US2357563A

US2357563A - Fuel injection pump

Info

Publication number: US2357563A
Application number: US452051A
Authority: US
Inventors: Jr Clyde W Truxell
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1942-07-23
Filing date: 1942-07-23
Publication date: 1944-09-05
Anticipated expiration: 1961-09-05

Description

Sept. 5, 1944. c. w, rRuxELl., JR

FUEL INJECTION PUMP Filed July 25, 1942 3 Sheets-Sheet 1 Suunto: .QZZwZ/ z c. w. TRUXELL, JR 2,357,563

FUEL INJECTION PUMP Sept. 5, 1944.

s sheets-sheet 2 Filed J'uly 23, 1942 Patented Sept. 5, 1944 FUEL INJECTION PUMP Clyde w. Truxell, Jr., No1-twine. Mich., assigner to General Motors Corporation, Detroit, Mich., a corporation of 'Delaware Application July 23, 1942', serial No. 452,051

9 claims.

This invention relates to plunger pumps with a plurality of ports in the cylinder wall, from different ones of which fluid is delivered at different points in the stroke of the plunger.

It relates particularly to such plunger pumps for supplying metered quantities of liquid fuel from a single pump cylinder, successively to dif- -ferent cylinders of an internal combustion engine.

The object of the invention is a pump with a plurality of delivery ports and a relief port, and a plunger cooperating with the cylinder to put the pump chamber in communication with the different delivery ports in different positions of reciprocation of the plunger, there being means independent of the pump plunger for closing ythe relief port to determine the periods ofdelivery through the different delivery ports.

`Another object vof the invention is a pump comprising a plurality of plungerpumps of the foregoing kind, with a single rotaryl valve means common to all the cylinders driven in timed relatonship to the plungers and adapted to close the relief port of each cylinder a plurality of times,

in the delivery stroke of each plunger, to determine the successive periods of delivery through the different delivery ports.

A still further object of the invention is a pump structure of the foregoing kind in which the relief port of each cylinder is a combined inlet and relief port which is only closed by the rotary valve means during the periods of delivery from the cylinder pump chamber, and is at all other times open to permit-a free iiow of liquid fuel to and fro between the cylinder and the source of fuel supply.

The above and other objects of the invention will be apparent 'as the description proceeds.

- According to the invention, the combined inlet and relief port of each cylinder opens into the pump chamber at a point unswept by the'pump plunger, while the delivery ports are longitudinally spaced and swept by thepump plunger which has an annular groove intermediate its ends and in communication with the pump chamber; the delivery port through which delivery nrsttakes place communicates directly with lthe pump chamber in the nrst part onf the delivery stroke of the plunger and is then covered by the end of the plunger, while the delivery port through which delivery next occurs is placed inv communication with the pump chamber through (Cl. 10S-173) nular groove in its periphery interrupted by a plurality of land areas to close the combined inlet and relief port of each cylinder a plurality of times in each revolution of the rotary valve member. The grooved area of the rotary valve member is adapted to put the combined inlet and relief port is communication with the source of sup'- plyl and this communication is only stopped as and when a land area closes the combined inlet and relief port to cause delivery of uid through one or another of the different delivery ports.

In a -pump unit, comprising a plurality of plunger pumps of the foregoing kind, the cylinders are conveniently arranged parallel to each other, in a circle, with their combined inlet and relief portsradiating in.v uniform angularly spaced relationship from a cylindrical central chamber containing the rotary valve member common to them all. The rotary valve member turns once in the time taken for all the pump plungers to lcomplete one cycle oi' movement and it must lhave as many land areas as there are delivery portsin each pump cylinder. The angle between the leading edges of the lands on the valve member may be equal to 360 divided by the number of pump cylinders and the number of delivery the annularl groove in the plunger. The rotary v multiple of the resulting figure which is neither a whole number multiple nor a whole number factor of the angle between relief ports. A11 the lands must traversethe relief port of a given cylinder during the time the plunger of that cylinder is on its delivery stroke. If all the lands are contained in less than half the circumference of the valve member the pump plungers can be driven by a simpi wobble plate with suction and delivery strokes extending through equal intervals of time and each through 180 of rotation of the wobble plate.

The drawings show the application ofthe in- -vention to a pump unit suitable .for supplying metered quantities prf fuel to the respective cylinders of a twelve cylinder internal combustion engine, and comprising six plunger pumps each of which has two delivery ports. It is driven at the speed of the engine cam shaft (engine speed `in the case of a two-cycle engine and half engine speed in the case of a four-cycle engine) giving one delivery. to a different cylinder every. 30 :of

crankshaft rotation in the case of atw'o-'cycle engine and every of crankshaft rotation vin the case of a four-,cycle engine.

