US2567367A - Fuel injection pump - Google Patents

Description

Filed March 5, 1947 5 Sheets-Sheet 1 ATTORNEY Sept. ll, 1951 D. J. DESCHAMPS FUEL INJECTION PUMP 5 Sheets-Sheet 2 Filed March 5, 1947 ATTORNEY Sept'. l1, 1951 D. J. DESCHAMPS 2,567,357

FUEL INJECTION PUMP Filed llarch 5, 1947 5 Sheets-Sheet 5 ATTORNEY Sept- 11, 1951 D. J. DESCHAMPS I 2,567,367

FUEL INJECTION PUMP Filed March 5, 1947 5 Sheets-Sheet 4 INVENTOR FIGJZ ATTORNEY SePf- 141, 1951 n.1. DEscHMPs 2,567,367

' FUEL INJECTION PUMP Filed Ilarch 5. 1947 5 Sheets-Sheet 5 fla/V657? JTKKE FIGJG.

FIG. I3

INVENTOR f/Rf d. afan/Anal" A ORNEY Patented Sept. 11, 19514L FUEL INJECTION PUMP Desire J. Deschamps. Rutherford, N. J., assignor to Deschamps Fuel Injection Corporation, New York, N. Y., a corporation of New York Application March 5, 1947, Serial No. 732,491

(Cl. S-37) 1 This invention relates to an improved high pressure fuel injection pump for injecting liquid fuel into the cylinders of an internal combustion engine, particularly high power multi-cylinder aircraft engines. More specifically, the invention relates to such a pump including a plurality of pumping units each operative to deliver liquid fuel selectively to more than one cylinder of an engine.

It nas been the practice in the past to provide fuel injection pumps with as many pumping units as there are cylinders on the engine, each pump plunger. also called pumping unit, delivering an accurately metered amount of fuel, with the proper timing, to its respective engine cylinder.

The steadily increasing speed and size of airplanes requires engines of greater power output and,v as there exists a practical limit as to the power output that can be obtained from a single engine cylinder, the solution has been to increase the number of cylinders rather than the cylinder size. Whereas nine cylinders represented the largest numberof cylinders used in engines up until recently, engines of 14, 16, 18, 24, 28, 36 and even 42 cylinders are now in use or are under development.

v For practical considerations the present fuel injection pumps used on aircraft engines have been limited to not more than 14 plungers (pumping units). and only a few experimental fuel injection pumps have been built with 18 plungers. This means that engines of more than 14 cylinders have been equipped with more than one fuel injection pump; for instance, two 9-plunger pumps for an 18-cylinder engine, two 12-plunger `pumpsvfor a 24-cylinder engine, two lli-plunger pumps for a ail-cylinder engine, etc.

The installation of several fuel injection pumps on a single engine creates many problems. It is difficult to find room on an engine for installing this number of pumps and to provide driving means therefor. As is well known, mounting padsand drive gearing have to be provided on an engine for various accessories leaving little available space for additional pumps.

Not only is the mechanical problem complicated lythe use of several pumps, but also the weight of the engine is appreciably increased. Another serious problem is that the necessary added gears. couplings and bearings increase the risk of mechanical failure and complicate the servicing and maintenance problems. Furthermore, difficulty, is experienced in connecting the capacity control of each pump to a common fuel control unit, and to obtain and maintain in service the accurate calibration of the fuel delivery from each pump, as is necessary in modern highpoweroutput engines.

Broadly the main object of this invention is to provide, a, fuel injection pump of which the plungers do "double duty." meaning that each pumping unit. instead of delivering fuel to only one engine cylinder, delivers an accurately metered and timed injection to two or more engine cylinders of which the power strokes are properly spaced. For instance, with a 9-plunger pump of the invention type, it is possible to supply fuel to the cylinders of an lil-cylinder engine, replacing the two 9-plunger pumps now considered necessary. This results in a simplication of the engine, as only one pump mounting pad and one pump drive have to be provided, all diiiiculties in properly synchronizing two separate pumps are removed, the new pump is lighter in weight and lower in cost than the two pumps it replaces, and its size is not much larger than the present 9-p1unger pump.

Although the pump, which is the object of this invention, replaces an lil-plunger pump, its production is far from offering the problems of the latter, and thenew pump is not expected to cost more than about of the total cost of the two pumps it replaces.

It is among the objects of the present invention to provide a fuel injection pump including pumping units capable of selectively delivering fuel under pressure to more than one engine cylinder; to provide such a pump including a rotating plunger of an improved design. acting not only as a pumping and metering unit but also as a distributor of the fuel to more than one engine cylinder; to provide such a pump of which each pumping unit includes a rotating plunger in a ported bushing effective to distribute fuel selectively to different ports of the bushing and in which the relation between the plunger distributing means and the ports of the bushing is not critical due to the use of means independent of the plunger rotation to accurately time and meter the amount of fuel being delivered at each injection.

A further object is to provide for such a pumping unit having a fuel compression chamber and a fuel distributing means, and a check or delivery valve arrangement disposed between such chambers and the distributing means to prevent back fiowof fuel during the suction stroke to affect the accurate metering of the fuel delivery.

Another object is to provide accurate means for effecting the line adjustment, as needed, of the fuel delivery from each individual pumping unit to equalize the pumping unit outputs; only a very minute variation in output being allowed from each plunger to another.

Still another object of this invention is to provide a pump having a housing divided into two main compartments, a fuel compartment in which are installed the plunger bushings and the fuel output controlling means and a drive vcompartment containing the pump shaft, bearasomo? ing means between the fuel compartment, drive compartment, and plunger to avoid the loss of lubricating oil into the fuel or the seepage of fuel into the drive compartment; to provide such a pump including a plurality of pumping units operated by tappets each having a roller engaged by a rotatable actuating cam driven from the engine; and to provide such a pump including guiding means for maintaining the tappets accurately aligned with the actuating cam.

An important feature of the pump is the utilization of means independent of the plunger rotation to control the injection timing. The closing of the fuel inlet port to the plunger and the opening of the spill port. which both govern the length, volume and timing of the injection are controlled by the reciprocating motion of the plunger and not by its rotating motion.

Another important feature is the avoidance of both mechanical and hydraulic side thrust on the plunger, so that the plunger may "float" in its bushing. This has been found to be extremely important to avoid rapid wear and even "sticking" of the plunger when pumping fuel with poor lubricating properties. such as gasoline.

Mechanical side thrust on the plunger is avoided by the use of a tappet between the plunger and the actuating cam. To avoid side thrust due to hydraulic pressure acting through the ports against the plunger, use is made of diametrically opposed ports in the bushing and diametrically opposed distributing grooves in the plunger, this arrangement insuring perfect hydraulic balance.

Therotating motion of the plunger in addition to its reciprocating motion has the added advantage of substantially reducing the danger of "sticking" plungers, as any foreign matter which accidentally may become lodged between the plungers and the walls of the plunger bushings is kept moving and works itself from between the plunger bearing surfaces in the bushings.

