US2405938A

US2405938A - Multiple injection pump

Info

Publication number: US2405938A
Application number: US545426A
Authority: US
Inventors: Beeh Louis
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-07-18
Filing date: 1944-07-18
Publication date: 1946-08-20
Anticipated expiration: 1963-08-20

Description

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ma@ 2@ im@ L.' BEEH MULTIPLE INJECTION PUMP Filed Juvly 18, 1944 2 Sheets-Sheet l INVENTOR. QU/5' 55E# ugo 25329 E94@ MULTIPLE INJECTION PUMP Filed July 18, 1944 2 sheets-sheet 2 L, I INVENTOR. HG' 6' LOU/.S 5E E H BY ,ma im L, BEEH i l 2,495,938 A Patented ug. 20, 1946 UNITED STATES PATENT OFFICE MULTIPLE INJECTION PUMP lLonis Beeh, Long Meadow, Mass. Application July 18, 1944, Serial No. 545,426

(Cl. S-173) 7 Claims. l

The invention relates to an injection pump for charging the cylinders of an internalA combustion engine, and aims to provide a relatively simple and low cost pump useful for engines of the spark ignition type as well as for those with compression ignition. In multiple cylinder engines for which the pump according to the invention is destined, it frequently happens that the cylinders are not uniform as to their fuel consumption so that the one or the other cylinder should be charged more or less than the remainder of the cylinders in order to attain highest or most economical output of the engine. The conventional injection pumps cannot or not readily be adapted to such differences. Furthermore, if in such a pump, parts such as'pump, Ibarrel or plunger are worn or become defective for other reasons, the entire pump is frequently beyond repair; also, any failures of the conventional pump will put the whole engine to be charged by the pump out of operation. The invention contemplates to overcome the indicated drawbacks by providin-g a pump comprising in one housing a plurality of pump units,`i.l e. as many as there are engine cylinders to be charged by the multiple pump which further comprises a timing and/or metering organ common to all the pump units and controlling their output as to time and quantity. The invention also provides a structure whereby the pump cylinders and plungers may be separately removed and exchanged. In this manner it is possible not only to replace defective parts individually but also to have pump cylinder and plunger units,` of

slightly different diameter combined in one pump as the diierences in the engine cylinders may requiref The common control organ, on the other hand, insures uniformity in timing and metering. Moreover, if during the operation of an engine charged by the pump, one of the units should become defective so that one of the cylinders of the engine cannot properly function, it will be necessary only, if at all, to disconnect the particular unit from the cylinder. The other units may then still operate as required to charge their coordinate cylinders in the same manner as before. The fac-t that the pump cylinders are not integral with the housing presents another advantage which will be particularly noticeable in the production of large series of such pumps. Correct metering of the fuel to be injected per each charging stroke of an engine cylinder requires utmost acuracy with practically no tolerences in the Vmanufacturing of the parts of the pump. With the pump vaccording tothe invenlcept in the event that one or the other unit of different size is desired in a pump for the reasons mentioned hereinbeiore. The difference in the output of pumps assembled of correct sized units in comparison to those of undersize or oversize may then be equalized by an initial setting of the control organ. In ordery to facilitate the correct tting together of a pump cylinder and a plunger, the latter may be provided with interior means, also according to the invention whereby it may be adjustably expanded to a slight extent. y

Further objects and details of the invention will be apparent from the description given hereinafter and the accompanying drawings illustrating an embodiment thereof by way of example.

In the drawings,

Fig. 1 is a longitudinal cross-section of a pump y according to the invention;

Fig. 2 is a cross-section along line 2 2 of Fig. 1;

Fig. 3 is a longitudinal cross-section of one of the plungers with a foot flange attached thereto;

Fig. 4 is a bottom plan view of the plunger and flange;

Fig. 5 is a side elevation of the control organ of the pump; and

Fig. 6 is a diagram illustrating the operation of the control organ.

