US1918076A - Internal combustion engine - Google Patents

Description

y 1933- L. M. WOOLSON 1,918,076

V INTERNAL COMBUSTION ENGINE Filed July 21. 1930 2 Sheets-Sheet 1 5113.4 Qwuemtom LI'UNEL M. NDULS'DN. 05: 5:0

5r HIS zxetu rmx EMMA E Nuns-cw July 11, 1933. M, WOQLSQN 1,918,076

INTERNAL COMBUSTION ENGINE Filed July 21, 1930 2 Sheets-Sheet 2 I I gwuanl'oz 51:75. E

Iz/JNEL MNJYULSUN, DECEASED 5r H15 sxscumzx EMMA f. Nauasazv Patented July 11,1933

UNITED STATES eisure PATENT OFFICE LIONEL M. WOOLSON, DECEASED, LATE OF DETROIT, MICHIGAN, BY EMMA F. WOOLSON, EXECUTRIX, 0F BLOOMFIELD VILLAGE, MICHIGAN, ASSIGNOR TOPACKARD'MOTOR CAR COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN INTERNAL COMBUSTION ENGINE Application filed July 21,

which fuel is forced by a pump actuated in its injection strokes by the release of a spring which is first compressed by a cam,

such injection being known as the loaded n, v spiing .type. When the cam is moving slowly, the action is sufficiently fast to cause the plunger actuating mechanism to closely follow the perimeter of the cam, however when the cam is speeded up, as it is when the engine is operating under normal load, the influence of the spring upon the plunger actuating mechanism is not as fast as the movement of the cam and, consequently, there is a delay in the forcing of the plunger actuating mechanism into contact with the base circle of the cam, and

consequently the timing of the fuel injection is delayed. Such delay in the timing of the fuel injection is undesirable and lessens the efficiency of the engine as well as limiting the time for the liquid fuel to mix 'with the compressed air before the piston.

reaches its top position in the cylinder during the compression strokes.

An object of the invention is to providefuel injecting mechanism, of the character described above, which will closely follow the periphery of a cam during all speeds at which it may be operated.

Another object of the-invention is to pro- 'vide a multi-cylinder engine, of the radial type, with individual fuel injection mechanism for each cylinder which are operated bx a single cam rotated from the engine in a manner such that there will be no delay in the time of the injections, relative to the relation of the cam with the actuating mechanism.

Another object of the invention is to provide a radial engine with separat fuel injecting devices for each cylindernwhich are actuated by a single cam in a manner to 1930. Serial No. 469,326.

provide a uniform timing for the fuel injections regardless of speed and with which a single adjusting member is associated for simultaneously varying the quantity of fuel contained in the injected charges.

These and other objectsof 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 a radial type of internal combustion engine incorporating the invention, portions of the engine being broken away and in section to illustrate the fuel actuating mechanism;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1;

'Fig. 3 is a sectional View of the nozzle portion of one of the injection devices associated with a fragment of one of the cylinders;

Fig. 4 is a fragmentary sectional view peripheral wall of the crank case and are secured in position by compression bands, one of which is indicated by the numeral 18. Each of the cylinders is formed with a dome 19 upon which is secured a head 20, the spaces between the domes 19 and the pistons 21 within the cylinders providing the combustion chambers in which the fuel mixture is intermingled and ignited through the heat resultingfrom piston compression. A single Venturi passage 22 extends through each of the associated heads and domes and provides an air inlet and an exhaust outlet, such passage being controlled by a valve 23 which is normally closed by the springs 24 and 1 opened by conventional mechanical means including a push rod 25 extending into the compartment 16 within the crank case. It will be understood that the engine illustrated 5 is of the four-stroke cycle ty e in which the air charges are drawn direct y into the cylinders during the suction strokes of the-pistons and during the com ression thereof and into which, airless liqui fuel charges under a high pressure and in an atomized condimounted upon the rear end 28 of the crank shaft is a cam 29 which is driven, preferably from the crank shaft, and at a reduced speed relative thereto. A retainer 30 is screwed upon the crank shaft tosecure the cam in a desired position axially, and a bearing 31 is interposed between the crank.

