US1951854A - Internal combustion engine - Google Patents

Description

March 20, 1934. WQQLSQN 1,951,854

INTERNAL COMBUSTION ENGINE Filed Oct. 3, 1930 2 Sheets-Sheet l gwoa'ntoz LIONEL f7. NUDLSDALDECEHSED,

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Patented Mar. 20, 1934 PATENT OFFICE INTERNAL COMBUSTION ENGINE Lionel M. Woolson, deceased, late of Detroit, Mich., by Emma F. Woolson, executrix, Bloomfield Village, Mich.,

assignor to Packard Motor Car Company, Detroit,Mich., a corporation of Michigan Application October 3, 1930, Serial No. 486,213

2 Claims.

This invention relates to internal combustion engines and more particularly to engines of the type in which liquid fuel is injected into the combustion chambers.

In engines of the above mentioned type, one method of producing the fuel mixtures is to inject fuel oil charges into air charges, being compressed in the cylinders, through means of injection devices actuated by a cam driven from the crank shaft at a reduced speed. In order to synchronize the injections with the air compression, the cam driving gears are associated so that thecam lobes will actuate the fuel devices when the pistons are in a position nearest that at which maximum efiiciency can be obtained. The angle between the teeth of the gear which is adjusted will determine the minimum timing adjustment, and therefore the regulations of the gearing are several degrees apart on the crank shaft. Under many circumstances such timing of the fuel injections is several degrees before or after the point where they should occur .to produce the maximum engine efficiency. V

An object of the invention is to provide an internal combustion engine in which the injections of fuel oilinto air being compressed in the cylinders can be timed within close limits through adjustment of driving mechanism for the pump actuating cam.

Another object of the invention is to provide an internal combustion engine in which the injections of fuel oil into air being compressed'in the cylinders can be timed through a Vernier adjustment between gearing for operating the pump actuating cam.

A further object of the invention is to provide a cam, for actuating liquid fuel injection devices, which is driven from the crank shaft through a train of reduction gears which can be adjusted from the exterior of the engine casing to vary the cam timing.

" These and other objects of the invention will appear from the following description taken in connection with the drawings, which form a part of this specification and in which:

Fig. 1 is a rear elevational view of an engine, partly broken away and partly in section to show one of the injection mechanisms and the operating means therefor;

Fig.- 2 is a similar view of the fuel actuating cams in a difierent position of the adjustment from that shown in Fig. 1;

Fig. 3 is a fragmentary sectional view taken on line 33 of Fig. 1;

Fig. 4 is a fragmentary sectional view of one of the injection devices associated with one of the cylinders;

Fig. 5 is a sectional view, showing the Vernier gear connection, taken on line 5-5 of Fig. 3.

Referring now to the drawings by characters of reference, 10 represents a barrel type of crank case from which a'plurality of cylinders 11 extend radially, and flanges extending from the cylinders, asindicated at 12, are secured against the crank case by a pair of compression hoops 13. A diaphragm 14 extends transversely of the crank case, in a plane with one of the hoops, and an end cover 15 is removably secured to the rear of the casing by bolts 16. The space intermediate the diaphragm and the rear cover provides a compartment in which is housed a mechanism for actuating fuel injection devices and valve mechanism. 7 p

A piston, as indicated at 17, is arranged within each of the cylinders andsuch pistons are connected to the crank shaft 18 by connecting rods of the conventional design used with radial engines. Each of the cylinder heads is preferably provided with a single venturi passage 19 which extends therethrough at an angleto the axis of the cylinder and. tangentially of the inner wall thereof, such passages serving both as the-air inlet and as the exhaust outlet. Each passage is controlled by valve 20 which is mechanically actuated to open through conventional mechanism-including the rock lever 21 and push rods 22 which extend through the casing 23 and within the crank case, while a plurality of coil springs 24 are associated with each valve and normally maintain them in closed position. Th engine illustrated is of the four-cycle compression ignition type, suitable for propelling airships, and thevalves are arranged to be held open duringthe' exhaust and suction strokes of the pistons and to be closed during the compression and working strokes of the pistons. Due to the arrangement 'of thepassages, air drawn into the cylinders will be caused to rotate, 'and' upon the compression stroke such air columns will continue their rotation. During the compression strokes of the pistons liquid fuel chargesare injected into the rotating columns of air prior to the time the pistons reach top center, and the fuel so injected intermingles with the rotating compressed air and forms an explosive charge which will be ignited by the heat of compression as the compression strokes continue.

