US1956923A

US1956923A - Fuel injection pump

Info

Publication number: US1956923A
Application number: US514293A
Authority: US
Inventors: Jendrassik George
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-02-07
Filing date: 1931-02-07
Publication date: 1934-05-01
Anticipated expiration: 1951-05-01

Description

May 1, 1934. @JENDRAsslK EUEL INJECTION PUMP Filed Feb. v. 1951 3 sheets-sheet' 1 May 1,1934. G. JENDRAsslK 1,956,923

FUEL INJECTIQN PUMP A Filed Feb. 7, 1931 I 3 Sheets-sheet A2 May l, 1934. G, JENDRAsslK 1,956,923

FUEL INJECTION PUMP FixedV Feb. '7. 1931. 3 sheets-sheet s Patented May l, 1934 Application February '3, 193i, Serial No. 514,293 En Hungary February 7, 1930 6 Claims. (Cl. 10S-38) Devices for operating pumps are known in whch the delivery stroke of the pump is not elfected by positive motion under the action of a cam, but by a spring released at the moment of injection by a cam which thrusts forward the piston of the pump.

The present invention concerns that group of these devices in .which the movement of a member of the mechanism effecting the movement of the piston is stopped by a stop at the end of the delivery stroke of the spring release. The adjustmentduring operation of the length of stroke is in the case of the known devices effected by shifting the position of this stop.

In the case of this method of adjustment the injection spring employed is except for the time of the suction and delivery stroke of the pump permanently supported on Ythese adjustment members. Therefore unless a. governing servomotor of very largelperformance capacity is ernployed, it is not possible to reduce the length of stroke of the pump i. e. the quantity of fuel injected, to zero because if the length of stroke of the pump is reduced to Zero, there is no suction stroke and consequently the governor would be unable to shift the position of the adjustment member against the action of the very powerful injection spr'ng. Another troublesome characteristi'c of lthis device is that the adjustment member influenced by the governor is subjected to shocks at the moment of impact, against which shocks it is not possible to make the adjustment member self locking, owing to which fact strong reactions ar`se on the governor. Another troublesome characteristic of this method of control consists in the fact that any slipping or" the nonself locking adjustment member under the action of the impact causes an increase of the quantity of fuel injected, and its disadvantageous after-dripping in the workng cylinder.

The device according to the invention does not possess these disadvantageous characteristics and in addition hereto provides other advantages also, owing to the fact thatthe injection spring is supported statically on the adjustment members during the time of the suction stroke only and its contact with the same is not effected with a shock at the speed of the rapid delivery stroke, but with the low speed of suction.

In accordance with the main conditions laid dozvn above the common fundamental element of the devices according to thev invention is in their simplest form a'lever loaded at one of its points by the injection spring in such a manner that the lever is supported against this spring action, on

the one hand on the operating member. e. g. on a cam, and on the other hand on the adjustment members, which lever during the delivery stroke also eifects the thrusting forward of the pump pston supported on it, in such measure in which the lever is freely displaced by the operating member.

This simple principle of design may lead to various arrangements according to the manner in which the guiding of the moving lever referred to is eifected. rhe guiding may, for instance, be provided by providing a straight line guide or by providing a joint guide the fixed pivot of which is situated outside the lever; a general condition being to guide the lever in such a manner as 'to perform the motion thereof in. both alternate di=1 rections in the same plane.

In the drawings: l

Each of the Figures l to 4 shows in cross section a form of the device shown by way of example, with a guiding member of the lever moved in a straight line.

Figure 5 illustrates a cross section of a further form of the device shown by way of example, in which the injection lever is guided by means of a joint guide;

Figures 6 to 'Z are variants of design of the adjustment member in case the mechanism is de signed according to Fig. l;

Figure 8 is a partial plan view of the control mechansm designed in accordance with Fig. 2, and

Figure 9 is a detail of the driving shaft of the mechanism according to Fig. 1 or according to Fig. 5.

