US3020902A - Fuel injection pump for multi-cylinder internal combustion engines - Google Patents

Description

Feb. 13, 1962 A. G. SJCBLOM 3,020,902

FUEL INJECTION PU FOR MULTI-CYLINDER INTERNAL co STION ENGINES 2 Sheets-Sheet 1 Filed Dec. 29, 1958 Feb. 13, 1962 A. G. SJGBLOM 3,020,902

FUEL INJECTION PUMP FOR MULTI-CYLINDER INTERNAL COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed Dec. 29, 1958 FIG.3

ATTORNEVS.

United States Patent OfiFice 3,020,902 Patented Feb. 13, 1962 1 3,020,902 FUEL INJECTION PUMP FOR 'MULTI-CYLINDER INTERNAL COMBUSTION ENGINES Anders Georg Sjtiblom, Sommarogatan 45B, Eskilstuna, Sweden Filed Dec. 29, 1958, Ser. No. 783,290 4 Claims. (Cl. 123-139) This invention relates to a fuel injection pump for multicylinder internal combustion engines, said pump containing a plunger performing reciprocating axial movement and at the same time continuous rotary movement which is reversed with the reversing of the engine, one part of said pump plunger being designed as a distributing circular slide valve by means of which, during the pressure stroke of the pump, the fuel injectors of the engine are successively connected with the working chamber of the pump, and a second part of said pump plunger being designed as a second circular slide valve by means of which the inlet of the pump is, during the suction stroke of the pump, connected with the working chamber, The invention is characterized in that said second circular slide valve is provided with a passage such as a groove or the like and is surrounded by an adjustable sleeve valve, the inner cylindrical surface of which constitutes the sliding surface for the circular slide valve and the peripheral wall of which is perforated with a number of openings corresponding to the number of injectors, the shape and the position of said openings being such that during operation of the pump, the working chamber is, in one position of the sleeve valve, adapted to be connected with an inlet chamber surrounding the sleeve valve via a communication consisting of said groove or passage and one of said openings during the whole of the pressure as well as the suction stroke of the pump plunger, while in another of the positions of the sleeve valve the working chamber is connected, through the said communication, with the inlet chamber of the pump during only part of the pressure stroke of the plunger and during the whole suction stroke of the plunger, the fuel quantity and the time for the beginning of the injection being variable by means of the sleeve valve and an unintentional reverse motion of the engine being prevented by the fuel being then pressed back into the inlet chamber.

According to a feature of the invention, the pump is provided with an adjustable drive device which upon movement thereof will simultaneously vary the moment for the beginning of the injection and the fuel quantity injected in order to enable the reversing of the engine.

The invention is illustrated in the accompanying drawings. Two different pump types embodying the invention will now be described by way of example with reference to accompanying drawings, in which:

FIG. 1 is a longitudinal section of a pump which is of the differential plunger type;

FIG. 2 is a longitudinal section of a pump provided with a cylindrical plunger;

FIG. 3 is a diagrammatic illustration of the plunger movement relatively to the sleeve valve, and a section on line IV-IV in this figure refers to FIG. 4;

FIG. 4 is a partial cross section on line IV-IV of FIG. 1 drawn to an enlarged scale, and

FIG. 5 is a partial cross section on line V-V of FIG. 2 also drawn to an enlarged scale.

FIG. 5a is also a partial cross section similar to FIG. 5 but showing a modified construction for the sleeve valve.

FIG. 6a is a side elevation with certain parts shown in section which is similar to FIG. 1 but taken at a right angle thereto. This view shows a regulating device for an operating component of the pump and also the details of a clutch mechanism, and

FIG. 6b shows a modified detail of FIG. 6a.

