of a special spring to accomplish this result. Extending up from the body member 17 there is a boss 24.- which receives a stem 25 extending downwardly therethrough. The lower, portion of this stem is threaded into the boss so that rotation of the stem will serve to force it up or down. The lower end of the stem carries a circular flange 26 which can be retracted into a socket 27 in the bottom face of the body member; and the bottom face of this flange 26 is preferably rounded as clearly shown in Figs. 2 and 4 to conform generally to the curvature of the diaphragm when deflected by the downward movement of the stem 25. Thus, when the stem 25 is adjusted to hold the diaphragm down somewhat below its normal upper limit of restoration, the curvature of the diaphragm as thus held down will conform generally to the form of the lower face of the flange 26 and the diaphragm will therefore suffer no damage under these conditions.

The upper end of the stem 25 may be carried through a stufling box 28 at the upper end of the boss 24; and the projecting end of the stem 25 may be provided with any suitable control connection, generally designated by the numeral 29 in Figs. 1 and 4. This control element serves merely to rotate the stem in whichever direction is desired to raise or lower the flange 26 and thereby either increase or decrease the movement of the diaphragm and thereby control the amount of fuel which will be drawn in and ejected per movement.

In the top portion of the body member 17 there is a chamber 30 into which compressed air is admitted from a connection 31 from any suitable source. The back end of the chamber 30 is closed by the plug 32. At the front end of said chamber 30 there is a tapered valve seat 33, and a poppet or mushroom type valve 34 on the back end of and integral with the stem 35 serves to control said valve opening thus established. A spring 36 serves to retain the poppet valve 34 normally seated in the position shown in Figs. 2 and 3. Reaching forwardly from the chamber 30 is a passage 37 through whichth'e valve stem 35 extends, and within said passage 37 there is located a artition 38 serving as a bearing and guide or the valve stem. Said partition 38 has a series of through passages 39 the front ends of which normally remain open to atmosphere as shown in Figs. 2 and 3. The block 38 terminates short of the rear end of the passage 37 so that there is established a small chamber 40 at said end. This chamber is normally open to the atmosphere. The stem 35 has slidably mounted on its extreme front end another valve member 41 which may be moved over to close the end of the passage 37 and thus seal-the small chamber 40 just referred to. Just in front of the valve element 41 there is'slidably mounted the small cap block 42 on the stem 35. There is a spring 43 on the stem 35 between the valve 41 and the cap block 42. The clearances are such that when the finger 44 is withdrawn to the position of Fig. 2 the cap block-42 and valve 41 may withdraw to the positions shown in Fig. 2. 'When the finger 44 is forced inwardly it first travels with the valve 41 independently of the stem 35, allowing said stem and the valve 34 to remain in the positioned dictated by the spring 36. The valve 41 is thus carried to the seating position and is seated by the spring 43. Immediately thereafter the cap block 42 comes against the end of the stem 35 and further movement of the finger 44 causes the stern 35 and valve 34 to be moved to the left with compression of the spring 43. Thus the valve 34 is opened while the valve 41 remains closed.

The block 42 is operated by means of a finger 44 which is pivoted to the bracket 45 projecting outwardly from the cylinder structure. The upper end of this finger or lever 44 works against a cam block 46 on the shaft 47, which shaft 47 is in turn driven by a gear 48 meshing with the gear 11 already referred to. The driving of the shaft 47 is at such speed that the valve stem is operated once for each working stroke of the engine piston. In the case illustrated, the gears 11 and 48 are one to one so that the valve stem will be properly driven, taking into account the fact that the engine is a two stroke cycle engine.

Reaching down from the body member 17 there is an extension 49. A fuel supply connection 50 leads to the lower end of a vertical riser 51 reaching up through the extension 49, so that the fuel rises to the position of a ball check valve 52 located in an enlargement 53 just below the diaphragm. Thus the incoming fuel is delivered to the bottom face of the diaphragm. There is also another vertical passage 54 reaching down through the extension 49 from the bottom face of the diaphragm and connecting at its lower end to the delivery lead 55 which in turn conneets into the cylinder at the desired point. A check valve 56 seats up against the seat atthe upper end of the passage 54, said check valve 56 being held in the up position by means of a spring 57 on the top end of a stem 58.; said stem being part of a plug 59 at the lower end of the passage 54.

