US2417137A

US2417137A - Fuel pump injection

Info

Publication number: US2417137A
Application number: US536711A
Authority: US
Inventors: Warren H Smith
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1944-05-22
Filing date: 1944-05-22
Publication date: 1947-03-11
Anticipated expiration: 1964-03-11

Description

I Mmh 11,1947.

w. H. SMITH 2,417,137

FUEL PUMP INJECTION 1 Filed nay A22. 1944 4 sheets-sheet 1 g lfw;

w. H. sMn'H 2,417,137 Y' v FUEL Pulp 'I uqxnon Filed lay 22,'{71944 n I TW! v4 Sheets-Sheet 2 gmac/who@ March 11, 1947. w. H. SMITH FUEL PUMP INJECTION Filed nay 22. 1944 4 Sheets-Sheet 3 March ll, 1947. w. H. s-MrrH Filed lay 22;'1944 4 sheets-*sheet 4 /M/:cr/alv fau. 6fm. MEN v Patented Mar. 1l, 1947 2,417,137 FUEL PUMP INJECTION trait, Mich., asslgnor to Warren H. Smith, De General Motors Corp corporation of Delaw oration, Detroit, Mich., a are Application May 22, 1944, serial No. 536,711

(Cl. s-41) 9 Claims.

clearance between the pumping elements, failure often occurs due to binding or sticking of the elements caused by unequal forces applied thereto by reaction of the pressure of the fuel and the actuating mechanism. Frequently these failures are the result of inadequate lubrication of the operating surfaces and the presence of l foreign particles in the fuel which start wear thereon and eventually cause binding and failure of the parts. Pumps of this type for aviation engines must be able to function to prevent engine failure even though certain of the pumping elements fail temporarily or permanently. It is also necessary to provide means for cooling the pumping elements and to prevent fuel leakage therebetween in order to accurately'meter the fuel delivered and eliminate any vapor in the fuel inthe pumping spaces and passages. It is also found desirable to control the start and finish of injection "by by-passing a partof the fuel in the pumping chambers before the start of injection and to cause by-pass of fuel from the pumping chamber directly to theA fuel tank in order to quickly reduce the pressure in the injectors of the engine cylinders, thereby preventing after-dribble of fuel therethrough and to prevent the formation inlet space.

of vapor in the fuel ments.

The means by which ent fuel injection pump, will become apparent by reference to the following detailed description and drawings illustrating one form of pumping mechanism provided with these improvements.

Figure 1 of the drawings is a vertical mid-sectional view of the fuel injection pump. Figures 2 and 3 are enlarged views of portions of certain of the pump'elem'ents.

Figures 4 and 5 are views taken on lines 4--4 and 5 5 of Figures 3 and 2, respectively.

Figure 6 is an enlarged perspective view of certain of the actuating elements of -the pump.

Figures 7, 8 and 9 are reduced cross sectional 2 views taken on lines 1-1, 8 8 and 9,-9 of Figure 1.

Figure 10 is a reduced vertical mid-sectional view similar to that shown in Figure 1 but taken on a line displaced angularly with respect thereto and with parts broken away.

Figure 1-1.is an enlarged vertical mid-sectional view of an injector supplied with fuel by the pump, and

Figure 12 is a port timing diagram to clearly show the, sequence of pumping, by-passing and fuel injection events.

As best illustrated in Figure l, the fuel pump mechanism is included in a two-part housing comprising. an upper pump housing I and a lower cam housing ns 5. An upper cap 1 is removably secured to the pump housing which is provided with a flange 9 secured by suitable cap screws to the cam housing 3 on which a lower mounting flange I0 is removably secured for attaching the pump assembly to the engine. 4The pump and cam'housin'gs are provided with aligned axial bores and four aligned bores equidistant and parallel thereto and spaced apart, as best shown in Figures 7, 8 and 9. A Valve sleeve I I is secured inthe axial bore of the pump housing and a pump cylinder sleeve I3 is secured in each of the other four bores in the pump housing and a plug -I5 is threaded in the upper endof each of these bores'.

A metering valve stem I1 is rotatably and slidably mounted in the valve sleeve II and a pump plunger I9 is rotatably and reciprocably mounted in each of the cylinder sleeves I3.

