US2573792A

US2573792A - Fuel injection pump

Info

Publication number: US2573792A
Application number: US794403A
Authority: US
Inventors: Jakobsen Svend Older
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-08-24
Filing date: 1947-12-29
Publication date: 1951-11-06
Anticipated expiration: 1968-11-06

Description

NOV. `6, 1951 5,' 0, JAKQBSEN v 2,573,792

FUEL INJECTION PUMP 5 Sheets-Sheet Filed ,neej 29, 1947 nimh! NA nl Nov. 6, 1951 s. o. .JAKoBsEN l 2,573,792

v FUEL INJECTION PUMP v Filed Dec. 29, 1947 4 5 sheets-sheet 2 Nov.'6,;l951 s. .,J;AKoBsE`N l f 2,573,792

l l J gI FUEL NJEcTIoN PUMP n Filed Dec. 29, 1947- i v v s sheets-sheet s f rE-g.' 1n- Patented Nov. 6, 1951 UNITED 'STATES PATENTV oFFlcE A 2.51am y FUELnmscrIoNPUMP Application December 29, 1947, Serial No. 794,403

Norway August 24, 1946 Section 1, Public Law 690, August 8,1946

Patent expires August 24, 1966 V 7 Claims. (Cl. 123-139) The present invention relates to a fuel injection pump provided with one or more pumppistons, for the injection of fuel into a number of internal combustion engine cylinders corresponding to the number of pump-pistons. It is the object oi the invention to provide a fuel'pump functioning reliably and more accurately and eectively than the pumps known hitherto. It is another object of the invention to make the pump better adjustable.l

The main feature of the invention is the fact that the fuel pump is provided with a special, adjustable valve, located outside the pump-cylinder or -cylinders, the object of said valve being to control the operations of all the pumps. It is a further characteristic feature of the invention that the valve body, which has a cylindrical form, is pivotably Aand axially displaceable in a cylinder, the valve being made in such a way that, when rotating, it opens and shuts olf respectively the ducts carrying fuel to the various pump-cylinders, one after the other in succession, whereas said valve. when axially displaced, causes a change in the-quantity of fuel injected with every pressurev stroke of the pump-piston, said quantity of fuel controlling the rotation speed of the engine. It

running through the'pump, owing to a changev in the rotation speed of the engine, acts upon the valve body in such a way that it is displaced axially in a manner dependent on the fuel pressure corresponding to the rotation speed of the engine. Other characteristic features of the invention are disclosed hereinafter.

The invention is, by way of embodiments, illustrated on the attached drawings.

Figure 1 shows an axial sectional view of an embodiment of the fuel pump; Fig. 2 is a partial axial sectional view of a reversing mechanism; Fig. 3 is a partial axial sectional view of a modied reversing mechanism; Fig. 4 is a top view of the embodiment sho'wn in Figure l; Fig. 5 is another axial sectional view of the embodiment shown in Fig. l taken at the right angle to the section shown in Fig. 1 and seen from right towards left; Fig. 6 is a cross sectional view of the fuel pump along the lines VI-VI in Fig. Fig. 'I is a cross sectional view of the valve body along the line VII-VII in Fig. 5; Fig. 8 is a cross sectional view of the valve body along line VIII-VIII in Fig. 5; Fig. 9 is a diagrammatical view of an arrangement for manual axial adjustment of the valve body; and Fig. 10 is an axial sectional view of another embodiment of the fuelpump.