In the drawings l Figure 1 is a longitudinal sectional view on 'line I--I ofFlgure 2.

Figure 2 is a view on line 2--2 of Figure l.

Figure 3 is a sectional view on line 3-3 of Figure 1.

Figure 4 is a sectional view online 4-4 of Figure 3.

Figurel is a development of the rotary valve member showing the associated inlet and relief ports radiating from the cylindrical central chamber superimposed in dotted outline.

The pump lbody is conveniently formed of a number of suitable sections I to 5 secured together.

The end section I and the section 2 are secured together by studs 1 with nuts, and are bored axially to provide a housing for the pump driving means and bearing support for the driving shaft 8 thereof. The

sections

42 and 3 are secured together by studs 9 with nuts, while the

sections

3 and 4 are secured together by tubular studs Iii with locknuts I andare bored axially for a liner providing a central low pressure fuel chamber I2 within which the rotary valve lmember I4 rotates. The section 3 is also bored for six cylinder barrels I to 20 arranged in uniformly spaced relationship in a circle concentric with the cylindrical central chamber and containing plungers 25 to 3|!V respectively provided with plunger followers 35 to 40 slidable in corresponding but larger bores inthe section 2. The cap section 5 is a housing for a rack 42 and pinion 43 by which the rotary valve I4 may be axially moved. It is secured to the section 4 by screws 44.

The sections I and 3 of the pump body are preferably of steel forirequisite strength while the

sections

2, 4, and 5 are of aluminum for lightness.

Three mounting lugs 41 (Figures 2 and 3) lare provided on the section I for securing the pump body to the frame or gear case 48 (Figure 1) of a twelve-cylinder internal combustion engine (not otherwise shown), while at the opposite end of the pump body on the section `3 is a stud 49 (Figures .2 and 3) by which it may be secured to any suitable outer end support.

The inner end of lthe driving shaft 8 is supported in a bushing 50 in the body section 2 vwhile the outer end is supported in a ball bearing .5| of which the inner race 52 is secured to :the shaft 8 and the outer race 53 is secured in loWers are/resiliently urged towards the wobble plate by springs such as 1|, vthus maintaining the attened areas of the balls which have universa] movement in their sockets, in contact with the wobble plate.

It will be appreciated that while the wobble plate 64 and the outer races 6|) and 6| are capable of. rotation, they are normally prevented from revolving by the frictional forces between these parts and between the at faces of the balls 61 and the wobble plate which merely wobbles and drives the plungers on their delivery strokes as the shaft 8 is turned by gearing from the engine crankshaft (not shown) to a gear wheel 14 splined on the outer end of the shaft 8 and secured thereto by a nut 15.

The inner end of the shaft 8 is internally splined asat 16 (with an odd flat for indexing purposes) to provide a driving connection to the reduced and externally splined end 11 of the rotary valve member I4, which is capable of axial movement relatively to the shaft 8.

' Each of the plungers 25 to 30 is provided with an annular groove such as 8U in its periphery at a point removed from its end, said annular groove vbeing in communication with the pump chamber through drilled ducts 8| communicating with a bore 82 in the end of the plunger. The opposite ends of the plungers are bored ,for lightness as at 83.

The pump chambers of the cylinder barrels I5 to 20 are closed by plugs such as 85 which are held in position by the section 4 of the pump body.

The pump chamber of each cylinder barrel at a point unswept by the plunger is provided with a combined inlet and relief port 81, said respective ports 81 lying in a plane normal to the axis of the rotary valve member and radiating in uniform angular-ly spaced relationship at 60 to each other from the central chamber I2 common to them all.

Each cylinder barrel has a pair of longitudinally spaced delivery ports such as 9| and 92 (Figures 3 and 4) through the side of the cylinder barrel at points swept by the plunger. The. ports 9| and 92 radiate from theirV respective cylinder barrels outwards in the section 3 of the pump casing, at an angle to each other, respectively to connect with drilled extensions therein of the tapped holes for an adjacent pair of the tubular studs I0 which constitute delivery outlets of which there are a total of twelve arranged in uniformly spaced relationship in a circle.

The tubular studs Il) are screw threaded throughout their length and are in screw threaded engagement with both

thesections

3 and 4 of the pump body in which they are locked by the lock nuts I0.