The valve stem I 'I is connected by means of splined stub shafts 2I and 23 to a driving shaft 25 rotatably mountedI in a bushing 2J in the axial bore in the mounting flange I0. Reciprocation of the valve stem I1 with reference to the valve ysleeve II, for controlling the amount of fuel Vdelivered by the plungers, is accomplished by rack 23 slidably mountedl in an axial counterbore in the cap 1 'and a sector gear 3| meshing with the rack and secured on a fuel control shaft 33 rotatably supported in the cap. The upper end of the valve stem is provided with a circumferential slot into which extends a yoke portion 35 of the rack 29.

As best illustrated in Figure 1 the splined stub shaft 23 is provided with a. bearing portion rotatably supported along with the upper end of the driving shaft 2-'5 in end portion 47 of 3 provided with external cooling a bushing 31 secured in the Each plunger driving gear 4I is l 3 plunger guide 49 which is slidably mounted in the bore in the cam ,housing by means of a compression spring 5| placed between a plunger driving gear 4| and a spring retaining washer 53 supported in a circumferential slot in the lower end portion 41 of the plunger I9. A spherical socket portion is provided on the lower face of the guide 49 which rests on the upper spherical surface provided on a cam follower shoe or button 51 supported on a cam plate 59 which is secured to the driving shaft 25. The lower surface of the buttons 51 are slightly conical to provide adequate lubrication therefor. The cam plate 59 is Provided with a radial lower thrust face supported on a step bearing 6| which is supported in a'counterbore in the upper face of the mounting flange I to take the downward force exerted by the plunger springs-|. A thrust washer 63 is placedbetween the lower face of the flange 9 of the pump housing I and a counterbore in each plunger driving gear 4I to take the upward force exerted by each plunger spring 5|. The upper face of the cam plate 59 is angularly inclined so that upon rotation thereof, the plungers I9 will .be reciprocated in the cylinder sleeves I3 and will also be rotated therein by the plunger gears 4| meshing with the pinion gear teeth 39 on the stub shaft 23.

A circular retainer plate B5, best illustrated in Figure 6, is provided for positioning the buttons 51. The retainer plate B5 is provided with an X- shaped slot, the four legs of which are spaced 90 apart and each shoe or button 51 is provided with a circumferential groove 56 so that one but'- ton is retained in each legof the slot and is accordingly prevented from moving outwardly therefrom by engagement of the edges of each slot leg by the bottom of the groove 66 in each button. Each button, however, can move-longitudinally in each leg of the slot in the retainer and radially with respect to the cam plate upper face an amount necessary to cause reciprocation of each of the plungers. It will be evident that the plungers I9 and the splined sleeves 43 secured thereto by the shear pins 45 are reciprocated'with reference to the plunger driving gears 4| splined on the sleeves when the plungers are rotated by the plunger driving gears- For a two stroke cycle engine the driving shaft 25 and therefore the valve stem I1 connected thereto, are rotated at engine speed in the direction of the arrow, as shown in Figure 1, and one stroke will be imparted to each of the fourplungers per revolution of the cam plate 59 by the engine. The plungers are, however, rotated at half engine speed by the plunger gears on account of .the plunger porting arrangement which will be described subsequently.

The above described plunger actuating mechanism causes minimum side thrust to be imparted to the plungers by rotation of the cam plate by reason of the spherical engaging surfaces provided on the plunger guides 49 and the cam follower shoes or buttons 51 and the slight resulting side thrust is taken by`plunger guides. The retainer 65 provided for the buttons 51 retains the buttons in position under the guides 49 even though a plunger should temporarily stick in the upper portion of its stroke so that upon return of the plunger by itsspring the spherical surfaces of the plunger, guide and button will re-align upon re-establishment of contact therebetween. Rotation of the cam plate tends to move the buttons outwardly in case a plunger sticks so that the spherical surface on the plunger guide in conlstern I1, stub tacting the spherical upper surface of the button causes re-alignment of the button. The plunger shear pins 45 are provided so that upon binding of a plunger I9 in a. plunger sleeve |3, the pin `45 will shear and permit. .continued rotation of the plunger driving gear and normal operation of the other plungers and, therefore, continued operation of the engine cylinders supplied with fuel by the other plungers.

