US1938282A - Internal combustion engine - Google Patents

Description

Dec. 5, 1933. H. c. EDWARDS 1,938,282

INTERNAL COMBUSTION ENGINE Filed July 21, 1930 2 Sheets-Sheet l 17555532" 5 EUNHEUS.

H. c. EDWARDS 1,938,282

INTERNAL COMBUSTION ENGINE Filed July 21. 1930 2 Sheets-Sheet 2 HERBERT C. EDNHRDS Dec. 5, 1933.

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Patented Dec. 5, 1933 PATENT OFFICE INTERNAL COMBUSTION ENGINE Herbert 0. Edwards, Detroit, Mich., assignor to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan Application July 21, 1930. Serial No. 469,474 a 10 Claims.

This invention relates to internal combustion engines and more particularly to engines of the compression-ignition type in which liquid fuel is injected into the combustion chambers through mechanism actuated by an engine part.

The invention has to do more particularly with the starting of engines in which airless liquid fuel is injected into compressed air charges under a pressure developed in accordance with the engine speed. With this type of engine, the degree of fuel atomization and the pressure at which the fuel is injected becomes less as the speed of the engine is reduced, and consequently when the crank shaft is being turned slowly in starting, the fuel is not injected into the compressed air in the combustion chambers at a pressure or in an atomized condition conducive to the formation of a mixture such that easy starting will result.

An object of the invention is to regulate the timing, the pressure and the atomization of liquid fuel charges injected into compressed air charges in the cylinders of a compression-ignition engine in a manner to promote the formation of a mixture readily ignited by compression when the engine is being slowly turned in starting.

Another object of my invention is to provide an internal combustion engine of the compression-ignition type in which the timing of the fuel injection is retarded, and the normal pressure produced against the fuel injected is increased beyond that developed by the normal actuating mechanism while a starting device is applied thereto.

A further object of the invention is to provide an automatic control for regulating the actuation of the fuel injection devices of a compressionignition engine so that during starting, fuel charges will be injected into the combustion spaces when the compressed air charges are at substantially their highest compression and under a pressure such that suiiicient penetration of the air charges occurs to quickly cause a thorough intermingling of the fuel mixture elements.

Still another object of the invention is to provide mechanism which is actuated during the starting of an engine of the compression-ignition type by a source of applied power to place in effective relation a faster moving fuel pump actuating cam than that which is eifective when the engine is operating under its own power.

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

Fig. 1 is a rear elevational view of a radial engine, partially broken away and partially in section to show a fuel injecting device and the actuating mechanism with the slower cam in effective position;

Fig. 2 is an elevational view showing the actuating cams for the fuel injection mechanism, with the faster cam in effective position;

Fig. 3 is a sectional view of the engine taken on line 3-3 of Fig. 1;

Fig. 4 is a fragmentary sectional view of one of the fuel injection mechanisms associated with an engine cylinder.

Referring now to the drawings by characters of reference, 10 represents generally the crank case of a compression-ignition type of internal combustion engine from which. nine air-cooled cylinders 11 extend radially, the cylinders being secured to the wall of the crank case by compression rings, one of which is indicated at 12. The cylinders are formed with an integral dome 13, and secured upon each of the domes is a head 14. Each of the associated heads and domes are formed with a single Venturi passage 15 leading into the interior of the associated cylinder, such passages'serving as both the air inlet and the exhaust outlet for the combustion chambers which are between the cylinder domes and the pistons 16. In order to control the passages 15, there is provided with each a valve 17 which is normally closed by a plurality of springs 18 and opened by conventional engine actuated mechanism including a push rod 19 which extends into the crank case.

A diaphragm, or internal wall 20 is secured within the crank case and is formed with a central opening in which is arranged a bearing 21 for supporting the rear end of the crank shaft 22, the crank shaft projecting axially through the crank case. Arranged in a relation substantially parallel to the diaphragm is a detachable rear wall 23 which closes the open end ofthe crank case, and detachably secured to the rear wall is a starting device, indicated generally at 24, which is preferably of the inertia type as illustrated in'Patent No. 1,739,469, issued Decemher 1%), 1929, to R. P. Lansing. Such starting device is arranged with an axially reciprocable jaw 25 projecting into the crank case in alignment with the rear end of the crank shaft so that it can be moved into a driving relation with a part of the cam driving mechanism.