Referring now to the drawings, the illustrated pump comprises a housing Ii) formed of a main body I I, a cover I2 and a top I3. The three parts are held together by means such' as bolts I4 engaging with their threaded lower ends I5 interiorbrackets I6 of the body Il. Gaskets such as indicated at I'I may be applied to insure fluidtightness where required. The body I I has a foot i8 and a lower extension I9 shaped as a bearing with its axis coinciding with the central axis a-a of the substantially cylindrical housing. Interiorly of the body II and coaxially therewith, a barrel 20 bears with a flange 2| on an interior shoulder 22 of the body wall, and the bolts III passed ttlngly through recesses 2 3'prevent the 3 barrel from turning. The barrel having a central bore 2li throughout its length extends from th'e top of body H downward, and its ange 2l is provided with a number of holes 25 according to the number of individual pump units. These holes are equidistant from the axis a-a and equally spaced as to each two neighbored holes. Each pump unit comprises a cylinder 26 tted into one of the holes 25 with' its axis parallel to the central axis a-a and bearing with a shoulder 27 on flange 2l. A gasket 28 is interpositioned between the shoulder and the flange. The arrangement may be such that a portion of the upper part of the cylinder 2li` is in close Contact with an outer wall portion of the barrel-21) which for this purpose is of a larger diameter above than below the flange 2l and is provided with arcuate recesses 29. Each pump unit further comprises a plunger 353 reciprocatable in cylinder 2B andV projecting therefrom with its lower or foot end 3! so shaped as to engage a cooperating driving element to be described herein after.- In view 'of the abovementioned requirements-of -an injection pump plunger as to the accuracyV of its dimensions, the plunger may be of a structure shown in Fig. 3, and which is also'part of the present invention. This plunger has abody consisting of a tube 32 closed at its lower end by a member 33 ttedinto and secured to the tube which, at its top end, is providedwith an interior threading 37. The tube is filled with a preferably elastic material 34 such as rubber and a tapered pin 35 is driven from the top into the filler. A nut 36 is screwed into the mentioned threading 3l of the top of the tube so as to bear on the pin 35. Thus, by turning the nut the depth can be adjusted to which the pin is forced into the ller 34, and more or less pressure can be exerted by the ller on the tube from the interior to expand the tube diameter to the very slight extent which may be required in order to t the plunger to its cylinder. The foot member 33 has a peripheral groove 38 and its lower endfface 39 is preferably curved or ball-shaped. A washer 4) with a radial recess 4l engages the groove 38, and a second washer 42 provided in its bottom face with a circular recess d3 according to the size of the wash'er 6G is slipped on the plunger 'in axial direction, so that both washers hold each other in position. The plunger Sii with the washers 4d and 42 thereon is inserted into its cylinder 2B from below and a compression spring 44 is interpositioned between the flange 2| and washer A132 so as to bias the plunger in a downward direction.

The pump units are secured in the housing by the cover l2 the lower face of which bears not only on the top rim of the body Il but also on the top faces of the -cylinders 2li and of the barrel 28. In the same radial planes as the cylinders 25 are arranged, the cover l2 is provided with chambers B opening towards the outside and having an interior threading 5l into which a connecting member 52 is screwed for the attachment of a pipe line'53 to an engine cylinder not shown. The chamber bottom 54 forms a seat for a valve such as ball 55 urged against its seat by a spring 5S bearing on the connecting member 52. Each valve 55 controls communication of a radial conduit 5l with its coordinate `chamber 5d. Conduit El has two branches 5S and 59 of which the former communicates with the interior of cylinder 26 whereas branch 59 is continued by a conduit Si! in the wall of barrel 2li. Each conports 6l being on the same level and equally 4 spaced in the periperal direction. Other ports' 62 are provided in the barrel. ,In the illustrated embodiment, they are arranged intermediate the ports Si, but their location may be selected differently as it will be clear from description hereinafter. The ports B2 are connected by conduits S3 to the space 84 constituting a fuel chamber between the wall of body H, the cover I2, flange 2l, and the upper portions of the cylinders 2B and the barrel 20. Chamber Ell has an opening 55 in the side wall of body H to which a pipe line (not shown) from a fuel source may be connected to charge the chamber.