In addition to the exterior cooling ns 6 provided on the cam housing 3, lubricating oil is supplied under pressure to certain of the injector parts and leakage of oil from these parts is directed to other parts to both lubricate and cool them. Certain of these lubricating and cooling passages are arranged to substantially equalize the pressure applied on opposite 4ends of the valve stem 11 so that it may be more easily reciprocated by rotation of the fuel control shaft 33. Lubricating oil is supplied directly to the plungers |9 and valve stem I1 to lubricate and prevent leakage of fuel along these parts.

Lubricating oil under pressure is supplied by an engine lubricating pump, notshown, connected to an oi inlet opening 61 in the mounting flange I9 and connecting passages 68 and 69 therein extending to radial openings driving shaft bushing 21, which openings 10 are located adjacent a circumferential groove 1| in the driving shaft 25, las best shown in Figure l, 12 are provided in the driving shaft 25 from the circumferential groove, 1I to an axial shaft passage 13 extending to the upper end of the driving shaft. The splined stub shafts 23 and 2| are likewise provided with axial passages 15 and 15, respectively, to connect the axial passage 13 in the driving shaft 25 with an a 'al passage 11' extending through the valve stem I1, as shown in Figures 1 to 5. The upper end of the axial valve stem passage 11 opens into a passage 18 extending from the yoke portion 35 in the rack 29 to the upper end thereof so that oil under pressure is supplied to the pump housing cap 1. It will be apparent that oil under pressure in the cap 1 and the oil under pressure vin the space between the driving shaft 25 and lower stub shaft 23 causes approximate equalization of pressure on' opposite ends of the valve stem |1 to permit it to be readily reciprocated with respect to the valve sleeve II by the rack 29 and sector `gear 3| upon rotation of the control shaft 33.

The oil under pressure in the upper end of the cap 1 will leak downwardly past the upper end of the rack 29 into the bottom of the bore in the cap 1. Oil is drained from the bore in the cap 1 to the cam housing 5 by an oil drain tube 19 secured in openings in faces of the pump housing I, as best illustrated in Figure 10, and this oil serves to lubricate the plunger actuating mechanism. Oil will, of course, leak outwardly between the ends of the valve shafts 2| and 23, and upper end of the driving shaft 25 from the axial passages therein to lubricate these parts and the parts adjacent thereto. I

The valve stem |1 is provided with a circumferential oil sealing groove adjacent the upper end and a helical oil groove 9| adjacent the lower end to provide lubrication of the valve stem and valve sleeve and to prevent leakage of fuel past these grooves. The upper sealing groove 80 is connected to the axial passage 11 in the valve stem by a radial passage 82 so that oil under the upper extremity of the bore in.

the upper and lower cylinder sleeves I I.

` is adapted to be connected by pressure is applied directly to the sealing-,groove 80. Registering passages indicated generally at 83extend radially through the lower portion oi the valve sleeve II, pump housing I and pump end of the valve stem is carried upwardly by the helical groove 8| in the valve stem to the passages 83 when the stem is rotated and when the valve stem is moved upwardly from the position, as shown, the passages 83 are uncovered to cause oil to be applied to lower position of the plungers I9, each of which is provided with a circumfer- Oil splashed on the lower and are provided with diametrically disposed fuel inlet ports 93 which are disposed radially with respect to the axis of pump housing I and open into the inlet fuel chamber 9|. as best shown in Figures 1 and 9. Each of the cylinder sleeves are also provided with a single fuel leakage port 95 located below the inlet ports and are directed radially outwardly with respect to the axisI of the central bore of the pump housing. The leakage ports 95 likewise open into the fuel inlet chamber 9|,

, as best shown in Figures l and 9. As best illusential oil sealing groove 84 which moves past the passages 83 to lubricate the plunger and plunger sleeve surfaces and to.\prevent leakage of fuel downwardly therebetweenand into the cam housing- 3. In addition to the oil applied to the plunger actuating mechanisir from the oil .drain tube 19 the oil leaking between the ends of the stub shafts 2| and 23 andthe lupper end of the driving shaft reaches the lower end of the valve stem and sleeve and pinion teeth 39 on the stub shaft 23 through the clearance space provided on either side of these teeth and oil also is applied to the plunger driving gears 4I and gear thrust washers 63 through this clearance space. The bushing 31 in which the stub shaft 23 and upper end of the driving shaft 25 is supported for rotation is lubricated by oil leaking outwardly be,-V