In the embodiment according to FIG. 1 the reference numeral 1 designates the casing of the fuel injection pump with a detachable intermediate part 2, a lower part 3, and an upper part 4. The lower part 3 is traversed by a shaft 6 which is rotatably mounted in a bushing 5, said shaft being driven from the crank shaft of the multi-cylinder internal combustion engine in any suitable manner. The shaft 6 and the bushing 5 extend through a disk 7 provided with rollers 8 acting against cam faces 9 of a cam disk 10 which is driven in continuous rotary motion from the shaft 6 through its part 14 which is formed as a clutch half so that the rotary motion of the plunger is reversed when the direction of rotation of the engine is reversed. During its rotation the cam disk 10 will also receive an axial reciprocating motion through the action of the cam faces 9 and the rollers 8 since a spring 11 holds the cam disk 10 with its cam faces 9 in contact with the rollers 8. The clutch is very simple. The shaft 6 forms a fork between the prongs of which a cross-piece 10a is disposed belonging to the disk 10. Said cross-piece moves up and down simultaneously with the cams 9 and transmits its move ment to plunger 13 which is fixed to the cross-piece by means of a pin 9a. The clutch details appear more clearly in FIG. 6a. The disk 7 may, either separately or in combination with an operating mechanism for rotating a pin 22 for the sleeve valve 17, be connected with the speed regulation device of the engine. In the embodiment shown the spring 11 rotates with the cam disk 10, and is, at its free end, journaled by means of a ball bearing 12 on the intermediate part 2 of the pump. The lower portion of the pump plunger 13 is secured to the cam disk 10 and the plunger 13 will thus receive the same motion as the cam disk, i.e. a reciprocating axial motion and a simultaneous rotary motion around its axis, The upper part of the pump plunger 13 is provided with an axially extending groove 16 constituting a part of the working chamber 24 of the pump from which fuel is conducted through passages 15 to the fuel injectors of the respective engine cylinders. Fuel is conducted to the groove 16 through a passage 18 which is shown in FIG. 1 in the form of a groove and in FIG. 2 in the form of a hole which, except in the axial groove 16, opens partly into the peripheral surface of the plunger, and partly into the upper (pressure) surface of the plunger.

The upper part of the pump plunger 13 is surrounded by a sleeve valve 17 which is adjustable about the c0mmon axis of the sleeve valve and of the pump plunger by means of the pin 22 and an operating member 21 which may be connected to the speed regulating device (not shown in the drawing) of the engine, either separately or in combination with an operating mechanism for rotating the disk 7 and which is shown in FIGS. 6a and 6b. The sleeve valve 17 is prevented from axial displacement by means of a screw 20 which is axially bored to constitute a bearing for the pin 22. The peripheral wall of the sleeve valve 17 is perforated with openings 19 the number of which is equal to the number of the engine cylinders. Through theopenings 19 the fuel from the inlet passage 29 and the inlet chamber 23 concentrically surrounding the sleeve valve 17 flows via the passage 18 into the working chamber. The sleeve valve 17 is the member which varies the fuel quantity and the moment for the beginning of the fuel injection and prevents unintentional reversing of the engine. Its function is clear from FIGS. 3 and 4.

In FIG. 2 the working chamber of the pump is designated by 24. It is in this case located above the plunger 13 and communicates through passages 25 and 26 with the axial groove 16, and through the passages 18a with 3 fuel inlet chamber 23 via the openings 19 of the sleeve valve 17.

FIG. 3 which is a developed view of a part of the peripheral surface of the pump plunger 13 and one of the openings 19, shows the movement of the leading edge of the groove 18 or passage 18a relatively to the opening 19, said edge in the following being indicated as point 38. Since the function of the pump plunger will be quite the same at both openings 19 only one of them is shown in FIG. 3. The engine is supposed to work normally when the point 38 of the groove 18 or passage 18a is moving from the left to the right (representing its rotary movement in the direction of the arrow in FIG. 4). When the plunger 13 is in its lower position, the point 38 of the groove 18 is located on the line a-a, and when the plunger is moving upwards, the point 38 follows the full line, i.e. a part of a helix. At the moment when, during the upward, i.e. the pressure stroke of the plunger, the groove 18 or the passage 18a is covered by the wall of the sleeve 17, and the plunger presses fuel through one of the passages 15 to an injector, but when the groove reaches the line bb in FIG. 3 i.e. one of the openings 19, as shown in FIG. 4, fuel flows through said opening and back into the inlet chamber 23, and the fuel injection in the engine cylinder ceases. The point 38 then travels downwards along the dashed line towards the lower plunger position, and the pump sucks in new fuel from the chamber 23 through the opening 19, until the groove 18 or the passage 18a reaches One of the edges 19a of the openings 19. The point 38 has now passed the points 27 2835P in FIG. 3. Then it follows the line a-a to the point 27 in front of the next opening 19 (not shown in FIG. 3) where the pressure stroke and feed injection begins again. The distance from point P to point 27 varies, of course, with the number of openings 19. However, the width B of each opening 19 may be so adapted that the pump can perform a whole pressure and suction stroke while the groove 18 or the passage 18a communicates with one of the openings 19, when the sleeve 17 is rotated to a position in which the contour of the opening 19 embraces the curve C shown in FIGURE 3. This position means that no fuel is injected into the cylinders of the engine. If the engine should unintentionally move in reverse, it is seen from the dashed curve that after the reversal the groove 18 or passage 18a is connected to the opening 19 during the pressure stroke. No fuel then enters the engine cylinder. If it is desired to reverse the engine (for example, in certain marine engines) so that it moves backwards, the position of the disc 7 must be adjusted in such a manner that the point 38 of the groove 18 will follow the dot and dash curve in FIG. 3 from the point 36 on line aa up to point 37 and then down again to line a-a (the last part of the curve not shown). Thus, the points 32 and 33 correspond to the points 30 and 31 and the points 36 and 37 correspond to the points 27 and 35, when the engine moves in reverse. The angle on Which extends from the line a-a to one edge of the opening 19, and the angle 6 which denotes the inclination of the cam disc, must be adjusted partly to the compression character of the engine, and partly to the desired design of the cams.

