US2031346A - Fuel injection pump - Google Patents

Description

Feb.- 18, '1936. G, A. WAHLMARK FUEL INJECTION PUMP Filed oct. 1'7. 1932 2 Sheets-Sheet 1 Feb. 1g, 193e. y G. A. WAHLMARK 2,031,346v

FUEL INJECTION PUMP Filed Oct. 1'7, 1952 2 Sheets-@Sheet 2 .Patented Feb. 1s, 1936 FUEL INJECTION PUMP Gunnar A. Wahlmark, Rockford, Ill., ais-signor of one-half to Charles H. Rystrom, Rockford,`

Ill.

Application October 17, 1932, Serial No. 638,070

6 Claims. (Cl. 103-3) More particularly the invention relates toa pump for injecting fuel into the cylinders of an internal ycombustion engine under pressure, and for controlling the speed and power output of the engine by varying the amount of fuell injected.

By injecting fuel directly into the cylinder of an internal combustion engine, under high pressure, a greatlysuperior performance is obtained over that which is had when using a carburetor. Maximum power is substantially increased at all speeds. This increasels due partly to the elimination of the pressure drop through the vcarbu-` retor and partly to the direct eiects of the spray itself. Since the supply o f fuel to the engine cylindersis under the direct control of the operator (and is not dependent upon the suction of the engine as when using a carburetor)` the acceleration and also `the operation of the engine under load is greatly improved. Furthermore the idling and starting characteristics of the engine are greatly improved inasmuch as slower idling is possible, and an instantaneous starting at low atmospheric temperature can be readily obtained.

By injecting fuel in measured quantities to the cylinders and accuratelymetering the quantity of fuel supplied to each cylinder, an even distribution of fuel is obtained together with the resultant economy and improved performance.

It is a general object of the invention to provide a new and improved fuel injection pump for internal combustion engines.

Another object is to provide, for internal combustion engines of the type used in automobiles, a multiple cylinder pump of new and improved construction for metering, timing and injecting quantities of fuel into the cylinders in properly timed relation with the movements of the pistons and the operation of the ignition system, thereby attaining such improved performance.

Another object is to provide'an improved fuel injection pump comprising a plurality of vertically disposed cylinders arranged in a circle, a

' member driven from the engine for reciprocating pistons in said cylinders in properly timed relation, and means operable by the accelerator of an automobile for varying the stroke of the pistons to vary the quantity of fuel injected into the cylinders.

Another object is to provide such a vpump embodying means for-depressing all of the pistons simultaneously for the purpose of priming the cylinderspreparatory to starting and for pumping" vapor out of the system.

Another object is to provide such a pump with accelerator operated meansyfor varying the stroke of the pump pistons together with manually operated means for increasing and decreasing the stroke of the pistons beyond the `normal stroke obtained by actuating the accelerator of the car.

Other objects "and advantages will become 5 readily apparent fromthe following detailed description taken in connection with the accompanying drawings, ln which:

Fig. 1 is a vertical central section through a preferred form of pump.

Fig. 2 is an enlarged fragmentary section through a pump cylinder.

Fig. 2a is a similar view showing a modied form of valve.

Fig.- 3 is an enlarged fragmentary section l5 through the upper end of a piston, showing the piston actuator in operative relation to the piston.

Fig. 4 is a horizontal section approximately along the line 4-4 of Fig. 1.

Fig. 5 is a horizontal section approximately 20 along the line 5 5 of Fig. 1.

Fig. 6 is a horizontal section approximately along the line 6 6 of Fig. 1.

. While there is illustrated in the drawings and shallherein be described in detail a preferred embodiment of the invention, it is to be understood that I do not thereby intend to limit the invention to the specific form and arrangement shown, but aim to cover all modications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, the fuel pump comprises a plurality of pistons Il and cylinders I 2, eight in number, arranged in a circle, each pump cylinder being yadapted to be connected to'an engine cylinder by a suitable conduit I4. The pistons are arranged to be reciprocated in properly timed relation to the engine crank shaft and the stroke of the pistons is 40 arranged to be varied to vary the quantity of fuel injected thereby to vary the speed of the engine. Preferably, the fuel is injected into the engine cylinder through a check valve type of nozzle device. Furthermore, as illustrated most clearly in Fig.\2, a check valve I6 is provided on the lower end of each pump piston so as to admit fuel into the pump cylinders and prevent return iiow of the fuel, and ball check valves I1 are inserted in the conduits leading to the injection nozzles so as to provide a relatively small compression chamber in the pump cylinders.

