US2346160A - Fuel injection apparatus - Google Patents

Description

April 11, 1944. o. FRENCH FUEL INJECTION APPARATUS Filed April 4, 1941 2 Sheets-Sheet 1 INVENTOR.

April 11, 1944. L. o. FRENCH FUEL INJECTION APPARATUS Filed April 4, 1941 2 Sheets-Shea, 2

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merited-Aer. 11,1944

' 'umrap STATES PATIENT OFFICE rust. imecrron mana'ms rmisoJi-encnmiwaukeewls. Application April 4', 1941, Serial No. same: i

12 Claims (cine-139) The invention relates to fuel injection apparatus and. more particularly to liquid fuel injec- 'tion mechanism for internal combustion engines.

The most widely used fuel injection pumps today provide a period of low pressure at the beginning of the delivery stroke, a high delivery pressure, and then a release of the high pressure through the operation of a by-pass valve usually formed by cooperative ports between the piston and its barrel whose operation is varied by rotating thepiston relative to the barrel. In most of thesepumps the timing of the beginning of injection as determined by the pump is constant and the timing varied by varying the angular advance of the pump drive cam. Manufacture of the, pumps above described requires considerable precision machine work including the cutting of relief edges on the plungers and the careful fitting of the plunger rotating mechanism which included toothed parts for each cylinder. Owing to the large amount of machine work that has to be done and the care that has to be exercised in stroke and return quickly independent of engine speed to'its initial position, thus producing a:

quick drop in. pressure and insuring a sharp cut oil of the-discharge valve which may be the injection valve of.- the engine or a valve controlling the operation of such injection valve. As a further advantage in the quick return of the plunger,

. v Fig. 4 is a detailed vertical sectional view taken the manufacture of these pumps, the cost is high,

and this to some extent has interfered with a more widespread sale of high speed Diesel'type engines. Furthermore, only relatively skilled mechanics understand the operation of pumps.

- The object of the present invention is to provide a pump which accomplishes the general result of the more complicated and costly pumps above described but which may be produced much more cheaply than said prior pumps and includesa fewsimple parts whose actions are readily visible while the pump is operating and easily understood and which also has certain advantages hereinafter referred to over said by-pass valve type pumps. More particularly, the invention embodies a pump whose plunger is timed by the engine and driven on its delivery stroke through a drive connection which may be rendered ineffective to drive the plunger during and at differ-'- ent points of the available delivery stroke from full stroke to no stroke to var the amount of fuel delivered to the engine and whose release permits a quick return of the plunger, independent of the control of the drive connection, to its initial position. With such a means for controlling the movement of the plunger the construction of the pump itself is greatly simplifled,.as the f a run an inlet port in the barrel during the initial part of its delivery stroke, be released from the. g

- enginedrive while in full motion on the delivery 5 A plunger follower 23 is slidably mounted in these on the line 4-4 of Fig; 1, parts being broken away;

Fig. 5 is a view similar to Fig. 1 showing certain modifications. parts being broken away.

Fig. 6 is a detailed sectional view showing certain modifications;

Fig. 7 isa detailed sectional viewshowing certain modifications.

The invention relates to fuel-injection apparasuitable metal having axially alined bores H and I2 and a cross bore' l3 in which end caps or plugs l4 and ii are mounted. An engine controlled and operated plunger actuator member IE is slidably mounted in the-bore H and I is keyed thereto by a pin ll working in slots 18 in said casing normally covered by an oil sealing sleeve l9 removably mounted on said casing.

A spring. urges the member it into engagement with one end of a medially pivoted lever 2| .whose other end is urged by said spring-against an engine driven cam 22 which may be designed to impart either constant velocity or uniformly accelerated motion or any desired kind of controlled ,motion to the pump livery stroke.

plunger on its dey the bore l2 and bears against a pump plunger 24 which reciprocates in a barrel 25 provided with forked ends of the member I! and formed at its otherend 23 to ride over a surface provided on a flat sided projection 34 formed on the follower 23 with which surface it is in thrust connection until released by an adjustable cam or trip control member 3| pivotally supported on the plug i4 and providing a control surface 32 with which a part 33 of the member 24 is normally held in contact by a spring 34. The surface 32 is in a chordal plane either at or close to the center of rotation of the controlmember 3| which provides a maximum arc of adjusting movement for said member and makes it easy to operate. The projection 34 is guided against turning during reciprocation of the plunger between the flat surface of the plug l4 and inner edge of the plug ii. The plugs l4 and I! may be secured in position by hook bolts 35 whose heads engage over the plug l4 and whose shanks pass through holes in the casing and in the outer flange of the plug II. The plug I4 is angularly adjustable so as to adjust the control member 3| relative to the finger 23. The member 3| has an arm 3| secured thereto which may be either manually or governor operated.

