US2942551A - Fuel injection systems for internal combustion and other engines - Google Patents

Description

June 28, 19 0 T. HITHOMPSON 2,942,551

FUEL INJECTION SYSTEMS FOR INTERNAL COMBUSTION AND OTHER ENGINES Filed July 5, 1957 2 Sheets-Sheet 1 IN VENTOR m1 WOMRSO/V,

ATTORNEYS June 28, 1960 T. H. THOMPSON I 2,942,551

FUEL INJECTION SYSTEMS FOR INTERNAL COMBUSTION AND OTHER ENGINES Filed July 5, 1957 2 Sheets-Sheet 2 9 w /E M Q N M \//M 22AM w m l 4 n 7 I i I 1/ Q M: m g a g h INVENTOR H 70M MmaM/zso/v,

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ATTORNEYS United tates Patent" fiice g ,,,,Z;F;ZZ3

. FUEL INJECTION SYSTEMS FOR INTERNAL COMBUSTION .AND OTHER ENGINES Tom H. Thompson, I-6 Ponce Iark, Daytona Beach, Fla. Filed July 5, 1957, Ser. No. 670,338

1 Claim. (Cl. 103-44) This invention relates to fuel injection systems for internal combustion and other engines and more particularly to such a system in which the fuel pumping action takes place at the injection nozzle and is activated by a closed circuit hydraulic system operated by a wobble plate pump with a variable stroke.

Fuel injection systems employing wobble plate pumps and special injector nozzle arrangements have been the subject of my early applications, such as Serial No. 383,538, filed October 1, 1953 now Patent No. 2,809,868 of October 15, 1957; Serial No. 472,118, filed November 30, 1954, now Patent No. 2,889,781; and Serial No. 578,732, filed April 17, 1956, now abandoned. Many of the features disclosed in those applications are employed here also but the systems diifer basically in that in the present system the fuel to be injected by the injector nozzles is supplied by any suitable means and in continuous quantities directly to the injector while operation of the injector to capture and meter the desired amount of such fuel for each injector, is effected through a separate and completely closed hydraulic operating system actuated by a wobble plate pump.

It is a general object of the invention to provide such a system.

A further object of the invention resides in employing similar sized bellows at each end of the closed system, which are substantially greater in area than the and area of the piston in the injector which they actuate, so that very small amounts of fuel may be injected, the amount being considerably less than the amount'of fluid being moved in the closed hydraulic operating system.

Still a further object of the invention is to provide a fuel injection system actuated by a closed hydraulic system having no valves and no lag to provide positive and accurate injection of fuel regardless of the amounts desired.

These and other objects of the invention will be more apparent from the following description and claims when read on the accompanying drawings, in which:

. Fig. 1 is an end elevation of the wobble pump forming a part of the invention;

Fig. 2 is a section taken on the line 22 of Fig. 1;

Fig. 3 is a bottom plan view of the injector forming a part of the invention; and.

Fig. 4 is a section taken on the line 44 of Fig.3.

.The system basically is comprised of a metering pulse pump driven by the engine and having individual closed circuit connections to injectors 11 to be actuated to supply fuel in accurately metered quantities to the engine combustion chambers or to the intake manifold, as the case may be. Each individual closed actuating circuitbetween the pulse pump and an injector is comprised of a bellows 12 in the pulse pump, a conduit 13 extending therefrom to an injector, and a similar bellows 14 in the inje'ctor, and, of course, hydraulic fiuid which fills the circuit when one ofthe bellows is expanded and the other is closed. a 9

The metering pulse pump 10 is a wobble plate pump, the wobble plate 15 of which is adapted when rotated to actuate successively each of the bellows 12 as will be described, and force fluid through conduit 13 to the bellows 14 in each injector. The bellows 14in each injector 11 is disposed to actuate an injector piston 16. Extending through each injector 11, transversely of the piston 16 is a fuel supply line 17 which extends right through the injector and continuously supplies ample fuel thereto under a predetermined constant pressure, of for example, four p.s.i. The arrangement is such that actuation of the bellows 14 and consequent movement of the piston 16 will cause the piston to extract fuel from the fuel supply line 17 and eject a predetermined amount of it through a, ball valve device 18 and then out through the nozzle 19 into the combustion chamber or intake manifold.

It will be noted that the closed circuit actuating each piston is in no manner in communication either with the outside atmosphere or with the fuel to be injected. As will be more apparent hereinafter, this arrangement makes for a much more stable and simple system since it is possible for the closed actuating circuits to have a volumetric capacity substantially greater than that of the injector.' Relatively large areas in the bellows of each closed actuating circuit make it possible to effect accurate injection of small amounts of fuel from the injectors. In order to understand specifically how this is accomplished, it will be advisable to describe the mechanism in more detail.