The method of operation is described referring to the device illustrated on Fig. l. The casing of this device consists of two parts viz. of a top casing l and of a bottom casing 3l with an inter`= mediate part 30 inserted between them. The cam i shaft 2 on which the operating cams 3 are arranged is supported in bearings in casing 1. The

injection spring l0 arranged in the bottom part 3l of the casing transmits the spring force by means of the top spring washer 9 to pin 5 which latter during the delivery stroke transmits the same to the transmitting peg 11 and to the pump piston, or respectively during the suction stroke transmits spring force to the injection lever 4 pivoted iny pin 5 in such a manner as to be pivotable around point 6. The injection lever 4 is at the time when it is subjected to the action of spring 10, supported at one end on the actuating cam 3 and at its other end on the adjustment members. Peg 7 is raised or lowered in the longitudinal direction by the adjustment members controlled by the governor so as to suit the load carried at any moment. Pin 5 moves in the long bore hole of plate 30.

During the suction stroke of the pump the cam 3 will press the lever 4 downwards, while the'latter turns around its end supported on peg 7. Together with lever 4 pin 5 also moves downwards against the action of spring 10 whereupon the return spring 14 presses down the piston 13 of the fuel pump 12 together with the transmitting peg 11. Thereby the suction stroke is effected, the length of which will correspond to the displacement of lever 4. During the further rotation of the cam the injection spring 10 will, at the moment when that edge of lever 4 which is supported on the cam leaves the edge of the cam, thrust pin 5 forward raising peg 1l and pump piston 13 against the action of the return spring 14 vthe strength of which is much less than that of the injection spring 10. This will. be continued until the enlarged bottom part of pin 5, attains the intermediate part 30, or in the case of different design, until the top portion of pin 5 strikes against the top casing. Before attaining this position the end of lever 4 situated below ther supporting peg 7 swings out freely downward; the adjustable screw 8 serving to limit this motion.

The variation during service of the length of stroke or respectively of the quantity of fuel injected is as mentioned effected by the longitudinal displacement of the supporting peg 7. In lorder to effect this displacement the top part of this peg is supported on a parallel pair of wedges 15-l6, of which 16 is the so-called base wedge, while 15 is the adjustment wedge, the latter being capable of being moved in a direction perpendicular to the plane of the drawing by means of spindle 17, operated by the governor. When effecting its function during service the governor displaces the spindle 17 and therewith the adjustment wedge 15 parallel with itself, whereby the thickness of the pair of wedges gliding on each other is suitably altered and thereby the axial displacement of peg 7 is likewise effected. The base wedge 16 can in the arrangement shown by way of example onthe drawings be adjusted by means of screw 18 in the longitudinal direction of the latter. Hereby it is possible to inuence the position of peg 7, also independently of the control taking place during operation. This possibility is of particular importance in the case of multicylinder engines in order to enable the quantity of fuel injected into the various cylinders to be accurately equalized.v It is understood that this adjustment can also be effected by other methods, by means of elements of design not shown on the drawings.

During thetime of the suction stroke of the pump the injection spring 10 is supported through lever 4 on the members l5 controlling the length of stroke. For this reason it is advisable to make the adjustment member selflocking, but any displacement during the time of the suction stroke will even in this case require such a force as a* governer not fitted with a servomotor is unable to supply. For this reason adjustment by the governor will in the case of single cylinder engines be effected' intermittently, the movement of the adjustment members being only possible while the.

pump is not performingits suction stroke. In view of the fact that the adjustment members of the various pumps are not free during the time of the suction strokes referred to it isnot permissible, in the case of a multicylinder engine, where suctions are distributed so as to overlap, to mutually connect the adjustment members, for instance the wedges, by means of rigid connections, but a spring connection should be preferably established between them.

A detail of such a connection is illustrated on Figs. 6 and 7.

In these embodiments of the invention shown by way of example the moving wedges l5 are supported on the fixed wedges 16, forming pairs of parallel wedges. The moving wedges are provided with an inner hole, through which the spindle 17 passes. Between the wedges 15 and the spindle 17 there is no xed connection but in the embodiment shown by way of example on Fig. 6 the wedges are connected to the spindle in a yielding manner by means of springs 21 supported on the inner shoulders 20 of the wedges and on the washers 19 fixed on spindle 17.