- The fuel pump. will be describedvaccording to the embodiments shown in Figuresl 1--8 incluslvely.V The various parts of lthe fuel pump. cylindersand channels are located in a pumphousing, consisting of a cylindrical cylinder-block I. which, at its lower end, is providedjwith a lid 2, and at its upper end with a cap or sleeve 3 so as to form a cyllndrically shaped cavityl I' between said cap 3 and the cylinder-block I. The lid 2 and the cap 3 are securedrto the cylinderblock I by means of. screw-boltsY (notshownl The cylinderfblock 4I has. an axiaLLbox'irigj serving asa valve cylinder, inwhich provided a cylindrical valve-body, which isfaiiiif` ally displaceable. Said valve-bodyv is, inthe way described below, connected t0 u SDIldle I, driven by. the engine, said spindle beinglaxiallyv disposed' in relation to the valve-body and projectinginto the pump-housing through a central boring 8 provided in the cap 3 insuch manner that the valve-body, when the engine is running, is set in rotation by the spindle, In the cylinder-block I, outside the valvefcylinder 5, are symmetrically provided a number of pumps, in a preferred embodiment six, consisting of pump cylinders 9 disposed parallel to the valve cylinder, said pump cylinders being provided with pump pistons I0 displaceable in the cylinders. Foreach engine cylinder there is provided one pump, the fuel being injected by the pumps into the respective cylinder from the lowe'.end of the pump cylinder through nipples II, which by means of tubings are connected with respective injection nozzles. f The driving mechanism for the pump pistons I0 comprises a circular disc I2 provided in the cavity 4 under the cap 3, said disc having an axial boring and being threaded on to the spindle 'i and locked thereon by means of a transversal bolt I3. The upper face I4 of the disc is disposed at a right angle with the spindle, slidingly engaging the radial inside face of the cap 3. The lower face I5 of the disc I2, on the other hand, defines a suitable angle with the direction of the spindle, and said sloping face I5 engages slidingly a relatively thin annular disc I6, which is looselymounted on the spindle 1. The latter disc is intended always to have a sloping position, as a pin I1 inserted into the spindle will prevent the higher part of the disc from coming down. The disc I6 is made non-rotatable by means of a sliding member I9 provided in an axial boring I8 in the cylinder-block I, the upper end of said sliding member engaging a recess 26 in the edge of the disc I6 and abutting against the lower face of the disc I2. The sliding member I9 is pressed in a vertical direction by a spring 2I provided in the cylinder I8. The sliding member is also provided with an axial channel 22 having at its upper end evacuation channels 23 in order to prevent the oil, being left in the cylinder under the sliding member, from remaining there and thereby hampering the movements of the sliding member. Between the radial face of the cap 3 and the upper face of the disc I2 as well as between the lower face of the disc and the annular disc I6 are provided annular grooves containing balls 24 in order to reduce the friction between the faces mentioned during the rotation.

During the rotation of the spindle 1 and the disc I2 the latter will slide on the disc I 6, whereby the latter will move in such a rocking way without taking part in the rotation, that'every part of said disc I 6 will be in constant reciprocating motion axially, but with a diierent phase. In this way new edge portions of the disc I6 will always, one after the other in succession, be in the lowest position, so that the pistons I0, the upper ends of which abut against, or, respectively, are engaged by the lower faceof the disc I6, in succession will be pressed downwards in the pump cylinders without any sliding taking place between the pistons and the disc I6. As soon as a piston has reached its lowest position while the rotation of the spindle is going on, the piston is brought back again to its upper position by means of a spring 25 provided in the pump cylinder (as shown in Figure 1) or by means of a reversing mechanism associated with the spindle. This mechanism may, similarly to the described mechanism for pushing the pistons downwards, consist of a sloping, nonrotatable annular disc 26, which slidingly abuts against the upper sloping face of the disc 28, which is secured to the spindle 1 by a bolt 21. The edge of the disc 26, as shown to the right in Figure 3, engages a groove 29 at the upper end of the piston, and as the disc 26, in the way already described, will be moving in a rocking manner, the pistons will, each in succession, be forced upwards into their upper position. In Figure 2 the enforcement" reversing mechinism is shown, the disc 26 abutting under a head 30 provided at the upper end of the piston. As shown, the upper ends of the pistons are given a conical shape with a sloping` angle equal to the. sloping position of the disc I6, in such a way that said disc, when being rocked up and down, will abut against, and roll on, part of the conical end faces of the pistons. Thus a portion movement of thev pistons is avoided.

ln order to make an adjustment of the stroke of the pistons possible and adjustment screw 3| with safety nut 32 is provided in the cap 3, one for each piston. The lower ends of these screws form abutments for the piston-heads, so that the upper positions of the pistons may be adjusted at will.