During the inward or delivery stroke of the member ID, the finger 23 thereon pushes on the follower 23 and thus moves the plunger 24 inwardly' to first overrun and cut off the ports 26 and then force the fuel past the spring closed discharge valve 36 and through piping to a separate hydraulically operated fuel injector valve (not shown but of conventional form) or through nozzle passages 31 of a unit injector into the engine cylinder or its supply manifold. During this delivery stroke depending upon the adjustment of the control 3|, the member 23 is pushed outwardly or laterally along (see Fig. 2) and finally from the top of the projection 30 (see Fig. 3) until its driving connection therewith is broken, and as soon as this occurs, the motion of the plunger 24 is immediately reversed and the spring 2'! acts to return it to its initial position as shown in Fig. 3 regardless of the position at that time of the member i6 and finger 28 which it will be noted is so formed as to permit this retin-n movement without its interference. Thus with this arrangement injection may always start at the same time or be changed through any suitable advance or retard mechanism associated with the cam 22 or its shaft and continue for full stroke or for any desired fractional amount of full stroke to no stroke, without changing the rate of injection as determined by the cam 22, by the angular shifting or rotating of the control member 3| which does not produce any side thrust on the plunger and which operates so easily that it is advisable to provide a certain amount of frictional effort to tum it. The quick return stroke of the plunger even at starting, insures the eflicient operation of the pump at low engine speeds. Shifting the control 3| so that the fingers stroke relative to the projection 30 is reduced causes the release of the finger therefrom sooner in the stroke of member IS with the result that the plunger 24 is given a shorter stroke until finally the finger 28 is prevented from contacting the projection 30 at all, and no fuel is delivered.

In the modification shown in Fig. 5 the engine controlled member 40 is slidably keyed to a hardened steel bushing 4| by a pin 42 working in slots 43 in said bushing, said pin having the finger 44 pivotally mounted thereon. This finger at its lower and bears against a surface 45 on the outer end of a lever 43 which is pivotally mounted on an eccentric 41 whose shaft 48 is .journalled in a casing 49 of aluminum alloy or other light weight metal. The outer end of the lever 45 has a rounded part 50 which bears against the top of a pump plunger follower 5| that is slidably mounted in a hardened steel bushing 52 secured to the casing 49. A fixed trip surface 53 is secured for limited range of initial adjustment to thecasing 49 by screws 53. A spring 44' normally holds the finger 44 in contact with the surface 53. The general operation of this form is the same as that previously described, but in this form the amount that the finger 44 is displaced by the trip surface 53 remains constant while the effect of this displacement on the stroke of the plunger is varied by moving the lever 46 lengthwise relative to the finger through the adjustment of the eccentric 41. Upward movement of the lever 46 is limited by a stop pin 46'.

Instead of a unit injector ora separate pump,

.the invention may be embodied in a form shown in Fig. 6-which has certain advantages of both these types. In this form instead of the plunger follower having a part directly engaged by a tappet operated member there is a hydraulic operating column betwee these two parts which takes the place of the usual lever and push rod of a lowered cam shaft arrangement, or the lever of a more elevated cam shaft, so that the cam shaft may be in the lowered position of the valve cam shaft in the usual L-head and overhead valve engines.

The pump, a unit with the injector, is formed by a plunger 54 working in a barrel 55 mounted in a casing 56. The barrel has inlet ports 51 supplied with fuel through grooves 58 that may b connected with a supply line 59 also shown connected by a conduit 62 with a space formed by the casing 58 and a cylinder 6| in threaded engagement therewith. A spring closed outwardly opening discharge valve 63 controls the flow of fuel to the spray passages 64. The plunger is normally moved outwardly on its suction stroke by a spring 65, and its upper end has a non-centering contact with a hydraulically operated piston 66 reciprocating in the cylinder 6| which is connected by piping 51 to a similar cylinder 68 in which a piston 69 having a suitably guided projection 69' reciprocates, this piston being similar to the plunger follower 23 of the first described form and similarly operated by a pivoted finger 10 mounted on a reciprocatory tappet member II held by a spring 12 in engagement with the timing and operating engine driven cam 13 mounted on a shaft journalled in a housing 14 that may form part of the crank case of the engine or be formed as a separate unit therefrom if desired. The tappet member ii is slidably keyed byfinger pivot pin 15 to a sleeve I6 secured to the housing 14. The finger is controlled by a control member ll similar to member 3| against which his yieldingly held by a spring 18. The operation of this arrangement is similar to the first described form, the plunger operating force being transmitted through. the I hydraulic column between the pistons 58' and 89 whose diameters are considerably greater than the damete'r of the plunger 54, so that the hydraulic operating pressure may be low compared a to the fuel injection pressure. To keep'the hydraulic system supplied with fiuidthe plunger 88' may-have an opening 18 in it normally closed by a check valve I8 andits spring 8| but permitting passage or fluid l'romthe space 50 to the piping between the pistons 88 and 59 at periods or low pressure. The piping 81 may include a riser 82 closed by a plug 88 to assist in the initial priming of the system. The hydraulic fiuid may as here shown be a part of the 1'51V fuel delivered to the space 58 by a fuel pump working against a spring closed relief valve (not shown) of from five to ten pounds pressure, or the supp y of fuel to the injector may be separate and a' heavier oil such as a lubricant may be delivered to the space 89 and used in the hydraulic system.