The ports El are controlled by the common control valve GB rotatably and axially movable in the barrel space 24. The valve 66, as clearly shown in Fig. 5, has two peripheral grooves 5l and `E58 `near the top and bottom thereof to serve as lubricating grooves. Intermediate its grooved portions the valve body is circumferentially recessed at 6e and within that recess a land 'IQ is provided which increases in width from` its top towards the bottom end. The outer surface of the land 'I0 constitutes a part of a cylinder with the same diameter as the inner diameter of the barrel. In consequence, if the land covers one of the ports 6I or 62 such port will be closed, whereas the other ports are free to com municate with the space H formed by the inner barrel wall and the walls of the recess Si). However, it should be noticed that closing of a particular port 62 does not interrupt, between chamber B4 and space il, the communication which Yis maintained through the other ports S2 and their connecting conduits 63. Hence, for proper operation of the pump it is immaterial how many ports G2 there are in the barrel and where they are located in relation to the ports 6l, provided the recess space 'H is in permanent communication with the low pressure fuel chamber 64. For this reason, it Will be necessary to consider hereinafter the effect of the movement of land l' on the ports El only as far as the operation of the pumpis concerned.

Furthermore, it will be clear that during the rotation of the valve 66 a port 6i will be closed the longer, the wider the portion of the land 'lil is, which covers such port. Thus, the lower the position of the valve Sii (shown in Fig. 1 in its lowermo'st position) in barrel 2S is, the longer the ports will be closed, one after the other. In the illustrated embodiment, the ank 72 is parallel to the axis, and flank 'I3 is so helically curved that the developments of Aboth ilanks are straightlined in which event the increase or decrease of the closing time of a port will be at the same ratio as a corresponding axial movement of the valve. If, however, some other ratio is desired, this can be attained by curving the flanks according to the law to be followed in controlling the ports. Presuming now that a certain port 6| is open, communication exists between chamber 64 with the interior of the coordinate cylinder 26 through at least a number of the conduits S3, valve recess space "il, port Si and

conduits

60, 59, 51, 58. If, however, land 'lll covers such port 6l the just described connection will be interrupted. In order to operate the movable parts of the Dump units and the common valve, a drive is provided which comprises a shaft l5 Which is rotatable in bearing I9 and has a collar 'i6 bearing on a surface 'il of the vbottom wall of housing ybody Il. The top end 78 of shaft "I5 is cylindrical, however with an axis at Yan angle to the central axis of the housing and the shaft '15. The

top surface 19 of collar 16 is in a plane at right Iangles to the inclined shaft head 18. A wobble or swash plate 80 is splined at 8| to shaft head 18 and the arrangement is 'such that the feet 3| of the plunger 30 bear on the plane top surface 82 of the plate 80, and the point of intersection c of the axis of the top end 18 with the axis a-a is preferably located in the plane of said top surface 32. Now it will be clear that during a rotation of the shaft each plunger 30 will be lifted against the restraint of its spring M to its topmost position shown in the left hand side of Fig. l and will be lowered by spring 44 to the position of the plunger on the righthand side according to the inclination of the face 82. Thus, each plunger will complete one reciprocation during each revolution of the shaft 15; however, the phases of such plunger movement will be displaced according to the number of pump units in the housing. In other words, if there are for instance eightV units, as shown in the present emu bodiment, that means if the pump is destined for an eight-cylinder engine, then the phase displacement between two subsequent plungers will be 45. A connection between shaft 15 and valve is provided so that both will rotate in syn chronism, howeven. in such a manner that the valve may be axially shifted in relation to the shaft during rotation. For this purpose, shaft head 13 is provided with a bore 83 in line with the central axis a-a and also with spline grooves 84 parallel to that axis. Similarly, valve 66 has a bore 85 with spline grooves 86. A connecting rod 81 engages in both said bores B3 and 85 and cross pins S8 and 89 are passed through rod 8'? so as to engage the grooves 84 and 68 respectively, If now, the lower end of shaft 15 projecting from the bearing I9 is connected to a driving means (not shown), rotation of shaft 15 will cause reciprocation of the plungers 38 and'simultaneous rotation of the valve 86. Connected to a four cycle engine, the pump shaft 15 should rotatie with half the R. P. M. of the engine crank shaft.