Every pump-piston is in association with the valve cylinder 5 through a channel 33, and the fuel is sucked through this channel into the pump cylinder 9 during the suction-stroke of the piston. The inlet openings from the valve cylinder 5 to these channels are opened and shut ofi respectively, in the way described below, by the valve-body 6 during the rotation of same. The fuel oil is, during the suction-stroke body may have.

of the pump pistons sucked into the fuel pump through the nipple 34 and the axial channel 35 provided in an adjustment screw 36, arranged in a central boring in the lid 2. The upper poriion 31 of said screw projects, without touching the sides, somewhat into the lower end of an axial boring 3B extending through the valvebody 6, and the upper end of the screw is rotatably abutting against the lower end of a rotatable bolt 39 axially displaceable in the boring 38. The upper end portion of the bolt 39 protrudes out of the valve-body 6 and extends into a boring 40 provided in the lower end of the spindle 1. By means of the devices described below the bolt 39 serves for coupling together the spindle 1 and the valve-body 6. The channel 35 provided in the screw 36 is associated with an axial channel 4I in the lower end of the bolt 39, and through a transversal boring 42 provided in the bolt the channel 4I is associated with a hole 43 in the wall of the valve, said hole opening up into a groove 44 provided in the outer Wall of the valve. This groove 44 extends over an angle of about and has such an axial position, that .the ends of the channels 33, which open up into the valve cylinder, always are located between the planes through the upper and lower end of the groove 44, whatever axial position the valve- When the channels 33 during the rotation of the valve-body are in a position just opposite the groove 44, the fuel will be sucked into the pump cylinders during the suction-stroke of the pump piston, the fuel flowing upwards through the nipple 34 and the channels 35 and 4I and thence through the boring 42 and the hole 43 into the suction-groove 44, whence it is sucked through the channels 33 into the pump cylinder. For each piston this suction takes place as long as the `channel 33 is in association with the suction-groove, that is to say: in the course of one half rotation of the valve-body.

Besides having the suction-groove 44 the valvebody 6 is provided with two pressure-

grooves

45 and 46, lying on a level with the suction-groove, but separated from this suction-groove by means of

axial partitions

41 and 48 respectively, the outer faces of which are aligned with the surface of the valve-body. The two pressure-grooves are separated from each other by a portion 49 of the valve-body, said portion not being provided with any groove, and which therefore during the rotation is tightly engaging the wall of the valvecylinder. This portion 49 is tapered downwardly, having suitably curved limiting edges 50 and 5I provided symmetrically on both sides of an axial plane. It is necessary that the limiting edges are symmetrically arranged in order that the fuel pump can be used whatever direction the engine may rotate.

The pressure-

grooves

45 and 46 are, through

holes

52, 53 and

axial channels

54 and 55, respectively, in association with a compression chamber 56 between the lid 2 and the lower end of the valve-body 6, and the suction-groove 44 is, through corresponding holes and

axial channels

51 and 58, associated with the boring 40 provided in the lower end of the spindle 1. 'I'he upper end of said boring 40 is, through a channel 59 in the disc I2, associated with the cavity 4 in the cap 3. In said channel 59 is provided a ball 60 serving as a valve-body, said ball being on account of the centrifugal power pressed against the inlet opening from the cavity 4 into the channel 59, the pressure increasing with the increased rotation speed of the engine.

The compression chamber 66 is, through channels 6| and `62, associated with the cavity 4. Between said channels is inserted a throttling valve y consisting ofv a cylinder 63 rotatably provided in a boring in the cylinder-block I, said cylinder having an axial boring 64. The cylinder may be rotated by means of a handle 65 provided at the end of a valve-rod 66 associated with the cylinder. Said valve-rod is rotatably housed in a housing 61, which is secured to the cylinder-block i by the screw 68. The valve cylinder is suitably acted upon by a spring 69. The channel 6l is associated with the open end of the boring I64 of the valve cylinder, and the channel 62 is associated with said boring through a hole 10 in the cylinder wall. This hole has a form suitable for the adjusting or throttling of the circulation area of the valve more or less, at will, and eventually, for shutting oir the valve completely, said adjustments being effected by turning the valve-rod 66.