Pipes such as 94 are connected to each delivery outlet I0 by nipples such as 95 and serve to conduct fuel therefrom to spring loaded injection valves for the respective cylinders of the engine (not shown).

The rotary valve member I4 has an annular groove |00 in its periphery, interrupted by two land areas IUI and |02. The land areas are tapered in width between their leading and following edges, the leading edges of both being parallel to each other and 90 apart as measured in a plane normal to the axis of the rotary valve member, and the following edges of both being similarly spaced and .parallel to each other, as

best shown in Figure 5.

Fuel from a low pressure source of supply (not shown) is conducted into and out of the central chamber I2 between the annular groove |00 and the inner wall of the liner through the bores |04 and |05.

The combined inlet and relief ports 81 of each cylinder barrel maintain communication between the central chamber I2 and the pump chambers at all times, except as the lands IUI and |02 move successively over each of the inlet and relief ports 81 and interrupt such communication during parts of the periods in which each pump chamber is open to one or the other of its delivery ports.

The delivery ports 9| and 92 of each pump cylinder lare so spaced longitudinally 6i the reand 4 for conveying the lubricating oil through spective, cylinders that one of them communi- L cates directly with the pump chamber in the rst part of the delivery stroke of the plunger andA is then covered by the end of the plunger, while the other delivery port is placed in communication with the pump chamber through the annularrelief ports of each cylinder twice in each vrevolution of the rotary valve member and willdetermine the periods of delivery in a repeating cycle first through the uppermost delivery porty of a given cylinder and then through the lowermost delivery .port of the cylinder next behind in the 'direction of rotation of the rotary valve member,

and thus in alternatingprogression through each delivery port of all the cylinders oncel in every revolution of the valve member and the wobble plate and providing a total of twelve deliveries wat 30 intervals in every revolution thereof.

The number of degrees of rotation through which the combined inlet and relief ports 8l are closed by Ythe lands4 lill and |02 and hence the quantity of fuel delivered through the delivery ports 9|, 92 depends on the width o fthe lands opposite the ports 8l.

Since the4 lands are tapered in width, axial adjustment of the rotary valve member ld will ,vary the quantity of fuel delivered through the delivery ports.

It is obvious that the land areas Iiil and |82 may be tapered uniformly or irregularly, sym

metricallyv or unsymmetrically or infany desired way. As shown most clearly in Egure 5,the leading and following edges of 'the lands are equally but oppositely inclined to vtheir axis of rotation and taper uniformly towards their narrower ends to 4provide for earlier closing with later opening of the combined inlet and relief ports 8l or vinefversa, and thus increasing or reducing the quantity of fuel delivered successively through the respective delivery .ports 9| and 92 in dependence onl the extent to which the` rotary yalve member is moved in one direction or the other axially of the liner Il.

'Iu'he `outer end of the rotary valve member' I4 .is reduced in diameter and grooved to forma s stud head |06 thereon, which loosely nts in a T slot ina piece |08 secured to the end of the rack A2 by a pin.|09, and forming a coupling which permits the rotary valve member to rotate while being held in any desired position of axial adjustment by the yrack 42, the position of which is controlled by the pinion 43. o

As shown in Figure 2,.'the pinion 43 is mounted on a shaft I having a serrated end I by which it may be turned manually or automatically by the engine governor (not shown) to vary th quantity of fuel supplied to the engine. i

"Referring now to Figure 4,;a ductA ||screw the short ducts |8 and 9 to the annular grooves and |2I, |22, and thence to the bearing surfaces of the rotary valve member |4, also through the short duct |24 to the annula'lflgroove |25 and thence to the shaft 8 in the bearing 50, and from the annular groove |22 through ducts such as |26 to each of the plungers 25 to 30. From the annular groove |25 there are short ducts such as |21 to each of the plunger followers 35 to 40.

s The ball bearings 5|, 58, and 59 and the balls such as 6J in their sockets are lubricated by oil in the housing which is retained therein at a level above the axis of the shaft 8.

I claim:

1. A plunger pump including a cylinder having a plurality of spaced delivery ports and a relief port, a plunger in the cylinder, said plunger cooperating with said delivery ports to place the pump chamber in communication selectively with dierent delivery ports in different positions of reciprocation of the plunger, and means independent of the pump plungerv for closing said relief port and determining the periods of delivery through said different delivery ports.

2. The combination according to claim 1 in whichthe means for closing said relief port is a rotary valve operated in timed relationshipvto j the plunger.