Other features of this pump are covered by the following applications copending herewith and assigned to the same-assignee as the present application: Application Serial No. 503,470, illed September 23, 1943, by Desire J. Deschamps and Douglas C. Clarke, now Patent No. 2,519,893, issued August 22, 1950; Application Serial No. 515.696, filed December 27, 1943 by Desire'J. Deschamps, Douglas C. Clarke and Frank E. Ferguson, now Patent No. 2,436,797, issued March 2, 1948; and Application Serial No. 591,914, filed May 4, 1945 by Desire J. Deschamps, now Patent No. 2,531,202, issued November 21, 1950.

As said, the description which follows is of a 9-plunger, ls-outlet pump. arranged to be driven at one half crankshaft speed for application to a four-cycle 18-cy1inder engine, and the porting control of the plunger has been provided for fixed timing of the beginning of the injection period and variable timing of the ending thereof.

Only minor changes, as will be explained at the end of the description. make this pump applicable for other methods of operation, such as running the pump at crank shaft speed on a four-cycle engine. Another variation is to provide for a fixed timing of the ending of the iniection and variable timing of the beginning of the injection with respect to the plunger reciprocating motion.

In general, the invention provides a novel, compact fuel injection pump capable of deliv- 4 ering fuel to a number of engine cylinders which number is a multiple of the number of pumping units incorporated in the pump, and which pump is simple in operation, easy to service and adiust, and capable of reliable operation.

The other novel advantages, features and characteristics of this pump will be apparent to anyone familiar with the art from the following detailed description and the accompanying drawings. In the drawings:

Fig. 1 is a longitudinal sectional view of a pump constructed according to the present invention. taken on the line I--i of Fig. 10.

Fig. 2 is an enlarged sectional elevation view of one of the pumpingunits of the pump.

Fig. 2A is a left-end elevation view of Fig. 2.

Fig. 3 is an elevation view, partly in section, of a rotatable pumping and distributing plunger forming an important feature of the present invention.

Fig. 4 is a cross-sectional view on the line 4-4 of Fig. 3.

Fig. 5 is a cross-sectional view on the line 5-5 of Fig. 3.

Fig. 6 is a longitudinal sectional view of a pumping unit bushing assembly.

Fig. 7 is a development of the ported plunger bushing.

Fig. 8 is an axial sectional view, on the line l-I of Fig. 9, of an arrangement of a pair of relatively adjustable sleeves for setting the iniection period of each pumping unit.

Fig. 9 is an end elevation view of the sleeves shown in Fig. 8.

Fig. 10 is a cross-sectional view on the line IO-II of Fig. l. showing the means for adjusting the injection period of the pumping units during operation of the pump.

Fig. 11 is a longitudinal sectional view on the line Il-II of Fig. l0.

Fig. 12 is an elevation view, partly broken away.

-of the face cam for operating the pumping unit.

Fig. 13 is a development of the cam surface.

Fig. 14 is a sectional perspective view, on the line M-M of Fig. 19. of a pumping unit at the end of the suction or intake stroke of the plunger.

Figs. 15 through 17 are views similar to Fig. 14, illustrating other positions of the pumping unit during a stroke. Fig. 15 shows the plunger at the beginning of injection, Fig. 18 at the ending of injection, and Fig. 17 at the ending of the compression stroke.

Fig. 18 is a sectional perspective view showing the plunger rotated from the position of Fig. 15 and ready to start delivery of fuel through a different set of fuel outlet ports.

Fig. 19 is a diametrlcal sectional view on the line ilof Pig. 14.

Figs. 20 through 23 are views similar to Fig. 19, but corresponding to Figs. l5 through 18, respectively.

Fig. 24 is a diagrammatical, diametrical sectional view illustrating the hydraulically balanced fuel delivery arrangement of a pumping unit in a position of the plunger corresponding to Figs. 15 and 20.

Fig.25isaviewsimilarto1ig.24,showingthe plunggr in a position corresponding to Figs. 18 and Generally speaking. the high speed fuel pump of the present invention includes a number of successively operable pumping units. each arranged to deliver fuel to more than one cylinder of an internal combustion engine. Each pumping unit includes a cylinder or bushing having separate sets of ports each connectible with an individual engine cylinder, and a plunger reciprocable and rotatable with respect thereto both to inject fuel into the engine cylinders and to distribute the fuel, on successive strokes, to different cylinders. The injection or delivery of fuel, and the timing of injection, is controlled by the reciprocation of the plunger. .The distribution of fuel to differentv cylinders is eiected by rotation of the plungers.

Rotatable face cam means, operated in timed relation with the engine crank-shaft, engage tappet means to reciprocate the plungers in succession, and means are providedto maintain the tappets accurately aligned with the face cam means. Gearingfoperated by the face cam means rotates the plungers between each stroke, to deliver fuel to different cylinders on successive strokes.

Other features of the invention comprise novel arrangement for mechanically and hydraulically balancing the plungers to eliminate side-thrust thereon and assure a substantially floating reciprocation of the plungers. Also, novel sealing means are provided between the fuel and driving lubricating oil into the fuel compartment, and

dilution of the 1ubricaung on in the driving cemv pumping unit must be spaced 360 from each other, andthe cam isrotated'at'one-half of the engine crank-shaft speed.

As an alternative to this arrangement, a single lobe cam operatedv at crank-shaft speed, with the plungers rotated at one-quarter crank-shaft shaft speed can be used with the plungers rotating at one-quarter crank-shaft speed.

In all of the above arrangements, the angular velocity of the plungers is equal to one-quarter the angular velocity of the cam multiplied by the number of cam impulses per cam revolution.

In the illustrated pump, nine pumping units are provided, equally spaced about the circumference of a circle and equi-distant from the axis of the pump drive-shaft. The pumping units are disposed with their axes of reciprocation parallel to the pump drive-shaft. This type of pump is usually referred to as a barrel pump. However, it should be noted that the illustrated embodiment is typical only, and that the principles of the invention are applicable equally to any fuel injection pump with a different number of pumping units, or with the units arranged in a different relation to the pump driving means.

Referring more particularly to the drawings. the general arrangement of the pump will be best understood from Figs. 1 and 2. As shown, the pump includes a fuel compartment 3| and a drive compartment comprising sections 32 and 33. These compartmentsare formed by the assembly of several elements constituting lthe' pump housing.

At the end of the pump nearest the engine, hereinafter referred to as the inner end of the pump, a pump head 34 is provided, closed by a plate 35 and vformed with a mounting flange 36 by means of which the pump is `attached to the engine. Head 34 is the supporting member for plunger-bushing assemblies 43, forming the cylinders of pumping units 30.