shaft and the cam. In order to drive a cam ata reduced speed from the crank shaft, a gear 32 is splined to the rear end portion of the crank shaft and meshes with a gear 33 which is carried by a shaft 34 supported by the rear cover wall of the crank case. Agear 35 is also mounted upon the shaft 34 and meshes with an internal gear 36 formed onthe inside of the periphery 37 of the cam. A starting jaw 38 is fixed to the extreme rear end of the crank shaft. The reduction driving mechanism can be provided with a non-reversing clutch mechanism, as shown in the co-gending' application Serial No. 419,547, led J anuary' 9, 1930, in order to prevent any kick-back or reversal in starting the engine.

A fuel injecting device, consisting generally of a nozzle portion 39 and a fpump portion 40, is associated with each 0 the cylinders. Each nozzle includes a barrel 41 having a removable end 42 projecting through the wall of the cylinder, the nozzle being rigidly secured to the cylinder by suitable fastening means 43 in the form of studs or bolts. Extending in an axial direction within the chamber 16 in the nozzle-barrel is a valve 44 having a head 45 arranged within the conical end of the-axial passage formed in the section 42 of the nozzle. In order to prevent the head 45 from touching the wall of the nozzle, a member 46 is screwed upon the outer end of the valve stem for engagement with a stop member 47, which can be suitablyadjusted for this purpose. A coil spring 48 surrounds the valve stem, within the chamber in the nozzle, and exerts a pressure against the member 46 normally tending to maintain the valve head in its nearest closing position.

The pump casing 49 is screwed upon a depending neck 50 of the nozzle and a. passage 51 establishes communication between the interior-of the pump casing and the chamber extending through the nozzle and opening into the cylinder, this arrangement of the neck 50 and the casing 49 clamps the pump barrel 52 in position. prevent return of oil or the passage of air from the nozzle chamber into the passage 53 in the pump barrel, there is provided a one-Way check Valve 54 which is normally seated by a suitable spring. A pump plunger 55 is arranged to reciprocate within the pump barrel, and a spring 56 engages the plunger head 57 and is associated in a mannet to normally cause movement of the plunger in a direction away from the nozzle. A fuel manifold extending around the cylinder is composed of a plurality of conduit sections 58 which are associated with unions- 59 secured around each of the pump casings by a nut 60. Transverse passages 61 extend through the pum casings and barrels to establish communication between the manifold unions and the barrel passages 53, there being a reservoir and a low pressure pump (not shown) for moving liquid fuel oil through the manifold and into the cylinders when the plungers 55 are in a relation uncovering the ports 61.

In order to,

With the type of fuel injection devicede- I scribed, the plungers are moved to a position uncovering the ports 61 by means of the springs .56, and when in such relation, liquid fuel will be moved from the manifold to completely fill the passage above the plunger. As the plungers are moved in their injection strokes, they serve to close the ports 61, thus cutting off the fuel supply, and the length of their strokes beyond the point where they close the orts 61 will determine the quantity of fuel 0 arges forced from the nozzles into the combustion chambers.

In order to regulate the length of the plunger strokes beyond the ports 61 to vary the fuel charge quantity, there is provided a ring 62 which is carried by the wall 14. A rack 63 is secured to the ring and co-operating with the rack is a gear segment 64 which is rotated by means of af'shaft 65 to which is fixed a lever 66 adapted to be actuated by suitable mechanism extending to a point for convenient manual operation. The plungers each have associated therewith a push rod formed of two sections 67 and 68, the sections 68 being connected to the ring 62 by links 63 so thatupon rotation of the ring the angular position of the sections 68 will be varied and thereby vary the effective injection stroke of the plungers.

