US1928774A - Internal combustion engine - Google Patents

Description

L. WOQLSQN' INTERNAL COMBUSTION ENGINE 2 Sheets-Sheet 1 Filed April 19, 1930 gwwnto'o LIUNEL MWUULEDN (1 HM M441 Oct. 3, 1933.

Oct. 3, 1933. L. M. WOOLSON 1,928,774

INTERNAL COMBUSTION ENGINE Filed April 19, 1930 2 Sheets-Sheet 2 grwenl o o ZJDNEL. M NaaL 501v dummy EEG. 5-

, Patented Oct. 3, 1933 INTERNAL COMBUSTION ENGINE Lionel M. Woolson, Detroit, Mich, assignor to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan Application April 19, 1930. Serial No. 445,748

12 Claims.

This invention relates to internal combustion engines and more particularly to engines of the Diesel or compression-ignition type.-

With one type of compression-ignition engine,

it is the usual practice to cause fuel injections by means of a pressure device, or devices, actuated in accordance with the crank shaft speed, and consequently the amount of pressure under which fuel is injected into the combustion chambers varies in accordance with the engine speed. One of the prime requisites in the continued operation of a compression-ignition engine requires that the fuel be properly atomized and sufliciently projected into compressed air charges in a manner such that there will be a homogeneous mixture of the fuel with the air, and with high speed engines the time in which such results must be attained is a very small fraction of a second. It is diflicult to maintain combustion when idling, and it is also more difficult to start the engine because the pressure behind the fuel under such circumstances is not sufiicient to give the desired penetration of the air charges by the fuel and also the desired atomization. An object of my invention is to provide an internal combustion engine, of the compression-ignition type, with actuating mechanism for the fuel injection devices which will cause substantially as high a pressure to be produced for injecting fuel charges during idling or starting as when the engine is running under load.

Another object of the invention is to assure the proper atomization of liquid fuel and its penetration into compressed air charges in an internal combustion engine through the speeding up of the injection mechanisms when the engine is running below a predetermined speed.

A further object of the invention is to provide an internal combustion engine, of the compression-ignition type, with mechanism for actuating fuel injection devices of the pressure type to which impulse movements are imparted when the engine is running below a predetermined engine speed.

Still another object of the invention is to provide mechanism for operating pressure fuel injection devices of a'compression-ignition engine in which a cam driven from the crank shaft has pivoted abutments associated therewith actuated to cause a faster movement of the fuel injection devices than that normally imparted when the engine is running in its slower speed range.

- Still another object of the invention is to provide cam mechanism, for operating pressure fuel injection mechanisms in an engine of the compression-ignition type, with movable lobe abutments which remain in a constant relation in the higher engine speed range but which are moved forwardly in the direction of the cam travel, when in actuating position, in the lower speed range. These and other objects of the invention will appear from the following description taken in to connection with the drawings, which form a part of this specification, and in which:

Fig. l is a rear elevational view of a radial type of engine partly broken away and partly in sec- .tion to show the elements essential to an understanding of this invention; 7

Fig. 2 is a vertical sectional view of a nozzle of one of the injection devices associated with a fragment of a cylinder;

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

Fig. 4 is a perspective view of one ofthe abutment members for actuating the fuel devices removed from the cam.

Referring to the drawings by characters of reference, 10 indicates the crank case of an internal combustion engine of the Diesel or compressionignition type from which a plurality of cylinders extend radially. The interior of the crank case is divided into two compartments by a diaphragm 12, and a removable cover plate 13 closes the open rear end of the crank case.

The cylinders are each preferably formed as a steel forging which includes a barrel ll-and an integral dome 14, and secured upon each of such domes is a head 15. In order to provide for air being drawninto and exhaust expelled from the combustion chamber 16, which is between the piston 17 and the dome, I provide a single Venturi passage 18 through the head and dome of each cylinder which is arranged at an angle to the cylinder axis and tangential with the inner wall thereof. This arrangement of ports will causeafull supply of air to enter the cylinders and to rotate in the combustion chamber. In order to control flow through each of the Venturi passages, there is provided a valve 19 which is actuated by suitable mechanism driven by the crank shaftand extending through the crank case and housings. 20 for opening the valve during the air intake stroke and the exhaust's'lroke, while a plurality of springs 21 are associated with each valve to normally close the same;