Secured to head 34 is a central housing member 31 having a fuel inlet port 38 and formed with a transverse flange or diaphragm 39 separating the fuel compartment 3| from the drive compartment 32, 33. Diaphragm 39 acts as a support for the sealing means between the two comfspeed can likewise effect delivery of4 fuel to two :1

' cylinders of a four-cycle engine from each pumping unit. Also, this can be accomplished vby a four-lobe cam operated at one-quarter crankshaft speed, with the pumping plungers likewise rotated at one-quarter crank-shaft speed.

The pump may also be used. with each. individual pumping. unit `supplying fuel alternately to two cylinders of a two-cycle engine, with the working strokes of the `cylinders spaced 180. This `canvbe accomplished with avtwo-lobe cam yrotating at crank-shaft speed, and the plungers rotating at one-half crank-shaftl speed. Also, a

single-lobe cam can be used operating at twice the crank-'shaft speed or1a four-lobecam operatl is for each troduce fuel to .the cylinder. plungers willdeliver fuel'alternately lto each nozzle onfalternateworking strokes of the'cylinder. This can be accomplished by a two-lobe cam rotating' at1 one-half crank-shaft: speed, with' the plungers lrotating at one-,quarter .crank-shaft vs1: eel...l\iso. a single-lobe cam rotating at crankpartments and also for plungers 90 of pumping units 30, and elements associated with the plungers.

. At its outer end, housing 31 yhas attached thereto a tappet housing 40 which supports tappets |05 and the inner bearingv |33 of rotatable face cam ||2. Housing 40 has a flange 4| bolted between the outer end of housing 31 and a flange formed on a cam housing 42. Cam housing 42 supports the outer bearing |34 of cam ||2,'and acts as a closure for the outer end of the pump.

Fuel compartment 3| is formed in housing 31 .between diaphragm `39 and head 34. The drive .pump housing elements are secured-'together in any suitable manner by two series of studs, screws or bolts, engaged in apertures provided in the joining flanges of the several housing sections.

As stated, the pump includes a number -of pumping units 30, nine in ythe present embodiment.

-assembly 43, a delivery or check valve 12, a plungyEach pumpingunit includes a bushing er 90, an output control sleeve assemblyY |10, and

' a plunger driving mechanism including'a geared sleevev |36 and a tappet mechanism |05. Geared sleeves |36, in a manner to.be described, effect rotary motion of plungers 90. Similarly, tappet ally, pumping units 30 are actuated 'by cooperation between tappetsA |05 andv a face cam |12 driven through a quill shaft |30 at aproper speed ratio with the engine crank-shaft. Also as will be described, the pump plungers Il are rotated by gearing interconnecting cam Il! and sleeves i A series of apertures equal in number te the number of pumping units are arranged in equispaced relation around the circumference of a circl'e centering on quill shaft ill and extending through pump head Il parallel to the axis of the quill shaft. These apertures receive bushing assemblies I3 which, as shown more particularly in Figs. 6 and '1, comprise an inner bushing 44 and an outer sealing sleeve 4I.

Bushing u is formed with a shoulder or rib M which locates the bushing by engagement in a recess in pump head Il. A collar 4l extends forwardly from shoulder 4i and cooperates with a recess in head Il to receive a packing ring 4l made of a suitable resilient material. The dimensions of the packing ring recess are such that the ring 4l is slightly squeezed and deformed when holding screws Il are tightened to secure plate I5 te head I4.

Bore M in bushing u is machined to such I dimensions as to give the proper sliding fit between the bore and pump plunger sl. The outer end of bore il forms a sharp comer edge il with the end of bushing u. The inner end of bore 53 is enlarged te form a compression space l! above the inner end of plunger Compression space I2 communicates with an external angular groove I4 in bushing M by means of one or more drilled channels 53.

Outwardly from groove Il, a set of four equally spaced apertures il are drilled radially through bushing u, connecting bore 5I with a second external annular groove l5. Substantially at its central portion, a third annular groove il and, close to its outer end, a fourth annular groove i1 are formed externally in bushing H. Halfway between grooves 56 and 51. a second set of four equally spaced apertures are drilled radially through bushing u.

Two diametrically opposed apertures Il of this second set each open into a longitudinal groove I on the external surface of bushing Il, communicating with groove It. The two other diametrically opposed apertures Il of the second set each communicate with a longitudinally extending external groove 62. Grooves l2 communicate, at their outer ends. with external annular groove il.

Outer sleeve 4l is assembled over, and preferably shrunk on bushing Sleeve Il seals grooves il, 55, 5t, Il, Il and I2, thus forming a system of fuel passages the purpose of which will be explained when the operation of the pump is described. A series of four holes, Il, 85 and ls are drilled through sleeve 4i and communicate respectively with grooves Il, il, il and 5l in bushing Il.

Referring more particularly to Fig. 2, bushing assembly Il is installed in its aperture in head u in such a manner that holes il, N, I! and in sleeve register with certain respective fuel channels formed in pump head Il. Holes and u register, respectively. with drilled passages ll and 6l closed at their outer ends by suitable means. such as plugs II. A passage Il interconnects passages 61 and tl. When no fuel is flowing through passage 10. the passage ls closed by a check or delivery valve Il installed in a bore in head Il.

A spring 16 biases valve 12 against valve seat Il formed by the intersection of passages 'Il and t8. In the particular arrangement shown in the drawings, spring 1C is centered ina cap 11 closing lthe housing of valve l2 and held in place by a set screw 1l. Valve 12 has a reduced portion Il of smaller diameter than the valve bore in order to form a substantially annular chamber 'Il adjacent seat 1I te facilitate the how of fuel. 'Ihis reduced portion 'II is shaped to form a tight sealing fit with valve seat 1I. In the illustrated embodiment, valve 1! has a spherical end Il seating against seat 1I. but it is within the contemplation of the invention to use a flat or angular valve seat and valve end. Holes Il and II in sleeve Il are the exits for fuel passing toward the engine cylinder.Y

Again referring to Fig. 2, the eighteen screws passing through holes l. in mounting flange Il not only secure the pump te the engine but also act as fuel fittings for the fuel lines carrying the fuel to the engine cylinders. Hole l. registers with a drilled passage II opening into a second passage It closed at its outer end by a plug I1. Channel It communicates with a channel Il terminating in an enlargement Il of bolt hole l0. One or more cross holes Il are drilled through the stem or bolt I2, intersecting an axial paasage II therein for the flow of fuel te an appropriate fitting for connecting the fuel line to the engine cylinder. As the details of such connection form no part of the present invention. thev have not been shown in the drawing.

In Fig. 6, the second fuel outlet hole 0I is illustrated as being in the same radial plane as hole il. Actually. hole It is in a different radial plane than hole It, as exemplified by the dotted line illustration in Fig. 2. Outlet holes Il and tl each communicate with a different bolt Il. and these bolts are located 20 apart on the mounting flange. Through its passage l., outlet hole l communicates with a bolt I2 in the same manner as does hole Il. However, this second bolt I2 islocated in a plane different from that of bolt I! shown in Fig. 2 of the drawing.