The engine illustrated is of the compressioni nition, or Diesel type operating on a four-stroke cycle, air charges being drawn into the cylinders through the passages 15 upon the suction strokes of the pistons, during which time the valves 17 are mechanically held open. The valves are next closed and the compression strokes then occur, and during the compression strokes, charges of airless fuel oil are injected under a high pressure at any engine speed and in an atomized condition into the air charges being compressed, so that the mixture thereof with the compressed air will form a combustion charge of a homogeneous character which will readily ignite by compression. There is associated with each cylinder a fuel injection device which consists generally of a nozzle portion 25 and a pump portion 27, the nozzle portion of the devices being secured rigidly to the cylinders and arranged to project through the walls thereof so that the fuel charges can be injected directly into the combustion space in the cylinders.

Each nozzle consists of a barrel 28 having a detachable end 29 extending through the associated cylinder-Wall and formed with a conical outlet opening in which thevalve head 30 is arranged. The valve stem 31 is arranged to be moved into engagement with the stop member 32 by a spring 33 and such stop member is adjusted to prevent the valve from entirely seating. The barrel 28 is formed with a downwardly ex tending neck portion Which is provided with a passage 34 leading to the hollow chamber in the barrel through which the valve rod extends. Such nozzle neck is screwed into the casing 35 of the associated pump unit and bears against a spacer 36 which secures the pump barrel 3'? in position within the casing 35, there being a pair of spring-pressed valves 38 associated with the spacer and the barrel to prevent liquid fuel re-,

turning to the pump structure from the nozzle structure. -A plunger 39 is arranged to reciprocate within the pump barrel and a fuel inlet manifold 40 communicates with all of the pumps, there being unions 41 in the manifold structure associated one with each of the barrels, and ports 42 extend through the casing and the barrel to establish communication :between the unions and the interior of the barrels. Such ports are controlled by the position of the plunger so that when the plunger uncovers the ports 42, liquid fuel is moved under low pressure from the manifold into the pump barrel completely filling the chambered portions therein. The pump plungers are moved in their injection strokes by adjustable associated mechanisms, which will be hereinafter described,

. and during such movement they close the ports 42, their stroke after closing such ports determining the quantity of fuel which is displaced from the nozzles into the cylinders.

It will be seen that the speed of the plunger movement determines the degree of pressure under which the fuel charge is forced past the nozzle valve head and into the cylinders. The effective stroke of the plungers will force fuel past the valve heads 30 and from the nozzles in a manner such that the fuel charges are directed into the cylinders in a conical spray. The air inlet passages are formed and arranged so that they cause rotation of the airy in the cylinders and such rotation continues during the following compression stroke of the piston, the fuel charges being sprayed into such compressed rotating air charges at a pressure of more than two thousand pounds per square inch. 7

The degree of fuel atomization and the extent of the pressure at which it is injected into the air in the cylinders determines the extent of the intermingling of the oil with the air and, therefore, it is necessary that there be sufficient atomized fuel penetration of the air to cause a uniform distribution if efficient engine operation is to result. It is also necessary that the atomization and penetration of the air by the fuel oil be of a certain character if combustion is to be attained when the cylinders are cold, as they are when starting. With the type of injection mechanism described, in which the pressure hehind the fuel varies in accordance with the crank shaft speed, difficulty is experienced, when turning the crank shaft at a slow speed in starting the engine, to produce a sufficient pressure behind the fuel charges, because of the consequent slow movement of the fuel. pumps, to cause the necessary atomization and penetration of the compressed air charges to produce a mixture which will i nite by compression.