It will be seen that by means of the arrangements just described downward deflections of the diaphragm will cause a pumping action to occur. Each time the diaphragm is forced down by the introduction of airpressure against its top face the fuel which was previously trapped beneath the diaphragm will be forced out through the passage 54, the check valve 56 yielding for that purpose and the check valve 52 seating firmly. Thereafter, as the air pressure is released from above the diaphragm the latter will flex upwards until limited by the stop block 26 and a fresh charge of fuel will be drawn into the space beneath the diaphragm, the check valve 52 yielding for the purpose and the check valve 56 remaining seated. Due to the nature of arrangement these pumping actions can be very rapidly performed. It will be explained presently how a blast of air is made to sweep past the bottom of the check valve 56 just after the fuel has been forced down by the diaphragm so as to sweep the charge of fuel into the engine cylinder.

The air for operation of the diaphragm flows from the passage 37 down through a port 60 to the space above the flange or abutment 26 already referred to. Said flange 26 is in turn provided with one or more ports 61 (one of which appears in Fig. 3) so that the compressed air will be admitted directly to the top face of the diaphragm when the valve 34 is opened. Prior to opening of the valve 34 the valve 41 has seated a ainst the end of the passage 37 stopping the 50w of air outwardly therethrough as long as said valve 41 is fully seated; but immediately upon the unseatlng of such valve by releasing of its stem, the entrapped air will be quickly released to atmosphere so that the pressure on the top face of the diaphragm will almost in stantly drop to atmospheric pressure. This will ensure a very rapid restoration of the diaphragm and corresponding improvement in operation.

Reaching sidewise from the block 38 there is a passage 62 which in turn connects with a down lead 63, and the lower end of said down lead connects with a return horizontal passage 64, all of which are best shown in Fig. 4. The ends of the passages 62, 63 and 64 are plugged as shown in Fig. 4, these passages being initially drilled throu h' as a matter of convenience in manufiicturing. The down lead 63 connects directly with one of the passages 39, (see Fig. :3 in particular),

'but the other passages 39 also serve to deliver air to the down lead 63 because said other passages 39 connect at-their front ends with the small chamber. 40, so that they can deliver air thereto, which air will then return to the down lead through the side-most of the passages 39.

The lower end of the return lead 64 communicates with the verticalpassage 54 at a point directly below the check valve 56 there in, so that the air delivered through the passages 62, 63 and 64 will finally bedelivered through the passages 54 and'55 and thereby freely into the cylinder. The blast of air so delivered past the check valve 56 and into these passages will serve to violently sweep that the delivery of this blast of sweepingair does not take place until after the charge of liquid fuel has been forced down past the check valve 56, since the first action of the onrushing blast of air is to flow through the large port 60 and down against the top face of the diaphragm thereby pumping and forcing the charge of liquid fuel past the check valve 56. Immediately thereafter the pressure will build up along through the passages 39, 62, 63 and 64 sufficiently to cause a heavy rush of air which will constitute the blast needed to sweep the fuel charge out of the passages and into the cylinder.

It will be noted that the air blast just referred to cannot reach the fuel supply line 50 because of the interposition of the two check valves 56 and 52. Furthermore, said blast cannot reach the underside of the diaphragm 23 due to the check valve 56.

It will be noted that I have provided an arrangement whereby a common supply of compressed air serves to perform the two functions of measuring off or metering the predetermined quantity charges of fuel, and also serves to thereafter sweep and deliver them into the engine cylinder: and that this arrangement is also such that the size of these char 'es may be very easily and accurately regulated under the control of the operator, or automatically. The main air supply may be under any suitable amount of pressure, as for example, 50-60 lbs. per square inch. Furthermore, that any suitable source of compressed air supply may be used.

It will also be noted that although I have chosen to illustrate and describe my present invention as applied to a two stroke cycle engine, still it may be used to advantage in connection with other forms and styles of engines. Therefore I do not intend to limit the use or the invention to engines of the two stroke cycle type, except as I may do so in the claims.

It is also to be noted that the engine main air valve 8 is adjustable according tothe principles disclosed in my aforesaid Patent No. 1,160,419, according to the momentary needs of the operation, as regards the amount of air to be retained in the cylinder.

Vhile I have herein illustrated and described only a single embodiment of thefcatures of my present invention, still I do not intend to limit myself thereto, except as I may do so in the claims.

I claim:

1. In a device of the class described, the combination of a diaphragm pump having on one side a connection for the supply of working gas under pressure, and on the other side connections for the supply and delivery of fuel which is pumped, and a cross connection from the working gas pressure side to the fuel delivery connection for the delivery of gas under pressure to the working side of the pump and to the fuel delivery connection, substantially as described.