Plunger 0I is a generally cylindrical member which, in the invention pump. performs three functions in cooperation with bushing assembly Il and other coacting parts to form the pumping units Il. The reciprocating motion of thc plunger not only draws in fuel and compreses it. but also controls the timing and volume of the injection through the plunger inlet and spill ports. Furthermore, the rotating motion of the plunger controls the distribution of the fuel to the proper fuel outlet.

The construction of plunger Il is more clearly illustrated in Figs. 3, 4 and 5. As therein shown, the inner end, or the end nearest the engine, is formed with a wide external annular groove Il forming a fuel chamber.. A pair of diametrically opposed longitudinal grooves I! communicate with groove Il. 'Ihe circumferential width of these grooves covers an are of sufficient length to insure communication. at the proper time in the rotation of the plunger, with either set of outlet holes Il or Il in bushing Il. Furthermore. grooves l2 are of suflicient length to insure free and unrestricted passage of fuel from groove 0| to outlet holes Il or Il during the maximum duration of the injection period.

The inner end of the plunger, as just described. has the function of distributing the fuel alternately to diderent outlets through the rotation of the plunger. The control of the length and volume of the injection is performed by a section of the plunger disposed outwardly, that is away from the engine, from groove Il.

trol the opening and closing of the fuel inlet and spill ports. Cross holes 05 connect grooves' 00 and 00 to an axial passage 00 in plunger 00. The two grooves are thus put into communication with compression space 52 at the inner end of bushing l0. l0

In the intermediate portion of plunger 00 are two external annular grooves 01 and 00. 'I'hese are relatively narrow grooves which receive packing rings 00 cooperating with sleeve |30 to provide an effective seal between fuel compartment 3| and drive compartment 32. The part of the plunger outwardly of groove 00 is of smaller diameter and carries driving lugs |00 registering with two diametrically opposed slots |0| in geared sleeve |35. The outer end of the 20 plunger terminates in a button |0| havinga convex surface |02 to obtain a point contact with a hardened thrust disk|03 (Fig. 2). Button also acts as a retaining shoulder for a slotted spring washer |00.

ed in cylindrical apertures provided 4in tappet housing 00. These apertures are parallel to the pump axis, are equally spaced around the circumference of a circle having a center on the 30 pump axis, and are each aligned with one of the pumping unit apertures in head-30. Each tappet body |00 is cylindrical in shape, with the inner end |0`|` being hollow to form a sleeve.

Sleeve |01 has the function ofy increasing the 35 bearing length of the tappet without an appreciable increase in weight. The outer part of the tappet body isslotted to receive a roller |00 having a floating bearing bushing |00. Roller |00 is heid in tappet bodyl |00 by a pin ||0 having 40 Pin I|0 "floats freely in its bore i convex ends. in the tappet but 4cannot move axially because, over the entire length of the tappet stroke, pin ||0v is confined in the tappet guiding passage in housing I0. 45

The outer end of the tappet forms a skirt partly cut away to give the tappet free movement past cam I|2 during the full stroke of the tappet. Referring to Fig. 2A, it will be seen that the remaining segment of skirt fits against 50 the periphery of cam ||2. This prevents rotation of the .tappet and keeps roller |00 properly aligned with the cam andthe axis of -pi'n ||0 directed toward the center of the cam rotation. `This arrangement is of great importance in in- ,55

suring proper rolling contact Ybetween cam I|2,

and rol1er|00;

, AIn the illustrated pump embodiment, roller |00 is a tapered roller and a tapered rim ||5 is formed on cam H2. The taper is at the proper00 angle to insure rolling contact over. the whole width of the surfaces in contact. `An alternative construction is to use avroller with a crowned rim working against a taper on a flat-faced cam.

However, this would give only point contact be- 00 tween the roller and cam, instead of the line contact with the illustrated arrangement.

Cam ||2 is a face cam formed by a shaft ||3 supported in bearings. |33 and |3I,.a disk ||0 and a rim ||5 (Figs. 1 and 12). Bearing |30 abv'l0v sorbs the thrust'load due to the plunger springs |02 and the hydraulic pressure on` the plungers. Inwardly of bearing |33, a 24-tooth gear |25. called a sun gear, is formed on shaft I3. Splines |`on'the inner end of shaft ||3 engage co- 7 l2:5 The tappet assemblies |05 are slidably mountl0 operating splines in drive shaft which is of the type usually called a quill shaft.

This type of drive allows for a certain amount of misalignment between the pump and the engine drive, and the size and proportions of quill shaft |30 can be selected to absorb the torsional vibration in the engine drive. To prevent shaft |00 from oating, `it is held in engagement withcam shaft ||3 by means of a spring lock. This lock comprises two small balls |20 biased apart by spring |20 and engaging an internal annular groove *|3I in the tubular coupling end of shaft`l30. The innermost end of shaft |30 has a splined coupling of the required dimensions to engage the pump driving means of the engine.

In the illustrated embodiment, cam ||2 is a two-lobe cam of which the design is best illustrated by the development of the cam surface shown in Fig. 13. Referring to this figure, the tops or noses of the two lobes are indicated at ||0 and as spaced 180 apart. On either side of eachiobe are the cam flanks ||0`and ||0 connecting the tops to the lower or level part |20 of the cam. 'Ihe flanks are straight and symmetrical and are joined to'at part |20 and noses ||0, ||1 by means of curves |2| land |23, respectively.

The vertical distance Av between part |20 and top defines-the stroke of plunger 00. In the illustrated embodiment, this distance is 0.5625". When roller |00 moves up the cam during the working stroke of the plunger, the distance from point |20A to point |22, referred to as B, represents the height of the fuel inlet port.` In the present case, this distance is 0.1907". At'point |22, the inlet port closes. The distance represented by the distance C is the maximum length or eifective delivery `stroke of the plunger. This distance may be, for example, 0.300". At the upper end of dimension C, the spill port opens relieving the pressure existing in compression space 52 at the inner end of bushing 00. 'I'he two flanks 4of each cam lobe could, of course, be made asymmetric, and the angle changed dependent upon the length of injection of other special injection 'characteristics lto be obtained. Diaphragm 30 is formed with aseries of apertures each perfectly aligned with the corresponding aperture in headf30 vand tappet housing 00. Bushings are permanently inserted in these apertures and project beyond the innerv face of diaphragm 30. ,Sleevesf |30 are assembled in bushings |35 with the proper running lit to lallow free rotation of each sleeve |30 in its bushing |30.

.An annular groove is formed in'the outer wall of sleeves |30 to receive av packing ring |31. Each sleeve |30 carries, intennediateits ends, 40tooth gear |30, and-is formed with a shoulder |30 by means of .which it is held 'against the flange of bushing |30 under the pressure of tensionI |00-having a pair of opposed slots` |0| receiving driving lugs |00 of plunger' 00. Slots |4| are suillciently long to provide for unrestricted reciprocating movement of plunger 00 -in sleeve |36, while providing for free rotation'of the plunger andsleeve as a unit.