Liquidfuel, in atomized form and under a relatively high pressure, isinjected intof-each of 5 the cylinders during the air compression strokes by a separate injection device consisting of a nozzleportion and a pump portion. The nozzle portions of the several units are connected together by a sectional fuel feeding manifold 22 which is connected in circuit with a source of fuel supply and through which circuit oil is moved under low pressure by suitable pump mechanism (not shown). Associated with the uppermost nozzle, there is a return conduit 23 which leads excess fuel oil from the manifold back to the source of supply (not shown). Each nozzle includes a barrel 24 having the forward end thereof extending through an aperture in a cylinder wall, and the nozzle and pump units are secured rigidly to the cylinders by bolts 25 which extend through flanges forming a part of the nozzle. A chamber extends axially through the major portion of the nozzle and arranged therein is a valve element 26 which is provided with a conical head reciprocable within the outer end of the nozzle chamber. Associated with the other end of each of the valve members is a stop member 2'7 which is adjusted to limit the movement of the associated valve so that it will never be quite closed. A coil spring 28 is arranged to normally urge each valve into its position of nearest closure. A pump casing 29 is screwed upon a depending neck portion of the nozzle, and arranged within the pump casing is a barrel 30 within which the plunger 31 is reciprocated. There is a passage establishing communication between the barrel and the chamber in the nozzle, such passage having therein a one-way valve 32 which prevents leakage of fuel oil from the nozzle back into the barrel. The barrel and casing are provided with a plurality of aligned ports 33 which are arranged to communicate with the fuel feeding manifold 22 so that when the plunger 31 uncovers the ports, oil will be moved into the nozzle and pump barrels to maintain the same full of oil, such communication being cut off when the plungers are moved to close the ports upon their injection strokes.

Plunger push rods 34 extend into the interior of the crank case and are arranged to engage with each plunger structure and cause their movement in a direction to close the ports 33 and displace fuel oil from the nozzle into the cylinder upon further movement thereof. A spring 35 normally moves each plunger into a position uncovering the associated ports 33. A rod 36 is associated with each push rod and is pivotally connected by a link 37 to a ring 38 which is secured by bolts 39 to the diaphragm 12, such ring being provided with slots to permit rotation thereof. When the ring is rotated by means of a rack and pinion 40, the links 37 will be moved to vary the angular relation of the rods 36, relative to the push rods 34, and in this manner the stroke of the plungers 31 relative to the ports 33 can be regulated, thus varying the quantity of fuel oil injected into the cylinders. A slipper 41 is arranged to be associated with each of the rods 36, such slippers being pivotally mounted upon shafts 42 carried by the end wall 13 and the partition 12. These slippers are provided with an arcuate surface against which the rods 36 are held by the spring 35.

A crank shaft 43 extends axially of the crank case and has mounted thereon, in fixed relation, a cam 44 extending within the rear end compartment. Rotatably mounted upon the hub portion of this cam is a cam member 45 having a plurality of lobes at its rear end for actuating the slippers 46 which are pivoted adjacent the slippers 41 on the shafts 42, such slippers 46 cooperating with valve push rods 4'7 which serve to actuate the valve mechanism extending through the housings 20. Fixed adjacent the rear end of the crank shaft is a gear 48 which meshes with a reduction gear 49 carried by the shaft 50. The cam member 45 is provided with an internal gear 52 with which the gear 51 fixed on the shaft meshes. This arrangement of gearing preferably drives the cam at one-eighth crank shaft speed and in a counterclockwise direction, looking from the rear of the engine.