Some forms of spray nozzles or fuel injectors require that fuel be furnished .to them at relatively high velocity, so thaton starting or at low engine speeds they do not work efficiently. Where the apparatus embodying the present invention is to be used with such equipment instead of the engine controlled member being operated directly by an engine driven cam it may be operated by a spring motor whose action is timed by the engine but which causes the finger carrying member to be operated at substantially the same rate regardless of engine speed, and in Fla. 7 I have shown one such motor for this purpose in which an oscillatory shaft 84 is moved in one direction by a lever 85 secured thereto and held by a spring 88 against a suitable engine operated cam (not shown), said shaft having a toothed disk 81 mounted thereon adapted for engagement with a pawl 88 yieldingly held against said disk by a spring 89. The pawl 88 is pivotally connected by a pin 90 with a reciprocatory member 9| which is guided in a cylinder 92 and keyed bythe finger pivot pin 93 working in slots 94. An energizing spring 95 is interposed between a shoulder 96 on the member 9| and a flange 91 on the cylinder; The clutch finger 98 is mounted on the pivot pin 93 and is similar to the finger 28 or 10 and adapted to cooperate with the plunger follower members previously described and the control member 8| or 11. With this structure movement oi. the disk 81 in an anti-clockwise direction pulls upwardly on the pawl link 88 and member 9| against the pressure of the spring 95, thus storing up energy in said spring 95 and moving the finger 98 back from a release position shown with finger 28 in Fig. 2 to the initial position shown in Fig. 1 and in this position the continued movement ofthe disk 81 causes it to push the pawl 88 out 01 en- 00 gagement with it and permit the spring 95 on its releasing its compression to push the member 9| and consequently the finger 98 outwardly independently of engine speed and thus operate the pump plungers of the structures previously shown and described. It is to be noted that the finger 98 may be in a release position for a considerable period of engine crank travel without effecting the follower which it operates and which is free to allow the return or the pump plunger independent of engine speed, and the amount of energy to operate the plunger may be the same at all speeds and regardless of the load.

I desire it to be understood that this invention is not to be limited to any particular i'ormor ar- 78 2,846,160 a I g 3 rangement of parts" except such limitation as included in the claims. v

What I claim as my invention is:-

1. In a fuel injection apparatus ior'internal" combustion engines, the'combination wast reciprocatory pump plunger and'a spring i 'ormov-' ing said plunger on itsnon-delivery stroke, oi,- engine controlled means for moving said plunger on its delivery stroke. includingl a tri pable member, and control trip means operable during the, delivery stroke to' trip. said trlppable member to render said engine controlled means incfiective to move said plunger to thereby control the efiective" stroke ofsaidplunger and, permit said spring to quickly return said plunger immediately after trippingis efiected and independentlyof the; speed 01'- said engine controlled means.

2. In a fuel injectionapparatus, the combination with a reciprocatory pump plunger and a spring for moving'sa'idplunger on its non-delivery stroke, of an engine-controlled plunger actuator,v means including a breakable drive connectionconnecting said actuator with said plunger including relatively movable thrusttransmitting members, and control means operable during the delivery stroke of said actuator to move said members relative to each other for causing the breaking of said drive connection during the delivery stroke of the plunger to determine the efiective stroke' of said plunger and to permit said spring to quickly return said plunger immediately after the breaking of said drive connection and before and independentlyv or the return oisaid actuator.

