JPS6019955A - Fuel injection pump for internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a fuel injection pump for an internal combustion engine, which comprises a pump piston ML that reciprocates within a pump cylinder and limits a pump working chamber, the pump working chamber being The compensating piston, which is guided into the cylinder under spring load, can be connected to the fuel injection conduit during at least part of the delivery stroke of the pump piston and via an extraction conduit, which also contains a throttle and a rotary nullifier. It relates to a type that can be connected to the front extraction chamber.

BACKGROUND OF THE INVENTION In a fuel injection pump known from German Patent No. 180 755 Φ, a compensation line is provided in which an outlet conduit is located coaxially with respect to the pump piston axis from the pump working chamber, also coaxially with respect to the pump piston. It extends to the extraction point in front of the piston. A rotary nullider whose axis is coaxial with the rune passage is disposed in the straddled lane conduit, and this rotary nullider is disposed in a fuel injection pump or operated by a mechanism. Ru. Such a device gently shapes the combustion course and prevents too much fuel from accumulating in the combustion chamber between the start of the first injection and the end of ignition, especially in compression ignition internal combustion engines with direct fuel injection into the combustion chamber. It is used to prevent it from burning too quickly. Such combustion results in a rapid pressure increase and, in turn, significant noise generation during combustion. The problem with this known device is that the shaft for actuating the valve must be additionally arranged in the drain line with precise guidance and a tight fit. Also, this perpendicular axis requires a large nuveine,
Furthermore, is it necessary to arrange an expensive linkage mechanism to operate this axis? This is inconvenient.

Problems to be Solved by the Invention The present invention seeks to solve the problems of the prior art devices, such as the high cost of arranging the shaft for operating the valve, and the need for a large nuvene and ancillary mechanisms.

Means for solving the problem A solution according to the invention for solving the above-mentioned problem is that the compensating piston itself is designed as a rotary slider and that a rotating device is provided to enable the axial displacement of the compensating piston. The compensating piston is provided with at least one control opening formed in the jacket wall of the compensating piston, which is permanently connected to the withdrawal chamber, and which control opening is connected to the connection of the withdrawal conduit extending from the pump working chamber to the cylinder. This may result in an overlapping situation with

Embodiments According to the embodiment of patent claim 2, the rotary mechanism or valve for shutting off the withdrawal conduit is arranged coaxially with the compensation piston to the pump piston axis, so that conventional fuel injection It can also be attached to a pump very advantageously. ? cp* This applies especially to distribution type fuel injection pumps with a reciprocating piston structure, and in such pumps, the end face is connected to the pump working chamber,
The attachment of auxiliary devices as described above is well possible.

The embodiment described in claim 3 is extremely complex.
allows for flexible structures. Furthermore, according to the embodiment of claim 5, the connection to the pump working chamber can be controlled independently of the axial position of the compensating piston.

Furthermore, according to the implementation recommendation stated in claim 6, 2
After the connection to the pump working chamber is interrupted, the pressure in the take-off chamber in front of the compensator is drained, thereby ensuring that in this off state the compensator piston is not moved into an undesired lifting position by leaking fuel. has been done. If such a piston malfunction occurs, as is known, when the compensation work is restarted, which is normally performed during the eye F' Conformity will occur.

Further, according to the embodiment described in claim 7, the drain conduit of the take-out chamber in front of the compensation piston is controlled to open immediately after the connection of the pump working chamber -\ is closed, so that the compensation 12 tons is Very little rotational momentum is required.

