JPH08210154A - Fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid nonconforming pressure actions generated from a working chamber through a control spool so as to avoid unstable position of an injection regulation piston. SOLUTION: A pressure discharging chamber 122 is arranged between a pressure chamber 56 and a working chamber 120 of an injection regulating piston 116, and the pressure discharging chamber 122 is partitioned by an end surface 121 of the injection regulating piston 116. The working chamber 120 is arranged on a side opposite to the pressure discharging chamber 122 in the injection regulating piston 116.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection pump, which is provided with an injection adjusting piston that works to adjust the injection start timing, and the injection adjusting piston partitions a working chamber in a cylinder. The working chamber is loaded with a controllable pressure medium, the pressure medium being adapted to move the injection regulating piston against a return force, the one side being provided on the injection regulating piston. A control spool movably arranged in the axial direction of the injection adjusting piston in a cylinder hole closed by, the control spool being movable and adjustable against a spring force of a control spring by a control pressure; Further, the control spool, in the cylinder hole, via a control edge portion, a pressure medium supply unit opened to the cylinder hole, and a pressure medium lead-out unit led out from the cylinder hole, The control pipe controls the movement of the control spool, and the pressure receiving surface, which is loaded by the control pressure, controls the movement of the control spool. The present invention relates to a type of projecting into a pressure chamber isolated from the working chamber.

[0002]

A fuel injection pump of this type is known from GB 925979. In this known fuel injection pump, a cylinder hole is formed in the injection adjusting piston as an axial through hole, in which case one side of the injection adjusting piston is loaded by a control spring which projects into the cylinder hole. There is. On the other hand, the control spring is fixedly supported on the housing. The other side of the injection adjusting piston projects from the cylinder bore, is guided through the working chamber, and projects into the pressure chamber through the bore. This pressure chamber is arranged in a threaded portion which is screwed coaxially with the cylinder. The working chamber is partitioned so that the end surface of the screwed portion faces the end surface of the injection adjusting piston. The pressure chamber is loaded with a control pressure, which further passes through the axial bore through a check valve to a control edge on the control spool. Via this control edge, the working chamber is loaded with the pressure medium, unloaded or closed. This known arrangement has the disadvantage that the pressure chamber and the working chamber are directly adjacent to each other. The introduction of the control spool into the pressure chamber is troublesome because it is performed using a sleeve that is slidable along the outer peripheral surface of the control spool. The sleeve has a circumferential flange which is clamped on both sides between two sealing rings, in which case the sleeve moves laterally with respect to the axial direction of the control spool. Can be carried out. Nevertheless, there is the risk of leakage flow along the guide between the sleeve and the control spool. This leakage flow occurs especially when high pressure pulsations occur in the working chamber. This is done regularly by the cam transmission mechanism provided to drive the high pressure delivery stroke of the pump plunger. During the discharge stroke, reaction force is generated, and this reaction force is continuously propagated to the injection control piston, and the injection control piston is returned in the direction of assisting the return spring against the position generated by the hydraulic liquid. And Such pressure peaks are much higher than the height of the control pressure, which control pressure can then be influenced by the overflow fuel flowing from the working chamber to the pressure chamber. As a result, the position of the injection adjusting piston, which follows the position of the control spool, becomes unstable.

[0003]

SUMMARY OF THE INVENTION The object of the invention is to improve a fuel injection pump of the type mentioned at the outset by avoiding the disadvantageous pressure effects which result from the working chamber via the control spool, and thus the injection. The object is to provide a fuel injection pump in which unstable positions of the adjusting piston are also avoided.

[0004]

In order to solve this problem, in the structure of the present invention, the pressure release chamber is arranged between the pressure chamber and the working chamber of the injection adjusting piston, and the pressure release chamber is The work chamber is partitioned by the end face of the injection adjusting piston, and the working chamber is arranged on the side of the injection adjusting piston opposite to the pressure release chamber.

[0005]

The fuel injection pump according to the present invention has the following advantages over the conventional one. That is, the working chamber is isolated from the pressure chamber by the pressure release chamber arranged between the working chamber and the pressure chamber. When a pressure shock occurs, the leaked fuel is released and flows into the pressure release chamber, which makes it impossible to influence the control pressure and the control result.