In the two ends of the spindle 1 and the valvebody 6 facing each other borings are provided,

4into which is inserted a compression spring li,

which tends to push the valve-body in a downward direction. However, the oil-pressure developed in the compression chamber 56 will exert a pressure on the valve-body in the upwards direction against said spring, and thus the axial position of the valve-body will depend on the extent of the oil-pressure. The tension of the spring must be adjusted in such a way that the springtension, by increased oil-pressure, will increase more rapidly than the oil-pressure itself, in such manner that a certain axial position of the valvebody always corresponds to each amount of oilpressure. y

The fuel pump here described makes possible an automatic adjustment of the rotation speed of the engine according to a certain value predetermined at will. The operations of the fuel pump are as follows:`

During the rotation of the engine, and thereby also during that of the valve-body, said engine parts going at a certain speed which is to be kept unchanged, the valve-body will take a certain axial position, whereby the channels 33 wil1 be shut on" from or, alternately, associated with the suction-groove 44 and the pressure-

grooves

45 and 46. Hereafter, only the operations of one of the pumps will be discussed because the opera--v tions of all the pumps, each in succession, are identical. When one of the channels 33 is in association with the suction-groove 44 during the suction-stroke of the pump piston, the oil, as it is already pointed out, will be sucked upwards through the channels 35 and 4l into the suctiongrooveand thence into the pump cylinder below the piston. When the piston has reached its top position, the valve-body will have rotatedso far that the opening of the channel 33 has reached the end of the suction-groove. Upon further rotation of the valve-body the channel 33 will pass by one of the partitions between the suctiongroove and one of the pressure-grooves, for instance the partition indicated at 48 in Figure 1, whereupon said channel will be associated with one of the pressure-grooves 46. The piston now has started its pressure-stroke, whereby the oil situated below the piston will be pressed into the pressure-groove 46. Thence the oil is pressed through the channel 6I, the throttling

valve

63, 64 and the channel 62 into the cavity 4, whence the oil is pressed by the valve-ball 60 through the channel 59 into the boring 40 provided in the spindle 1 and further through the channels 5l and @il down into the suction-groove 44. During the operation of the fuel pump all the said channels and enclosures will be lled with oil, and a constant Iiow of oil will be circulating through the

throttle valve

63, 64. Upon further rotation of the valve-body the opening of the channel 33 will pass the limiting edge :5| of the portion 49 and will remain completely shut off as longas the passing of this portion takes place. As long as this is the case, the oil cannot escape .through said pressure channels, whereby the oil pressure in the pump cylinder will increase to such a degree that the oil will be injected into the engine cylinder. This injection will continue until the opposite limiting edge 50 of the portion 49 has reached the opening of the channel 33, the length of the injection period thus being dependent upon the axial position of the valve-body relatively to the opening of the channel 33.

After the termination of the injection period, the pump piston will continue its pressure-stroke, and now the opening of the channel 33 is in association with the second pressure-groove 45. Part oi the oil will now, as previously described,- be pressed through the channel 54 down into the compression chamber 56, thus maintaining the oil circulation through the throttling

valve

63, 66.

In describing the functioning of the fuel pump a constant rotation speed of the engine and a certain axial position of the valve body without any displacement taking place has been assumed. In case the speed of the engine, for one reason or other, is changed, for instance increased, the speed of the pump piston will increase, and thus a greater quantity of oil will be pressed down into the compression chamber 56 and further through the system of pressure channels per unit of time. Consequently the oil will circulate more quickly through this channel system, whereby the circulation resistance will be increased. Owing to this fact the oil pressure in the compression chamber 56 will increase to such a degree that the valve-body will be pressed upwardly against the tension of the spring 1i. However, as the tension of the spring will increase more rapidly than the oil pressure, the valve-body wi`l, after being suitably displaced, take another axial balanced position. In this new position of the valvebody the opening of the channel 33 will be closer to the lower point of the valve portion 49, this causing a shortening of the injection period. Consequently, a smaller quantity of oil will be pressed into the engine cylinder per unit of time. At the same time, a correspondingly greater quantity of oil will ybe pressed through the pressure chamber system, this again causing a further increase of the pressure in the compression chamber 56. On account of the reduced injection of oil per unit of time, the rotation speed of the engine now will decrease, whereby the number of pump piston strokes per unit of time Will decrease, this fact effecting a decrease of speed in the compression chamber. As a result of all this, the pressure in the compression chamber 56 will decrease, so that the spring 'll will bring the valve back into its original position. In the case of a reduction of engine speed, the adjustment, obviously, will be carried out in the manner already described, only in the reversed order.