On Fig. 7 the part 22 (of the spindle-17) guided loosely in the wedges, is made of larger diameter over a length equal to the length of the wedge. The springs 23 are supported by means of the loose spring washers 24 either on the wedges or 100 on the shoulders of the parts of increased diameter 22, according to whether the wedge on the spindle is in the central position or not.

The operation of the device as shown on either of the two figures referredto is as follows:

In case of displacing spindle 17 those wedges which are not free, i. e. to which the pegs 7 transmit a certain amount of pressure, will remain in their places, owing to which fact the

springs

21 or 23 respectively will be elastically deformed. 110 The spring tension thus created will at the moment when the Wedge is released displace the Wedge until the latter again returns into the central position as compared to the spindle. By these means the process of governing is effected 115 in a gradual manner, not all cylinders being regulated simultaneously. The dilerence between the devices shown on Figures 6 and 7 consists in the fact that in the device according to Fig. 6 the force which effects the return in the case of 120 a relative displacement of a wedge and of the spindle will be equal to the difference between the spring forces on the two sides and will accordingly increase in proportion to the displacement from zero upwards'while in the case of the device illustrated on Fig. 7 it is only the spring on one side of the wedge which in case of displacement will exert an action on the wedge, in consequence of which fact the force effecting the return will not increase gradually from zero upwards, but will even in the case of a very slight displacement immediately attain the amount of the force of one of the springs. It is however not necessary to provide spring connection between every wedge separately and the spindle, it being 135 also possible to mutually connect rigidly a number of wedges so as to form a group and to effect only the connection of these groups with the spindle in a resilient manner. Only such wedges can however be united into such a group which during -a certain time are free simultaneously.

The device shown on Fig. 9 represents an arrangement connecting the helical gear wheel 25 driving the camshaft 2 with its shaft. 'I'he purpose of this device is to prevent fracture in case the engine for some reason should make a few turns in a sense opposite to the sense in which it is rotating during service. Notably in such a cme the step portion of cam 3 would entangle itself with'the indection lever 4 and fracture can be L3 avoided only if gear wheel 25 is connected to the shaft 2 in such a manner as to make the connection act in one direction only. Accordingly the gear wheel 25 is supported on shaft 2 in such a manner as to be able to rotate freely, but its hub is provided with a single claw device 26 permitting engagement in one relative position only. On shaft 2 also a counter part 27 is provided which is in rigid connection with the shaft and also carries a corresponding claw. The spring 28 permanently presses wheel 25 on to part 27.

In operation this device is, if rotation takes place in the sense indicated by the arrow, capable of transmitting a torque from wheel 25 to shaft 2 because in this case owing to the claw 26 the Wheel hub and the piece 27 will engage. In case of rotation in the contrary sense of wheel 25, however, the hub will glide along the helical surface 29 of part 27 and will be able to transmit such torque only as corresponds to the tension force of spring 28. It is most essential that the coupling device acting in one direction only shouldbe itted with a single claw only, in order to avoid for instance in the case of a device according to -Fig. 9 any change of the relative mutual position of the cams 3 and the crank shaft. As long as this requirement is duly observed, other devices, for instance a ratchet and pawl device, can also be employed for the purpose in view. Finally from the point of view of operation the rider 42 yielding only in one direction, illustrated on Fig. 2 will of course be just as suitable; while however such a rider would have to be employed at the end of each injection lever 4, the disconnecting device described according to Fig. 9 or the ratchet and pawl device (not illustrated) referred to are able by themselves alone to safeguard a complete multicylinder fuel pump.

The pump operating device described can be made in a very large number of variants.