In an advantageous construction according to claim 2, it is advantageous that the control spring is also arranged in a part of the housing fixed which is separated from the working chamber by the pressure relief chamber. This forms a compact unit that can be easily inserted from one end of the cylinder, as claimed in claim 3. In this case, it is advantageous if the control pressure in the pressure chamber is additionally influenced by an electrically controlled valve. In order to completely eliminate the influence of leaking fuel on the drive of the control spool, in an advantageous configuration according to claim 6, the spring chamber in which the control spring of the control spool is arranged is connected to the pressure relief chamber. ing. In this case, it is particularly advantageous if, as claimed in claim 5, the connection between the piston and the control spool is provided by a tappet. The tappet is frictionally connected to the control spool. As a result, it is possible to simply and effectively compensate for an error in alignment between the cylinder hole provided in the injection adjusting piston and the axis of the pressure chamber. The frictional connection between the control spool and the piston for operating the control spool in the pressure chamber is preferably provided by a retaining spring. In this case, it is also possible to load the control spool in the return direction by means of the pressure medium as described in claim 9. In order to simplify the assembly of the housing-fixed insert, this insert can be loaded either by the pressure in the relief chamber or by the support of a return spring which loads the injection regulating piston, so that the cylinder is It can be retained in a cover that closes.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

Distributor-type fuel injection pumps are equipped with axially driven pump plungers, which act as pumps, both as distributors and as pump plungers, or in a feed passage arranged in the distributor in a radial direction. It is also possible to provide a radial plunger for pumping the fuel at. FIG. 1 shows in cross section such a radial plunger pump of known construction. In the embodiment shown, four pump plungers 1 are provided, which are arranged on the distributor 2 at equal angular intervals in a common radial plane with respect to the axis of the distributor 2. It is mounted slidably in a radial bore 3 which is defined. One end face of these pump plungers 1 surrounds a common pump working chamber 4. The pump working chamber 4 is of a known type (not shown), and the pump plunger 1
Is filled with fuel through a metering device during the radial outward stroke of the pump, and is provided on the outer peripheral surface of the distributor 2 through the discharge conduit (also not shown) during the radial inward stroke of the pump plunger 1. It is connected to a distributor opening, which in this case controls a plurality of injection lines led out of the peripheral surface of the distributor 2. When the pump plunger 1 is moved inward, each injection line is supplied with fuel brought up to the injection pressure. This distributor 2 is rotationally driven by a drive shaft via drive means (not shown) such that on the one hand the distributor opening can perform its control function and on the other hand the pump plunger 1 is moved in the circumferential direction. To be done. A tappet 6 with a roller is in contact with the side opposite to the pump work chamber 4. The roller tappet 6 is driven along a cam track 7. This cam track 7 is a cam ring 8
Of the annular surface facing the distributor 2 towards the inside. The cam ring 8 constitutes a substantially stopped portion of the cam drive device of the pump plunger 1. On the other hand,
A device for moving the pump plunger 1, for example a ring 9 for guiding a roller tappet 6 connected to a drive shaft.
Form the moving part of the cam drive. The cylindrical outer wall of the cam ring 8 is guided in a corresponding cylindrical notch 10 provided in the pump housing 11 of the fuel injection pump. By adjusting this cam ring 8,
Early or late rolling of the roller 12 of the tappet 6 with rollers along each cam 13 is caused. Cam 1
3 are arranged so that all the tappets 6 with rollers are synchronously moved inward or outward by the same stroke. As a result, the start of the discharge stroke of the pump plunger 1, that is, the start of injection is changed as compared with the driving of the fuel injection pump.