tween the ends of these shafts and falls on the upper surface of the cam plate 59A to lubricate the cam surface and cam follower shoes and buttons 51. Due to the buttons 51 having slightly conical lower surfaces they are lubricated by the wedge action of the oil on the uppersurface of the cam plate 59. The excess oil from the plunger driving gears falls into the plunger guides 49 and on the plunger guide bores in the cam housing 3 and lubricates these surfaces. Suitable drain holes 85 and 86lare provided in the Walls and the lower spherical surfaces of the plunger guides 49 to apply oil directly on the guide bores and also on the upper spherical surface of the cam shoes o1' buttons 51. cam plate step bearing 6I is provided with radial oil grooves 81 which are supplied with oil leaking' through the clearance space 88 around the driving shaft 25 from the upper end of the driving shaft bushing 21. Excess oil in the cam housing 3 is drained outwardly through a drain hole. 89 provided in the lower mounting flange I0. -The above described lubricating system reduces the friction and cools the parts and the oil sealing grooves provided on the plungers I9 and valve stem I1 enables these parts to be operated at high speed in the cylinder sleeves I9 and valve sleeve II with very small clearance therebetween, which is necessary, when 4light fuel oil The upper surface of the i jector |03, shown trated in Figures 1 and '1 the' cylinder sleeves I3 are also provided with diametrically spaced ports 91 and 99 disposed radially with respect to the central bore of the pump housing and vertically spaced above the inlet ports 93. The ports 91 are fuel outlet or supply ports and each of these ports open into a'separate radially outwardly directed fuel supply opening |0I in the pump housing I. Each supply opening |0| is adapted to be connected to a separate fuel inand suitable fittings. Each injector |03 is adapted to be screwed in a separate engine cylinder opening and is provided with pressure opened check valve |01 and spray nozzle openings |09. Each of the four by-pass ports 99 opens into separate radially inwardly directed by-pass passages 4||I in the housing I, and each of the four passages open into a separate radially directed by-pass port II3 in the valve sleeve II. `The ports` I|3 are spaced 90 apart in thevalve sleeve I.`

The plungers I9 are provided with anV axial counterbore-| I5 extending downwardly from the top thereof and forming a pumping' chamber bei tween the lower. end of the plunger counterbre and the plugs I5 in the upper ends of the cylinder sleeves. Each vplunger is of vertically spaced cally arranged-90 plunger counterbore or pumping chamber II5. The lower pair of plunger ports I I1 .serve as fuel inlet ports and cooperate with the inlet ports 93 of plunger ports |I9 serve as outlet ports and cooperate with the fuel outlet and by-pass ports 91 and 99, respectively, of the-cylinder sleeve I3.v A circumferential fuel leakage groove I2I is provided in each plunger to cooperate with'the leakage port 95 in the cylinder sleeve I9 tol return ports ||1 and II9 diametrifuel leaking downwardly along ythe plunger to' Y the inlet-chamber 9|.

or gasoline is supplied to the pump chamber I for injection into the respective engine cylinders .by the combined actionof the plungers I9 and valve stem I1 acting in timed relation. y

The fuel passages provided in the pump housing I, plungers I9, valve stem I1 and sleeves I3 and I enable variable quantities of fuel to be injected into each engine cylinder in the following manner:

The pump housing I is provided with a fuel inlet opening 90, best shown in Figure 8, opening into a fuel inlet chamber 9|. The inlet opening an engine driven fuel pump, not shown, connected to a fuel tank to supply fuel under slight pressure to the-fuel inlet chamber 9|. The pump cylinder sleeves I3. extend through the fuel inlet chamber 9| |39 extends angularly The valve stem I1 is provided with an external by-pass 'groove |23 having a lower circumferential edge |25, shown in Figuresl and 10, and an upper .edge of irregular shape, best shown in Figures 2 and 3. The upper edge ofthe valve stem by-Dass groove comprises a circumferential edge portion |21 and helical and longitudinal edge portions |29 and |3I, respectively, extending downardly away from the upper circumferential edge portion and connected at their lower extremity by alower circumferential edge portion |33 to form a valve stem land |35. A helical groove |31 is provided in this land and a passage bottom of the groove |31 to a groove I4I extending circumferentially part way around the valve stem directly opposite the angular groove |35, as `shown in Figure 2, in order to substantially equalize the pressure of the fuel in opposite sides of the valve stem and thereby prevent side thrust and unequal wear on the stem in a manner which will be described subsequently.