Referring in more detail to the drawings, the pump is illustratedas comprising a baseI 20 having a plurality of vertically extending bores arranged in a circle so as to provide leight vertically extending cylinders I2 having their lower ends closed. 'I'he pistons II are positioned in the cylinders and are preferably mounted in sleeve liners 2| which nt into the bores and have their upper ends projecting upwardly from the base.

'Ihe pump pistons II are arrangedto be reciprocated in timed relation to the movements of the engine pistonsand as illustrated herein, are arranged to be driven from the crank shaft of the engine by means including a stub shaft 25 ro tatably mounted on a vertical axis in the lower portion of the base 20. A sleeve 26 extends through a central bore inthe base 21 and has an actuator shaft 26 rotatably mounted therein. 'Ihe lower end of this actuator shaft is cut away at 29 and is arranged to fit into a slot 30 in the upper end of the stub shaft 25 so as to be driven thereby. The short shaft has a shoulder 3| engaging a bearing disk 22 which is secured to the sleeve 26 by means of a collar 33. The actuator shaft 28 carries a tapered roller 34 rotatably mounted on an inclined radially extending pin 35 so as to be freely rotatable thereon, and is preferably balanced by means of a weight 36. During rotation of the shaft 26 the roller 34 is arranged to actuate the pistons II.

Preferably the pistons have cap members or lportions 40 on the upper ends thereof Vslidable in bores 4I in a spider 42 which is slidable vertically on the upper end of the sleeve 26. Thus during the rotation of the shaft`28 the pistons are depressed one by one by means of the roller 34. The pistons are returned to their raised positions by means of coiled springs 43 positioned between the pistons and the closed 'ends of the cylinders I2. The members 40 have annular flanges 4 I at their lower ends arranged to engage the spider 42 to limit the upward movements of the pistons. As illustrated herein, the upper ends of the members 46 (Fig. 3,) are grooved at 44 to Y conform to the curvature of the rollers 34 so as to place the pressure on the center of the pistons and eliminate side thrust. As will be apparent from Fig. 3, the arcuate portion formed on the cap 40 by the groove 44 is on the advance side of a vertical plane extending through the axis of the roller and the left-hand edge of the groove.

Fuel in liquid form is supplied to a port -45 (Fig. 4) in the base 20 by means of a conduit 46 (Figs. l and 4), and means is provided to carry iiuid from this conduitto the lower ends of the pistons so as to supply uid to the cylinders when they are raised. In the preferred form of the invention the pistons are provided with annular grooves 41 and have transverse ducts 48 therein communicating with the upper ends of vertical ducts 49 ywhich extend downwardly to the lower ends of the pistons, as shown most clearly in Fig. 2. The lining sleeves 2i are also provided with transverse ducts 50 which communicate with an annular chamber I formed between an annularly grooved' ring 52 and the top of the base 20. This ring is secured to the base by means including a. collar 53 on the sleeve 26 and a plurality of screws 54 (Fig. 4). Fuel is supplied to the chamber 5I from the conduit 46 by means of the horizontal port 45-and a vertical port 55.

As illustrated in the drawingsthe lining sleeves are provided with annular anges 2|' which are clamped intermediate the ring 52 and the top of the base so as to seal the lining to the base.

As mentioned hereinbefore, check valves I6 are preferably provided onv the lower ends of the pistons II. The devices are in the form of thin accises disksV or plates without stems, and are arranged Y to engage the ends of the 'pistons to close the lower endsof the ducts 49 and are normally held in engagement with the pistons by means of .coiled springs 58 (Fig. 2) positioned between the preferably provided in outlet ports 65 from the' cylinder so as to prevent fluid in the conduits I4 from being drawn back into the cylinders. It will be readily apparent that, with the construction disclosed, any fuel leaking back along the pistons isfreturned to the annular supply groove 41 or the chamber 5I, which are under low pressure, so that there is no opportunityl for the fuel to get into the driving mechanism within the casing 1I. In the form illustrated in Fig. 2a the spring 58 is omitted, the bushing 6thl being curved upwardly at 6I!b to support the disk valve I6 in its open position. Preferably the valve has a movement approximately equal to its thickness.