2. In a device of the class described, the combination of working and pumping chambcrs, a flexible diaphragm separating said chambers in gas tight fashion, a connection for the delivery of gas under pressure to the working chamber, a vent opening in conjunction with the working chamber, a valve member serving the gas connection and said ventand 0 erative to close the vent concurrently with t 1e opening of the pressure gas connection and vice versa, fuel-supply and delivery connections in conjunction with the pumpmg chamber, check valves serving to prevent back flow of fuel through said connections, and a connection from the working chamber to the fuel delivery connection at a point beyond the check valve therein measured in the direction of fuel flow therethrough, substantially as described.

3. In a device of the class described, the combination of working and pumping chambers, a flexible diaphragm separating said chambers in gas tight fashion, a connection for the deliver of gas under pressure to the working chum er, fuel supply and delivery connections in conjunction with the pumping chamber, check valves therein serving to prevent backfiow of fuel therethrough, and means for delivering gas under pressure from the working chamber connection to the fuel delivery connection at a point beyond the check valves therein measured in the direction of flow therethrough, substantially as described.

4. In a device of the class described, the combination of working and pumping chambers, a flexible diaphragm separating said chambers in gas tight fashion, a connection for the deliver of gas under pressure to the working chamber, fuel supply and delivery connections in conjunction with the pumping chamber, check valves therein serving to prevent backflow of fuel therethrough, and means for delivering gas under pressure to the fuel delivery connection at a point beyond the check valves therein measured in the direction of fuel flow therethrough, and concurrently with the delivery of gas under pressure to the working chamber, substantially as described.

5. In a device of the class described, the combination of working and pumping chamhers, a flexible diaphragm separating said chambers in gas tight fashion, said diaphra gm normally moving towards a given restoration position, a movable stop in the working chamber for limiting the restoring movement of the diaphragm therein, a connection for the delivery of gas under pressure to the its Working chuml cr, fuel supply and delivery connections in onj him with the pumping clunuucr, chrclc Yul" therein scrving to prevcni' buck flow oi? incl.thcrcthrough, and menu or rlclivcrinu gas uncler prcssurc to the. furl dcli'vcrv connection no 21 point yoncl the check valve ilicrcin measured in the direction of fuel. flow through the some, and concur ently with the 6 very of gas under pressure. to the working chamber, substantially as described.

6. Ir a device of the. class described, the combination of Working and piunping chainhers, a flexible diaphragm separating said chambers in gas tight fashion. said (linhrugm normally moving towards :1 given rc lorulion posifioln a movable stop in the Working chamber for limiting the restoring movement of the diuplnugun therein. a con I]P"'-l0fi for the dclrvorv of unrlcr pressure to the working chuinher. a valvc iherein, fuel supply unrl delivery conncclions in coniuuclion Willi rho pumping clunnhcr, check valves rlicrci serving to arment the hack lion rolluough. curl con 4 unilconalve fuel l the class ricscriheil, the. Uinm'ion of working nucl pumping chainiicrs, movuhle power delivery element heu ecu said chuznhcrs serving to deliver pumppower from the one in he other While liu'lniningr said chambers isolui'crl from hcr in. tight fashioiu a connection .znirtenl delivery of under n"' ssurc to the Working chumher, incl. snpand delivery connections in conjunction clumping: chamhcr check vol LlIClx-lll SQIVlB Qf to prevent backward flow of fuel thr-rcthrougln and a cross connection worn the pressure gas connection to the fuel delivery connection at a noint hcyond the rhccl: valve ihcrcin measured. in the (limetime of fuel. flow therclhrough, substantially as described.

8. in nclcvicc oi" the class clescriherh the comhinul'ion of Working and pumping churnu momhle power delivery elcmcnt hetween said chambers serving to dcliver pumpinc power from the one to the other While vmainruiningr said chamhcrs isolnreri from each other in gas tight fashion. a connection for the supply or gas under ru'essure to the Working chamhcrz a valve for controlling said connection. incl supplv and. delivery connections in conjunction with rho pumping chamhcr. check valves therein. serving" to prevent backward flow of fuel rhcrel'hmugrh and a connection from the working clmmhcr to fihc fuel delivery connecrion at :1 point hovonri the check valve therein measured in the direction of flow, substantially as described,