In the variant shown on Fig. 2 it is the screw spindle 32 iitted with the selflocking opposite

threads

33 and 34 which acts as a member for adjusting the length of stroke. By means of the nut 35 on which pivots 36 are provided on both sides, the injection lever 4 is connected in an articulated manner, so as to be capable to turn around .these pivots. In the case of this form of the device the injection lever is only in articulated'connection with the members for adjusting the length of stroke, an arrangement by which its tangential position relatively to cam 3 is duly nxed. In this case the pin 5 guided in a straight line motion is supported on the injection lever or respectively on peg 11 by means of the roller 38 supported in the injection lever by means of pin 37. The stop flanges 39 or respectively 40 serve for limiting the length of stroke. The arrangement of the governing device may instead of that shown on the drawing also be arranged in such a manner that the thread 33 is not screwed immediately into the casing casting 1 but into a bush (not shown) which latter can be turned in the casing. It is possible to effect the articulated suspension shown on Fig. 2 of the injection lever in that case also in which it is not a screw which is used for adjustment, for instance, according to Fig. 1 in such a manner that lever 4 is supported on a pivot on peg 7 so as to be capable of rotation.

The protection of the device in case of a sense of rotation contrary to the sense in which rotation takes place during operation lcan also be effected by means of the rider 42 giving way in one direction, mentioned already in connection with Fig. 1 which rider is connected to the injection lever 4 in such a manner as to be able to rotate around pin 45 in one direction only. The rider 42 is pressed on to the shoulder of .the injection lever by means of spring 41 but of course in this case also it is possible to employ the safety device according to Fig. 9. The employment of the riders described may have the particular advantage that they can be combined with cams 44 rotatable around shaft 43 by means of which it is possible to deflect the riders to such an extent as to entirely interrupt contact with the cams 3 and the engine can thus be shut down.

In the case of the arrangement shown on Fig. 3 the part 5 guided in a straight line is supported direct on the peg 11. Bush 48 is tted on both sides with pivots 49- which are rotatably supported in the injection lever 4. The injection spring during the suction stroke is supported with the intervention of the pin 5 guided in a straight line and of the ring 50 on the bush 48 which latter transmits the force to the injection lever by means of the pivots 49. The bush 48 surrounds the projecting part of peg 11 or respectively of part 5 so as to leave a gap, similarly a gap is also left between the stop flange 51 and the bush 48. Above the bush 48 the at plates 52 are arranged. In the case of this arrangement the injection lever can at the end of the injection stroke when either the flange 51 or the flange 40 will effect stopping, continue its motion until the top plate of bush 48 will completely compress the shock damper plates 52. Accord- Sil ingly. in the case of this arrangement separate motion limiting stops are provided for the injection lever 4 and for the injection spring. This device as well as the device shown on Fig. 1 can further be simplified by making peg 11 and part 5 as one integral piece. In this case the straight line guide of pin 5 or that of peg 11 can be dispensed with.

In the device shown on Fig. 4 the spring washer 9 is directly supported on the part 56 rigidly connected to lever 4 while lever 4 is suspended in an articulated manner on some other part, e. g. on the screw spindle 32. In the case of this arrangement it is the part 56 itself which owing to its very small deiiection assures the guiding of the lever.

Finally in the case of the embodiment shown by Way of example in Fig. 5 the guiding in a straight line of lever 4 is replaced by a joint guide the fixed pivot of which is situated outside the lever. For this purpose lever 4 is rotatably pivoted on point 55 of a guiding lever 54 which latter is pivoted on a xed point 53 of the casing 1. In thisdesign the injection spring 10 transmits the load to the injection lever as shown also in the preceding Fig. 4 in a direct manner through peg 56 and the latter also'effects in a direct manner the motion of the transmitting peg 11 bearing down on the top end of peg 56. The length of stroke is regulated in the case of this arrangement shown by way of example also by means of the screw spindle described in connection with Fig. 2 on the end`34 of which fitted with a thread of contrary direction the screw bush 58 guided in slots '57 is screwed for the purpose to enable the bottom surface of the latter to supply the necessary support for lever 4. The device acting as 3L a safeguard against rotation in the contrary sense may be any one of those perviously described.