In order to project the liquid fuel charges into the cylinders, there is preferably rigidly attached a separate injection device to each cylinder which consists generally of a nozzle section 25 and a pump section 26. Each nozzle section comprises a tubular casing 2'7 having a detachable end which is arranged to be inserted in an aperture in the wall of the cylinder, while flanges 28 extend from the casing and are secured to the cylinder by bolts 29. The casing and its removable end are formed with an axially extending passage into the outer end of which a stop member 30 extends, While the end projecting into the cylinder is flared for cooperation with the head 31 of the valve member 32. The coiled spring 33 surrounds the-valve stem, within the axial passage and normally urges the valve in the direction against the stop member 30, thus urging the valve head to a position of nearest closure. In order to prevent the valve head from striking the wall of the nozzle casing end, the stop' mem-' ber is adjusted inwardly of the axial passage. When such passage is filled with liquid fuel and pressure is exerted thereagainst, the valve will be moved toward the interior of the cylinder, thus opening the outlet space through which the fuel pases in traveling into the cylinder. v V

The pump casing 34 is screwed upon the neck 35 of the nozzle casing, and a barrel 36 is arranged within the pump casing and is held in position by a spacer element 3'7 when the pump casing is screwed upon the nozzle neck. There is a passage extending through the spacer and nozzle neck which establishes communication between the interior of the barrel and the axial passage in the nozzle casing, and a pair of check valves 39 prevent the return of fluid which has once passed into the nozzle section. A collar 39 is wedged upon flanged portions of the pump casing by a nut 40 and provides witlun the pump casing a manifold junction, there being conduit sections 41 connecting such collars. A plurality of ports 42 are provided through the pump casing and the barrel, interiorly of the ring member 39, so that liquid fuel is free to be moved into the barrel and nozzle when the plunger 43 is in a position uncovering such ports. Liquidfuel is preferably moved from a source of supply by means of a low pressure pump (not shown) through thefuel feeding manifold so that the barrels are substantially filled with fuel whenever the plungers 43 uncover the ports42. I

A tappet 44 carried by a guide 45v extends through the wall of the casing into the chamber intermediate the diaphragm and the innerwall, the outer end of such tappet carrying an adjustable piston engaging member 46 while the inner end of the tappet is recessed to receive the head of a rod 4'7. Therinner end of such rod is adjustably associated with a curved seat in a slipper 48 which is pivotally mounted on a shaft 49 secured across the space bounded by the wallsl4 and 15. In order to regulate and secure the articulated rod 4'7 in position, there is provided a link 50 which ispivotally secured by apin 51 to a regulating ring 52. This regulating ring is secured to the diaphragm 14 by bolts 53 which extend through arcuate slots 54' formed in the ring. It will be understood'that an actuating mechanism of the character described is associated with each-plunger. Rotation of the regulating ring by means of the manually operable shaft 90 through the gear 91 and rack 92 will move the rods 47 simultaneously in a lateral'direction relative to the slippers and such adjustment will vary the stroke of the plungers 43 relative to the ports 42. Slippers 55 are carried on the shafts 49 adjacent the slippers '48 and coact with the valve push rods 22 which engage with the free ends thereof. A coil spring 56 is arranged within each of the pump casings for urging the plunger head toward the crank case and thereby normally uncovering the ports 42 when actuating mechanisms permit. Y I g I Mechanism, preferably driven from the crank shaft, is provided for causing injection strokes of the plunger and opening movement of the valve tappet rods 22, such mechanism including a connection whereby a Vernier adjustment can be made to provide for a very fine degree of fuel injection with respect to the piston position on the compression stroke.