In Aorder to vary the quantity ofA iiuid discharged by each piston I I, means is preferably provided for adjusting the shaft 28 axially. In the form illustrated in the drawings (Fig. 1) the upper end of this shaft is rotatably mounted in a bushing supported in a casing or cover 1I which surrounds and encloses the mechanism of the pump above the base 20. This cover is detachably secured to the base by means of screws 12. "I'he upper end of the shaft 28 is rounded at 13, and is engaged by the lower end of a control shaft 14 which is'rotatably mounted in a bushing 15, which bushing in turn is rotatably mounted inthe upper end of the casing 1 I. control shaft 14 has a cam formation or portion of a screw thread 16 formed on the lower end thereof, which cam is arranged to engage a corresponding cam formation 11 on the lower end of the bushing so thatwhen the control shaft 14 is rotated it is moved axially in the bushing '15 so as to move the drive shaft 28 axially. Preferably a coiled spring 18 is positioned between the lower end of the drive shaft and the stub shaft 25 so as to maintain the drive shaft in contact with the en d of the control shaft. As illustrated ...in Fig. 1, the control shaft 14 carries an arrn 80 on its upper end and may be connected to the foot pedal accelerator of an automobile.

In order to control the idling speed of the engine and to vary the speed, an arm 90 (Fig. 1)

is secured to the sleeve 15 and may be connected by means of a suitable rod'l to a control handle on the dash. By rotating the sleeve the control shaft 14 is adjusted axially through the action of the cams 16 and 11. i

In addition means is preferably provided for injecting fuel into all of the engine cylinders l simultaneously for starting purposes. .As illus- The` ' tion means is provided so that this priming action may be accomplished from the dash. For this purpose a pin 9|)y (Fig. 1) is slldably mounted in the upper portion of the casing 1|,and has its lower end positioned in a bore 99 in the member 95. 'I'he pin 98 is provided with a collar |00 engaging the upper end of the member 95. Pivotally mounted on the casing 1| on a pin |0| is a curved lever '|02 the upper end of which engages the pin 98. The lower end of the lever |02 may be connected by means of a link or rod to a control handle on the dash. Thus by actuating the control lever |02` the operator can prime all engine cylinders simultaneously. 'Ihis means for reciprocating all of the pistons simultaneously serves also as a means for .'pumping vapor and entrained air out of the intake lines of the pump.

If desired the priming mechanism can be connected to the starter of the car so that the priming is accomplished simultaneously with the starting.

is obtained. Furthermore by directly varying the strokes of the pistons to vary the amounts of fuel, a simple and efllcient accelerating and power varying means is provided. As illustrated herein the strokes of the pistons are varied by adjusting the drive shaft 28 axially and by rounding the upper end of the drive shaft which. engages the control shaft there is no tendency for the control shaft to rotate with the drive shaft. Lost motion is effectively eliminated by maintaining thev drive shaft inengagement with the thrust bearing formed at its upper end and by providing the coiled springs for urging the pistons upwardl ly into engagement with the cap members and maintaining the cap members normally with the flanges 4| against the spider 42. By providing a tapered roller freely rotatable on a pin carried in an inclined position on the drive shaft a perfect rolling laction between the roller and pistons is obtained, thus eliminating friction and wear and permitting the use of a widevcontact between the roller and pistons. I

The construction disclosed effectively eliminates any possibility of the fuel getting up into the operating mechanism. As pointed out hereinbefore any leakage past the piston or lining sleeve is caught in the low pressure supply groove ,41 and chamber 5|. I preferably connect the casing 1| to the oil supply of the engine by means of a conduit |30 (Flgs. 1 and 5) and througha suitable pressure reducing valve (not shown) so that the casing is lled with oil and the oil pressure within the casing is slightly greater than the fuel pressure in the chamber 5|. 'Ihus the tendency would be for the lubricant to get into the fuel rather than vice versa.

Preferably the valves controlling the inlet 'of fluid to the cylinders are carried on and are reciprocable with the pistons and are in the form of thin disks as illustrated. Thus the opening and closing of the valves is assisted by the movement of the pistons, the upward movement of the pistons during the suction stroke tending to open the valves to admit fluid, and the downward movement of the pistons tending to close the valves.