The cam ring 8 has a protrusion 14 for adjustment. The projection 14 is engaged with a notch 15 provided in the cylindrical outer peripheral wall of the injection adjusting piston 16. The injection adjusting piston 16 is slidable in the cylinder 17 in a dense manner and encloses the working chamber 20 together with the closed end of the cylinder 17 on one end face 18 and on the other end face 21 on the opposite side. Cylinder 17 closed at this place
The spring chamber 22 is surrounded inside. A return spring 23 is arranged in the spring chamber 22. This return spring 23
Is supported on the one hand by a cover 24 closing the cylinder 17, and on the other hand by the other end face 21 of the injection adjusting piston 16. Therefore, the return spring 23
One end surface 18 of the injection adjusting piston 16 is connected to the cylinder 1
It is tightened in the direction of bringing the cover 7 into contact with the closing cover 25 from the opposite side.

Furthermore, the injection adjusting piston 16 is provided with an axial blind hole 27 as a cylinder hole for guiding the control spool 28. This blind hole 27 is open towards the spring chamber 22. The control spool 28 inserted at this location surrounds the pressure chamber 30 at its one end face 29 together with the closed end of the cylinder bore 27 and at the other end it projects into the spring chamber 22. At location the control spool 28 is loaded by a control spring 31. On the other hand, this control spring 31 is likewise supported by the cover 24. A connection conduit 32 extending from the one end face 18 as a starting point extends in the injection adjusting piston 16 in parallel with the cylinder hole 27. This connecting line 32 is radial,
The cylinder hole 27 is opened in the range of the overlap with the control spool 28. This opening can be closed by the annular collar 33 of the control spool 28. in this case,
The annular collar 33 separates a first annular groove 34 and a second annular groove 35 on both sides. The first annular groove 34 is the diaphragm 3
6 is connected to the pressure chamber 30 and the second annular chamber 35 is connected to the spring chamber 22 via an axial blind hole 37. The spring chamber 22 is released from pressure via a pressure release line 38. The annular edge that separates the annular collar 33 forms the control edge. This control edge allows the control spool 2
At the time of relative movement of 8, the connection conduit 32 is connected to the pressure medium supply conduit 39 via the first annular groove 34, or the second
It is connected to the spring chamber 22 via the annular groove 35. In this case, the first annular groove 34 is always connected to the pressure medium supply line 39. The pressure medium is supplied from the pressure accumulating chamber 40 to the pressure medium supply pipe 39. The fuel pump 41 works to supply the pressure medium to the pressure accumulating chamber 40. The fuel pump 41 includes a pressure control valve 42 connected in parallel. The fuel pump 41 and the pressure accumulating chamber 40 cooperate to supply pressure in a known manner. This pressure increases as the speed of the fuel injection pump or the associated internal combustion engine increases.
It increases almost in relation to the rotational speed. This pressure is always created in the pressure chamber 30 as well, in which case the control spool 28 is slid relative to the control spring 31 in response to changes in this pressure. The control spring 31 is contracted or relaxed in response to the movement of the control spool 28. The annular collar 33 exerts a control function, in which case the pressure medium is supplied to the working chamber 20 when the control spool 28 slides to the right in the drawing, which occurs when the pressure increases. , The injection adjusting piston 16 is continuously moved against the spring force of the return spring 23,
This is done until the previously opened connection line 32 is closed again. On the contrary, when the pressure in the pressure chamber 30 decreases, the working chamber 20 is released until the connecting line 32 is closed again. The pressure in the pressure chamber 30 may be relieved or regulated by a relief line 43 having an electrically controlled valve 44.

In this known device for adjusting the injection start timing, the following problems occur. That is, when the pump plunger 1 is driven, the cam ring 8 is passed through the roller 12.
An undesired force is transmitted to the injection adjusting piston 16, which in this case is the working chamber 20.
The pressure within is impulsively increased within the compressibility of the fuel, which acts as a pressure medium present at this location. This pressure is also formed in the annular collar 33, and the fuel also flows into the pressure chamber 30 due to the leakage flow through the annular collar 33, causing an increase in pressure at this location. This increase in pressure adversely affects the position of the control spool 28. As a result, an unstable characteristic of the injection adjusting piston 16 or an unstable characteristic of the entire apparatus for adjusting the injection start timing is generated.