The periphery of the cam member, adjacent the valve actuating lobes, is provided with four equally spaced slots 53 through each of which an abutment member 54, or movable lobe section, projects. Such abutment members are pivotally mounted upon pins 55 which are secured to the hub of the cam member 45. A coil spring 56 bears against the toe of each of the abutments and also is seated against the inner face of the peripheral wall of the cam member, and such springs normally urge the projecting ends of the abutments into their forward position in the slots 53 which is an advanced position when the cam member is being rotated. The cam 44, which is fixed to the crank shaft, is arranged to rotate axially of the abutment members in a clockwise direction, and the springs 56 urge the abutment members into a riding relation against such cam. This cam is formed with a single lobe 57 which drops abruptly from the peak to the base circle so that the abutment members when riding thereover will be given an impulse movement toward the base circle resulting in the contacting ends moving forwardly in the slots, below a predetermined engine speed. It will be understood that the crank shaft and the cam 44 which is fixed thereto are rotating in a clockwise direction as viewed from the rear end of the engine and that the cam member 45 is being rotated in an anti-clockwise direction at one-eighth crank shaft speed so that an impulse movement will be given to the abutment members as the lobe of the cam 44 passes thereunder. Each of the abutment members has a leaf spring 58 associated with the forward wall thereof in relation such as to contact with the forward end of the slots when an impulse movement is imparted to the abutments, and in this manner the forward movement of the abutments relative to the cam member is cushioned.

When the crank shaft is turning in its lower speed range, the cam member 45 is rotating so slowly that the springs -56 act fast enough to move the abutments from their rear position to their forward position in the slots 53 during contact with the slippers 41, so that the resulting movement imparted to the slippers is greatly accelerat'ed over that which Would occur if the abutments remained at the rear end of the slots and moved at the same speed as the cam member.

This accelerated or impulse actuation of the.

slippers, when running below a predetermined speed, will cause a fast movement of the plunger operating mechanism associated Withthe slippers and will, therefore, produce a greatly increased pressure upon the fuel being injected into the cylinders. In this manner, the pressure at which fuel is injected into the air charges in the cylinders and the degree of atomization of such injected fuel is substantially the same when running in the slow speed range as when the engine is running under load. Without this faster fuel injection device operation at slow engine speeds, the pressure behind the fuel and its atomization would not be sufficient to penetrate the air charges or to mix therewith sufiiciently to form a combustion supporting fuel charge, however with this mechanism for speeding up the action of the fuel injection mechanism at slow engine speeds, a proper atomization and intermingling of the fuel with the air takes place so that regardless of temperature conditions combustion is assured in a compression-ignition engine when idling, and, furthermore, starting is facilitated.

At some predetermined point in the engine operation, the speed at which the cam member 45 is driven becomes great enough so that the abutments 54 are moved in their slipper contacting relation while still at the rear end of the slots because the actuation of the slippers will occur before the springs 45 will have had time to cause a forward movement of the abutments in the slots, in other words the lag of the spring actuation upon the abutments at such a predetermined speed, and thereabove, permits the abutments to cause fuel injection actuations while still in their rear positions in the cam member slots. It will thus be seen that the cam mechanism will automatically assume the proper operating relation for the two ranges of engine speed. It will also be seen that with a nine cylinder engine, such as that illustrated, and with four abutments for actuating the nine injection mechanisms, there will be a complete cycle of fuel injections upon'each two revolutions of the crank shaft, as the cam member-'45 is operating at one-eighth crank shaft speed. The cam 44 operating at crank shaft speed can, therefore, be timed so that the high lobe portion will pass under each of the abutments while they are in actuating relation with the fuel injection mechanism.

Withthe device above described, the fuel mixture is properly prepared to insure combustion regardless of atmospheric temperature when the engine is running at a slow speed, and furthermore starting of the engine is greatly facilitated.

While I have herein described in some detail a specific embodiment of my invention, which I deem to be new and advantageous and may specifically claim, I do not desire it to be understood that my 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 scope of my invention.

What I claim is:

1. In an internal combustion engine, a crank shaft, a rotatable cam driven at a speed several times less than that of the crank shaft, a fuel injection device including a plunger mechanism, abutments carried by the cam for actuating the fuel injection plunger mechanism, said abutments having contact portions movable a limited extent relative to the cam and in the direction of the cam movement, and means for moving the contact portions of the abutments faster than the cam when the engine is operating below a predetermined speed.

2. In an internal combustion engine, a crank shaft, a rotatable cam'driven at a speed several times less than the crank shaft rotation, fuel injection mechanism including a plunger, an abutment member pivoted to the cam and extending through the periphery of the cam for actuating the injection mechanism, the portion of said abutment member extending through the cam being movable in the same direction as the cam rotation, a cam fixed to the crank shaft with which the abutment member engages, and spring means urging the protruding portion of the abutment member into its forward position relative to the low speed cam and the inner portion into contact with the cam fixed to the crank shaft, the abutment being moved to its forward position relative to the slow speed cam during actuation of the fuel injection mechanism while the crank shaft is rotating below a predetermined engine speed.