the lcentral bore in the in Figure 1l, by a tube |05 provided with two pairs A apart and opening into theA in the cylinder sleeve I3.` The upper pair of and upwardly from the an internal leakage groove |41 surrounding the stem and connecting passages When the valve stem is in its lowest position, shown in Figure 1, the lower circumferential edge of the valve stem by-pass groove |25 is positioned below the lower edgeof an internal circumferential by-pass groove I4I provided in the valve sleeve and the upper circumferential edge portion |21 of the valve stem groove is positioned in a plane intersecting the upper edges of the by-pass ports I|I of the valve sleeve I|. It will be evident that when the driving shaft 25 is rotated in the direction of the arrow, as viewed in Figure 1,-the valve stem will be rotated counterclockwise, as viewed in Figure 1, and the valve stem land |35 will accordingly cause successive interruption of fuel flow through the by-pass ports H3 in the valve sleeve. The helical edge portion |29 of the land is the leading edge which closes each of the sleeve by-pass ports |I3 suc- `cessively and the longitudinal edge portion I3I of the land is the trailing' edge which opens each of the by-pass ports successively. Due to the helical edge portion |29 of the land it will be apparent that when the valve stem is in the lowest position in the valve sleeve, as shown, each sleeve by-pass port II3 is closed for a longer interval than when the valve stem is moved upwardly from this position. The lowest position of the valve stem is accordingly the maximum fuel injection setting of the valve stern and the highest position is the zero fuel injection setting position, which causes shut down of the engine, as then the land does not close off the by-pass ports I|3.

As best shown in Figures 8 and 10 the by-pass groove |23 in the valve system is connectedby a radial passage |43 in the pump housing I to an opening` |45 therein which is connected by a suitable tube and fittings directly to the fuel tank for returning by-pass fuel directly thereto. Leakage of fuel upwardly along the valve stem I1 is also returned to the passage |43 through in the valve sleeve |49 and |5I between the groove |41 and passage |43, as best shown in Figure 10. The by-pass groove |23 in the valve stem is in constant communication with the by-pass groove |4I in the valve sleeve I I which is connected directly to the fuel tank by the passage |43 and opening |45 in the pump housing I for all positions of the plunger I1 with respect to the valve sleeve The squence of events occurring by movement of each plunger I9 from the bottom of its stroke and back to this position by rotation of the cam plate 59 through one revolution will be better understood by' reference to Figure 12. In this figure the lift of the plunger is plotted against degrees of 4revolution of the cam plate 59 and valve stem |1, and the' duration of port opening and closing events are also shown.

With one of the pump plungers I9 at the 4bottorn of its stroke, corresponding to zero degrees will be noted that the fuel inlet plunger are in register with the fuel inlet ports 93 ,in the plunger sleeve I3 and fuel under pressure in the inlet cavity 9| enters the pumping space I I within the plunger through these open ports and completely fills the chamber. Upon further rotation of the cam plate 59 through an angle of 10, the plunger is rotated and moved upwardly to cause closure of the inlet fuel ports II1 in the plunger. o f the cam plate and valve stem I1 through an angle of 10 causes the plunger outlet ports II9 to rotate and move upwardly into register with in Figure 12, it ports II1 in the Further rotation the outletport 91 and by-pass port 99 in the plungery sleeve |9. As the by-pass port 99 is connected by the by-pass passage I to the valve sleeve by-.pass port II3, which is then uncovered by the'land |35 of the valve stem, fuel will be by-passed therethrough until the camlplate and valve 'stem has rotated through an additional 40 angle, after opening of the plunger by-pass ports, and then the helical edge portion |29 of the valve stem land |35 covers the by-pass port in the valve sleeve to stop further by-pass of the fuel from the pumping chamber when the valve stem is in its lowermost position, as shown. The fuel by-passedfrom the pumping chamber previously explained is returned directly to the fuel tank through the registering 'py-pass' grooves in the valve stem and sleeve |23 and |4I, connecting passage |43 and fuel tank outlet opening |45 in the pump chamber I. It will be evident that by lmoving the valve stem and the a helical edge portion thereon upwardly from the pass port and by-pass of lowestposition, as shown, causes delayed closure of the by-pass port in the valve sleeve. When the valve stem is moved upwardly to its highest position the land |35 thereon does cover the byfuel from the plunger continues until the plunger moves downwardly. With the valve stem in its lowest position it will be evident that when by-pass of fuel from the pumping chamber ceases by closure of the valve sleeve by-pass port ||3 by the valve stem land |35 the pressure in the pumping chamber will increase in theoutlet passage pump chamber and tube |05 connecting this opening with the fue] injector |03 to cause unseating of the check v'alve |01 therein and injection of fuel through the spray openings |09 in the injector nozzle. Fuel injection continues until further revolution of the cam disk and valve stem through an angle of 60 which causes the vertical edge portion |3I of the valve stem land to uncover the by-pass port ||3 in the valve to then permit the high pressure in the injector,