The embodiment of the invention shown in FIG. 2 avoids the above drawbacks. Also in this case, the injection adjusting piston 11
6 is provided. The injection adjusting piston 116 has a cylinder hole 127 as in the case of the embodiment shown in FIG. A control spool 128 is also provided in the cylinder hole 127. This control spool 128
Has an annular brim 133. Injection adjusting piston 11
6 is provided with a connection line 132, which is one end surface 118 of the injection adjusting piston 116.
Is connected to a work room 120 provided in the. Ring brim 13
On the one hand, 3 partitions the chamber 46 together with the closed part of the cylinder bore 127, which chamber 46 is always connected to the pressure medium supply line 39. The other side of the annular collar 133 partitions the annular groove 135.
Reference numeral 5 corresponds to the second annular groove 35 of the embodiment shown in FIG. The annular groove 135 is connected to the spring chamber 12 via a pressure relief line 47 extending to the injection adjusting piston 116 in this embodiment.
Always connected to 2. In this spring chamber 122,
A compression spring is arranged as the return spring 123 similarly to the spring chamber 22 shown in FIG. This compression or return spring 123 loads the other end face 121 of the injection adjusting piston 116. In this spring chamber 122, the control spool 1
28 is inserted and has a pressing plate 48 at this position. A tappet 49 is in contact with the pressing plate 48. This tappet 49 is the injection adjustment piston 1
It extends coaxially with respect to the axis of 16 or the axis of the control spool 128. Furthermore, the tappet 49 projects into the insert body 51 via the axial hole 52 on the side opposite to the end surface 121 of the injection adjusting piston 116. This insert 5
1 is tightly inserted in the cylinder 17 so as to close the spring chamber 122 and also serves to support the return spring 123. A closed working cylinder 53 is arranged in this insert 51. The working cylinder 53 follows coaxially with the axial bore 52, and the working cylinder 53
The other end is closed by a plug 54. A piston 55 is slidably arranged in the working cylinder 53. The piston 55 partitions the pressure chamber 56 on the side facing the spring chamber 122 and is in contact with the tappet 49 at this location. On the other side of the piston 55,
The control spring 131 is contracted between the piston 55 and the plug body 54. The control spring 131 has the same function as the control spring 31 shown in FIG. The spring chamber 57 accommodating the control spring 131 is connected to the spring chamber 122 via the connecting conduit 58.
The spring chamber 122 also forms a pressure release chamber. In this case, a pressure relief pipe line 138 corresponding to the pressure relief conduit 38 shown in FIG. 1 is led out from this pressure relief chamber. The pressure chamber 56 is always connected to the pressure accumulating chamber 40 via the pressure medium supply pipe 139. In order to adjust the pressure in the pressure chamber 56, the shut-off throttle 6 is installed in the pressure medium supply line 139.
1 can be provided. In addition, a pressure relief line 143 corresponding to the pressure relief line 43 in FIG. 1 is led out from the pressure chamber 56. In this case, an electrically controlled valve 44 is attached to the pressure release line 143. This valve 44
Is controlled by the corresponding control device 45 in accordance with the operating parameters of the internal combustion engine for the purpose of adjusting the injection start timing.

The functional form of this device is almost comparable to that of FIG. When the control pressure changes, for example, when the control pressure increases, the piston 55 is moved against the control spring 131. Since the control spool 128 is hydraulically loaded from the chamber 46, the control spool 12
8 is followed by the piston 55 via the tappet 49,
At this time, one of the control edges opens the connection to the connection line 132. In this case, the pressure medium can flow into the working chamber 120 via the pressure medium supply line 39. As a result, the adjusting piston 116 is moved until the connecting line 132 is closed again by the annular collar 133. Conversely, when the pressure in the pressure chamber 56 decreases, the control spring 131 moves the piston 55 together with the tappet 49,
As a result, the control spool 128 is also moved. In this case,
The connection line 132 is connected via the second annular groove 135 to the pressure relief line 47 and thus to the spring chamber 122, in this case
The connecting line 132 is released toward the spring chamber 122 until the injection adjusting piston 116 is acted on by the return spring 123 and again overlaps the annular collar 133 in the connecting line 132.