In'the case of all the last-named arrangements with regulation by screw spindle it is of course also necessary to provide for the controlling elements belonging to the various cylinders in the case of a multicylinder engine to be fitted with yielding mutual connections for the same reason as detailed in connection with Figures 6 to '7. The arrangement corresponding to this purpose, described in accordance with the arrangement shown on Fig. 8 is as follows:

The spindle 47 also shown on Fig. 2, the motion of which is effected from the governor at the forked ends of the control levers 46 passes with a small gap as far as the adjustable stop screw 60 provided in the lug 59. At the front end as well as at the rear end of the control spindle as well as between each pair of levers fixed spring washers 61, and on the two sides of the forks of the levers relatively to the spindle (loose spring washers 62) moving together with these forks are provided. Accordingly when the governing rod is displaced, for instance in the direction I, it is the springs 63 while in the case of its being moved in the direction II it is the springs 64 which are compressed and by their means the corresponding positions of levers 46 are also shifted in the same order of sequence in which the pressure exerted during suction on the adjustment members of the pumps of the various cylinders ceases.

The various elementsvof the devices described can be mutually combined in a variable manner. They may be of the most variable designs and arrangement. For instance the injection spring can also be placed above lever 4 various designs of which can be employed. Thus a double arm lever may also be employed instead of a single arm lever and in the case of an arrangement according to Fig. 5 the guiding lever 54, if given a suitable shape may also take up the pressure of the injection spring direct. Possibly this lever may also effect in a direct manner the motion of the transmitting peg 11 etc.

It is understood that my invention is not limited to the embodiments described or Vshown in the figures, and any possible combination of the characteristic members suitable to perform the functions detailed above must also be considered as a further embodiment exemplifying my invention.

, I claim:

1. A mechanism for controlling fuel'injection pumps of internal combustion engines, comprising a spring, a lever loaded by said spring, means suitable for gradually increasing the strain of said spring by moving the lever and for decreasing the said strain rapidly, said'means also forming a support of said lever when the strain of said spring is being increased; adjustable means forming a further support of said lever only when the strain of said spring is being increased, said support being displaced by the controlling devices of the engine substantially in the direction of the load exerted upon said support by said lever; guiding means for ensuring the performance by said lever of its alternate motion in the same plane; a piston for said fuel injection pump being pressed to said lever by a spring and thrust forward thereby towards the outside extreme pov`sition of the lever and moved in the opposite direction by this lever when the strain of the rst mentioned spring is decreased, and a non-controlled stop limiting the movement of the piston in this opposite direction before said lever reaches said means effecting th movement of the lever against said spring.

2.A In a mechanism for controlling fuel injection pumps of internal combustion engines,. a

spring, a lever loaded by said spring, a rotating cam effecting the increase and subsequent rapid decrease of the strain of said spring and forming a support of said lever when said spring strain is increased; safeguard means to avoid entanglements of said lever and of said cam when the shaft of lsaid cam rotates in a sense opposite to that of normal operation; adjustable means forming a further support of said lever only when said spring strain is increased, said support being displaced by the controlling devices of the engine substantially in the direction of the load exerted upon said support by said lever; guiding means to ensure the performance by the said lever of its alternate motion in the same plane; a piston for said fuel injection pump being pressed to said lever by a spring and thrust forward thereby towards'the outside extreme position of the lever and moved in the opposite direction by this lever when the strain of the rst mentioned spring is decreased, and a non-controlled stop limiting the movement of the piston in the opposite direction before said lever reaches said cam effecting the movement of the lever against said spring.