As already stated the rotation speed of the engine is .dependent upon the circulation resistance in the pressure chamber system. By means of the automatic control the circulation resistance is changed through a variation of the* circulation speed in the pressure chamber system. Said .topmost position. In this way the opening of the channel 33 will not be closed during the rota- 1tion of the valve, so that there will be no fuel injected into the engine cylinder.

The spindle 1 is coupled together with the valve-body 6 by means oi' the axial bolt 39, which in its upper end is locked to the spindle by means of the transversal split-pin 21. 'Ihe bolt 361scoupled together with the valve-body 6 by means of a ball 12 engaging an axially provided groove 13 in the inner wall of the valve-body, said bolt 12, in addition, engaging a transversal groove 14, which extends over 180 Yin the bolt 39. Thus said bolt 39 may be displaced axially relatively to the valve-body 6 as well as to the spindle 1. The upper end oi' the bolt 39 is actuated by a compression spring 15, whereas the lower end of same is rotatably abutting against the upper end of the top portion 31'of the adjustment screw 36 in such a way that the bolt may be displaced axially by adjusting the screw 36. This axial displacement of the bolt 39 changes the angular position of the valve-body relatively to the 'spindle 1. 'I'his is obtained by the split-pin 21 engaging a downwardly tapering recess 16 provided in the upper end of the bolt 39. When the bolt by means of the screw 36 is displaced vertically, the split-pin 21 will assume during the rotation different angular positions relatively to the bolt according to its higher or lower position in the recess 16. Said recess isV located symmetrically relatively to the portion 49 of the valve-body controlling the injection.

When the direction of the engine rotation is to be changed, the valve-body has to be rotated 180 relatively to the spindle 1, which is made possible by the fact that the ball 12, by changing the direction of the engine rotation, moves 180 along the groove 14 provided in the bolt 39.

In case the oil pressure developed in the pressure channel Asystem during the pressure-stroke should rise too rapidly, the oil will be pressed through the

channels

51 and 58 into the suction.

groove 44, and thence return to the oil-tank through the channels 4| and 35. Further safety is obtained by the fact that the oil, in the case of an abnormally high pressure in the compression chamber 56, will be driven upwards around the top portion 31 of the screw 36 and push the bolt 39 in an upward direction, whereby the oil from the compression chamber will be forced directly into the channel 35 and thence llow back to the oil-tank.

The fuel pump may also be adapted for manual adjustment of the rotation speed of the engine. For this purpose, a manually operated adjustment-rod 11 may be provided in the cylinderblock l. as shown, diagrammatically, in Figure 7, the inner end of said adjustment-rod 11 being provided with an eccentrical pin 16 engaging an annular groove in the valve-body 6. By rotating the rod 11 the pin 18 will cause an axial displacement of the valve-body into the position corresponding to the desired rotation speed.

A modified embodiment of the fuel pump is shown in Figure l0. According to this embodiment a change may be made in the angular position of the rocking, non-rotatable disc 19 moving the pump pistons, said change being carried out in such a way that the piston strokes of all the Pumps may be controlled by simply adjusting one nut 86. The lower edge of said nut is, by a split-pin 6I, associated with an annular disc 62 slidingly abutting against another annular disc 63. Both said annular discs are located in a rotatable cylinder 84, the lower annular edge of which is tapered. Against this sloping edge the annular disc 65, which is slidingly provided on the rocking disc 19, is abutting, at least at the lowest point 66 of said sloping edge, in such a way that both said discs may be swung somewhat about this point into different sloping positions. Between the

annular discs

83 and 85, on

the side of the spindle 1 which is diametrically opposite the said point 86, is provided a transversal bolt 61, the ends of which engage recesses n 66 in the edge portion of the cylinder 64. The

bolt 61 forms an abutment for the top-most edge portion of the annular disc 65, the annular disc 1 9 and 65 being kept in an up-turned position by the pump pistons acted upon the springs 25. When the nut is turned the bolt 81 will be displaced vertically so that the sloping position of the

annular discs

19 and 85 is changed. The annular disc 19 is slidingly resting upon the ends of a split-pin inserted through the spindle 1, said split-pin sliding along the disc during the rocking motion of same.