The piston 55 has a pressure receiving surface larger than the pressure receiving surface provided on the chamber 46 side by the end surface of the annular collar 133. As a result, the pressure in the pressure chamber 56 also has an extremely large effect on the position of the piston 55. The chamber 4 which may also be caused by a leakage flow when the injection regulating piston 116 is subjected to a shocking load.
Pressure fluctuations within 6 are only observed on a significantly smaller scale with respect to adjusting the control spool 128. Pressure chamber 56
Is completely separated from the working chamber 120 by an intervening spring chamber or pressure release chamber 122. In particular, it is completely excluded that a high pressure flows into this pressure chamber 56 as a leakage flow and thus influences the adjustment result of the control spool 128.

FIG. 3 shows a modification of the embodiment shown in FIG. In the embodiment shown in FIG. 2, the insert 51 has a flange 63 located on the outside,
The insert 51 can be screwed to the pump housing via the flange 63. On the other hand, in the embodiment shown in FIG. 3, a cover 64 that closes the cylinder 17 is provided, and the insert 151 that protrudes into the cylinder 17 is supported by this cover 64. This insert 15
1 is formed as a stepped cylinder. This cylindrical body has a portion 65 on the cover side, the outer diameter of which coincides with the cylinder 17, and a portion 66 of a small outer diameter, which continues to this portion 65 toward the injection adjusting piston 216. A shoulder 67 is formed between the portions 65 and 66. The return spring 123 is supported on the shoulder portion 67. The small outer diameter portion 66 of the insert 151 is the injection adjusting piston 2.
It projects into 16 cylindrical notches 68, and in this case,
An end surface 69 located outside the injection adjusting piston 216,
An annular chamber 70 is formed between the insertion body 151 and the insertion body 151. A return spring 123 is enclosed in the annular chamber 70.
The annular chamber 70 forms a spring chamber 222 together with the cutout 68, and this spring chamber 222 also forms a pressure release chamber as in the embodiment shown in FIG. The insert 151 further includes the stepped hole 7
It has 1,72. The stepped holes 71, 72 are formed as through holes. Of the stepped holes 71, 72, the stepped hole portion 71 having the larger diameter is closed by the cover 64 to accommodate the piston formed as the head 73 of the tappet 149. This piston partitions the pressure chamber 156 toward the cover 64 side. This pressure chamber 15
6 is a pressure medium supply line 139 equipped with a cut-off throttle 61.
Is opened, and a pressure relief line 143 having a valve 44 electrically controlled is led out from the pressure chamber 156. On the other side of the head 73, the control spring 23
1 is supported and, on the other hand, the control spring 231 is in contact with the transition between the stepped hole portion 71 and the stepped hole portion 72. In the stepped hole portion 72 having a small diameter, the tappet 149 has a piston-shaped increased diameter portion 74. The tappet 149 is guided to the stepped hole portion 72 via the increased diameter portion 74. The portion of the tappet 149 which projects from the stepped hole portion 72 into the range of the notch 68 projects axially in this case also into the axial blind hole 227 provided in the injection adjusting piston 216, and this position To contact the control spool 228. This control spool 228 also has an annular collar 233, which in this case is arranged directly adjacent to the end of the tappet 149 and at this location the connecting line 13
Control 2 entrances. Control spool 128 annular collar 2
33 between the piston-shaped guide portion 75 of the control spool 128 and a first groove similar to the annular groove 34 shown in FIG.
An annular groove 134 is provided. This first annular groove 1
34 is always connected to the pressure medium supply pipe 39. On the other side of the guide part 75, this guide part 75 surrounds the compression spring 76 in an axial blind hole 227.
The compression spring 76 axially loads the control spool 228, in which case the control spool 228 remains in constant contact with the tappet 149. This part of the blind hole is released into the spring chamber 222 through a release hole (not shown) provided in the control spool 228 or the injection adjusting piston 216. A tappet 149 protruding into the axial blind hole 227,
An annular chamber 235 remains between the blind hole 227. Through this annular chamber 235, a connection is made to the cutout 68 when the connecting line 132 is opened. This notch 68 is provided with a spring chamber 222 for accommodating the return spring 123 and a spring chamber 222 through the flow cross section between the small diameter portion 66 of the insert 151 and the injection adjusting piston 216.
The pressure can be released to a pressure release line (not shown) derived from. Further, it is advantageous that the stepped hole portion 71 having a large diameter is also connected to the spring chamber 222 on the control spring side of the head 73.
This ensures a smooth working style of the piston or tappet 149 with the head 73.