It is readily apparent that the downward movements of the pistons are extremely sudden and rapid due to the form of contact between the roller 34 and the members 40, so that a quick injection of the fuel into the engine cylinders is obtained.

In the form illustrated in the drawings, the

pump'is readily adapted for economical manufacture. By providing hardened lining sleeves 2| intermediate the cylinder block and pistons an accurate mounting for the pistons is readily obtained. The sleeve linings need not be a fluid prevented by clamping the annular flanges 2|' of the linings between the top of the cylinder block and the ring 52.

A simple means is provided for adjusting the drive shaft axially to vary thev strokes of the pistons. The provision of the adjustable'cam facilitates the varying of the idling speed of the engine.

The mechanism as disclosed is extremely eilicientin operation. By connecting the intake conduit 46 to the gasoline tank of an automobile, the pump will effectively suck gasoline into the supply chamber 5|' even though the gasoline tank is in the rear of the car and below the level of the pump.

I claim as my invention:

1. A pump comprising, in combination, a cylinderblock having a plurality of cylinders, hardened lining sleeves positioned in said cylinders and projecting from the block, hardened cylindrical pistons slldably mounted in said sleeves, a spider positionedabove the cylinders, a cap member for each piston slldably mounted on said spider in alinement with the pistons, and having portions arranged to engage the spider to limit the. upward movement of the pistons, a drive shaft, means on said drive shaft for actuating the pistons, and means for depressing said spider vto actuate the pistons simultaneously'.

2. A pump comprising, in combination, a cylinder block having a plurality of vertical cylinders arranged in a circle, flanged lining sleeves in said cylinders projecting upwardly therefrom with the flanges against the top of said block, pistons slldably mounted in said sleeves and extending beyond the upper ends thereof, means for reciprocating the pistons, means for supplying fuel to the lower ends of said cylinders including a grooved ring positioned on said block engaging said flanges to secure said linings in place and forming an annular supply chamber, ports formed in said lining sleeves and pistons connecting said chamber and cylinders, and check valves normally closing the ports in the pistons during the comv pression strokes of ,the pistons.

3. A pump comprising, in combination, a cylinder block having a plurality of cylinders arranged in a circle, pistons in said cylinders, adrive shaft extending centrallycf said cylinders, means for rotatably supporting said drive shaft, a control shaft positioned axially of said drive shaft and in engagement with the upper end thereof, a sleeve surrounding said control shaft, cam means on said shaft and sleeve operable when said control shaft is rotated to move the control shaft and thereby the drive shaft axially to vary the stroke of the pistons and means for rotating said sleeve independently of the control shaft to vary the stroke of the pistons .when the control shaft is in its minimum stroke position.

4. A pump comprising, in combination, a cylinder block having a plurality of parallel cylinders arranged in a circle, pistons in said cylinders,

tight'flt in the cylinder block, any leakage being tion of the shaft, "a member slidably mounted for movement longitudinally of said shaft and having a plurality of bores into which the ends of the pistons project, means for limiting the upward movements of the pistons in said member, and means for depressing said member to actuate all pistons simultaneously.

5. A purnp comprising, in combination, a cylinder block having a plurality of parallel cylinders arrangedin a'f circle, pistons in said cylinders, a drive shaft extending centrally of said cylinders, means forrotatably supporting'said drive shaft, means carried on said drive -shaft arranged to actuate saidpistons'in sequence during rotation ofthe shaft,\a spider slidably mounted for movement longitudinally of saidshaft and having a plurality of vertically extending bores into which the upper ends "of the pistons project, tubular bushings in said bores having closed upper ends resting on said pistons and arranged Ato be engaged by said actuating means, said bushings having annular flanges on their lower ends engagfor reciprocating said pistons comprising a drive shaft extending centrally of said cylinders, and a tapered roller carried on said drive shaft and arranged to engage the ends of the pistons in sequence during rotation of the shaft, means for depressing all of the pistons simultaneously, means for controlling the inlet and outlet of fluid to and from the cylinders, and means for adjusting said drive shaft axially to vary the strokes of the pistons.

GUNNAR A. WAHLMARK.

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