According to the embodiment shown in Figure l the split-pin 21 may, by inaccurate adjustment, abut only against one side of the recess 16 and thereby cause a pressure side-ways on the bolt 39. In order to avoid this, a wedge-shaped. downwardly tapering coupling-member 9| has, according to Figure 8, been mounted upon the bolt 21, said member protruding down into the recess. The wedge-shaped member being rotatable on the split-pin, it will, when the bolt 39 is turned `round always take such a position that it will be in contact with both sides of the recess.

The axially extending groove 13 in the inner wall of the valve-body is, according to Figure 10, slightly wedge-shaped longitudinally, in such a way that both edges of the groove suitably form equal angles relatively to the axial direction. During the rotation the ball 12 will abut against one or the other ofthe two edges of the groove, dependent upon the direction of rotation, and when the valve-body during the adjustment operations is displaced axially, it will, as a consequence, be turned simultaneously.

When the direction of rotation is changed, the spring 1I, when it is used as shown in Figures 1 and 5, on account of its friction against the spindle 1 and the valve-body 6, may couple together these last mentioned members with such a great force, that the valve-body does not turn the relatively to the spindle, made possible by the ball 12 rolling in the groove 14 provided in the bolt 39, all this causing an incorrect position. In order to avoid this, the spring 1i, according to the embodiment shown in Figure l0, is located in the end of the valve-body facing in the opposite direction of the spindle 1, the outer end of said spring engaging a rotatable disc 92, whereby said spring will not be able to couple together the valve-body and the spindle. In this case the valve-body must have an inversed position relativelyto its position shown in Figures 1 and 5, and the oil compression chamber 56 will be located between the upperend of the valvebody and the spindle. While the operations are identical with those already described. the various circulation channels are not shown in Figure 10. In this embodiment of the fuel pump, these channels are not associated with the cavity 4, which only contains lubricating oil. Fuel-oil, which, on account of leakage, is driven up surrounding the pistons, is absorbed by grooves 93 provided in the piston-cylinders, and is thence, through channels 94, brought back to the circulation channels. y

In order to avoid leakiness, which may arise because the pistons are unevenly worn, the lower portions of said pistons may, as shown in Figure l0, be divided into shorter pieces 95, which are loosely abutted against each other.

In the pump construction disclosed here the lower ends of the piston springs abut (against the nipples Il, whereby thesprings arebasily dismountable upon the screwing off thefyi'pples.

The construction may vary in details/'from the one here described. Furthermore, the pumps and the valves may have a reciprocal position different from the one shown on the drawings.

The pumps may for instance be located in the same plane and the valve may have a position below and transversely to the pumps in the plane through the latter.

I claim: I

1. An oil admission valve for fuel pumps comprising in combination a cylindrical valve housing; a cylindrical valve chamber within said cylindrical valve housing; a rotatable valve `body arranged within said cylindrical valve chamber slidably in axial direction; at least one oil conduit reaching from a point of the cylindrical surface of said valve chamber to the fuel pump to which oil is to be supplied; a recess in the surface of said rotatable valve body arranged so as to communicate during part of each revolution of said valve body with said fuel conduit; means combined with said recess for varying the length of communication of said recess with said fuel conduit depending upon the axial position of said rotatable valve body; means arranged within said valve body for admitting oil into said recess during rotation of said valve body; means for rotating said valve body; an oil pressure chamber arranged at onel end of said valve body so that oil injected into said chamber under pressure is adaptedto move said valve body in axial direction; rst conduit means within said valve body adapted to connect during part of each revolution of said fuel conduit with said pressure chamber; second conduit means within said valve housing and said valve body connecting said pressure chamber permanently with said recess in said valve body; and means for adjusting the flow of oil through said second conduit means.