Since the operating force of the compression spring 76 is made smaller than the operating force applied by the tappet 149, the position of the control spool 228 is mainly the head 73.
Position or tappet 149 position. This position is influenced by the pressure in the pressure chamber 156, as can be seen from the drawing. This pressure causes the head 73 to move as a piston against the spring force of the control spring 231. In this embodiment, the pressure chamber 1 is also
56 is completely isolated from the other high pressure created on the working chamber 120 side of the injection regulating piston 216. In this case, first, not only the spring chamber 222 is located between the pressure chamber 156 and the working chamber 120, but also another spring chamber 222 is provided between the spring chamber 222 and the back surface of the head 73 on the spring side. The throttle connection cross section is located. In this case, this throttle connection cross-section is formed in the stepped hole portion 71 by a radial hole provided in the smaller diameter portion 66 of the insert 151, or with respect to the notch 68, the increased diameter portion 7
4 may be formed in the flow-through cross section.

FIG. 4 shows a modification of the embodiment shown in FIG. Also in this case, the insert body 351 is held in the cylinder 17 by the cover 64 as in the embodiment shown in FIG. However, this insert 351 is formed as a generally cylindrical member.
The insert 351 has stepped hole portions 371 and 372 which are also formed as through holes. This stepped hole part 3
The larger diameter stepped hole portion 371 of 71, 372 also houses the head 373 of the tappet 349. However, the chamber formed between the head 373 and the cover 64 is formed as the pressure release chamber 77. The pressure release chamber 77 is connected to the return chamber 79 via a pipe line 78. The return chamber 79 is formed in the cylinder 17 between the insert 351 and the rear end surface 321 of the injection adjusting piston 316. In the return chamber 79, the head 3 of the tappet 349 is
The end following 73 is plunged. This tappet 349
Is the return chamber 7 through the stepped hole portion 372 having the smaller diameter.
You are guided to 9. A piston for operating the head 373 or the control spool 328 is loaded from the pressure chamber 356. This pressure chamber 356 is in this case arranged on the side opposite to the pressure relief chamber 77 in the larger diameter stepped hole portion 371, where the pressure medium is similar to the embodiment shown in FIG. It is connected to the pressure release side having the supply line 139 and the pressure release line 143. The control spring 331 used in this embodiment is arranged in the return chamber 79 and is supported axially on the one hand by the insert 351 and on the other hand by a spring bearing 80 mounted on the tappet 349.
The end of the tappet 349 also projects into the axial blind hole 227 to form an annular chamber, as in the embodiment shown in FIG. In this blind hole 227, the control spool 328 described in the embodiment shown in FIG. 3 is arranged, and this control spool 328 is similarly arranged in the connecting line 13.
2 and pressure medium supply line 39. Similarly, a compression spring 76 is also provided which holds the control spool 328 in contact with the end of the tappet 349.

In this case as well, the return chamber 79 functions as a pressure release chamber as in the case of the embodiment shown in FIG.

[Brief description of drawings]

1 is a cross-sectional view of a distributed fuel injection pump of known construction having a radially located pump plunger and a device for adjusting the injection start timing.

FIG. 2 is a sectional view showing a first embodiment of the fuel injection pump according to the present invention.

FIG. 3 is a sectional view showing a second embodiment of the fuel injection pump according to the present invention.

FIG. 4 is a sectional view showing a third embodiment of the fuel injection pump according to the present invention.