The control valve 66 may be moved in axial direction by any suitable and conventional means and according to any law desirable according to the engine to which the pump is applied. In the present embodiment, the valve may be actuated in axial direction by and according to the vacuum prevailing in the manifold of the engine for which the pump is destined.V For this purpose the valve is provided with an upper threaded bore 90 1nto which a nut 82 is screwed. The nut has an axial bore through which a headed rod S3 is passed so as to bear against the lower surface of the nut 92 and the bottom of bore 9|) without being clamped so that the valve 88 with nut 92 can freely rotate about the rod. Rod 93 extends upward through cover I2 and has a threaded upper end 80. A diaphragm 95 is clamped between the cover I2 and the dome-shaped housing top I3 so that it forms a partition between a lower chamber 88 and an upper chamber 91. The diaphragm is reinforced 1n its central part by a lower disc 8S and two upper concentric discs 89 and |00, and a bushing ||ll is secured to the center of the diaphragm aI d the discs 08 and |00. Rod 93 is screwed through ushing 10|, and two nuts |02 and |03 are provided to hold the rod adjusted relatively to the diaphragm. The central portion of the housing cover is recessed at |05 so that the bushing |0| may rest on the recess bottom |01. Between the reinforcing disc |00 and the housing top Part I3, a spring |08 is interpositioned, tending to urge valve downward into its lowermost position the top portion of the housing part 3.

'6 which is reached when bushing |0| bears on the said surface |01. Chamber 05 opens at |08 into the atmosphere while the chamber 91 may be connected to the mentioned engine manifold by means of a pipe (not shown) which may be screwed into the threading |09 of a bore ||0 provided in the wall of the housing top I3. Thus, if a vacuum prevails in chamber 81 the diaphragm will bend upward against the restraint of spring |06 and thus lift the Valve 66 in axial direction. The rotary movement of the valve will not be transmitted to the diaphragm because valve '65 with nut 92 is free to rotate about the rod 93 as stated hereinbefore. Upward movement of the valve may be limited by an adjustable stop which may have resilient qualities. For this purpose, a buiferspring II is mounted interiorly of a cap nut ||2 screwed into an axial threading H3 in I Thus, when valve E5 is lifted sufciently high, nut |03 will engage the end face of the downwardly provjecting spring I, whereby the axial valve movement will be stopped by the force of that spring. A headed nut IIB may be provided to close the opening into which nut ||2 is screwed. In order to lubricate the movable parts of the pump, the

`'free space in body I underneath the barrel flange 2| may be used as an oil chamber |20 which may be charged through an opening |2I in the side wall of the body. From this chamber oil conduits may lead to the movable parts as for instance conduit |22, leading to longitudinal grooves or recesses |23 in the wall of the cylinder 20. Also the plungers 28 may be provided with peripheral grooves |25 (not shown in Fig. 3) for this purpose, if the wall of the plunger tube 32 is sufficiently thick. Similarly, a conduit |25 may carry oil to the bearings 19 of the wobble plate and |9 of the shaft 15. Furthermore, a conduit |26 may be provided through the length of valve 56 so that oil may pass from chamber 24 to chamber |23 when the valve moves in axial direction.