9. In. a, device or ho class icsc-ri )ecl, the combination of working i pumpizi hers, u movable powcrklel very o tween them serving to clcll cr pumping povver from the Working to the pum inp; chanr her, said chambers being isol l c om ouch other in gas tight fashion, cccnncclzion for delivery of pumping gas under pressure in the Working chamber, a valve in will connection, fuel supply and delivery connections in conjunction with the pumping; chamber, check valves therein serving: "to prevent hue. flow of fuel therethr'oug and a connection from the pumping gas Cl 4 clarion to blue fuel delivery connection an". l m hcvond the check valve therein moosu l direction of flow suhsizanrially as o 10. In. a device of the ss described. the combination of i WQ Cl'llllllllln 5 one of which. is a work ing chamber and 'ijlic other of which is 5%- pumping church-en e. movnlno clement ho tween said clunubr s serving (ielivcr power i cm lilo WOT lo tho pumping}; ('llfiltlJQl iillil" (l clu'uuhcrs arc scparatecl from each fuel su ip v and delivery conncc'i'i iin conjunction W1 "iilie pumping chumhci; check v'n. ves therein serving to preventhzick Zlow of fuel therethrough, and u conueciion from the working clmrnoer to the fuel delivery connection at a polar. bevoncl the check valve therein measured in the direc tion of fuel flow, substantially as dcscribccl.

11. In a device. of the class described, tho combination of :1 working chmuhcr and a pumping chamhcr, a, movable partition element between said chambers and separating them in substantially gas tight fashion a connection for The supply of gas uncle: pressure to the working chamber, 21 valve in connection for controlling rho some, a gucl supply connection leading to the pumping chamber, a check valve therein for preventingback flow of fuel thorethrough, a "fuel delivery connection leading from the pump inn chamber, a, check valve therein for pre venting hack flow of fueltherethough, cml u connection from the Working chamber to the fuel rlcliverv connection at a point beyond the check valve therein measured in the direction of fuel flow, substantially as described.

12. In n device of the class described ill-3 combination of a. body member, a bottom plate in conjunction therewich serving to establish a rliaphrugm cluinihcr, diaphragm dividing said. chamber working uncl pumping compartments 2; con tion fol-fairs supply of gas under pressure, passages chorefrom tothe working compurhncnl: llfOMFililL a valve in said passages controlling thorn a fuel supply connection loading lo ihe pumping compartment, a check valve the-rein scrw inc; to prevent backward movementof fuel thsrcthrough, a, fuel delivery connection local" ing movement of fuel therethrough, and a connection from the passages leading to the working compartment, to the fuel delivery connection at a point beyond the check valve therein measured in the direction of fuel delivery, substantially as described.

13. In a device of the class described, the combination of a body member, a bottom plate in conjunction therewith serving to establish a relatively thin diaphragm chamber,

a diaphragm dividing said chamber and secured to the edges 0 e chamber in gas tight fashion, a connection for the supply of compressed'air, a passage therefrom to the top face of the diaphragm, a valve eontrollin said connection and normally in closed posimunicating with the top face of the diaphragm to the fuel delivery connection at a point beyond the fuel delivery check valve in the direction of fuel flow, substantially as described.

GEORGE R. LAWRENCE.

tion, means for operating said valve periodically to admit the supply of compressed air to the top face of the diaphragm, a connection for the suppl of liquid fuel, passages scribed.

14. In a device of the class described, the

to prevent backward movement of combination of a body member having a downwardly extending peripheral flange, a

bottom plate threaded up into said flange and member against the bottom face of the bed its marto make contact therewith aroun ginal portion, the marginal portions ofthe body member and the bottom plate and clamped therebetween, a stem threaded through the body member and having on its lower end an en-,

a diaphragm seated between lartgecl portion adapted to make contact with I an limit the upward movement of the diaphragm during restoring movement thereof, means in conpmction with said stem for turning the same to adjust the limit of upward movement of the diaphragm in restoring movement, a compressed gas connection on the body member, passages leading there-' from to the upper face of the diaphragm, a valve in said connections and serving to control the deliver of gas therethrough, other,

connections lea ing from said first mentioned connections to atmosphere and normally open to permit discharge of pressure from t tion to the bottom face of the diaphragm, an inlet check valve therein, a fuel delivery connection from the bottom face of the diaphragm, a delivery check valve therein, and connections leading from the passages come top face of the diaphragm, a fuel inlet oonnec

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