2, An oil admission valve for fuel pumps cornprising in combination a cylindrical valve housing; a cylindrical valve chamber within said cylindrical valve housing; a rotatable valve body arranged within said cylindrical valve chamber slidably in axial direction; at least one oil conduit reaching from a point of the cylindrical surface of said valve chamber to the fuel pump to which oil is to be supplied; a recess in the surface of said rotatable valve body arranged so as to communicate during part of each revolution of said valve body with said fuel conduit; means combined with said recess for varying the length of communication of said recess with said fuel conduit depending upon the axial position of said rotatable valve body; means arranged within said valve body for admitting oil into said recess during rotation of said valve body; means for rotating said valve body; an oil pressure chamber arranged at one end of said valve body so that oil injected into said chamber under pressure is adapted to move said valve body in axial direction; first conduit means within said valve body adapted to connect during part of each revolution said fuel conduit with said pressure chamber; second conduit means within said valve housing and said valve body connecting said pressure chamber permanently with said recess in said valve body; means for adjusting the ow of oil through said second conduit means; and spring means permanently tending to move said valve body within said valve chamber against the pressure exerted by the oil within said oil pressure chamber.

3. An oil admission valve for fuel pumps comprising in combination a cylindrical valve housing; a cylindrical valve chamber within said cylindrical valve housing; a rotatable valve body arranged within said cylindrical valve chamber slidably in axial direction; at least one oil conduit reaching from a point of the cylindricalI surface of said valve chamber to the fuel 'pump' to which oil is to be supplied; a recess in the surface of said rotatable valve body arranged so as pressure is adapted to move said valve body in axial direction;'iirst conduit means within said valve body adapted to connect during part of each revolution said fuel conduit withsaid pressure chamber; second conduit means within said valve housing and said valve body connecting said pressure vchamber permanently with said recess in saidpvalve body; means for adjusting the flow offoil through said second conduit means; shaft means for rotating said cylindrical valve body; and connecting means for connecting said shaft means'with said cylindrical valve body so as to automatically change the angular position of said cylmdrical valve body relative to said shaft means when said cylindrical valve body is moved by oil injected into said oil pressure chamber in axial direction.

4. An oil admission valve for fuel pumps comprising in combination a cylindrical valve housing; a cylindrical valve chamber within said cylindrical valve housing; a rotatable valve body arranged Within said cylindrical valve chamber slidably in axial direction; at least one oil conduit reaching from a point of the cylindrical surface of said valve chamber to the fuel pump to which oil isto be supplied; a recess in the surface of said rotatable valve body arranged so asto communicate during part of each revolution of said valve body with said fuel conduit; means combined with said recess for varying the length of communication of said recess with said fuel conduit depending upon the axial position of said rotatable valve body; means arranged within said valve body for admitting oil into said recess during rotation of said valve body; an oil pressure chamber arranged at one end of said valve body so that oil injected into said chamber under pressure is adapted to move said valve body in axial direction; rst conduit means within said valve body adapted to connect during part of each revolution of said fuel conduit with said pressure chamber; second conduit means within said valve housing and said valve body connecting said pressure chamber permanently with said recess in said valve body; means for adjusting the flow of oil through said-second conduit means; shaft meansfor rotating said cylindrical valve body: connecting means for connecting said shaft means with said cylindrical valve body so as to automatically change the angular position of said cylindrical valve body relative to said shaft means when said cylindrical valve body is moved by oil injected into said oil pressure chamber in axial direction; and spring means permanently tending to move said valve body within said valve chamber against the pressure exerted by the oil within said oil pressure chamber.

5. A fuel pump comprising in combination a pump cylinder; a pump piston arranged slidably within said pump cylinder; driving shaft means; operating means driven by said driving shaft means for periodically moving said pump piston from suction position into compressing position; moving means for periodically moving said pump piston back from compressing position into suction position; a cylindrical valve housing; a cylindrical valve chamber within said cylindrical valve housing; a rotatable valve body arranged within said cylindrical valve chamber slidably in axial direction; an oil conduit connecting a point of the cylindrical surface of the valve chamber with the space within said pump cylinder; a suction recess in the surface of said rotatable valve body arranged so as to communicate during part of each revolution of said valve body with vsaid fuel conduit; a pressure recess in the surface of said rotatable valve bodyl arranged so as to communicate during another part of each revolution of said valve body with said fuel conduit; connecting means between said driving shaft means and said valve body for rotating the latter in such a manner that said suction recess communicates with said oil conduit while said moving means move said pump piston from compressing position into suction position and said pressure recess communicates with said oil conduit while said operating means driven by said driving shaft means move said pump piston from suction position into compressing position; an oil pressure chamber arranged at one end of said valve body so that oil forced into said chamber under pressure is adapted to move said valve body in axial direction; first conduit means within said valve body connecting said pressure recess with said oil pressure chamber; second conduit means within said valve housing and said valve body connecting said pressure chamber permanently with said suction recess in said valve body; and means arranged in said valve housing for adjusting the flow of oil through said second conduit means.