. A cam 5'7 having a single lobe 58 upon. its periphery is provided with an elongated hub 59 which telescopes and is carried by the crank shaft adjacent the diaphragm 14. Rotatably mounted upon the hub of the cam 57 is a dual cam 60 having four lobes 61 in one vertical plane for actuating the fuel pump operating mechanism, and a second row of lobes 62 arranged in parallel relation with the lobes 61on the periphery and in a vertical plane to actuate the slippers 55 of the air valve actuating mechanism. The lobes6l and the lobe 58 are both arranged-to engage and operate the fuel mechanism actuating slippers 48. The rear end of the crankshaft is hollow and a coil spring 63 is arranged therein and bears against the plunger 64 which is slidably mounted within the hollow end of the crank shaft, such plunger carrying the pin 65 which extends therethrough and into diametrically disposed, axially extending slots 66 in the crank shaft. The starter jaw 67 extends into the hollow end of the crankshaft and is provided at its end with dogs 68which are adapted to be engaged by the starter jaw -69, such starter jaw being associated with a starter as indicated at '70 which can be of the inertia type such as shown in Patent No. 1,760,988 to R. P. Lansing, of June 3, 1930. The jaw 6'7 is provided with diametrically disposed slots which extend at an angle to the axis of the crank shaft and through which the pin 65 passes. Asleeve '71 is arranged intermediate the starter jaw and the crank shaft and is provided with a pair of diametrically disposed slots '72 extending at a, similar but opposite angle to the slots in the starter jaw. The pin 65 also extends through the slots 72. A gear '73 is formed on the rear end of the sleeve '71 and is driven by the crank shaft through the associationof the pin 65, and by means of the pin 65 from the starter jaw 67 when the engine is being started. The dual cam is provided with an interior gear '74 and a gear '75 meshes therewith, such gear being driven by the idler gear '76 through a connection to be hereinafterdescribed, the idler gear being in mesh with the driving gear 73. A cap nut '77 is screwed upon the end of the crank shaft and serves to prevent axial displacement of the cams and the sleeve '71. The train of gears provide a reduction drive between the crankshaft and the dual cam which preferably drives the cam at one-eighth the crank shaft speed and in a direction opposite to the direction of rotation of the crank shaft, while the cam 57, being fixed to the crank shaft, rotates therewith in a clockwise direction, looking at the rear of the engine.

With compression ignition engines using fuel oilinjected by devices, of thecharacter described, in which the stroke of the plunger determines the timing and quantity of the charges, the degree of atomization and the pressure when injected, and where the plunger stroke varies with the engine speed, it is difiicult to secure the desired atomization of the fuel charges and the desired penetration of the compressed air rotating in the cylinders'when the engine is idling or being started; The cam 57 is therefore providedand brought into effective position to operate the slippers 48 during starting of the engine. Thiscam will move eight times as fast as the dualcam and consequently will impart a much higher degree of pressure to the'fuel charges, thus causing the fuel to be properly atomized and projected into the compressed air cylinders to" form a mixture which will' ignite under compression by the pistons. With the mechanismabove'described, the single lobe cam 57 is automatically brought into effective p'osi'-. tion when the starter is applied to rotate the crank shaftbut at all other times the dual cam 60 will be "effective to'cause actuation of the slippers 48. When the starter is applied to the jaw 67 to rotate the same, the first rotation will move the pin forwardly to the front of the slots 66 and the angular slots in both the starter jaw and the sleeve 71. Under such circumstances the plunger 64 is moved forwardly against the tension of the spring 63 and the sleeve 71 is partially rotated in a direction reverse to that of the jaw 67 .and will cause rotation of the dual cam so that the four lobes thereon in their later rotation will be ineffective because they are disposed angularly in respect to the crank shaft in a relation to pass under the slippers 42 while they are being held in effective position by the lobe on the starter cam 57, as shown in Fig. 2.

' As long as the starter is rotating the crank shaft,

the dual cam will be maintained in such retarded, ineffective relation, but when the starter is released from the crank shaft the spring 63 will move the piston 64 rearwardly carrying the pin 65 therewith and causing rotation of the sleeve 71 and the starter jaw 67, so that the rotation of the sleeve will rotate'the gear 73 which in turn will rotate the dual cam through the intermediate gear and place the cam lobes in a relation so that they are effective to actuate the slippers 48, as shown in Fig. 1. Whenthe dual cam is effective to actuate the slippers 48 the timing is advanced relative to that of the lobe on the starter cam, and the slippers will be held in a raised position by the lobes 61 when the starter cam lobe passes thereunder, consequently the two cams serve to shield one another, depending upon which is in the effective position. For a more complete description of this form of actuating mechanism for the fuel injection devices for starting and running conditions, reference may be had to the co-pending application Serial No. 441,811 to Lionel M. Woolson, filed April 5, 1930.