[Explanation of symbols]

1 pump plunger, 2 distributor, 3 radial holes, 4 pump working chamber, 6 tappet with roller,
7 cam tracks, 8 cam rings, 9 rings, 1
0 notch, 11 pump housing, 12 roller, 13 cam, 14 protrusion, 15 notch,
16 injection control piston, 17 cylinder, 18
End face, 20 working chamber, 21 end face, 22 spring chamber, 23 return spring, 24 cover, 25 cover, 27 blind hole, 28 control spool, 29 end face, 30 pressure chamber, 31 control spring, 32 connecting pipe line, 33 annular collar , 34 first annular groove, 3
5 Second annular groove, 36 throttle, 37 blind hole, 38
Pressure relief line, 39 Pressure medium supply line, 40 Accumulation chamber, 41 Fuel pump, 42 Pressure control valve, 43
Pressure relief line, 44 valves, 45 control device, 46
Chamber, 47 pressure relief line, 48 pressing plate, 49
Tappet, 51 Insert, 52 Hole, 53 Working Cylinder, 54 Plug, 55 Piston, 56
Pressure chamber, 57 spring chamber, 58 connecting pipe line, 61 shut-off throttle, 63 flange, 64 cover, 65
Part, 66 Part, 67 Shoulder, 68 Notch,
69 end face, 70 annular chamber, 71, 72 stepped hole portion, 73 head, 74 increased diameter portion, 75 guide portion, 76 compression spring, 77 pressure release chamber, 78 conduit, 79 return chamber, 80 spring receiver, 116 injection Adjusting piston, 118 end face, 120 working chamber,
121 end face, 122 spring chamber, 123 compression spring, 127 cylinder hole, 128 control spool,
131 Control Spring, 132 Connection Pipeline, 133
Annular collar, 134 first annular groove, 135 second annular groove, 138 pressure relief pipeline, 139 pressure medium supply pipeline, 143 pressure relief pipeline, 149 tappet, 15
1 Insert, 156 Pressure Chamber, 216 Injection Control Piston, 222 Spring Chamber, 227 Blind Hole, 228
Control spool, 231 control spring, 233 annular collar, 235 annular chamber, 316 injection adjusting piston,
321 end face, 328 control spool, 331
Control spring, 349 tappet, 351 insert, 3
56 pressure chamber, 371, 372 stepped hole portion, 373
head

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Thomas Kurder Steinheim Karl-Siegristo-Strasse 7 Federal Republic of Germany 7 (72) Inventor Hubert Greif German Groningen Platanenweg 53

Claims (15)