The wobble plate metering pulse pump 10 is mounted within a cylindrical casing 20 having end walls 21 and 22. Suitably mounted in the end walls for rotation within the casing, is the drive shaft 23 on one extended end of which is a drive pulley 24 through which the shaft is adapted to be driven from the engine.

Mounted in end wall 21 of the pump 10 are a plurality of outlets 25, the inner ends of which carry the bellows 12. These preferably are of special design employing a plurality of Belleville springs which are arranged, for example, similarly to those shown and described as the embodiment of Figure 3 of my co-pending application, Serial No. 578,732, filed April 17, 1956.

Each of the bellows 12 in succession is adapted through an actuating ball 26 to be compressed by actuation of the wobble plate 15. The wobble plate mechanism herein illustrated may be similar to those illustrated and described in my co-pending applications Serial No. 383,538, filed October 1, 1953 or Serial No. 472,118, filed November 30, 1954. The wobble plate 15 has an outer race 27 connected through bearings 28 to an inner race 29. The inner race 29, in turn, is rigidly connected to a lever 30. At one point the lever 30 is pivotally connected by a link 31 to an arm 32'which is secured rigidly to the-drive shaft 23 to rotate therewith. At a diametrically opposite peripheral point on the inner race 29 the lever 30 is pivotally connected by a link 33 to an arm 34. This arm 34 is rigidly secured to an outer race 35 connected through bearings 36 to the inner race 37 of a sleeve 38 positioned on the drive shaft 23 for axial movement thereon. The sleeve 38 has a portion connected pivotally as at 39 to a control lever 40 pivotally mounted on the casing 20 of the pump.

The arrangement described permits adjusting the angle of the wobble plate so, in turn, to control the amount of actuation (compression) of the bellows. It should now be apparent that movement of the control lever 40 to the right in Fig. 3 will cause sleeve 38 to move to the left on shaft 23 and through the linkage (arm 35, link 33, and lever 30) will force the wobble plate 15 into a position more nearly perpendicular to the drive shaft 23. When .fully perpendicular to shaft 23 the wobble plate 15 will the bellows 12. The control lever 40 thus acts as a throttle lever for the engine.

Reference will not be made to the structure and arrangement of the injectors 11, one of which will be described in some detail. Each injector is formed of main body 41 having an axial passageway 42 and the transverse fuel line passageway 17 to which the fuel to be injected is constantly being furnished under pressure supplied by any suitable source. Threaded on the upper end of the injection body 11 is a tubular housing 43 in the up'perend of which is mounted the inlet 44 connected by conduit 13 to the pump, as described. The inlet 44 has a flange 45 disposed within the housing 43. There is a bellows 14, which is similar in size to those in the wobble pump, but which employs flat washers instead of cupped Bellevilles, in order to omit return springs. This bellows 14 is connected between the flange 45 and the flanged head of the injector piston 16. The piston :16 extends downwardly almost to the lower end of the injector body 41 and is adapted to be moved in its axial direction by actuation of the bellows 14. In such movement the piston will be guided by a sleeve spider 46 disposed within an enlarged axial opening forming a chamber 47. At its lower end the piston will be guided in its axial movement by the injector body itself which isat this point (below the transverse fuel line passageway 17) has an axial opening 48 just large enough to permit the piston to move therein.

At its upper end the chamber 47 communicates with a chamber 49 formed by the tubular housing and extending to the top thereof. At its lower end the chamber 47 communicates with a chamber 50 formed-in the fuel line passageway 17.

It will be noted from the drawing (Fig. 4) that the axial opening near the lower end of the injector body 41 and below the lower end of the piston 16 forms a chamber 51 having a diameter the same as that of the piston. This chamber 51 communicates through a greatly reduced passageway 52 with the ball check valve device 13 which, in turn, communicates will the opening in the nozzle 19 leading to the combustion chamber to be supplied with fuel. The ball check valve device 18 may have the structure and characteristics of that disclosed in my co pending application, Serial No. 383,538, filed October 1, 1953.

At its lower end the piston 16 is provided with a'T- shaped passageway 53, the arms of the T passing transversely through the piston 16 and the leg of the T extending to the lower end of the piston.

It will be noted when the piston 15 is in the raised position shown in Fig. 4 the fuel to be injected and which enters the injector 11 through the fuel line passageway 17 will flow into all of the chambers in the injector filling the space around the bellows 14, the space in chamber 4% (the bellows travel area), the space in chamber 47 not occupied by the spider sleeve 46, the chamber 50 in the fuel line passageway 17, the T-shaped passageway 53 in the lower end of piston 16, the chamber 51 below the piston, and the reduced passageway 52 all. the way down to the ball valve device 18.