This invention has to do particularly with mechanism for injecting fuel oil in an atomized condition and at a sufficient pressure to cause an intermingling with the compressed air in the cylinders such that i nition will readily result from compression when the crank shaft is being slowly turned through the application of a starting device. To this end, I utilize the regular fuel injecting devices andprovide an auxiliary actuating mechanism therefor which is effective only when starting. This auxiliary actuating mechanism is automatically made effective by and during the application of the starter device, and is automatically placed into ineffective relation when the starting device is released from the crank shaft. propose that the liquid fuel charges will be injected, during the turning of the crank shaft by the starting device, at a pressure which will cause the fuel to penetrate substantially to the center of the cylinders and ina finely atomized Under normal running operation, crank shaft actuated mechanism is provided for causing the pump plungers to move in their injection strokes, and such mechanism is returned to a position uncovering the ports 42 by means of the coil spring 43. A fuel plunger push rod 44 extends through the crank case and has associated therewith a'rod 45 which is pivotally connected with a link 46 carried by a regulating ring 47 which is rotatably mounted within the crank case. The ring 47 can be rotated through the association of a tooth segment 48 with the rack 49 which is fixed thereto, the segment being rotated by means of the shaft 50 which is in turn actuated through suitable mechanism'connected with the lever 51.

Associated with each of the rods 45 is a slipper or rock lever, as shown at 52, 53 and 54, carried by the shafts 55 which are supported by the diaphragm and the rearcasing cover 23. e The free ends of the slippers are formed with a longitudinally curved groove in which the associated rods 45'are adjustably positioned by means of the ring 47 and the connecting links 46, so that upon movement of the rods 45, lengthwise of the slippers, the effective portion of the injection stroke of the pump plungers can vbe simultaneously varied.

Arranged interiorly of the pivoted slippers, for actuating the same to cause an injection stroke of the pump plungers, is a cam 56 having four similar and equally spaced lobes 5'7, 58, 59 and 60. The periphery of the cam is formed with an internal gear 61 with which the gear 62 meshes, and this gear is mounted integrally on the same shaft with the gear 63which is arranged adjacent the end wall of the casing. Meshing with the gear 63 is a gear 64 formed on the rear end of a driven sleeve 65. The sleeve 65 extends into a bore formed in the rear end of the crank shaft 22, and is formed to provide two sets of spaced internal helical splines 66 and 67. A rod 68 extends axially through the sleeve and is splined at its forward end to the crank cheek, as indicated at 69, such rod having a helical spline 70 meshing with the helical spline 66 at the front end of the sleeve. A starter jaw member 71 extends into the rear end of the hollow sleeve 65 and is provided with a helical spline 72 which meshes with the helical spline 67 within the sleeve, the rod end projecting through the starter jaw is threaded and nuts 73 are screwed thereon to maintain the flanged end of the starter jaw axially in position. A compression spring 74 is arranged within the bore of the rear end of the axle surrounding the sleeve 65, and bears at its forward end against the splined end of the rod 68 and the crank shaft wall and at the other end against the forward end of the gear 64 formed on the sleeve 65. The cam 56 is provided with a plurality of lobes 75 which are arranged in a plane to actuate slippers 76 which are pivotally mounted on the shafts 55 adjacent the slippers which actuate the fuel injection mechanism rods 45, and such slippers 76 have associated therewith the valve push rods 19 so that rocking of the slippers 76 by the cam lobes 75 will result in imparting an opening movement to the valves 17.

A cam 77 having a single lobe 78 on its periphery is provided with an extended hub 79 which is keyed to the crank shaft, and the hub of the cam 56 telescopes the extended hub 79 and is rotatably mounted thereon. It will be seen that as the cam 77 is fixed to the crank shaft, it will rotate at the same speed and in the same direction therewith. The train of gears 64, 63, 62 and 61 are of the reduction type so that the cam 56 will be driven from the crank shaft at oneeighth the speed thereof and in a reverse direction. Looking at the engine from the rear end, as shown in Fig. 1, the cam 77 rotates in a clockwise direction with the crank shaft, while the cam 56 rotates in an anti-clockwise direction at one-eighth the speed of the crank shaft. A retainer 80 is screwed upon the end of the crank shaft to fix the cams in an axial position.