, 3. In a fuel injection apparatus for internal combustion engines, the combination with a reciprocatory pump plunger and a spring for moving said plunger on its non-delivery stroke, of a reciprocatory engine controlled member provided with is pivoted clutch finger, a reciprocatory plunger operating member operatively connected to said finger, and a trip means for releasing said finger for varying the .stroke of said plunger operating member as compared to said engine controlled member.

4. In a'fuel injection apparatus, the combination with a reciprocatory pump. plunger and a spring for moving said plunger on its non-delivery stroke, of an engine controlled reciprocatory member provided with a pivoted clutch finger, a 0 plunger moving member provided with a projection in thrust engagement with said finger, and a rotatably adjustable finger deflector member with which said finger engages during the delivery stroke to release said finger from thrusting en-r gagement with said projection and permit the quick return of said plunger independent 01' said engine controlled member.

5. In a fuel injection apparatus, the combination of a casing having alined bores and a bore at right angles thereto, an engine controlled reciprocatory member slidably mounted in one of said alined bores and provided with a movable clutch finger, a pump plunger operating member slidably .mounted in the other alined bore and provided finger deflector member mounted in said casing, a pump plunger operating member slidably mounted in said casing, a lever between said finger and plunger operating member and in thrust connection therewith, said lever being shiftable to vary the efl'ective thrust connection between said finger and lever under theaction of said deflector member during the delivery stroke of said reciprocatory member.

7. In a fuel injection apparatus, the combination oi a casing having alined bores and a bore at right angles thereto, an engine controlled reciprocatory member slidably mounted in one of said alined bores and provided with a pivoted clutch finger, a pump plunger operating member slidably mounted in the other alined bore and provided with a projection for thrust engagement with said finger, plugs for the ends of said right angle bore and forming guides for said projection, one of said plugs being angularly adjustable relative to said casing, means for securing said last named plug in adjustable position, and a finger deflector member rotatably mounted in said angularly adjustable plug for moving said finger out of thrust en agement with said projection during the delivery stroke of said plunger operating member.

8. In a fuel injection apparatus for internal combustion engines, the combination with a reciprocatory pump plunger and a spring for moving said plunger on its non-delivery stroke, of an engine-controlled plunger actuator, a drive connection between said actuator and said plunger including relatively movable members, and control means operable during the delivery stroke of said actuator to move said members relative to each other to render said drive connection ineffective to move said plunger to thereby control the effective stroke of said plunger and permit said spring to quickly return said plunger immediately after said drive connection is rendered ineflective and before and independently of the return of said actuator.

9. In a fuel injection apparatus for internal combustion engines, the combination with a reciprocatory pump plunger and a spring for moving said plunger on its non-delivery stroke, of an engine-controlled plunger actuator, means including a releasable drive connection having relatively movable thrust transmitting members connecting said actuator with said plunger, and control means for causing the release of said drive connection during the delivery stroke of the plunger to vary the stroke of said plunger as compared to said actuator and free said plunger from the control of said actuator to permit said spring to return said plunger immediately after the release of said drive connection and during the delivery stroke of said actuator and at a rate of speed independent of the speed of the engine.

10. In a fuel injection apparatus for internal combustion engines, the combination with a reciprocatory pump plunger and a spring for moving said plunger on its non-delivery stroke, of a reciprocatory engine controlled member provided with a movable drive connector, a reciprocatory plunger operating member, said drive connector having a driving connection with said plunger operating member, and means for varying the stroke of said plunger operating member as compared to said engine controlled member, including means for releasing said connector from its driving relation in said connection to free said plunger from the control of said engine controlled member and permit said spring to return said plunger immediately after the release of said connector and before and independently of said engine controlled member.

11. In a fuel injection apparatus for internal combustion engines, the combination with an injector including a reciprocatory pump plunger, of plunger operating mechanism including a constant stroke engine timed member and variable stroke thrust member for imparting variable strokes to said plunger from the same initial position and without changing the beginning of the injection the speed of the engine and immediately after the release of said plunger from said engine timed member, and means distinct from said plungerreturn-spring for returning said engine timed member.

12. In a fuel injection system for internal combustion engines, the combination with a reciprocatory pump plunger and a spring for moving said plunger on its non-delivery stroke, of a plunger actuator, means controlled by the engine for operating said actuator at a rate independent of the speed of the engine, a drive connection between said actuator and said plunger including relatively movable members, and control means operable during the delivery stroke or said actuator to move said members relative to each other to render said drive connection ineffective to move said plunger to thereby control the effective stroke of said plunger and permit said spring to quickly return said plunger immediately after said drive connection is rendered ineflective and before and independently of the return of said actuator.

LOUIS O. FRENCH.

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