The operation of the device willnow be described.

As shown in Fig. 3 the bellows i2 is at the startof a maximum stroke. Compression of this bellows 12 by the wobble plate 15 will cause hydraulic fluid in the closed system to travel through conduit 13 to the bellows 14 in the injector 11. Bellows 14 will thus be expanded to its maximum extent thus moving the piston 16 downwardly. As piston 16 moves downwardly the T-shaped passageway 53 in the lower end of the piston will move below the fuel line chamber 56 and thus trap the fuel in the Tshaped passageway and in the chamber 51 there'- below. :Farther downward passage of the piston will then force fuel past the ball check valve 18 and eject through the nozzle 19 and into the combustion chamber, or intake manifold as the case may be. Since there has been a-maximum stroke of the bellows 12 there will 4 be a maximum sized injection under such circumstances.

Let us assume for example that dimensions are chosen which would cause the wobble plate pump 10 to pump for each Vs inch of stroke on its bellows 12, /2 cubic inch of fluid into its closed circuit. If the bellows 14 at the other end, in the injector 11, has the same volumetric dimensions, there will then be a A5 inch stroke of the piston 16. However, assuming that the lower end of the piston has area of of the area of the bellows 14, it is clear that a inch stroke of the piston 16 within the injector 11 results in a considerably less volume of fuel being injected than the volume of fluid being moved in the closed circuit which actuates the bellows. This diflers radically from previously known systems, such as described in my earlier applications, in which the volumetric capacity of the wobble plate pump had to be exactly the same as that of the fuel being metered. In such instances, as during idling of the internal combustion engine, the product of each bellows might be of cubic inch per stroke, which is a very small amount when it is realized that the expansion and contraction of the pump metal itself can account for perhaps :two .to three times as much stroke as would be represented by 36 cubic inch of output on a inch piston.

In contra-distinction to this, in the present newsystem enough fluid is pumped in the closed bellows circuit to make for a stable system, regardless of the small amount of fuel it is desired to eject by the injector at each stroke of the piston. As is now apparent, the bellows system has no valves and it operates with no lag so as to provide accurate injection of fuel regardless of how much or how little is to be ejected at each stroke. The injectors are actuated at the nozzle by the closed bellows system which has no communication with the fuel supply system.

One of the salient features of this arrangement is that the stroke is varied from top dead center downward, and thus there is always a completely exhausted compartment at the end of each strokeregardless of stroke size.

Chamber 49 performs several useful functions. 'It traps air where it can do no harm. It provides an individual nozzle fuel reservoir. Moreover, whenrthe bellows 14 moves into this chamber 49 the chamber provides a positive pressurized filling all the way down through chamber 51.

While for usual operation the system illustrated and described will function most satisfactorily, it is conceivable that in some installations under some circumstances the inertia forces may be great enough .to cause an cvcrlap such as wouldhinder operation. Forsuch cases, the invention incorporates'what may he referred to as .a ball bearing power transmission disposed between the wobble plate and eachinjectorpiston. In such arrangement each tubular conduit connecting the wobble plate pump to a bellows in an injector instead of containing fluid, is filled with bearing balls of a diameter only infinitely less than the inner diameter of .the tubular conduit. At each end, that is at the wobble plate pump end, and in each injector, pistons are provided instead of the bellows. With this arrangement, positive actuation of a pistonin the wobble pump will be transmitted immediately, positively, and in like amount to the piston in an injector, which in turn will actuate the injector .piston. It is apparent that such a system must include some spring means or the like to return the actuating piston to :its initial system, which ofcourse is not necessary in the fluid .system described where the bellows themselves perform the function of returning themselves to their :initial position.

Obviously, many modifications and variations of the present invention are possible in the light .of the above teachings. What is claimed as new and desired to be secured by Letters Patent is:

In combination, a plurality of fuel injectors, an injector piston in each injector, an injector nozzle, .a fuel passageway extending transversely through said injector,

and means for actuating said piston'to segregate a portion of the fuel in said passageway and eject it from said nozzle, said means comprising a bellows in each injector disposed to actuate said piston, a pump, a plurality of similar bellows in said pump, one for each injector bellows, individual conduits connecting each bellows in the pump with a bellows in an injector, hydraulic fluid in said conduits, each connected pair of bellows comprising a closed hydraulic operating system, and means in said pump for actuating the bellows therein in succession in any predetermined amount.

References Cited in the file of this patent UNITED STATES PATENTS

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