As shown in Fig. 1, the two cam members are angularly disposed relative to the crank shaft for the operation of the engine under its own power. In this position the lobes on the cam 56 will be effective to cause upward movement of the slippers for moving the pump plunger push rods in a direction to cause an injection stroke. Preferably, the lobes are arranged so that the effective injection strokes of the fuel pump plungers will be caused in a range extending between forty and twenty degrees before the pistons reach the top of their air compression strokes, whereas the cam 77 is angularly disposed upon the crank shaft so that its lobe will cause an upward movement of the slippers, associated with the plunger push rods, to cause an effective injection stroke of the plungers at approximately ten degrees before the pistons reach the top of their air compression strokes. As previously stated, when the cams are in position for the regular running operation of the engine, the lobes 57, 58, 59 and 60 of the cam 56 are effective because they will lift the slippers in advance of the lobe on the cam 77 and maintain the slippers in a raised position while the lobe 78 is passing thereunder in its rotation, so that in this manner the cam 77 is ineffective. The adjustment of the rods 45 by the rotation of the ring 47 will control the quantity of fuel injected, as previously explained, and will also control the time of injection somewhere in the range specified when the cam 56 is effective. When the cam 56 is in effective position, the coil spring 74 will maintain the sleeve 65 in its rearmost position and will automatically return the sleeve to such position when the jaw 25 of the starting device is released from operating relation with the starter jaw 71.

It will be seen that when the engine is running under its own power, the cam 56 is driven from the crank shaft through the shaft 68 and the sleeve 65 and through the train of gears 64, 63, 62 and 61, such gears reducing the rate of rotation imparted by the crank shaft to the cam to a one-eighth speed. Of course, in this driving arrangement the coil spring 74 creates sufficient pressure to maintain the sleeve in its rearmost position and in this way forms an indirect part of the driving mechanism.

When starting the engine, the inertia starter 24 is first energized until it is desirable to associate it with the engine, whereupon the jaw 25 is moved axially through manual or other means into driving engagement with the starter jaw 71. During the first rotation of the starter jaw by the starter, the jaw will cause the sleeve 65 to move forwardly because of the meshing helical splines 67 and 72, and as the sleeve 65 is also helically splined to the rod 68, which splines extend at a different angle than the splines on the starter jaw, the sleeve 65 will rotate in its forward movement, the rod 68 and the crank shaft 22 under such circumstances being stationary, due to the inertia of the elements connected therewith being greater than that of the cam 56 and its associated elements, until such time as the sleeve 65 has reached the limit of its forward movement whereupon rotation of the entire crank shaft and cam driving structure will take place. In the meantime, the rotation of the sleeve 65, which has taken place prior to the actuation of the crank shaft, will have rotated the reduction gearing suiiiciently to move the cam 56 angularly relative to the crank shaft so that the lobes for actuating the fuel injection mechanism slippers will be in a relation to cause rocking of the slippers at approximately the time when the pistons on their compression strokes have reached top center, which is several degrees behind the time when the lobe on the cam 77 will have actuated the slippers. In other words, this changing of the position of the cam 56 relative to the cam 77 will place the lobes 57, 58, 59 and 66 into an ineffective position and will, therefore, permit the lobe on the cam 77 to be effective to actuate the fuel mechanism operating slippers, and such relative positions will be maintained so long as the inertia starter is related with the starter jaw in a manner to crank the crank shaft. When the engine is operating under its own power, the

starter jaw 71 will overrun the jaw 25 and the 1 spring 74 will force the sleeve 65 to its rearmost position causing the cam 56 to be returned to effective slipper operating position. The lobe on the cam 77 is of suiiicient length such that when it is in effective position during starting,

it will maintain the rocker levers in a raised position at the time the lobes 57, 58, 59 and 60 pass thereunder, and thus when the cam 77 is effective it will the lobes of the cam 56, and vice versa. These rnas'king results are obtained due to the relative speed of the two cams and to the length and arrangement of the lobes.