A slipper 69 is associated with each of the push rod sections 68 and is mounted to rock upon a shaft 70 which extends across the compartment 16 and is supported by suitable aligned bearings 71 formed in the partition wall 14 and the end cover wall 12. The end of the slippers with which the push rod sec;

remove .crank shaft is turning in a clockwise direction and the cam is being driven therefrom at one-eighth the speed and in an anti-clockwise direction. With this reduced speed of operation, difiiculty is encountered when the engine is idling in providing a sufficiently fast motion to the pump plungers to create a high enough pressure to cause the fuel charges to be injected into the compressed air charges in the cylinders a sufficient distance to result in an inter-mingling such that compression thereof will cause combustion. The Venturi ports 22 are arranged'tangentially of the cylinders so that air drawn therein is rotating while it is being com pressedand it is requisite that the fuel charges be atomized to a certain extent and penetrate substantially to the axis of the rotating compressed air in order that the fuel may be distributed to form a homogeneous mixture in a very short space of time,-the fuel charges being injected preferably in a range extending between forty and twenty degrees of the crank shaft angle before the pistons reach the top of their compression strokes. With the fuel injecting mechanism so far described, actuation of the slipper heels 73 by the forward end of the lobes 74 will not impart a fast enough stroke to the plungers to produce'the neces sary pressure behind the fuel charges when the engine is running at idling speeds or therebelow, such as it may when being cranked. I

In order to increase the s eed imparted to the plungers upon their in ection strokes, when the engine is rotating in its lower speed range, there is provided mechanism associated with the slipper and the cam, which-will now be described. A rod 7 5 extends radially of the crank case and in substantially a parallel relation with each of the push rods and is pivotally associated with the end of the slipper opposite from the plunger push rod. This rod has a spring retainer 76 associated therewith and a coil spring 77 surrounds the rod and bears against the retainer at one end and against a plate 78 at the other end, such plate extending into an aperture in the crank case and being enclosed by a cover 79. Suitable bolts or studs 80 are provided to secure the covers and the plates to the crank case. A spring washer 81 is arranged intermediate the plate and cover and the head 82 of the rods 75 pro ects throuh such washer. The washers 81 are normaly bowed and serve the function of resisting nfovement of the rods in-,

wardly of the crank case. The slippers are provided with a toe portion 83 for engagement with the periphery of the cam while therear end 84 of the lobes 74 is formed to permit the toes 83 of the slippers to 'substantially immediately be pressed against the base circle of the cam'when the lobes pass beneath the slipper toes. In other words, the rear faces 8% pf the lobes are very 1 abrupt.

' The cam is also provided with a plurality of lobes arranged in a plane on the periphery 37 at the rear of the lobes 74 for actuating slippers 85 with which the valve push rods 25 are associated. The slippers 85 are mounted upon the shafts 70 adjacent the slippers 69 and the lobes are arranged so that the valves 23 will be opened during the exhaust and suction strokes of the pistons.

When the engine is running in its lower speed range, the springs 77 press the toes 83 of the slippers against the periphery of the cam so that when the toes ride upon the lobes of the cam, the spring 77 will be compressed, and the plungers 55 will be' moved into a position uncovering the ports 61. Thus, when the lobes 74 pass from beneath the toes 83 of the slippers the builtup spring energy will cause a fast movement of the toes and of the siippers toward the base circle of the cam and such movement will impart an injection stroke to the fuel plunger push rods and the plungers. In this manner, when the cam is turning slowly, a much faster movement of the plungers will result than if they were actuated by the contact of the heels '73 with the cam lobes, and consequently, a much higher pressure is exerted upon the fuel to inject charges thereof into the compressed air in the cylinders.

It is found, however, that with such fuel injecting mechanism when the engine is running in its higher speed range, the cam moves aster than the unloading reaction of spring end, and, consequently, the cam moves several degrees in its rotation before the toes 83 are moved toward the base circle by the springs 77. This delays the time at which the. fuel charges are injected into the cylinders, and such a condition is undesirable because of the short space of time in which the fuel must be intermingled with the compressed air in order to provide a desirable and efiicient operation of the engine. In order to overcome this undesirable condition, the length of the lobes 74 and the distance between the heel and toe of the slippers is arranged so that during a fast cam rotation,

- the forward end of the lobewill strike the under. In other words, the lag of the springs 77 in functioning, as it effects the slippers,

- when the cam is moving fast has been compensated for by constructing and associating the lobe and the slipper so that injection strokes will be caused by another means of contact which is accurate and re ular in its action regardless of the cam spce With this arrangement, the length of the lobes 7 4 must be only slightly shorter than the distance between the heel and toe of the slip rs. It will thus be seen that when the engine is running in its slower speed range the releasing of the springs 77 causes fast fuel injection strokes of the plungers, while a contact between the forward end of the cam and the heels of the slippers will cause a fuel injection stroke when the cam is run-' ning in its higher speed range. With this form of plunger actuating mechanism, the timing of the fuel injection will remain substantially constant regardless of the speed of the engine and an efiicient engine operation will result.