The bore of sleeve |30 is sufficiently large to allow an appreciable p amount of clearance with plunger 9.0, to provide rfor possible misalignment of bushings |35 with the corresponding apertures in head 34 and tappet housing 00, or for lack of concentricity ofthe parts. It will be noted that the seal between the fuel and drive compartments is not dependent upon a close sliding fit of plunger in bushing |30 but that two special packing rings 00 are provided for sealing purposes.

In previous pump designs, the oil under pressure lubricating these moving parts insured a fairly satisfactory seal while the pump was in motion. However. with the engine at rest, the fuel from the fuel compartment slowly dissolved the oil from between the bearing surfaces and finally seeped into the drive compartment and from there through the pump drain into the engine sump where it diluted the oil. In the present design. such seepage is avoided by packing rings 00 and |01.

Cam ||2 has two lobes, causing each plunger 00 to make two full strokes for one revolution oi' the cam, successive strokes being spaced 180. In order to align distributing grooves 02 of plunger 00 with the proper outlet ports to deliver fuel to alternate cylinders on each stroke,.plungers 90 must rotate 90 between impulses. In eect, the plungers must rotate at one-half the cam velocity. This is obtained by the use of gearing, having the proper reduction ratio, between cam shaft H3 and sleeve |00.

In the center of the pump is a sleeve member |00 pressed permanently into place in a central 'aperture in diaphragm 00. The outer end of sleeve |00 is enlarged to abut against a thrust washer |01 engaging diaphragm 30. The portion of sleeve |00 projecting through diaphragm 09 is reduced in diameter at |00 to form a shoulder abutting pump head 00. Reduced portion |00 has a sliding nt in a central aperture of head 34, and a leak-proof joint is obtained by two packing rings |00. Any longitudinal motion of sleeeve |00 is prevented by its pressed flt in diaphragm 00 and by retaining ring |00.

The radially outer surface of sleeve |00 is plated with silver, or other suitable bearing material, to provide a bearing surface for a ring gear ISI. A gear cage |02 is secured against sleeve portion |00 by means of screws 202. Cage |02 supports a series of satellite gears |80 each rotatably moimted on a pin |00. In the illustrated embodiment there are three such satellite gears but a different number might be used depending on the load involved.

Gear on cam shaft III meshes with a relatively large 28tooth gear on satellite |00. `A relativeLv small 20-tooth gear |66 on the satellite meshes with a 'l2-tooth internal gear |01 of ring gear |0|. An external 84-tooth gear |60 of ring gear |0|. meshes with the 40-tooth gears |39 of' sleeves |00. Sleeves |00 rotate plungers 00 through the interengagement of slots |4| and driving lugs |00.

As previously described, groove 00 of plunger 00 forms the spill or by-pass port and the opening thereof is controlled by porting sleeve |10. This control sleeve has the same close sliding fit with plunger 00 as the latter has in bore 00 oi.' bushing 00. During the inward or delivery stroke of plunger 90, the intake port, represented by groove 03. closes when the outer edge 290 of groove 00 reaches edge 0| of bushing 00. As bushing 00 is non-adjustable, the point when the inlet port closes does not change during the operation of the pump` Therefore, the timing of the inlet port closing and thus the beginning of the injection is fixed with respect to the plunger motion and the angular rotation of the pump driving shaft.

Groove 00 is covered by sleeve |10 during the injection period, when plunger 00 is delivering the fuel to the engine cylinder after closing of inlet port 90. At a point during the inward movement of the plunger, the inner edge 200 of groove reaches edge |1| of sleeve |10. This opens the spill port. relieving al1 pressure in oompresslion space 02 and ending the injection.

All of the control sleeves |10 are .held in adjusted position by a control member |00 operated by the central capacity control mechanism of the pump. When sleeves |10 are moved by member |00 toward mounting flange 00 the point where the spill port opens is retarded. This lengthens the fuel delivery period, increasing the volume of the injection. It should be noted that the timing of the ending of the injection period is variable with the pump output. whereas the timing of the beginning of the injection period is fixed.

The delivery from each plunger should not vary by more than 1% from that from any other plunger. This requires extreme accuracy in the adjustment in the length of injection. which accuracy is not obtainable even by extremely accurate machining of the moving parts. Accordingly, an individua-l primary adjustment is provided for the exact point of the plunger stroke for each sleeve |10 where edge 200 of plunger groove 00 is aligned with edge |1| of sleeve |10.

Such adjustment is provided by threading sleeve |10 into an outer or adjustment sleeve |12. Sleeve 12 is ilxed against longitudinal movement relative to central control member |00. Screwing sleeve |10 into sleeve |12 changes the position of edge |1| with respect to sleeve |12.

thus adjusting the exact point during the plunger stroke when spill port 00 opens.

Sleeve |10 has a threaded portion 212 and a circular flange |10 in which are `cut an even number of equally spaced notches |10. For example. there may be ten notches |10. Sleeve |12 has an enlarged part |10 at one end aligned with flange |13. A groove is cut around the outer surface of part |10 and an odd number 'of equally spaced holes |10 are drilled through the bottom of this groove. Holes |10 may be eleven in number, for example. These holes receive the hooked end |10 of ring |11, which vengages one of the notches |10 to secure sleeves |10 and |12 against relative rotation. Wrinkle spring |00 is biased between flange |10 and the bottom of the recess in sleeve |12 to avoid any longitudinal motion of the sleeve due to play in the threads.

The use of a different number of notches44 and holes constitutes a vernier arrangement whichperrnits an extremely close adjustment of sleeves |10 and |12. Sleeve |12 is formed with a pair of spaced annular ribs III, |02 defining a groove |03. As shown ln Figs. l and 10, this groove receives control member |00.

Control member |00 is slidably mounted on extension of sleeve |00 and held against rotation by a key |06. Member |00 has a sleeve portion formed with a helical spline. or a coarse "Acme" type thread |00. Intermediate the ends o! member |05 is a circular ange 200 in which are cut notches |01 each engaging the groove |00 of a sleeve |12`. Between each notch is a radial arm |83 extending into each groove |00.

Spline or thread |09 of member |00 engages mating spline or a thread on another sleeve |00 carrying a gear i0! Sleeve |00 is held against axial movement by a, collar |02 having an edge resting against the inner face of gear |0|. Screws |94 secure collar |02 tightly to diaphragm 00.

13 Collar |92 has a slot |93 through which gear |9| meshes with an idler gear |95 mounted on one of the bushings or sleeves |35 (Figs. 2 and 10). A snap ring |96 holds gear |95 in place.

As best seen in Figs. 10 and l1, idler gear |95 meshes with a sector gear |91 on the inner end of a control shaft |99. Shaft |93 is supported in housing 31 and a capacity control lever |99 is secured to its outer end. Movement of lever |99, through shaft |96, sector gear |91, and idler gear |95 eiiects rotation of gear |9| and sleeve |99. As control member |95 is non-rotatable, to key |96, and sleeve |99 is held against axial movement by collar |92, rotation of sleeve |99 effects axial movement of control member |95. Thus the positions of control sleeves |19 are all adjusted simultaneously.