Air charges are drawn into the cylinders during the suction strokes of the pistons, and dur ing normal operation the valves are closed a little past bottom center position of the pistons. The compression of the air charges then proceeds and variable liquid fuel charges are introduced into the compressed air charges in a variable time range such that peak pressures caused by burning rill occur when the pistons are adjacent top center position. Injection timing with respect to fuel quantity varies with different engines depending upon the type 'of fuel," the compression ratio, the shape of the fuel spray, the amount of turbulence, the shape of the 00111- bustion chamber, et cetera; and with the present engine I have found that peak pressures are attained when the piston is near top center if the fuel is injected in a range extending between forty and twenty degrees before top center position of the pistons. When the engine is being started, the air valve will close later than when the engine is operating under its own power due to the retarding of the cam 56, and the degree of lateness is determined by the angular adjustment of such cam. In the present instance the cam 56 is retarded about thirty-six degrees in starting and, therefore, the air valves will be open much later than when the engine is running under its own power, thus varying the volume of air trapped in the cylinders. During starting, the air charges are reduced in volume but they are compressed until the pistons closely approach top center before fuel injection takes place and, therefore, the compression ratio at the time fuel is injected between starting conditions and running conditions varies considerably. In the present instance the compression ratio at the time of fuel injection when starting is considerably higher than that present under normal running conditions. As a consequence, during starting the high compression ratio at the time fuel is injected produces a high temperature which causes quick burning of the fuel and thus the heat conditions in the cylinders are substantially the same when the crank shaft is being turned slowly in starting as when it is turning fast in the regular running conditions, it being understood, however, that in starting fuel injcctions of maximum volume are introduced.

With the cam 77 in effective position during starting, a materially increased speed of the pump plunger strokes will result because the cam is moving ei t times as fast as the cam 56, and

this faster movement of the pump plungers is requi e order to project the fuel charges far enough into the rotating compressed charges to cause an intermingling which will result in a mixture of a type which will ignite under com pression of the pistons. When the engine is running under its own power, I find that the pressure behind the fuel charges, as developed by the cam 56, is sufficient to produce such a mixture. It will also be seen that when the cam '7'? is effective, the time of the fuel injections is retarded relative to the timing when the cam 56 is effective, and such a retarding of the timing will cause the injection strokes into the compressed air in the cylinders at substantially the highest compression thereof, thus assisting the combustion ofthe mixture because of the maximum heat attainment, and in this manner starting will be assisted and economy of operation will also result.

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 of the compression-i nition type, a pressure device including a plunger for injecting charges of liquid fuel into compressed air charges in a combustion space, a cam for causing effective injection strokes of the plunger, a crank shaft, arotatable starting jaw associated with the crank shaft, a sleeve helically splined to the crank shaft, 2. driving connection between the jaw and the sleeve, and reduction gearing intermediate the sleeve and the cam.

2. In an internal combustion engine of the compression-ignition type, a pressure device for injecting charges of atomized liquid fuel into compressed air charges in a combustion space, a crank shaft, a cam rotatably mounted relative to the crank shaft in a relation to actuate the device, reduction gearing between the crank shaft and the rotatably mounted cam, and means including a helically splined sleeve connected to reduction gearing and with the crank shaft, said sleeve being movable axially a limited extent relative to. the crank shaft upon rotation to rotate the reduction gearing independently of the crank shaft and thereby chan e the angular position of said cam relative to the crank shaft.

3. In an internal combustion engine of the compression-ignition type, a pressure device for injecting charges of atomized liquid fuel into compressed air charges in a combustion space, a crank shaft, acam rotatably mounted on the crank shaft in a relation to actuate the device, reduction gearing connecting the crank shaft with the cam, said reduction gearin having a gear thereof formed with a helical spline, and means cooperating with the helically splined por tion of said gear and connected with the crank shaft for rotating the splined gear a limited de gree independently of the crank shaft rotation, the rotation of said gear rotating the angularly of the crank shaft due to the inerita of such rotated parts being less than that of the crank shaft.

4. In an internal combustion engine of the compression-ignition type, a pres e device for injecting charges of atomized Lquid fuel into;

compressed air charges in a combustion space, a crank shaft, a cam fixed to rotate with the crank shaft in a relation tov actuate the device, another cam rotatably mounted relative to the crank shaft and in a relation to actuate the device, said cams having their lobes of such length that the leading cam shields the device from the following cam, reduction gea ng between the crank shaft and the rotatably mounted and the other cam and thereby position said rotatkii ably mounted cam with its lobes in advance of or behind the lobes of the fixed cam.