6. A fuel pump comprising in combination a pump cylinder; a pump piston arranged slidably within said pump cylinder; driving shaft means; operating means driven by said driving shaft means for periodically moving said pump piston from suction position into compressing position; moving means for periodically moving said pump piston back from compressing position into suction position; a cylindrical valve housing; a cylindrical valve chamber within said cylindrical valve said cylindrical valve chamber slidably in axial direction; an oil conduit connecting a point of the cylindrical surface of the valve chamber with the space within said pump cylinder; a suction recess in the surface of said rotatable valve body arranged so as to communicate during part of each revolution of said valve body with said fuel conduit; a pressurerecess in the surface of said rotatable valve body arranged so as to communicate during another part of each revolution of said valve body with said fuel conduit; connecting means between said driving shaft means and said valve body for rotating the latter in such a manner that said suction recess communicates with said oil conduit while said moving means move said pump piston from compressing position into suction position and said pressure recess communicates with said oil conduit while said operating means driven by said driving shaft means move said pump piston from suction position into compressing position; an oil pressure chamber arranged at one end of said valve body so that oil forced into said chamber under pressure is adapted to move said valve body in axial direction; first conduit means within said valve body connecting said pressure recess with said oil pressure chamber; second conduit means within said valve housing and said valve body connecting said pressure chamber permanently with said suction recess in said valve body; means arranged in said valve housing for adjusting the flow of oil through said second conduit means; and spring means permanently tending to move said valve body against the direction of pressure exerted by oil in said pressure chamber.

7. A fuel pump comprising in combination a pump cylinder; a pump piston arranged slidably within said pump cylinder; driving shaft means; operating means driven by said driving shaft means for periodically moving said pump piston from suction position into compressing position and back; a cylindrical valve housing; a cylindrical valve chamber within said cylindrical valve housing; a rotatable valve body arranged within said cylindrical valve chamber slidably in axial direction; an oil conduit connecting a, point of the cylindrical surface of the valve chamber with the space within said pump cylinder; a suction recess in the surface of said rotatable valve body arranged so as to communicate during part of each revolution of said valve body with said fuel conduit; a pressure recess in the surface of said rotatable valve body arranged so as to communicate during another part of each revolution of said valve body with said fuel conduit; connecting means between said driving shaft means and said valve body for driving the latter in such a manner that said suction recess communicates with said conduit while said operating means move said pump piston from compressing into suction position and said pressure recess communicates with said oil conduit while said operating means move said pump piston from suction position into compressing position; an oil pressure chamber arranged at one end of said valve body so that oil forced into said chamber under pressure is adapted to move said valve body in axial direction; first conduit means within said valve body connecting said pressure recess with said oil pressure chamber; second conduit means within said valve housing and said valve body connecting saidpressure chamber permanently with said suction recess in said valve body; means arranged in said valve housing for adjusting the housing; a rotatable valve body arranged within flow of oil through said second conduit means;

, 13V and adjusting means forming part of said connecting means between said driving shaft means and said valve body for automatically changing the angular position of said valve body relative to said driving shaft means during rotation of v the same when said valve body is moved in axial direction by pressure of oil forced into said oil pressure chamber.

' SVEND OLDER JAKOBSEN.

REFERENCES CITED The following references are of record in the le of tnis patent:

Number Number UNITED STATES PATENTS Name Date Hoifer Dec. 9, 1941 Amery Aug. 4, 1942 Truxell, Jr 7.. Sept. 5, 1944 FOREIGN PATENTS Country Date Great Britain Dec. 21, 1943 Germany Mar. 15, 1934