Lubrication of the pump is effected in the following manner. Oil under pressure from the engine oil pump is delivered to a passage 29| in diaphragm 39. From there it enters an annular groove 292. Holes 293 in bushing |35 register with groove 292 and the oil may thus enter between sleeve |35 and sleeve |36 to lubricate these parts during relative rotation. Holes 294 allow oil to enter between sleeve |36 and plunger 93. A passage 295 connects groove 292 to an annular groove 296 in diaphragm 39. This groove is in communication with an axial passage 291 in pin |64, communicating with the inner bearing surface of satellite |63; furthermore, through a drilled passage (not shown), oil from annular groove 296 reaches the bearing surface of sleeve |46 receiving ring gear |6|. Thus, oil under pressure is supplied to these several parts for lubri-l 35 cation.

Leakage from between satellite |63 and its pin |64 allows oil to enter the main part of drive compartment sections 32 and 33, to reach the other relatively moving surfaces. Lubrication of roller |93 and its bearing |99 is effected through an axial passage 299 in pin ||9 having radial passages extending therefrom to an annular groove 299 in communication, through other radical passages 2|9 with the inner surface of roller |99.

Through a passage (not shown) drilled longitudinally through the wall of housing 31, oil

under pressure reaches an annular groove 225 formed by a chamfer on housing 31. Nine equispaced passages 226 drilled radially in tappet housing 49 each connect groove 225 to one of nine annular grooves 221, each formed in one of the tappet receiving apertures in housing 49. A longitudinal groove 229 is cut in each aperture, intersecting annular groove 221. Grooves 229 are sufficiently long to remain in communication with axial passages 298 in pins ||9 throughout the entire strokes of the tappets. The oil returns to the engine sump through suitable conduits or passages not shown in the drawing.

In the operation of the pump, fuel at a pressure of from four to twelve pounds is delivered from a transfer pump to inlet 38 where it enters fuel compartment 3|. The fuel lls compartment 3|, expelling vapor therefrom through the following arrangement. At the upper end of housing section 31, a cap member 2|5 is provided enclosing a vapor discharge space. Referring more particularly to Figs. 1 and 10, a valve 2|6 controls the flow of vapor from compartment 3| through a passage 2|1 to an outlet passage 3|3 from which it may be conducted outside the engine or its enclosure by a suitable conduit or the like. Valve 2|6 is reciprocable by a lever 2|3 through the medium of a pin 2|9. Lever 2|3 is pivoted in section 31 at 223 and has at one end a float 22|. At its opposite end, lever 2|3 is provided with a machined flat 222 resting against a shoulder 223 in the lower position of float 22|. This maintains float 22| slightly spaced from a shoulder 224.

In the position of the float shown in Fis. 10, valve 2li is open permitting vapor to be discharged through passages 2l1, 2|3 as the fuel level rises in compartment 3l. When the fuel reaches float 22|, it lifts the latter closing valve 2|6 and thus sealing the outlet of chamber 3|.

With fuel compartment 3| filled, fuel is delivered from the compartment by the several pumping units. This operation will best be understood by reference to Figs. 19 through 23.

Referring first to Figs. 14, and 19, plunger 39 is illustrated at the end of the suction or intake stroke, and ready to begin its inward or working stroke. The fuel has filled the interior of plunger 39 and compression space 52 during the preceding outward or suction stroke. It will be noted that, at the beginning of the inward stroke of plunger 99, compression space 52 is still in communication with fuel compartment 3| through inlet port 93.

Figs. 15 and 20 show the position of the plunger at the beginning of fuel injection. It will be noted that plunger 99 has rotated clockwise from the position of Figs. 14 and 19, as viewed in Fig. 29, and that longitudinal grooves 92 are now fully registered with bushing ports 59. At the same time, the plunger has moved inwardly so that the outer edge 295 of inlet groove 93 is aligned with lower edge 5| of plunger 44. Communication is thus. cut off between compartment 3| and compression space 52. The plunger continues to move inwardly, and the fuel in compression space 52 is compressed and forced out through aperture 53 into channel 54. From channel 54, the fuel passes through aperture 93 into passage 61. The pressure of the fuel lifts check or delivery valve 12 and the fuel iiows through cross-passage 19 into passage 69. From here, the fuel passes through aperture 64 into channel 55. Apertures 59 of bushing 44 permit passage of the fuel to groove or fuel chamber 9| which is in communication with grooves 92.

Grooves 92 deliver the fuel to bushing apertures 59 from which the fuel passes to grooves 69 and thus to channel 56. From channel 56, the fuel is delivered toa sleeve aperture 65 into channels connecting this aperture to the engine cylinder spray nozzle as previously described.

The ending of the period of injection is shown in Figs. 16 and 2l, wherein grooves 92 are still in full registry with apertures 59, plunger 99 having rotated clockwise from the position of Fig. 20. The upper edge 296 of spill channel 94 is aligned with the edge |1| of control sleeve |19. During the movement of the plunger as previously described, the spill port has been closed by control sleeve |19, maintaining a sealed compression space within the pumping unit.

The plunger continues to advance to the position shown in Figs. 17 and 22, which represent the ending of the compression stroke. In this latter position, the plunger has rotated further in a clockwise direction, but grooves 92 are still aligned with ports 59. However, the inward movement of the plunger has caused spill port 94 to be uncovered by control sleeve |19 and thus the interior of the plunger is now at the pressure '5l in bushing u.

l5 of fuel compartment 3i and the delivery of fuel to ports ll'has ceased.

Prom the position shown' in Pig. 17, when the plunger has reached to center, plunger Il begins its outward or suction stroke. Check valve II is closedI and some fuel enters plunger Il through spill port I4 until this port is closed by sleeve III during outward movement of plunger Il. As the plunger continues to move outwardly with ports f3 and Il closed, a partial vacuum is created in space I3 and channel until intake port 33 opens. l'uel, under the combined action of such vacuum and, the pressure in compartment 3|. rushes through port 33 filling all, the space in bmhing M After the plunger reaches bottom center and begins its next inward stroke, intake port I3 is still open and fuel still enters the pumping unit. Once the bushing and plunger spaces are filled, plunger Il starts to displace the fuel. Part of the fuel, and any vapor present, are expelled. Only solid fuel remains in the pumping unit after inlet port 33 closes as shown in Pk. 18. During its outward and the following partial inward movement, plunger 3l has continued to rotate clockwise and grooves Il are thus brought into registry with bushing ports 8i.