Operation Next, the operation of the above technical means will be explained using FIG. When the device is switched on, fuel from the pump working chamber 3 is introduced into the take-off chamber below the piston through the control opening 1g of the complementary pinuton 16, raising the piston and increasing the pressure of the injected fuel from the pump. Compensate for. When the device is subsequently switched on, the rotation of the compensating piston 16 drains the fuel in the removal chamber and returns it to its starting position for the next operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a portion of a distributor fuel injection pump. In this case, the pump piston 1 closes a pump working chamber 3 in the cylinder 2 and is given a rotary movement by means not shown, simultaneously with a reciprocating pumping movement, during which the pump piston acts as a distributor. Via a distribution groove in the jacket wall of the pump piston 1, fuel is conveyed from the pump work chamber 3 into one of several injection lines 5, which are used to supply the associated internal combustion engine with fuel. They are distributed around the cylinder 2 in accordance with the number of cylinders to be used and are guided to the respective individual injection valves 6. At the end of the injection, fuel is drained out of the pump working chamber 3 via a drain line 7 which branches off from the pump working chamber 3 and extends inside the pump piston 1, so that during the further stroke of the pump piston the fuel is drained away from this drain line 7. As soon as the opening control is activated, the displaced fuel is not discharged into the injection line 5 but via the rune line 7.

Furthermore, an extraction conduit 9 is led out from the pump working chamber 3 in the longitudinal direction of the pump 21/n 1.

This extraction conduit 9 is connected to the casing 12 of the fuel injection pump.
The static rotating device 1 is inserted into the cylinder 15 of the static rotating device 1 through a hollow screw 10 which is screwed coaxially to the pump piston axis into the head of the device and serves to fix the static rotating device 14 to the casing 12 of the injection pump. being guided. A compensating piston 16 is guided throughout the cylinder 15, and a take-out chamber 17 is closed within the cylinder 15 by the f111 surface of the compensating piston 16. A section of the extraction conduit 9 passes through a compensating piston 16 , which has a longitudinal groove 19 formed as a control opening in the outer surface of the compensating piston 16 , which can be opened via a throttle 20 into an axial bag. A blind hole 21 connected to the bore 21 starts from the end face of the compensating piston 16, which limits the removal chamber 17. At a given rotational position of the compensating piston 16, the longitudinal groove 1
9 is the process where compensation focus>16. Regardless of its position, it is connected to the connection port of the outlet conduit 9 to the cylinder 15.

Due to the longitudinal groove 19 formed in the compensating piston 16, the compensating piston 16, in addition to its function as a movable wall of the fuel storage mechanism, also has the function of a rotation nullifier.

2) the end of the compensating pin 16 opposite the extraction chamber 17 projects into the spring chamber 23 and is provided with a molded member 24;
This molded part 24 projects into a corresponding and adapted recess in the spring receiver 25. A return spring 26 is supported by the spring receiver 25, and the opposite side of the return spring 26 is supported by the opposite end surfaces of the spring chamber 23. A pin 29 is guided coaxially to the axes of the compensating piston 16 and the spring chamber 23 into a guide hole 28 of the cover 27 which is to close the spring chamber 23, and this pin 29 is connected to the spring receiver 25.
It has a small pin 30 which engages in a corresponding notch 31 of the holder. This small pin 30 is the end face 3 of the collar 33 of the pin 29.
2 , the collar 33 axially fixes the pin 29 together with a portion of the cover 27 . Furthermore, the pin 29 has a blind hole 34 starting from its end face 32, into which the molded member 2+ can be pushed until the spring receiver 25 comes into contact with the end face 32 of the collar 33. The length of the small pin 30 is such that it is in a mating connection with the spring receiver 25 in every position of movement of the small pin or the spring receiver 25, so that the compensating pin 16 is connected to the pin 29 on the outside of the casing of the silent rotation device 14. It is arranged to ensure that rotation is possible via the coupled lever 39. The other extreme position of the spring catch 25 is defined by the bottom of the spring chamber 23 or by the part of the bushing 35 provided for the guide 1 of the compensating piston 16 and having the cylinder 15 that projects into the spring chamber 23. ing. The bushing 35 is adjustable to adjust or limit the stroke of the compensating piston 16 and is connected to the outlet conduit 9 and the longitudinal groove 19.
It has a suitable opening for connection to the container. The above-mentioned molded member 24, spring receiver 25. Pin 29. Small pin 30. The bushing 35 forms a rotational mass for the compensating piston 16 .

From the spring chamber 23 a drain conduit 36 and also from the cylinder 1
5 leads out a drain line 37, the connection of which is formed as a second longitudinal groove 38 which is to be connected to the axial blind bore 21 of the compensating piston 16 in its second rotational position. It can be connected to the extraction chamber 17 through the cutout formed therein. In this second rotational position, the other recess, i.e. the longitudinal groove 19, in the compensating piston 16
does not overlap with the connection port of the extraction conduit 9 (see FIG. 2).

