US2192387A - Fuel injection pump - Google Patents

Description

March 5, 1940- o. scHLAuPlTz FUEL 1NJECTI0N PUMP Filed Nov. 8, 1937 .fl/ afro/@Nera Patented Mar. 5, 1940 PATENT OFFICE FUEL INJECTION PUlVIP Oswald Schlaupitz, Canton, Ohio, assignor to The Timken Roller Bearing h10, a corporation of Ohio Company, Canton,

Application November 8, 1937, Serial No. 173,327

v 4 Claims.

This invention relates to fuel injection pumps of the type wherein the pump plunger at a predetermined point of its pressure stroke by-passes fuel from the pressure space in theppmmylim Vr der t0 an Overflow .P91235 Eill'efiffaihllyrrliewing the pressure in .said space and terminating the fuel delivery.

In such a pump construction, fuel is drawn into the pressure space, during the suction stroke lo of the plunger, through the overflow port and, quite commonly, through an additional inlet port also, and the surplus fuel in said space is discharged through the overflow port during the pressure stroke -of said plunger after injection, i5 with the result that the fuel adjacent to said overflow port is in a state of commotion or turbulence, thereby preventing the proper quantity of fuel from being drawn into the pressure space on the following suction stroke of the plunger. The principal object of the present invention is to provide improved means for preventing such interference with the filling of the pressure space on the suction stroke of .the plunger, to provide an improved arrangement for rotating the reciprocating pump plunger to vary the quantity of delivered fuel, and to provide for simplicity and cheapness of construction and compactness of design. The invention consists in the fuel injection pump and in the parts and combinations and arrangements of parts here- .inafter described and claimed.

In the accompanying drawing, which form part of `this specification and wherein like symbols refer to like vparts wherever they occur.

Fig. 1 is a view partly; in plan and partly in horizontal sectionon the line I-I in Fig. 2 of a multi-cylinder fuel injection pump embodying my invention,v l n Fig. 2 is a vertical transverse section through osaidpump at one of the cylinders on the line Z-ZinFlal,

Fig. 3 isv a fragmentary, horizontal section on the line in Fig, 2;' and. I

Figs. 4 and 5 are fragmentary sectionssir'nilar "to Figs. 2 and 3, respectively, illustrating a modified form'ofnon-rotary axial sliding connectionj' between the plunger yand the turning sleeve therefor:y

Referringto the accompanying drawing, my

5g invention is illustratedl in connection with a multi-cylinder fuel injctionpump for multicyllnder internal combustion engines of the compression ignition type. Said pump comprises a suitable housing I having upper and lower lonu gitudinal chambers 2 and 3, respectively, a plurality of vertical bores 4 that are spaced apart lengthwise of said'housing and lead downwardly into said upper chamber, andbores and 8 disposed-fin, axialialine'mnitwitliftlribores Galland extending"respectively through horizontal lug's 6 1 on one yside wall of said housing and the partition wall 8 between the two longitudinal chambers. Located in the lower chamber 3.of the pump housing is a cam shaft 9 provided with cams or tappets I0 adapted to engage rollers II l0 journaled on pins I2 mounted in blocks I3 that are mounted for axial sliding movement in the vertical bores 6 in the partition wall 8 ofusaid housing.

Mounted in each of the vertical bores 4 in 15 the top of the pump housing I is a cylinder I4 having lan enlarged upper end portion I5 that rests on an annular seat I6 in said bore. Mounted in said bore is a tubular member I1 which seats on the upper end of the cylinder I4 and is 20 provided at its upper end with a seat for a fuel discharge valve I8. The cylinder I4 is held down on its seat I6 and the valve seat member is held down on said cylinder by a cylindrical shell I9 that is threaded into the upper end of said bore and encloses a spring 2li for holding the valve I8 down 0n its seat. A fuel-delivery pipe or line 2| is secured to the upper end of the shell I9 by means of a cap nut 22 threaded thereon. Working in the cylinder I4 is a plunger or piston 30 23 whose lower end seats on the head of a cap screw 24 that is threaded inthe upper endof the roller supporting block I3 and located therebelow. Located in the upper chamber '2 around the portion of the pump cylinder therein is a piston retracting spring 25, the -upper end of which seats in acircular'recess provided therefor in the top of said chamber and the lower end. of which bears against a Washer y26 that isl sleeved on said plungersand seatson a collar 40 21 formed integral therewith.l u'

The head of each cylinder If4fis provided on one side with an inlet port 28 and on the opp'o-, v site side .with an `overflow by-pass ormetering port 29 that is preferably located ata lower 45 level than said inlet port. The pump housing is provided. above the upper vvchamber 2 with two longitudinal' bores 30 and 3| thatl extendfrom end toend o f said housing on opposite sidesl of' the cylinder and are cross-connected at Vone l end of saidhousing-preferably .by a removable fitting orcap 32. yThe bore 30 extends alongside and at the level of the inlet ports 28 and is vin,l direct communication therewith. 'I'he other'` bore 3| extends alongside and at the level of the 55 Aas overow ports 29 and communicates therewith throughthreaded pins or screws 33, which prevent the cylinders from rotating in the pump housing. Each of these screws is threaded horizontally through lthe outer wall of the housing l and extends through the bore 3| transversely thereof and through an opening between said bore and the adjacent overflow port 29 into the outer end of the latter. As shown in the drawing,` the inner end of the screw 33 is provided with a passageway 34 that establishes communication between the overflow port 29 and the bore 3|. An inlet or supply pipe or conduit 3G leads from a suitable supply pump (not shown) to the end of the bore 28 remote from the cap 32; and a suitable return pipe or conduit 31 leads from the corresponding end of the other bore 3l back to said supply pump or to the source of fuel supply. y l