The pump according to the invention operates in the following manner. When shaft 15 is rotated the wobble or swash plate 80 will also turn and will thereby enforce axial reciprocation of the plungers in cooperation with their springs 44. The plunger on the lefthand side of Fig. 1 is in its topmost position, that means the compression stroke of this plunger has just been completed and withshaft 15 rotating in the direction of the arrow b, the plunger will have been shifted into the lowermost position after i. e., into the position of the plunger in the righthand side of Fig. 1, in which its suction stroke is completed. As stated hereinbefore, the valve recess space 1| is in permanent communication with the low pressure chamber vE54, and as furthermore, the relative position of the valve is such that, during the .suction stroke of the plunger, the coordinate port El is uncovered, fuel will enter and fill the free cylinder space of the contemplated pump unit. When now, during further rotation of the plate 80, that means during the compression stroke or part of the compression stroke of the plunger, the land 10 of valve 86 covers the coordinate port 6|, communication between the recess and the cylinder space will be interrupted and the fuel pressure in the cylinder will act on the connected check valve 55 to open it so that fuel will be ejected through the valve chamber 50 into the pipe line 53. If then, during a later portion of the compression stroke land 10 has passed the port 6| the remainder ofthe fuel in the cylinder will be 7 returned to the space ll and the low pressure chamber 64.

If now during the operation of the pump the vacuum of the engine manifold increases, :the higher difference of pressure between chambers 9S and 91 will cause the diaphragm 95 to bend upward and thereby to raise the valve. In consequence, a narrower portion of the land will pass the ports 6 I, with the result that each port 51 will be closed for a shorter portion of a revolution of swash plateV 80 and that fuel will be ejected through a smaller portion ofthe compression strokes of the plungers. It is of course necessary to position valve 66 so from the start that the leading edge 12 of land 'l0 `just has completed or nearly completed covering a certain portion 6| when the coordinate plunger is in that position in which it is intended to start ejection of fuel. This is diagrammatically shown in Fig. 6, where curve I indicates the plunger movement during one complete revolution of the swash plate `8l) or what amounts to the same during one revolution of the valve 66. For sake of illustration, the plunger to which curve I relates may be denoted as the fth of the number of eight unit plungers in the pump.

Thus the point A is identified as the upper dead center of the fifth plunger, B is the lower dead center, and C the upper dead center reached after one plunger reciprocation, Underneath this curve the ports SI and 62 are shown on the line Il, and the ports 6I are further distinguished by the reference numerals I to 8 according to the number of the pump units or plungers to which they are coordinated. At III the land l is shown as a development of the surface of valve 65, and it is assumed that rotation occurs or that the land advances in relation to the ports 6| and 62 in the direction of the arrow d. If it is further assumed that ejection of fuel from the fifth pump unit is intended to start at the point D of the plunger compression stroke BC, then, the relative position of the parts should be as shown, that means the leading edge 'I2 of the land 'Hl is in a position in which the land just covers the port 6 I -5 shown on top of it. This port will stay cov- .f

ered until the trailing edge 'i3 of the advancing land begins to clear it. If during the time of the land passing port {il-5 the level :r-r of the land was in registry with the level of the. ports, the plunger will have risen in the meantime to point E so that the quantity of ejected fuel will correspond to a piston movement according to the length of the line et. Similarly if valve 5 has been so lowered that its level y-y ,is in registry with the ports, the land will cover the port Sl--E to cause fuel ejection during the plunger stroke portion from D to F or according to the length of line n. It will be clear that the operation of the other pump units is similaito that just described, with tlle dierence. however, that the stroke of each subsequent plunger is delayed in phase according to 360 divided by the number of units in the pump. Thus, the quantity of ejected fuel can be metered by the shape of the land and by the law according to which the valve 65 will be shifted, in axial direction. However, it is also possible to attain an adjustment of the timing of .the start of each ejection period. It will be noticed that in the illustrated embodiment the leading edge 'I2 is shown at right angles to the direction d .of the advancing valve. In consequence, closing of port SI- will occur always when the plunger is at point D. On the other hand, owing to the inclination of the trailing edge k73, closing of the v.port will last as long as the `piston requires to move from D to F when the valve is lowered from m to jy. Similarly, a dclayed or advanced opening of the ports 6| can be attained if `the leading edge is inclined with its lower end backward or forward respectively. Thus, the valve may serve for timing as well as for metering the quantity of the ejected fuel.