.connecting tube and outlet passage to be bypassed directly to the fuel tank through the bypass passages thereby causing a sudden reduction in pressure in these passages. This allows the injector check valve to seat promptly and stop further fuel injection into the engine cylinder and prevent after-dribble of fuel into the cylinder. When the valve stem is in the lowest position fuel is accordingly injected into the engine cylinder for 60 of revolution of the cam disk and valve stem and the start of fuel injection may be delayed to reduce the amount of fuel injected into the engine cylinder by upward movement of the valve stem. When the stem is in its uppermost position by-pass of fuel from the pumping chamber is continuous which prevents any injection of fuel to the engine cylinder and accordingly causes stopping of the engine. lFurther rotationY of the cam through an angle of '10- causes rotation and maximum lift of the'fu'el plunger and closure of the plunger outlet ports after the start of downward movement of the plunger by the spring 5I.- Further revolution of the cam disk through 10 causes the inlet in the cycle of operation of each of the remaining three plungers are identical to that described above and these events occur each of revolution of the cam disk and valve stem.

, timed relation, said 9 It will be apparent that when the valve stem I1 is in the lower postions with the valve stem land |35 covering any of the by-pass ports H3 of the valve sleeve to cause greater amounts of fuel to be injectedinto a particular working cylinder of the engine, the helical groove |31 in the land will register with a valve sleeve vby-pass port. The total area of the helical groove |31 and each by-pass port ||3 is made equal to the area of the groove |23 extending circumferentially part way around the valve stem on the side oi the stem opposite the helical groove. As the helical groove |31 is connected to the circumferential groove |23 by the through passage |39 in the valve stem, the high injection ,fuel pressure is simultaneously applied to opposite sides -of the valve stem to equalize the force on opposite sides of the valve stem thereby preventing cocking and binding and unequal wear thereon4 and to allow the stem to be easily moved longitudinally in the valve sleeve by rotation of the control shaft 33 in order to control the amount of fuel injection. The control shaft 33 may be adjusted manually or connected to a. suitable gov-v y1inder,-a plunger therein, means-for reciprocating and rotating said plunger in timed relation in saidcylinder, said cylinder and plunger "having cooperating fuel inlet ports and fuel outlet ports and a by-pass valve rotating in timed relation with said plunger and connected to a cylinder outlet port to open and close said outlet port in order to control periodic discharge of pressure from another cylinder outlet port.

2. A fuel injection pump comprising a plurality of pump cylinders, plungers in said cylinders, means for rotating and reciprocating -said plungers in timed relation, said cylinders and plungers having cooperating fuel inlet ports and fuel outlet ports to cause successive inlet and discharge of fuel from each of said cylinders, a by-pass valve having separate -icy-pass connections to one of each of said cylinder outlet ports, said by-pass valve being rotated in timed relation with said plungers to periodically interrupt by-passof fuel from one outlet port of each of said cylinders successively in order to cause high pressure fuel delivery from the other outlet port of each of said cylinders successively..

3..A fuel injection ypump comprising a fuel pump cylinder, aplunger therein, means for positively rotating and reciprocating said plunger in cylinder and plunger having diametral fuel inlet and outlet ports axially spaced apart'to cause from the pump cylinder, a rotary by-pass valve connected to one of said cylinder outlet ports, said rotary by-pass valve being rotated in timed relation with said plunger to periodically interrupt by-pass of fuel from one of said cylinderoutlet ports in order to cause high pressure fuel delivery through another cylinder outlet port.