Each plunger 23 is preferably provided near its upper end with an annular groove 33 which is in constant communication through a longitudinal groove 39 in said plunger with the pressure space thereabove. During the pressure stroke o f the plunger, kthe annular groove 39 thereof is adapted to be placed in communication with the overflow port 29 in the cylinder therefor and thus cause the fuel in said pressure space to be by-passed through said overflow port and the passageway 34 in the screw 33 into the longitudinal bore 23. The annular groove 38 in the plunger is preferably provided with an' inclined or helical edge 43, whereby the eective delivery stroke of the plunger may be regulated by turning the plunger in its cylinder to vary the point in the delivery stroke of the plunger at which the overflow port 29 is placed in communication with space above said plunger through the grooves 38 and 39. With this arrangement, delivery of the fuel begins as soon as the plunger on its way coversA the inlet and overflow ports and ends as soon as the inclined edge 40 of the annular groove 33 opens the overow port and relieves the pressure in the space above .said plunger,

The mechanism for simultaneously rotating the reciprocating plungers 23 to vary the point at which the annular grooves 3l therein open into-the overow ports 29 comprises a rack rod 4l that extends longitudinally of the pump housing from end to end thereof and is mounted for axial sliding movement in a longitudinal bore therein. The connection between the rack rod 4I and each of the pump plungers 23 comprises a sleeve 42 having a flatsided opening extending therethrough adapted to receive a similar ilatsided portion 43 of said plunger, thereby permitting relative axial sliding movement of said sleeve and plunger but preventing relative rotary movement thereof. The sleeve 42, is journaled in the vertical bore 5 in the lateral lug 1 -in the upper chamber 2. The lug I is provided between its upper and lower ends with a horizontal opening or recess 44 adapted to receive and support a pinion 45,- which meshes with and is driven by the rack rod 4I. As shown in the drawing, this pinion 45 is split and is provided with a suitable clamping screw l43, whereby it may be rigidly clamped to the sleeve 42. This clamp connection between the pinion 45 and the sleeve 42 also permits relative angular adjustment thereof in order to obtain the desired initial setting of the inclined upper edge 43 of the anthe overflow port 29. l

In the modified construction shown in Figs. 4 and 5, the non-rotary but axial sliding connection between the pinion receiving sleeve 42a nular groove 433 in the plunger with respect to and the plunger 23a comprises longitudinally exl tending ribs 43a on opposite sides of the plunger that fit within diametrically opposite longitudinal grooves 42o provided thereforv in the plunger receiving bore of saidsleeve.

By the arrangement described, the longitudinal bores 30 and 3l in the pump housing and the cap 32 cooperate to form a single fuel passageway that provides a continuous flow of fuel along both the inlet and overflow sides of the cylinders, and returns the surplus fuel to the supply pump or source of fuel supply. With this arrangement of fuel feed, any turbulence or disturbance created in the fuel stream adjacent to the inlet and overflow ports by the return flow of the fuel therethrough is carried along and absorbed by said stream, thereby eliminating or greatly minimizing the effect of such disturbance on the fuel drawn into the inlet and overflow ports during the next suction stroke of the plunger. `This continuous flow of fuel past the ports in the cylinder also serves to carry away any bubbles created by the return ilow of v the fuel and thus further increases the eniciency of the pump.

What I claim is: Y

1. A fuel injection pump comprising a cylinder having inlet and overow ports in oppositevsides thereof, and a plunger reciprocating in saldi cylinder, said pump having a single fuel passageway that extends across and communicates with the inlet port on one side of said cylinder, thence across said pump to the opposite side thereof, and thence across and in communication with the overflow port on that side of said cylinder,

the inlet and outlet ends of said passageway being located in the same face of said pump.

2. A` fuel injection pump comprising a plurality of cylinders having inlet and overow ports facing the opposite sides of said pump, 'plungers reciprocating in the respective cylinders, said pump being provided on 'opposite sides of said cylinderspwith longitudinal bores that extend through said pump from end to end thereof and communicate respectively with the inlet and overilow ports of said cylinders, and a member removably secured to one end of said pump and forming a connecting passageway between the two bores at that end of said pump, the opposite ends 'of said bores being adapted to receive fuel supply and fuel return conduits.

across and in communication with the overflow ports on the opposite sides of said cylinders and having an outlet connection adjacent to said end of said pump and a portion other than said ports and cylinders` located exteriorly of said pump adjacent to the other end thereof for establishing continuous communication between said inlet and overflow portions.'

4. A fuel injection pump comprising a plurality of4 cylinders having inlet and overow ports facing opposite sides of said pump and plungers reciprocating in the respective cylinders, said pump having a. combined fuel inlet and overow passageway with portions spaced apart on opposite sides of said cylinders and communicatingV respectively directly with saidinlet and overflow

Images