Pressure behind the injected fuel is maintained suflicient to insure the proper intermingling of the fuel with the air.in the properly atomized condition so that in this manner stalling of the engine, when running at slow speeds, and delayed timing, when running at high speeds, are substantially eliminated.

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 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 scope ofthe invention.

What isclaimed is:

1. In a fuel injection mechanism for internal combustion engines, a pump plunger,

plunger operating mechanism, a spring for actuating the mechanism to cause plunger injection strokes, another spring for retracting the plunger mechanism between injection strokes, and an engine rotated cam for compressing and suddenly releasing the actuating spring to cause an effective stroke of the plunger below 'a predetermined engine speed, said cam co-operating-directly with the plunger operating mechanism above a predetermined engine speed to cause the plunger injection stroke.

2. In a fuel injection mechanism for internal combustion engines, a pump barrel having fuel inlets therein and an. outlet spaced from the inlets, a plunger reciprocable in the barrel and controlling the inlet ports, plunger operating mechanism, a spring for actuating the mechanism to causethe plunger to close the inlets and force fuel through the outlet, another springfor-retracting the plunger sufliciently to uncover the fuel inlets in the barrel between injection strokes, and an en ine driven cam for compressing and sud enly releasing the actuating spring to cause effective plunger strokes below a predetermined engine speed, said cam coacting directly with said operating mechanism to cause eifective plunger strokes above the predetermined engine speed.

3. In a fuel injection mechanism for internal combustionengines, a pump plunger, operating. connections for the plunger including a rock lever, a spring pressed member engaging one end of the rock lever, a spring for causing retraction of the plunger between injection strokes, a spring pressed member exerting pressure againstthe rock lever in a direction to cause an injection stroke of the plunger and exerting greater pressure than the retraction spring, and an engine driven cam for actuating the rock lever to build up energy behind the member and then suddenly release the same to cause an effective stroke of the'plunger below a' predetermined engine speed, said cam coacting directly with the rock lever above the predetermined engine speed to cause the effective injection strokes of the plungers.

4. In a multi-cylinder internal combustion engine, fuel injection devices each including a plunger, individual means retracting the plungers between injection strokes, mechanism including circularly disposed rock levers associated one with each plunger, reciprocable members under spring and cause plunger actuation of the associated mechanism, and a cam for moving the rock levers to store energy behind the recipr'ocable members and then suddenly release the same, said cam directly actuating the rock levers to cause plunger injection strokes whenthe engine is running above a predetermined speed.

5. In .an internal combustion engine, mechanism for injecting atomized liquid fuel under high .pressure into air in the combustion chamber comprising a nozzle unit, a pump casing communicating with the nozzle unit, a reciprocable plunger adapted to trap liquid fuel in the casing and to eject the trapped liquid fuel from the nozzle, a rock lever, a push rod structure intermediate the plunger and one end of the rock lever, a rod bearing against the other end of the rock lever, an engine rotated cam having lobes projectin from its base circle, said rock lever bearing against the periphery of the cam, a spring associated with the plung er exerting pressure against the push rod 105 tension associated to actuate the rock levers eflective actuation of the plunger.