4. A fuel injection pump comprising a plurality of pump cylinders each having circumferentially spaced fuel outlet ports, a valve sleeve located centrally with respect to said cylinders and having a plurality of circumferentlally spaced bypass ports. each by-pass port in said valve sleeve being separately connected to one cylinder outlet l port, a plurality of circumferentially spaced inlet ports in each cylinder spaced axially from said outlet ports and adapted to be connected to fuel pressure source, a separate by-pass port in said valve sleeve spaced axially from said circumferentially spaced by-pass ports and adapted to be connected through a return passage to a fuel reservoir, a valve stem rotatably mounted in said sleeve having a land thereon of variable arcuate length, said land being rotatable past said circumferentially spaced by-pass ports in said valve sleeve, means for moving said valve st em and land thereon axially in said sleeve to vary the time said land covers each of said by-pass ports,

and plungers reciprocated and rotatedin timed relation with each other in said cylinders and also with said valve stem, each of said plungers having inlet and outlet ports cooperating with said cylinder ports upon rotation and reciprocation of said plungers in timed relation with each other and with said valve stem whereby the amount of fuel delivered successively from each of said cylinders through one cylinder outlet port is controlled by the radial and axial position Vof the valve steml land with respect to said circumferentially spacedvby-pass ports in said valve sleeve.

5. A fuel injection pump comprising a plurality of pump cylinders, plungers in said cylinders, plunger operating means for rotating and reciprocating said plungers in said cylinders in timed relation, said cylinders and plungers having a pluralityof cooperating circumferentially spaced fuel inlet and fuel outlet portsvaxially spaced apart, a valve sleeve located centrally with reaspect to said cylinders and having circumferentially spaced fuel by-pass ports, each of said bypass ports in said valve `sleeve being separately connected to one cylinder outletport, each of said other cylinder outlet ports adapted to be sepainlet and discharge of fuel valve sleeve in timed relation ratelyconnected to separate fuel injectors, said valvesleeve also having a separate fuel by-pass port axially spaced from said clrcumferentially spaced by-pass ports and adapted to be connect- `ed by a separate return line to a fuel reservoir, a variable angular width adapted to` be rotated successively past said circumferentially spaced by-pass ports in said I with said plungers to interrupt by-pass of fuel from each of said cylinders to cause fuel to be discharged at'highV pressure from one outlet port of each of said cylinders successively, means for moving said valve stem axially with respect to said sleeve to vary the interval of fuel by-pass from each cylinder thereby to control the amount of fuel discharged therefrom, said valve stem having a passage extending angularly therethrough, said angular passage opening at one end into an axial slot in said,land and opening at the other end into a circumferential slot in said `valve stem, said circumferential slot having an area equal to eachone of the circumferentially spaced by-pass ports in said valve sleeve so that equal force is applied to opposite-sides of the valve stem by the pressure of the fuel in each cylinder.

6. A fuel injection pump comprising a plurality of pump cylinders, pump plungers therein, actuating means for rotating andreciprocating said plungers in timed relation in said cylinders, said cylinders and plungers having a plurality of cooperating fuel inlet and fuel outlet ports, a rotary fuel by-pass valve located centrally of said cylother outlet'port, said a plurality of pump cylinders 11 inders having a separate connection to one of each of said cylinder outlet ports and a common return' connection to a fuel reservoir, said rotary valve being rotated in timed relation with said plungers to control interruption of fuel by-passed from each pump cylinder through one outlet port to control the amount of fuel discharged from each of saidcylinders respectively through angrcoves, means for supplying oil torsaid'lubricating oil sealing grooves and fuel leakage ports in each of said cylinders with which said fuel leakage grooves of said plungers cooperate upon rotation and reciprocation of said plungers.