The operation of this silent rotation device 14 is as follows. If this silent rotation device 14 is switched on, for example during idle operation of the internal combustion engine, in order to create a gentle combustion process, then during the delivery stroke of the pump piston 1, a portion of the fuel quantity delivered by the pump piston is removed. It is sent to cylinder 15 via conduit 9. In this on state, the compensating piston 16 is in a rotational position in which its longitudinal groove 19 overlaps the connection opening of the extraction conduit 9, so that fuel is extracted from the pump working chamber 3 via the throttle 20 and the blind hole 21. It is designed to reach within. This extraction chamber 17
The pressure created therein creates an axial movement of the compensating piston 16, so that the corresponding extracted fuel is stored in the extraction chamber 17. In this case, the aperture 20 is
In conjunction with the absolute length of the discharge period of the compensating piston 16, given by its stroke H, it defines the amount of fuel to be extracted.

By turning the lever 39, this quiet rotation device 14 is simply switched off and at the same time the outlet 17 is connected to the drain line 37. In this off state, leakage fuel is therefore prevented from collecting in the removal chamber 17 and moving the compensating piston 16 into an undesired deflection (lifting) position.

FIG. 3 shows a variant embodiment of the rotating device for the compensating piston shown in FIG. In this example, the length of the extraction conduit 9 is extremely shortened, so that the undesirable gap between the pump work chamber 3 and the extraction chamber 17a can be kept as small as possible. The silent rotation device 1a in this case consists of a closing member 40 which is screwed into the head of the casing 12 of the fuel injection pump coaxially with respect to the pump piston axis and tightly closes the end face of the pump working chamber 3. ing. A bushing 41 is tightly fitted into this closing member O, and a compensating piston 16a is guided in the cylinder holder 5 with bushing +1. An end face 42 of the compensating piston 16a closes off a take-off chamber 17a in the cylinder 15. The bushing 41 is fixed in position by a cup-shaped insert 43 screwed coaxially to the axis of the compensating piston 16'a, inside which a spring chamber 23 is formed. The pin 29a also projects into the spring chamber 23 through the bottom of the insert 43. This pin 29a is rotated by means of an adjustment lever 3Q& disposed on its outer portion. A protrusion 44 is disposed on the end face of this pin 29a facing the compensation L' nut 16a, and this protrusion 44 is connected to the spatula 1. It protrudes into a correspondingly formed groove 45 corresponding to the end face of the compensating piston 15a, and allows a constant axial movement of the compensating piston 15a, and is always in a mating connection with the compensating piston 16a during this movement. . The pin 29a is surrounded by a return spring 26 supported between the inner bottom of the insert 43 and the end face of the spatula l'46.

An extraction conduit ga extends from the pump working chamber 3 to a bush 41, and at its connection point, on the wall of the bush 41,
A throttle 47 is formed which forms a radial connection to the cylinder 15.

The compensating piston 16a is formed with a longitudinal groove 48 as a control opening starting from the end face 2 of the compensating piston 16a.
This longitudinal groove 48 therefore overlaps the choke shaft 7 in a given corresponding amount of rotational position. In this position, the silent rotation device is in the on state and operates in the same manner as in the previous embodiment. When the pin 29a is rotated to stop this silent rotation device, the vertical groove 48 is inserted into the radial hole 4 in the wall of the bush +1.
9, the squeeze cow 7 is closed. A drain conduit 37a is always connected to this radial hole 4-9, and this drain conduit 37a is also connected to the spring chamber 23 via another drain conduit 36. In this rotational position, the removal chamber 17a is drained, thereby ensuring that the functioning of the silent rotation device at the time of switching on is not disturbed by the collected leakage fuel. The central arrangement of this embodiment has the great advantage that the extraction conduit 9a can be made very short.