Figs. 18 and 23 show the pumping unit at the beginning of the injection period for ports 6I.l

Grooves 92 are fully registered with ports Il and the outer edge 295 of inlet channel 33 is sealed by the lower edge si of bushing u. 'rne fuel is compressed and delivered in the same manner as previously described from compression space 52 past valve I2 into grooves I3. Grooves l2 deliver the fuel to ports il which are connectedby` longitudinal grooves 62 which connect withannular channel l. The fuel is delivered from channel 51 through sleeve ports 0I into the passages leading to another engine cylinder. Thus, on alternate strokes, plunger 9| distributes fuel to ports l! and 8|, respectively.

As stated, the plunger is designed to discharge fuel simultaneously in diametrically opposite directions to neutralize the hydraulic thrust on the plunger. 'Ihis is best Ishown by tic representations ln Figs. 24 and 25. Fig.' 24 corresponds to the position of the plunger shown in Figs. and 20. Diametrically opposite grooves 32 are registered with diametrically opposite ports Ports 5l deliver the fuel through es 23|, 23| to a single e 2li which may represent port Il of sleeve llig. 25 corresponds to Figs. 18 and 23. Grooves l! are now registered with apertures Il which de,- liver fuel simultaneously to passages 233, 232 to `a single passage 233 which corresponds to sleeve port il. Thus, the fuel is delivered in .opposite directions at the same time whereby the hydraulic side thrust on plunger Il is neutralized.

The described pump comprises a novel and efilcient unit for delivering fuel under pressure to a number of engine cylinders with not more than one half the number of pumping units hitherto thought necessary. The rotatingplunger acts as Aa fuel distributor to alternate cylinders on alternate injection strokes. The timing of the injection is controlled independently of the pilinger rotation by means cooperable with the reciprocatory motion of the plunger. Furthermore. a novel and eillcient plunger driving mechanism is provided as w ell as effective sealing means between the fuel and driving compartments. The pump is so constructed that it may be readily discomprising,

.including a cylinder and a 16 mantled for inspection or repair, either as a whole or as sub-units.

While a speciilc embodiment of the invention has been shown and described in detail to illustrate the application of the principle thereof, it

should be understood that the invention may be otherwise embodied without departing from such principles.

What is claimed is:

1. In a fuel injection pump, e means for delivering fuel under pressure to an engine; a pumping unit including a cylinder and a plunger enacting therewith, said cylinder having diametrically opposed ports in communication with said passage means and a compression spa beyond said plunger; said plunger having an annular fuelchamberinitsoutersurfaceandapairofdiametrically opposite longitudinal grooves communieating therewith and arranged tc register simultaneously with a pair of said cylinder fuel receiving ports; passage means interconnecting said compression space and said fuel chamber; means effective to reciprocate said plunger and to rotate the same relatively to said cylinder, both in a predetermined relation to the engine crank shaft speed and to the relative angular position of the engine cranks, to inject fuel under pressure into said passage means; and adjustable eil'ective to regulate the amount of fuel delivered during each stroke of said plunger.

2. In a fuel injection pump, a pumping unit plunger coacting said cylinder and compression space;

therewith, the inner ends of plunger cooperating to form a said cylinder having two pairs of diametrically opposite ports; rst e means communicating with said ports to deliver fuel under pressure to an engine; said plunger being formed with'a fuel chamber comprising an annular groove in its extermi surface and a pair of diametrically opposite grooves intersecting said chamberand selectively resisterable with either pair of said cylinder ports; second passage means effective to amanaiinieeam llldilmlylinderand wilhJ-helnnerendsof piteportunrsc passage means comm with said ports mum to deliver fuel under pressure to 4. In a fuel infection pump, a pumping unit in combination, a cylinder, a plunger and rotatable relatively to said cylmeerv ma two amm' passage means arranged i conduct fuel under amasar `cylinder and plunger cooperating to form a compression space: said cylinder having a thick wall with fuel passages formed therethrough and flrst and second pairs of annular grooves and first. and second pairs oi'v diametricaily opposite longitudinal grooves formed in its'outer surface, each pair of longitudinal grooves intersecting one of said` 'and a pair of diametrically opposite longitudinal l'grooves extending therefrom-and forming dis- .tributing means; certain of said cylinder fuel passages registering with said second pair of cyl- 'inder annular grooves to interconnect said compression space and said fuel chamber; the other fuel passages being arranged as two 'pairs of di- Vame'trically opposed fuel ports, each port registering withv one of said cylinder longitudinal 'grooves and also registrable with one of said dis- -tributing means whereby rotation of said plunger will distribute fuel alternately to said passage means.

5. A fuel injection pump comprising, in combination. a fuel compartment; a drive compartinent; partition means separating said compartments; a pump drive shaft; a plurality of pumping units, each comprising a, cylinder mounted in said fuel compartment and a rotating plunger coacting with said cylinder; a plurality of sleeves [extending through said partition means, each of said plungers extending through one of said sleeves into said driving compartment; said plungers being reciprocable through said sleeves but being xed against rotation relative thereto; first sealing means between said plungers and lsaid sleeves: second sealing means between said partitionnieans and said sleeves; a pair of passage means for delivering fuel under pressure to `an engine from each of said pumpingunits; each :cylinder having two pairs of diametrically opposed ports. each pair of ports connecting with of said passage. means; impulsing means in said drive compartment operable at a rate proportional to the engine crank shaft speed to suceessively reciprocate said plungers to inject fuel under pressureinto a passage means; said mechanism operable by said pump drive shaft to rotate said sleeves and their associated plungers to deliver fuel alternately to each pair of diametrially opposed ports of each cylinder during alternate strokes of said plungers.

A fuel injection pump comprising, in combination, a fuel compartment; a drive compartment; partition means separating said compartments; a pump drive shaft; a plurality of pumppressure to an engine, said v ing units, each comprising a cylinder mounted in said fuel compartment and a rotating plunger coacting with said cylinder, said units being equispaced and parallel-with thevpump shaft; a plu,l

is pressure toan engine from eachof said pumping funits; each cylinder having two pairs of diametrically opposed ports, each pair oi' ports connecting with one of said passage means; a tappet connected `with the end of each plunger in the drive compartment; a roller mounted on each tappet; a shaft rotatably mounted in said'drive compartment `and having a circular face cam formed with a lobed skirt engaging `said rollers to reciprocate said plungers successively to inject fuel under pressure into said passage means; mechanism operable by said shaft to rotate said sleeves andtheir associated plungers to deliver fuel alternately to the spaced ports of each cylinder during alternate strokes' of said plungers;

andV a driving connection between said shaft and the engine.

7. A fuel injection pump comprising, in comi bination, a fuel compartment; a drive compartment; partition means separating said compartments; a pump drive shaft; a plurality of pumping units. each comprising a cylinder mounted in said fuel compartment and a rotating plunger coacting with said cylinder, said units being equispaced and parallel withthe pump shaft; a plurality of sleeves extending through said partition means, each of said plungers extending through oneeof said sleeves into said driving compartment; said plungers being reciprocable through said sleeves but being fixed against rotation relative thereto; rst sealing means between said plungers and said sleeves; second sealing means between said partition means and said sleeves;v

a pair of passage means for delivering fuel under pressure to an engine from each of said pumping units; each cylinder having two pairs of diametrically opposed ports, each pair of ports connecting with one of said-passage means; a tappet connected with the end of each plunger in the drive compartment; a roller mounted on each tappet; a shaft rotatably mounted in said drive compartment and having a circular face cam formed with a lobed skirt engaging said rollers to reciprocate said plungers successively to inject fuel under pressure into said passage means; and gearing connecting said shaft and said sleeves to rotate the associated plungers to deliver fuel alternately to each pair of spaced ports of each cylinder during alternate strokes of said plungers.