In both embodiments one part of the pump plunger is thus designed as a distributing circular slide valve by means of which, during the pressure stroke of the plunger, the fuel injectors of the engine are successively connected with the working chamber 24 of the pump, and a second part of the pump plunger is designed as a second circular slide valve by means of which the inlet of the pump is, during the suction stroke of the pump, connected with the working chamber, said second circular slide valve being surrounded by the adjustable sleeve valve 17, the inner cylindrical surface of which constitutes the sliding surface for the circular slide valve and the peripheral wall of which is perforated with the openings 19, the number of which openings corresponds to the number of fuel injectors, the shape and position of said openings being such that, during the operation, the working chamber is connected with the inlet chamber 23 surrounding the sleeve valve 17 via one of said openings 19 during an inoperative part of the pressure stroke of the plunger which is in dependence upon the position of the sleeve valve 17, and during the suction stroke of the plunger. By this the fuel quantity and the moment for the beginning of the injection are consequently variable by means of the sleeve valve 17, and an unintentional reverse motion of the engine is prevented by the fuel being then pressed back into the inlet chamber 23.

When the fuel supply of the engine increases, the number of revolutions of the engine is increased at constantly counteracting torques, and consequently an earlier injection of the fuel into the cylinder is required. By rotating the disk 7 the fuel injection can be caused to begin at the desired moment. It is seen from FIG. 3 that if the disk 7 is rotated in such a manner that an earlier injection is obtained, i.e. the point 27 is displaced to a position further to the left along the line aa, the distance between the points 28 and 29 and thus the fuel quantity injected will increase. An arrangement for controlling rotation of disk 7 in accordance with the change in engine speed is illustrated in FIGS. 6a and 6b. In these two views it will be seen that the operating member 21 previously described is connected to a pulling rod 48 which is moved in accordance with the change in engine speed. As the pivoted operating member 21 swings back and forth with a change in engine speed, it actuates a crank 43 over crank pin 43a which slides in a groove 49 in the member 21. Crank 43 is connected to a vertical spindle 44 for turning the latter about its axis, and spindle 44 is mounted in upper and lower bearings 47 fixed to casing 1 of the pump. The turning movement of spindle 44 is transmitted to disk 7 and rollers 8 by means of a crank 45 secured to the lower end of spindle 44, an arm 46 secured to sleeve 5 which in turn is secured to disk 7, and which has a pivotal motion about the sleeve axis, and a connection between arm 46 and crank 45 which is constituted by a crank pin 45a which slides in a groove 50 in arm 46. Thus by turning disk 7 in accordance with a change in engine speed, the exact time of fuel injection is controlled. It may be observed that according to FIG. 6a, the disk 7 is turned opposite to the direction of plunger 13. In the modification shown in FIG. 6b, disk 7 will be turned in the same direction as plunger 13 owing to the fact that the crank 46 in FIG. 6b has an initial position which is opposite to the position shown in FIG. 6a. Since also the sleeve valve 17 is rotatable, the moment for the ending of the fuel injection and thus also the fuel quantity may be varied by means of the sleeve valve 17. If there is exact agreement between the fuel quantity and the moment for the beginning of the injection, the pump can be controlled solely by rotating the disk 7. If there is no exact agreement the sleeve valve 17 must also be rotated. These rotary motions are preferably received from the speed regulation device of the engine. The fact that by not making the edge of the opening 19 purely axial but such that the angle on becomes greater than the cam angle 5 must be increased to get the same fuel quantity injected, is also of interest. On the other hand, the cam angle 5 can be reduced if the angle a is made smaller than 90, but in this case the groove 18 must be replaced by apertures, for example, and an axial passage as in the construction according to FIG. 2. However, in this case the opening of the passage in the upper surface of the plunger must be plugged.