Effects In the fuel injection pump according to the invention, the compensating piston simultaneously serves as a valve closing mechanism (rotary nullifier), and for this purpose the piston requires very few structural changes, and the rotating device for the piston is also simple. It is large and easily manufacturable. Therefore, according to the present invention, the above-mentioned problems of Mi are effectively solved.

[Brief explanation of the drawing]

The drawings show two embodiments of the invention, the first
1 is a partial vertical cross-sectional view showing the head portion of a fuel injection pump according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a control section of the compensation piston of FIG. 1, and FIG. FIG. 10 is a cross-sectional view of the control section of the compensating piston of FIG. 3; FIG. 1...Pump piston, 2...Cylinder, 3...
Pump work room, cow...distribution groove, 5...injection conduit, 6
...Injection valve, 7, 36, 37.37a...Drain conduit, 9,9a...Takeout pipe, 10...Hollow pipe,
12...Casing, 14,1Φa...Silent rotation device, 15...Cylinder, 16.16&...Compensation piston, 17.17a...Takeout chamber, 19,38.48
...Vertical groove, 20,47...Squeeze, 21,3 cow...
bag, 23... spring chamber, 24... molded member, 25
...Spring receiver, 26...Return spring, 27...Crack-228...Guide hole, 29.29&' pin, 3
0...4X pin, 31...notch, 32.4-2.
... end face, 33... collar, 35.41... bushing,
3g, 39'a... Reno ζ-14-0... Closing member, Cow 3... Insert body, 44... Projection, 45...
Groove, 46...Head, 49...Rashia FIG, 3 FIG, 4

Claims (1)

[Claims] 1. A fuel injection pump for an internal combustion engine, which has a 2-ton pump that moves back and forth within a pump cylinder and limits a pump working chamber, and the pump working chamber is a pump piston discharge pump. an extraction chamber upstream of the compensating piston guided into the cylinder under spring load via an extraction conduit which can be connected to the fuel injection conduit during at least part of the stroke and which also contains a throttle and a rotary nullifier; In the connectable version, the compensating piston (16) is itself formed as a rotating 2 rider and has a rotating device (2Φ, 25, 30, 2
9.35) is installed, and the compensation is 12 tons (1
6) is formed with at least one control opening (19) permanently connected to the withdrawal chamber, which control opening extends from the pump working chamber (3) to the cylinder (15). Fuel injection pump for an internal combustion engine, characterized in that it can be brought into overlap with a connection port of a conduit. 2. A guide element is arranged on the end face of the compensating piston (16) facing away from the removal chamber (17), which guide element correspondingly adapts the rotating device connected in the direction of the axis of the compensating piston. 2. The fuel injection pump according to claim 1, wherein the fuel injection pump is rotationally fitted and connected to the formed member. 3. the rotating device has a rotatable pin (29) arranged coaxially with respect to the axis of the compensating piston (16);
This pin [29] loads the compensation piston with a return spring (
26)
Fuel injection pump as described in section. 4. The fuel injection pump according to claim 2, wherein the guy 2 member is formed in a prismatic shape. 5. The fuel injection pump according to any one of claims 1 to 2, wherein at least one longitudinal groove (19, 38) is formed as a control surface on the compensation piston (16). . 6. The fuel injection pump according to claim 5, wherein a drain conduit (37) branches from an area of the cylinder (15) that overlaps the longitudinal area of the longitudinal grooves (19, 38). , a second longitudinal groove (38) is formed in the compensating piston (16), which is always connected to the removal chamber (17).
, in the rotational position of the compensating piston (16) in which the removal conduit (9) is to be closed, this second longitudinal groove (38) is connected to the drain conduit (37). fuel injection pump. 8. Fuel injection pump according to one of the claims 1 to 7, characterized in that the compensation 12 tons is positioned axially parallel to the axis of the pump piston (1). 9. The casing receiving the compensating piston (16a) and the rotating device for the compensating piston is located in the pump working chamber (3),
9. Fuel injection pump according to claim 8, characterized in that it is formed by a closing member (circle) inserted into the casing (12) of the fuel injection head. 10. The fuel injection pump according to any one of claims 1 to 9, wherein the fuel injection pump is a distribution type injection pump having a reciprocating structure.