8. In a fuel injection pump, a pair of passagel means for delivering fuel under pressure to an engine; a pumping unit including a cylinder and a plunger coacting therewith, said cylinder having a first pair of diametrically opposite ports both communicating with one passage means, and a second pair of diametrically opposite ports both communicating with the other passage means; said first pair of ports being spaced ninety degrees from said second pair; said plungerhaving a fuel chamber and a pair of diametrically opposite fuel passages communieating with said chamber and arranged to register simultaneously with both ports of one of said pairs of cylinder ports, whereby said plunger is hydraulically balanced to eliminate binding thereof in said cylinder during discharge of fuel under pressure to said passage means; impulsing means operable in a predetermined relation to the engine crank shaft speed to reciprocate said plunger to inject fuel underpressure into a passage means; and mechanism operable by said impulsing means to rotate said plunger ninety degrees during each stroke to deliver fuel under pressure alternately to said passage means.4

9. A fuel injection pump comprising. in com- 19 bination, a drive shaft: a plurality of pumping units. each including a cylinder and a plunger coacting therewith, said units being equi-spaced and parallel to laid shaft: a plurality of pairs of passage means, each pair being operative to deliver fuel under pressure from one of said units to the engine; each cylinder having a first pair of diametrically opposite ports both communieating with one passage means of the pair associated with its respective pumping unit and a second pair of diametrically opposite ports both communicating with the other passage means of the pair associated with its respective pumping unit: said first pair of ports being spaced ninety degrees from said second pair; each plunger having a fuel chamber and apair of diametrically opposite fuel passages communieating with said chamber and arranged to register simultaneously with both ports of one of said pairs of cylinder ports, whereby said plunger is hydraulically balanced to eliminate binding thereof in said cylinder during discharge of fuel under pressure to said passage means; a cam rotatable by said shaft in a plane perpendicular thereto and having impulsing means effective to reciprocate said plungers successively to deliver fuel under pressure to said passage means; and mechanism operable by said cam to rotate each plunger during each stroke to deliver fuel under pressure alternately to its associated passage means; the angular velocity of said plungers being equal to one-fourth of the angular velocity of said cam multiplied by the cam impulses per plunger per cam revolution.

10. A fuel injection pump comprising. in combination, pairs of passage means for delivering fuel under pressure to an engine; a plurality of pumping units each associated with one of said pairs of passage means and each including a cylinder and a plunger coacting therewith, each cylinder having a first pair of diametrically opposite ports both communicating with one of its associated passage means, and a second pair of diametrically opposite ports both communicating with the other of its associated passage means; a fuel reservoir: each plunger cooperating with its cylinder to form a compression space and having a fuel chamber communicable with said compression space and a pair of diametrically opposite fuel passages communicating with said chamber and arranged to register simultaneously with both ports of one of said pairs of cylinder ports. whereby the plunger is hydraulically balanced to eliminate binding thereof in its cylinder during discharge of fuel under pressure to its associated passage means; each plunger extending into said fuel reservoir and having an inlet port and a spill port spaced longitudinally from each other arranged to connect its compression space to said reservoir; impulsing means operable by a drive shaft in a predetermined relation to the engine crank shaft speed to reciprocate said plungers to inject fuel under pressure into the passage means; mechanism operable by said impulsing means to rotate said plungers ninety degrees during each stroke to deliver fuel under pressure alternately to the associated passage means of each pumping unit; said plunger fuel paages having a greater circumferential length than that of said cylinder ports; and control sleeves in said reservoir each adjustable longitudinally of a plunger relative to its spill port to adjust the length of the fuel injection period independently of the rotation speed of the plung' 20 er: whereby the relative circumferential dimensions of said plunger fuel passages and said cylinder ports are not critical.

1l. A fuel injection pump comprising. in combination. pairs of passage means for delivering fuel under pressure to an engine: a plurality of pumping units each yassociated with one of said pairs of passage means and each including a cylinder and a plunger coacting therewith, each cylinder having a first pair of diametrically opposite ports both communicating with one of its associated passage means. and a second pair of diametrically opposite ports both communicating with the other of its associated passage means; a fuel reservoir; each plunger cooperating with its cylinder to form a comprsion space and having a fuel chamber communicable with said compression space and a pair of diametrically opposite fuel passages communicating with said chamber and' arranged to register simultaneously with both ports of one of said pairs of cylinder ports, whereby the plunger is hydraulically balanced to eliminate binding thereof in its cylinder during discharge of fuel under pressure to its associated passage means; each plunger extending into said fuel reservoir and having an inlet port and a-spill port spaced longitudinally from each other varranged to connect its compression space to said reservoir; impulsing means operable by a drive shaft in a predetermined relation to the engine crank shaft speed to reciprocate said plungers to inject fuel under pressure into the passage means: mechanism operable by said impulsingm'eans to rotate said plungers ninety degrees during each stroke to deliver fuel under pressure alternately to the associated passage means of each pumping unit; control sleeves in said reservoir each adjustable longitudinally of a plunger relative to its spill port to adjust the length of the fuel injection period independently of the rotation speed of the plunger; a disk mounted coaxially with the drive shaft and including means engaging all the plunger control sleeves simultaneously; mechanism for'- shifting said disk axially to adjust the pump output; and means for individually adjusting each of said control sleeves with respect to said disk 'to equalize the outputs of the respective pumping units.

DESIRE J. DESCHAMPS.

REFERENCES crrnn l The following references are of record in the ille of this patent: t

UNITED STATES PATENTS Number `Name Date 1,791,600v Onions Feb. l0, 1931 2,223,757 Dillstrom' Dec. 3, 1940 2,223,759 Dillstrom Dep. 3, 1940 2,306,950 v Jacoby et al Dm. 29, 1942 2.381.585 Gambrell Ati'. 7, 1945 2,413,115v Sheehan Dec. 24, 1946 2,417,137 Smith Mar. ll, i947 2,423,373 Chandled July 1, 1947 2,428,408 Beeh Oct. 7, 1947 2,429,806 Deschamps Oct. 28. 1947 2,436,797 Deschamps et al. Mar. 2, 1948 `2.474,39!! Groves June 28, 1949 2,519,893 Deschamps et al. Aug. 22, 1950 2,531,202 l Deschamps Nov. 2l, 1950 FOREIGN PATENTS Number Country Date 359,603 Great Britain Oct. 29, 193i.

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