3. In an internal combustion engine having cylinders, a crank shaft, fuel injection devices associated with the cylinders, a cam member having slots in the periphery, means for rotating'the cam member from the crank shaft at a reduced speed, abutments pivoted to the cam member and extending through the peripheral slots therein, said abutments being arranged to actuate the injection devices during rotation, means for rocking the abutments to accelerate their movement while engaging the injection devices, and cushioning means intermediate the abutments and the cam wall through which they project.

4. In an internal combustion engine having cylinders, a crank shaft, fuel injection devices associated with the cylinders, a cam member having slots in the periphery thereof, means for rotating the cam member from the crank shaft at a reduced speed, abutments pivoted to the cam member and extending through the peripheral slots therein, said. abutments being arranged to actuate the injection devices during rotation,

means for rocking the abutments to accelerate,

their movement while engaging the injection devices when the engine isrunning below a predetermined speed, and cushioning means attached to the abutments for engaging a wall forming the front end of the peripheral slots in the cam member.

5. In an internal combustion engine having cylinders, a crank shaft, fuel injection devices associated with the cylinders, a cam member having slots in the periphery thereof, means for rotating the cam member from the crank shaft at a reduced speed, abutments pivoted to the cam member and extending through the peripheral slots therein, said abutments being arranged to actuate the injection devices during rotation, means rocking the abutments to accelerate their movement while engaging the injection devices during slow speed operation, and spring means attached to the forward wall of the abutments.

6. In a radial internal combustion engine having a plurality of cylinders adapted to be supplied with air charges, a crank shaft, a pressure device for injecting fuel associated with each cylinder, a cam member arranged centrally of the fuel injecting devices, means for rotating the cam from the crank shaft at a reduced speed, a plurality of equally spaced abutments extending through the periphery of the cam member and pivotally carried thereby, said abutments being movable a limited extent in the direction of the rotation of the cam, a cam fixed to the crank shaft upon which the inner ends of the abutments ride, said fixed cam having a sharp drop, and spring means for causing an impulse movement of each abutment forwardly as it passes over the sharp drop portion of the cam, said cam fixed to the crank shaft, cooperating with the abutments to permit such impulse movements thereof as each fuel injection device is contacted with.

'7. In an internal combustion engine, a crank shaft, a member connected to be rotated ,from

the crank shaft, a fuel injection device including 1 gaging portion thereof faster than the carrying member and in the same direction of rotation thereas when the crank shaft is turning below a predetermined speed.

8. In an internal combustion engine, a crank shaft, a member rotated from the crank shaft, a pressure fuel injection device including a plunger, abutment means movably mounted on the member and arranged to actuate the fuel device, and crank shaft driven means for causing impulse movements of the contacting portion of the abutment means in the same direction as the rotation of said member and while actuating the fuel injection device.

9. In an internal combustion engine, an engine rotated member, a pressure fuel injection device including plunger mechanism, abutment members movably mounted on the member and arranged to contact with and actuate the plunger mechanism, a driven cam arranged to engage said abutment members in a relation to move their plunger mechanism contacting portion in the same direction of rotation as that in which the engine rotated member is traveling, and spring means associated with the abutment members for urging them toward one extreme position of their movement relative to the member.

10. In an internal combustion engine, a crank shaft, a rotatable cam driven from the crank shaft at a reduced speed relative thereto, fuel injection mechanism including a plunger, an abutment pivoted to the cam and arranged to actuate vices associated to be actuated through contact of a portion of the abutments therewith, and spring means for rocking the abutments in one direction while contacting with the fuel injection devices when the crank shaft is rotating below a predetermined speed, said fixed cam member rocking the abutments in the opposite direction to that caused by the spring means and prior to contact with the injection device.

12. In an internal combustion engine, a low speed cam, pressure injection devices for fuel including plungers, pivoted abutments carried by the cam for actuating the fuel injection devices, the outer portion of said abutments engaging the fuel injection devices and being movable relative to the cam in the direction of its movement, a high speed cam with which the inner end of the abutments engage, and springs in the low speed cam arranged to urge the abutments against the high speed cam.

LIONEL M. WOOLSON.

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