It will be apparent to those skilled in lthe art that many alterations and modifications of the mechanism illustrated and described are possible without departing from the spirit and essence of my `invention which for this reason shall be limited only by the scope of the appended claims.

I claim:

1. In a fuel injection pump comprising a plurality of pump units, each including a cylinder with -reciprocatable plunger therein, the combination of a common fuel supply chamber, as many discharge valves as there are pump units and coordinated to the latter respectively, first conduits from said supply chamber to said discharge valves respectively, a rotatable valve in controlling relationship to said conduits so as to cyclically close said conduits each during va portion of the pressure stroke of the coordinate pump unit plunger, and second conduits connecting the cylinders respectively with the coordinate first conduits at points between the rotatable valve and the discharge valves.

l2. A fuel injection pump comprising a plurality of parallel pump units arranged on a circle, each unit including a cylinder barrel with a, reciprocatable plunger therein, a cover for the cylinder barrels, said cover being provided with ports opening into said cylinders respectively, as many discharge valves as there are pump units and coordinated to the latter respectively, a common fuel supply chamber, first conduits from said supply chamber to said discharge valves respectively, a rotatable valve in controlling relationship to said conduits, a common drive for cyclically reciprocating the plungers and for rotating said rotatable valve so as to cause the latter to close said first conduits each during a portion of the pressure stroke of the coordinate pump unit plunger, and second conduits con-l necting said ports respectively with the coordinate iirst conduits at points between said rotatable valve and said discharge valves.

3. A fuel injection pump comprising a substantially cylindrical housing, a plurality of parallel pump units includingeach a cylinder with a reciprocatable plunger therein, and arranged on a circle within the housing so as t0 form a peripheral fuel supply chamber substantially between said cylinders and said housing, a centrally located barrel constituting an inner chamber, said inner chamber having ports, one for each pump unit, on the same level in the wall of said barrel, a permanently open connection between said two chambers, as many discharge valves as there are pump units and coordinated to the latter respectively, rst conduits each connecting one of the discharge valves with one of said ports, a rotatable valve in said barrel, a com-mon drive for cclically reciprocating said plungers and for rotaing said valve so as to cause the latter to close said ports each during a portion of the pressure stroke of the coordinate pump unit plunger, and second conduits connecting said first conduits with the coordinate cylinders respectively.

4. A fuel pump as claimed in claim 3 further comprising a common cover for said housing and ,said cylinders, said discharge valves, lportions'fltf.

9 said first conduits, and said second conduits being arranged in said cover.

5. A pump as claimed in claim 3- wherein said housing includes an inner shoulder and said barrel includes a flange bearing on said shoulder and provided with holes in which said cylinders are inserted, said flange constituting a partition of said housing so as to form said peripheral fuel supply chamber on the one side and an oil chamber on the other side thereof.

6. A fuel injection pump comprising a substantially cylindrical housing, a plurality of parallel pump units including each a cylinder with a reciprocatable plunger therein and arranged on a circle within said housing, a plurality of discharge valves, one for each unit, a centrally 1ocated barrel constituting an inner chamber and forming on its outside together with said housing and said cylinders a peripheral fuel supply chainber, said barrel being provided with two sets of ports each set comprising as many ports as there are pump units, first conduits connecting .the ports of the first set with said peripheral chamber, second conduits, each connecting one of the ports of the second set with one of said discharge valves, third conduits each connecting one of said second conduits -to one of said cylinders, a rotatable valve within said barrel in controlling relationship to the por-ts of said second set, and a drive for said valve so as to cause' the latter to cyclically close the ports of said second set, each during a portion of the pressure stroke of the coordinate plunger.

7. A pump as claimed in claim 6 wherein 'said iirst conduits are arranged each between two adjacent cylinders, and each port of the one set is located intermediate two ports of the other set.

. LOUIS BEEH.