The gears 73 and 74 are preferably formed with fourteen and fifteen teeth respectively. The gears 75 and 76 are detachably secured together and are formed with a driving connection so that their relative position angularly of the crank shaft can be varied when a vernier adjustment between the gears 73 and 75 is desired. The rear end of the gear 75 is formed with twenty-nine circularly disposed teeth 78 arranged to mesh with similar teeth 79 formed on the front end of the gear 76. The rear cover is formed with a bearing 80 in which is arranged a bushing 81 for the reception of the hollow hub portion 82 of the gear 76, and extending through such hollow hub is a shaft 83 which is formed integral with the gear 75. A nut 84 is screwed on the shaft 83 and locks the teeth- 78 and 79 in engagement, and a pin 85 "extends through thenut and shaft 83 to secure the nut against rotation when once adjusted. A cap 86 is secured'over the rear end'of the shaft 83 and the nut 84 by a plurality of studs 87 which engage th rear cover. Y i

When adjustment'between the teeth 78*and 79 is desired the pin 85 is removed from the nut 84 and the shaft 83, whereupon the nut c'an'be backed off so that the shaft 83 can be -moved inwardly of the crank case, thus disengaging the teet'h 78 from the teeth 79. Without detaching the rear cover 15, rotation adjustment of the gear 75 can be made when it is moved axially whereupon the pin 85 can be inserted to pre-.

vent rotation of the nut.

In assembling the engine, the cam driving mechanism and the cover 15 are associated so that the relation of the cam timing with the piston movement can be observed. If the timing is too far off, then the nut 84 is backed away from the shaft 82 and the shaft 83 is moved inwardlyso that adjustment of the connection between teeth 78 and 79 can be made as above described in order that the timing of the cam is at least within 248 of the timing desired. After making such adjustment, the nut 84 is again screwed on the shaft 83 and against the shaft 82, thus securing the gears 75 and 76 together by engagement of the teeth 78 and 79.

In order to obtain a minute or vernier adjustment of the cam timing, the cover 15 is unfastened and moved away from the crank case sufficiently for the gear 76 to disengage from the gear 73. The nut 84 is then backed away from the shaft 82 and the gear 75 is rotated in either direction to change the relation between the teeth 78 and 79 as may be des red to minutely regulate the cam timing. A one tooth adjustment in the relation of the teeth 78 and 79 in either direction will change the dual cam angle relative to the crank shaft approximately 31 and therefore the timing of the crank shaft approximately 24.8 due to the eight to one reduction drive between the crank shaft and the dual cam, but by mak ng a one tooth difference of the gear 73 with the gear 76, through turning the crank shaft in the opposite direction from that in which the gear 75 has been turned in adjusting, the dual cam angle is changed approximately 32 or a timing change of approximately 257. relative to the gear 76 and in opposite directions will change the dual cam angle approximately .1 which makes a timing change of the crank shaft angle of approximately .8 due to the eight to one reduction drive. In this manner, the timing can be changed in fractions of degrees throughout the adjustment has been made between gears 73 and 76 and between the gears 75 and 76, the cover is Thus the adjustment of gears 73 and 75 the cam driving mechanism.

While there is herein described in some detail a specific embodiment of the invention, which is deemed to be new and advantageous and may be specifically claimed, it is not desired to be understood that the invention is limited to the exact details of the construction, as it will be apparent that changes may be made therein without departing from the spirit or scopeof the invention.

;What is claimed is:

1-. In an internal combustion engine, a crank case having a removable cover plate, cam driving gearing in thelcrank case, a shaft fixed to one gear of the gearing, and another shaft fixed to another gear of the gearing, said shafts being associated telescopically and carried by and movable with the cover plate.

2. In an internal combustion engine, a crank case having a removable cover plate, cam driving gearing in the crank case including a pair of axially associated gears having adjacent differently serrated ends adapted to interlock, a shaft fixed to one of said gears, another shaft fixed to the other of said gears, said shafts being associated telescopically and carried by the cover plate, and means engageable with said shafts and operative to secure the serrated ends of the gears in interlocked relation.

EMMA F. WOOLSON, Executria: of the Estate of Lionel M. Woolson,

Deceased.

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