3. A plunger pump including a cylinderhaving a pluralityy of delivery ports and a relief port, a plunger in the cylinder, said plunger and said cylinder cooperating to place the pump chamber in communication with different delivery ports alternately and successively in different positions of reciprocation of the plunger and means independent of the pump plunger for closing said relief port to determine the period of delivery through said' different delivery ports; said plunger .having an annular groovesintermediate Aits ends and in communication with the pump'` chamber; that delivery port through which delivery first takes place communicating directly with the pump chamber in the ilrst part of the delivery stroke of the plunger and then being covered by the end of the plunger while that delivery port through which delivery next occurs is placed in communication with the pumpchamber through the annular groove in the plunger.

4. A plunger pump including a cylinder having first and second delivery ports and a relief port,

, a plunger in the cylinder, said plunger and said cylinder cooperating to place the pump chamberv `chamber; said first delivery port communicating directly with the pump chamber in the first part of thedelivery stroke of the plunger and then threaded for aplpe cohnectionto a supply of lubricating oil (not shown) is provided in the section 3. The duct ||5 is connected to a longi" tudinal duct I6 extending into the sections 2 being covered by the end of the plunger while lthe second delivery port is placed inl communication with the pump chamber through the an nular groove in the plunger.

5. A pump comprising, in combination, a plurality of plunger pumps each including a cylinder having a plurality of delivery ports, a relief \port,.and a plunger cooperative to place .the

pump chamber of itscylinder in communication w with different delivery ports during. its vstroke movement,V means independent of the pump plungers for closing said relief ports to determine the periods of delivery through said different delivery ports and means for reciprocating said plungers and driving the relief port closing means in timed relationship.

6. A pump comprising, in combination, a body having a plurality of parallel pump cylinders arranged in a circle and in uniformly spaced relationship, a central low pressure fluid chamber, a combined inlet and relief port for each cylinder, said combined inlet and relief ports radiating in uniform angularly spaced relationship from said central chamber, a plurality of longitudinally spaced delivery ports in each of said cylinders, a plunger in each of said cylinders, said plungers being cooperative with their respective cylinders to place their pump chambers alternately in communication with the different longitudinally spaced vdelivery ports during their stroke mvement, a rotary valve member in said central chamber, and means for driving said valve member and said plungers in timed relationship; said valve member being adapted to close said combined inlet and relief ports to determine the periods of delivery through said different delivery ports respectively of each cylinder,

7. The combination according to claim 6 in which the rotary valve member has an annular groove in its periphery interrupted by as many land areas as there are delivery ports in each of said cylinders, said grooved area being adapted to put the combined inlet and relief ports in communication with the central chamber, and each of said land areas effecting closure of said combined inlet and relief ports of each cylinder once in each revolution of the valve member.

8. The combination according to claim 6, in which each cylinder has a pair of longitudinally spaced delivery ports and the rotary valve member has an annular groove in its periphery interrupted by two land areas, said grooved area being adapted to put the combined inlet and rclief ports in communication with the central chamber, and said land areas effecting closure of said combined inlet and relief port of each cylinder twice in each revolution of the rotary valve member.

9. A pump unit comprising six parallel pump cylinders arranged in uniformly spaced relationship in a circle, a central low pressure iiuid chamber, a combined inlet and relief port for each cylinder, said combined inlet and relief ports radiating at to each other from said central chamber, a pair of longitudinal spaced delivery ports in each of said cylinders, a plunger in each of said cylinders, said plungers being cooperative with their respective cylinders to place their pump chambers in communication with one and the other of the delivery ports of each cylinder alternately during their stroke movement, a rotary valve member in said central chamber, said rotary valve member having an annular groove in its periphery interrupted by two land areas with leading edges spaced apart as measured in a plane normal to the axis of the rotary valve member, and means for driving said valve member and said plungers in timed relationship including a wobble plate, turning at the same speed and in the same direction as the valve member for driving said plungers; said land areas of said valve member successively effecting closure of said combined inlet and relief port of each cylinder twice in each revolution of the rotary valve member to determine the periods of delivery in a repeating cycle rst through a delivery port in a cylinder in advance and then through a delivery port in the cylinder next behind in the direction of rotation of the rotary valve member and thus in alternating progression through each delivery port of all the cylinders once in every revolution of the valve member and the wobble plate, and a total of twelve deliveries at 30 intervals in every revolution thereof. f

CLYDE W. TRUXELL, Jn.