3. In a mechanism for controlling fuel injection pumps of internal combustion engines, a spring, a lever influenced by said spring, a rotating cam effecting the increase and subsequent rapid decrease of the strain of said spring and forming a support of said lever when said spring strain is increased; safeguard means to avoid entanglement of said lever and of said cam when the shaft of said cam rotates in a sense opposite to that of normal operation; a plurality of adjustment members having self-locking surfaces one of which members is influenced by the controlling device of the engine, said adjustment members forming a support for said lever only when the strain of said spring is increased said support being displaced by said controlling devices substantially in the direction of the load exerted upon said support by said lever; guiding means to ensure the performance by the said lever of its alternate motion in the same plane; a piston for said fuel injection pump being pressed to said lever by a spring and thrust forward thereby towards the outside extreme position of the lever and moved in the opposite direction by this lever when the strain of the rst mentioned spring -is decreased, and a non-controlled stop limiting the movement of the piston in the opposite direction before said lever reaches said cam effecting the movement of the lever against said spring. I

4.In a mechanism for controlling fuel injection pumps of internal combustion engines, a spring, a lever influenced by said spring by means of a pin, said pin being `arranged and guided in the centre line of said spring in the pump casing, a rotating cam effecting the increase and subsequent rapid decrease of the strain of said spring and forming a support of said lever when said spring strain is increased; safeguard means to avoid entanglement of said lever and of said cam when the shaft of said cam rotates in a ksense opposite to that of normal operation; a

plurality of adjusting members having self-locking surfaces one of which members is influenced by the controlling device of the engine, said adjustment members forming a support for said lever only when the strain of said spring is increased said support being displaced by said controlling device substantially in the direction of the load exerted upon said support by said lever;

guiding means to ensure Athe performance by the said lever of its alternate motion in-the same plane; a piston for said fuel injection pump being pressed to said lever by a spring and thrust forward thereby towards the outside extreme position of the piston and moved in the opposite direction by this lever when the strain of the first mentioned spring is decreased, and a non-controlled stop limiting the movement of the piston in the opposite direction before said lever reaches said cam effecting the movement of the lever against said spring.

5. In a mechanism for controlling fuel injection pumps of internal combustion engines, a spring, a lever loaded by said spring by means of a pin, said pin being arranged and guided in the centre line of said spring in the pump casing, a, rotating cam effecting the increase and subsequent rapid decrease of the strain of said spring and forming a support of said lever when said spring strain is increased; a loose gear wheel on the shaft of said cam; safeguard shaft couplers disconnecting said shaft and wheel when rotating in a, sense opposite to their normal sense of rotation; a spindle threaded into the pump casing being turned by the controlling device of the engine; a screw nut guided in a manner preventing rotation arranged on an oppositely threaded part of said spindle and forming a further support of said lever` only when the strain of said spring is increased; guiding means for ensuring the performance by the said le'ver of its alternate motion in the same plane; a piston for said fuel injection pump being pressed to said lever by a spring and thrust forward thereby by a spring towards the outside extreme position of the lever and moved in the opposite direction by this lever when the strain of the first mentioned spring is decreased, and a non-controlled stop limiting the movement of the piston in the opposite direction before said lever reaches said camA eiecting the movement of the lever against said spring.

6. In a mechanism for controlling fuel injection pumps of internal combustion engines, a spring, a lever loaded by said spring by means of a pin, said pin being arranged and guided in the centre line of said spring in the pump casing, a rotating cam effecting the increase and subsequent rapid decrease of the strain of said spring and forming a support of said lever when said spring strain is increased; a loose gear wheel on the shaft for said cam; a coupler fiange fixed on said shaft; a spring-loaded countercoupler ange united with said gear wheel, both coupler anges having claws which in case of rotation in the normal sense of rotation mutually engage whilst in the case of rotation in the opposite sense they glide over each other without mutually engaging; a spindle threaded into the l pump casing being turned by the controlling device of the engine; a screw nut guided in such a manner as to prevent rotation arranged on an oppositely threaded part of said spindle and forming a further support of said lever only when the strain of said spring is increased; an articulated junction between said lever an'd the pump casing; a piston for said fuel injection pump being pressed to said lever by a spring and thrust forward thereby towards the outside extreme position of the lever and moved in the opposite direction by this lever when the strain of the first mentioned spring is decreased, and a non-controlled stop limiting the movement of the piston in the opposite direction before said lever reaches said cam effecting the movement of the lever against said spring.

y GEORGE JENDRASSIK.