[Claims] 1. A fuel injection pump, which comprises an injection adjusting piston (116, 216) for adjusting an injection start time.
Is provided and the injection adjusting pistons (116, 21
6) divides the working chamber (120) in a cylinder (17), which working chamber (120) is loaded with a controllable pressure medium, which pressure medium represents the injection regulating piston (116, 216) is moved against the return force, and the injection adjusting pistons (116, 2)
16) a cylinder hole (1
27, 227) with the injection adjusting piston (116, 2)
16) A control spool (128, 2) that is movable in the axial direction
28) is arranged and the control spool (128, 2)
28) is a control spring (131, 231) depending on the control pressure.
Movement of the cylinder spool (12, 228) is adjustable against the spring force of the cylinder bore (12).
7,227) via the control edge to the pressure medium supply section (39) opened to the cylinder hole (127,227).
And a pressure medium lead-out portion (47) led out from the cylinder holes (127, 227), and the cylinder holes (127,
227) to the connection conduits (32, 132) leading to the working chamber (120), and the pressure receiving surface loaded by the control pressure for adjusting the movement of the control spool is a housing. Fixed part (51, 15
In the type which is disposed in 1) and projects into the pressure chamber (56, 156, 356) isolated from the working chamber (120), the pressure chamber (56, 156, 356) and the injection adjusting piston ( 116, 216) work room (120)
A pressure release chamber (122, 222, 77, 79) is disposed between the pressure release chamber and the pressure release chamber (122, 222, 77, 79).
Is the end surface (12) of the injection adjusting piston (116, 216).
1, 321) and the work room (12
0) is arranged on the side of the injection regulating piston (116, 216) opposite to the pressure release chamber (122, 222, 77, 79). 2. The fuel injection pump according to claim 1, wherein the control springs (131, 231) are arranged in a spring chamber (57) also provided in the housing-fixed part (51, 151). 3. A portion of the housing fixed is a pressure chamber (5
6, 156, 356) and the spring chamber (57) to close the pressure release chamber to the outside and to be formed as an insert body (51, 151) inserted in the housing of the fuel injection pump. The fuel injection pump according to claim 2, 4. The pressure chamber (56, 156, 356) is connected to both the control pressure source and the pressure relief line (143), and the valve is electrically controlled in the pressure relief line (143). (44)
The fuel injection pump according to claim 3, wherein the fuel injection pump is arranged. 5. A housing fixed portion (51, 151,
351) and the closed cylinders (53, 71, 37).
1) is formed, and the cylinder (53, 71, 17) is formed.
1), a piston (55, 73, 373) is arranged, and the piston (55, 73, 373) connects the cylinder (53, 71, 371) to the pressure chamber (56, 156, 3).
65) and a spring chamber (57; 157; 77, 79), and further the piston (55, 73, 373).
Of the tappet (49, 14
Control spool (128,228) via 9,349)
5. The fuel injection pump according to claim 1, which is frictionally connected to the fuel injection pump. 6. The piston (55, 73, 373)
A spring chamber (57) partitioned by the piston (55, 73, 373) on the side opposite to the pressure chambers (56, 156, 356) is connected to the pressure release chamber (122).
The fuel injection pump according to claim 5. 7. The fuel of claim 6, wherein the control spool (128,228) is connected to the piston (73,373) by a retaining spring (76) carried by the injection regulating piston (116,216). Injection pump. 8. The end of the control spool (128, 228) opposite the pressure relief chamber (122, 222, 79) is located within the cylinder bore (127, 227). 8. The fuel injection pump according to claim 7, which is loaded by a retaining spring (76) supported on the closed side. 9. The end of the control spool (128,228) located on the side opposite the pressure relief chamber (122,222,79) is chambered together with the closed side of the cylinder bore (127,227). Surrounding (46), the chamber (46)
9. The fuel injection pump according to claim 7 or 8, which is loaded by a pressure medium. 10. The pressure chamber (56, 356) according to claim 6, wherein the pressure chamber (56, 356) is arranged on the side of the piston (373) facing the pressure relief chamber (122, 79). Fuel injection pump. 11. The pressure chamber (156) comprises a piston (7).
The fuel injection pump according to any one of claims 6 to 9, which is arranged on the side of 3) opposite the pressure relief chamber (222). 12. The insert (51) is the insert (5).
For the purpose of fixing 1), the housing of the fuel injection pump (1
1) having a flange (63) in contact with the outside,
12. The fuel injection pump according to claim 1, wherein the fuel injection pump projects into a cylinder (17). 13. The inserts (151, 351) are tightly inserted in the cylinder (17), the return force (123, 79) loading the injection adjusting piston (216) causing the cylinder (17) to move to the outside. Fuel injection pump according to any one of the preceding claims, which is held in contact with a cover (64) that closes with respect to. 14. The fuel injection pump according to claim 1, wherein a compression spring (123) for applying a restoring force to the injection adjusting piston is arranged in the pressure release chamber (122, 222). . 15. The pressure chamber (356) is a pressure release chamber (79).
Is formed in an insert (351) inserted into the housing (11) of the fuel injection pump, which closes the valve to the outside, and a pressure chamber (356) is formed in the control pressure source and the pressure release line (14).
3) also has an electrically controlled valve (44) arranged in the pressure relief line (143) to form a closed cylinder (371) in the insert (351). The cylinder (371) has a piston (37
3) is arranged so that the piston (373) surrounds the pressure chamber (356) in the cylinder (371) on the side facing the pressure relief chamber (79) and on the opposite side the pressure relief chamber (356). 79) enclosing a chamber (77) connected to it, said piston (373) being supported by an injection regulating piston (316) via a tappet (349) closely guided from a cylinder (371). The tappet (349) is connected to the control spool (228) by a retaining spring (76) and the tappet (349) is inside the pressure relief chamber (79).
1) loaded by the control spring (331)
Is a stopper (8) provided on the tappet (349).
0) and the insert (351) is clamped and fixed between the end face wall that partitions the pressure release chamber (79).