FIG. 5a shows a cross section of the sleeve valve in a modified embodiment. The sleeve valve 17 has here a (possibly several) groove or opening 40 with a communication passage 41 to the inlet chamber 23 to obtain divided injection in which the supply to the fuel distributor is interrupted a short time after its beginning during part of the plunger stroke through a communication of short duration between the working chamber and the inlet chamber 23 of the plunger. Furthermore, one or more holes 18b are bored radially through the pump plunger so that a mouth 42 is provided for each engine cylinder, and thus only a single opening 19, and 40 and 41 respectively, is required in the sleeve valve 17 to serve all the cylinders of the engine.

What I claim is:

1. A fuel injection pump for multicylinder internal combustion engines, said pump containing a fuel inlet chamber, a Working chamber and a plunger performing reciprocating axial movement relative to said working chamber and at the same time performing a continuous rotary movement which is reversed with reversing of the engine, one part of said pump plunger being constructed as a distributing circular slide valve by means of which, during the pressure stroke of the pump, the fuel injectors of the engine are successively placed in communication with said working chamber, and a second part of said pump plunger being constructed as a second circular slide valve by means of which, during the suction stroke of the pump, said Working chamber is placed in communication with said fuel inlet chamber of said pump, characterized in that second circular slide valve is provided with a passage and is surrounded by a cylindrical sleeve valve adjustable about the axis of said second circular slide valve in a rotational but non-axial manner, the inner cylindrical surface of said sleeve valve constituting the sliding surface for said second circular slide valve and the peripheral wall of said sleeve valve being provided with at least one opening therethrough leading to said fuel inlet chamber, the configuration and position of said opening being such that during operation of the pump said working chamber is, in one position of said sleeve valve, placed in communication with said fuel inlet chamber via said passage in said second circular slide valve and said opening in the peripheral wall of said sleeve valve during the whole of the pressure as well as the suction stroke of said pump plunger, while in another position of said sleeve valve, said working chamber is placed in communication with said fuel inlet chamber via said passage in said second circular slide valve and said opening in the peripheral wall of said sleeve valve during only part of the pressure stroke of said pump plunger and during the whole suction stroke of said pump plunger, the fuel quantity and the time for the beginning of the fuel injection being variable by adjusting the position of said sleeve valve, said sleeve Valve also serving to prevent any unintentional reverse motion of the engine when said sleeve valve is positioned to let said pump plunger press back the fuel into said fuel inlet chamber.

2. A fuel injection pump according to claim 1, characterized by a drive device for the pump plunger, said device being adjustable in such a manner that the plunger, when movement occurs, at the same time varies the moment for the beginning of the fuel injection and the fuel quantity in order to enable the reversing of the engine.

3. A fuel injection pump according to claim 1, characterized in that the sleeve valve has at least another opening with a communication passage to the inlet chamber to obtain divided injection, in which the supply to the fuel distributor is interruped a short time after its beginning during part of the plunger stroke through a communication of short duration between the working chamber and the inlet chamber of the pump.

4. A fuel injection pump according to claim 1, characterized in that at least one hole is bored radially through the pump plunger so that a mouth is obtained for each engine cylinder and thus only a single opening is provided in the sleeve valve to serve all the cylinders of the engine.

References Cited in the file of this patent UNITED STATES PATENTS 2,784,670 High et a1. Mar. 12, 1957 FOREIGN PATENTS 359,603 Great Britain Oct. 29, 1931

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