6. In a fuel injection mechanism for internal combustion engines, a pump barrel having an inlet and an outlet, a nozzle. communicating with the barrel outlet, a plunger reciprocable in the barrel, said plunger controllin the inlet port, a cam having lobes extending from a base circle, engine driven means for rotating the cam, a rock lever pivoted intermediate its ends adjacent the cam,

an extension at each end of the rock leverprojecting in a direction toward the cam,

a rod structure intermediate one end of the rock lever and the plunger, a rod bearing against the other end of the rock lever, a spring exerting pressure against the rod structure in a direction toward the rock lever, another spring exerting pressure against the rod in a direction toward the rock lever, said rod spring exerting greater pressure than the other spring, rotation of the cam causing the lobes to tip the rock lever in a direction compressing the rod spring and then suddenly releasing the same, the length of the cam lobes being slightly less than the distance between the rock lever extensions to cause engagement of the lobes with one of the extensions prior to the return of the other extension to thescam base circle upon release of the rod spring, when the cam is rotating above a predetermined speed.

7. In a fuel injection mechanism for internal combustion engines, an engine casing, a pump barrel having a fuel inlet and an outlet, a plunger reciprocable in the barrel and controlling the inlet, a nozzle "arranged in communication with the barrel outlet, an engine driven cam rotatable within the casing, a rock lever pivoted intermediate its ends within the casing and ma position to be engaged by the lobes of the cam, said rock lever having a toe-extension adapted to ride upon the periphery of the cam, a rod engaging the rock lever, said rod being piloted within the casing, a coil spring encircling the rod and associated therewith and with the casing to exert pressure againstthe rock lever in a direction toward the cam, a rod structure intermediate the plunger and the heel end of the rock lever, and spring means for holding the rod structure against the rock lever.

8. In a fuel injection mechanism for internal combustion gngines, a pump barrel having fuel inlets therein and an outlet, a nozzle communicating with the outlet of the barrel, a plunger reciprocable. in the barrel and controlling the inlets, a rock lever, a rod structure intermediate one end of therock lever and vthe plunger, spring means for maintaining the rod structure in contact with the rock lever, a rod engaging the other end of the rock lever, a cam cooperating with the rock lever, spring means urging the rod against the rock lever to cause the adjacent end thereof to rideupon the periphery of the cam, said ca'm having lobes formed to raise and suddenly release the end of the rock lever with which the rod is associated, and sh'oclg'absorbing means associated with the rod adapted to become operative whenthe rod is released from the cam lobe.

9. In a fuel injection mechanism for internal combustion engines, a pump barrel having a fuel inlet and a fuel outlet port, a plunger reciprocable in the barrel and controlling the inlet port, a nozzle associated with the outlet port, an engine casing, an engine driven cam mounted within the casing, a rock lever within the casing" and pivoted thereto intermediate its ends,

a rod structure intermediate the plunger and one end of the rock lever, a rod extending through the casing and bearing against the other end of the rock lever, said rod having a head portion exterior of the casing,

shock absorbing means intermediate the casv ing and the head of the rod effective upon the movement of .the rod inwardly of the 'casing, a spring forpressingthe rod structure. against the rock lever and a coil spring for pressing the rod against the rock lever, said coil spring exerting a greater force than the rod structure spring to cause the adjacent end of the rock lever to ride upon the periphery of the cam, said cam being formed with lobes causing movement of the rock lever in a direction to compress the coil spring and'suddenly release the same.

10. In a fuel injection mechanism for internal combustion engines, a pump plunger, an engine driven member, plunger operating means including a rock lever d1- rectly actuated by the driven member above a predetermined engine speed, and releasable compression means co-operating dlrectly with the plunger operating means and imparting sudden operative movement thereto below a predetermined engine speed.

11. In a fuel injection mechanism for internal combustion engines, a pump plunger, plunger operating means including a pivoted member, an engine driven cam engaging the pivoted member to actuate the plunger when the engine. is running above a predetermined speed, and releasablecompression means co-operating with the pivoted member to suddenly actuate the plunger abutment at each end, an engine driven cam engaging the rock lever, and spring pressed means engaging one end of the rock lever, said cam operating in a direction so that the lobes will first engage the end of the cam with which the spring pressed means co-operates to store up energy therein which is released before engagement by the lobes of the other end of the rock lever to thereby impart sudden rockingmovement to the lever in a direction effectively operating the plunger.

In testimony whereof, I have hereunto subscribed my name this 17th day of J uly,

EMlWA F. AWOOLSON, Ewemtm'm of the Estate of Lionel M. Woolson, Deceased.

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