7. A fuel injection pump comprising apump housing including fuel inlet and return passages, a plurality of pump cylinders and a valve sleeve located centrally with respect to said cylinders, rotatable and reciprocable plungers in said cylinders, said cylinders and plungers having cooperating fuel inlet and fuel outlet ports, said inlet ports opening into said fuel inlet passage, a rotatable and reciprocable valve stem in said valve sleeve, said valve sleeve having circumferentially spaced by-pass ports separately connected to an outlet port of each cylinder and a separate by-pass port axially spaced from the other by-pass ports and connected to the pump housing fuel return passage, said valve stem having an external fuel by-pass groove of variable axial length the edges of which groove cover and uncover said circumferentially spaced by-pass ports in said valve sleeve to interrupt return of fuel to the reservoir from each of said cylinders in order to vary the amount of fuel discharged from each of said cylinders respectively, in said housing, cam follower buttons, a retainer for holding said buttons in -angularly spaced relation on said cam, plunger guides slidable in said cam housing, said guides and buttons having cooperating spherical bearing surfaces, springs for urging said plungers into contact with said guides and said guides into contact with said cam follower buttons' for reciprocation by said cam, and means for connecting said plungers and valve stem to said cam for rotation thereby in timed relation, said means including a sliding and frangible connection for each plunger and a sliding connection for said valve stem.

8. .A fuel injection pump comprising a com posite housing including fuel inlet, discharge, bypass and return passages and lubricating pressure inlet and return passages, a centralvalve cylinder,

equally spaced radially and circumferentially around' said valve cylinder, a valve stem in said valve cylinder, plungers in said pump cylinders, said pump cylinders and plungers having diametral fuel inlet ports cooperating with said fuel inlet passage and cooperating diametral discharge and by-pass ports axiallyspaced -from said inlet ports and cooperating with separate fuel discharge and bypass passages, said cylinders also havinglsepa- Arate fuel leakage and lubricating ports opening respectively into the fuel inlet and lubricating passages and each of said plungers having external fuel and lubricating sealing grooves cooperating respectively with respective pump cylinder fuel leakage and lubricating ports, a valve stem in said valve cylinder, said valve cylinder having circumferentially spaced fuel by-pass plungers and said valve having fuel leakage and lubricating oil sealing a cam rotatably supported ports, each opening into a separate fuel by-pass passage connected to a separate pump cylinder outlet port, an axially spaced fuel by-pass port opening into a fuelreturn passage and a lubricat'ing port opening into a lubricating passage, said valve stem having a circumferential fuel bypass groove cooperating with said valve vstem bypassports of variable width with a land portion extending into said groove, said land portion having a helical leading edge and an axial trailing edge adapted to be rotated past and moved axiallyv with respect to each of said circumferentially spaced by-pass ports in said valve cylinder, said stem having an axial lubricating passage opening into a lubricating pressure passage to equalize the pressure in opposite ends thereof and external sealing grooves, one of which is connected by a through passage to said axial opening in said valve stern and another sealing groove of helical `form cooperating with the' lubricating port in said valve cylinder opening into a lubricating passage, vand actuating and control means including a cam, cam followers and gearing for causing rotation and reciprocation of said plungers in timed relation and for also causing rotation of said valve stem in timed relation with said plungers, and control means for moving said valve stem axially to control the amount of fuel delivered from each of said pump cylinders successively, said actuating and control means being lubricated by leakage from said plungers and valve stem.

9. A' fuel injection pump comprising a housing including a central said sleeve, a rotatable driving shaft, splined driving connections between adjacent ends of said driving shaft and valve stem, said driving shaft, splined connections and sleeve having axial aligned openings, an oil pressure passage in said housing, and an opening in said driving shaft cooperating With said axial opening in said shaft and said oil pressure passage, a plurality of pump cylinders equally spaced around said sleeve, oil passages between said sleeve and said cylinders, plungers in said cylinders, said valve stem and plungers having external oil sealing grooves cooperating with said oil passages, a cam secured to said driving shaft, plunger guides mounted for reciprocation in said housing, cam follower buttons between said guides and said cam, springs for'holding said plungers in contactwith said guides and said guides in contact with said cam, slidable connections including shear pins operably connected between each plunger and said splined driving connections with said valve stem to cause rotation of said plungers in timed relation with said valve stem, said plunger and valve stem driving mechanism being lubricated by leakage of oil from said valve stem and plungers, and an oil return passage in said housing.

WARREN H. SMITH.

'REFEnNcEs crrEn The following references areof record in the file of this patent:

valve sleeve, a valve stem in