5. In an internal combustion engine of the compression-ignition type, a pressure device for injecting charges of atomized liquid fuel into compressed air charges in a combustion space, a crank shaft, a cam rotatably mounted on the crank shaft in a relation to actuate the device,

reduction gearing between the crank shaft and the rotatably mounted cam, helically splined sleeve means fixed to one of the gears of the reduction gearing, a starter jaw having helical splines meshing with the splined portion of the sleeve, a starter device adapted to engage and rotate said jaw, and a connection between the crank shaft and the splined sleeve whereby initial rotation of the starter jaw by the starter device i ill move the sleeve spirally and rotate the rotatably mounted cam angularly on the crank shaft a limited extent before the crank shaft is rotated thereby.

6. In an internal combustion engine of the compression-ignition type, a pressure device for injecting charges of atomized liquid fuel into compressed air charges in a combustion space, a crank shaft, a cam rotatably mounted on the crank shaft a relation to actuate the device, reduction gearing between the crank shaft and the rotatably mounted cam, one of the gears of said reduction gearing being spirally movable, spring means for holding the spirally movable gear in one extreme position, and means associated with the gear and the crank shaft for moving said gear spirally against the pressure of the spring, such spiral movement of said gear shifting the cam angularly on the crank shaft due to the inertia of the cam and the reduction gearing being less than that of the crank shaft.

'7. In an internal combustion engine of the compression-ignition type, a pressure device for injecting charges of atomized liquid fuel into compressed air charges in a combustion space, a crank shaft having a recessed end, a cam rotatably mounted on the recessed end of the crank shaft in a relation to actuate the device, reduction gearing between the crank shaft and the rotatably mounted cam, a sleeve in the recess in said crank shaft end fixed to one of the gears of the reduction gearing, and means for moving said sleeve spirally a limited extent to change the position of the cam angularly of the crank shaft.

8. In an internal combustion engine of the compression-ignition type, a pressure device for injecting charges of atomized liquid fuel into compressed air charges in a combustion space, a crank shaft having a recessed end, a cam rotatably mounted on the recessed end of the crank shaft, reduction gearing connecting the crank shaft with the cam, a gear of said reduction gearing having a sleeve portion extending into the the recessed end of the crank shaft, a rod fixed in the recessed portion of the crank shaft on which the sleeve is helically splined, and means slidable on said rod and helically splined to said sleeve for moving the sleeve spirally a limited extent, the spiral movement of said sleeve shifting the reduction gearing and thereby changing the position of said cam angularly relative to the crank shaft due to the inertia of the cam and the reduction gearing being less than that of the the sleeve portion of the gear is helically splined, I

and starter means including a starter jaw mounted on the rod and helically splined to the sleeve portion of the gear to drive the crank shaft, the initial operation of said means on the rod driving the sleeve spirally and changing the position of said cam angularly relative to the crank shaft due to the inertia of the cam and the reduction gearing being less than that of the crank shaft.

10. In an internal combustion engine of the compression-ignition type, a pressure device for injecting charges of atomized liquid fuel into compressed air charges in a combustion space, a crank shaft having a recessed end, a cam rotatably mounted on the recessed end of the crank shaft, reduction gearing connecting the crank shaft to the cam, a gear of said reduction gearing having a sleeve portion formed with internal splines and extending into the recessed end of the crank shaft, a rod fixed in the recessed end of the crank shaft, said rod having a helically splined portion with which the splined portion of the sleeve meshes, a starter rotatably mounted on the rod and having helical splines meshing with the splined portion of the sleeve, and a spring in the recessed portion of the crank shaft urging the sleeve outwardly of the recess, the initial rotation of the starter jaw in starting the engine moving the sleeve spirally and changing the position of the cam angularly relative to the crank shaft, further rotation of the starter jaw driving the crank shaft through the sleeve and rod connection.

HERBERT C. EDWARDS.

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