JP3056263B2 - Fuel injection pump used for internal combustion engine - Google Patents

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 for use in an internal combustion engine, which is provided with a pump plunger for limiting a pump working chamber, and the pump plunger reciprocates via a cam transmission. The pump working chamber is filled with fuel through an inlet controlled in relation to the rotation angle by the pump plunger during a suction stroke. Discharges fuel under injection pressure from the pump working chamber to a plurality of pressure conduits connected to the injection valves, respectively, in a compression stroke or a discharge stroke, and further includes an injection regulator. ,
The injection regulator is adapted to shift the position of a stroke curve constituted by the pump plunger with respect to the rotation speed of the pump plunger with respect to the rotation position of the pump plunger, and to increase the rotation speed. And a shift in the direction of "early" in the direction of "early" and with the decrease of the rotation speed in the direction of "late".

[0002]

2. Description of the Related Art In a fuel injection pump of this type having a distributing structure (DE-A-2,503,345), a drive in which a pump plunger rotates via a cam transmission synchronously with a camshaft of an internal combustion engine. Driven by a shaft, the pump plunger rotates with the drive shaft and simultaneously performs an axial stroke movement. In this case, the stroke of the pump plunger is defined by the cam geometry of the cam transmission in relation to its angle of rotation. In such a cam transmission, a cam disposed on an end face of a cam plate which is non-rotatably connected to the pump plunger rolls on rollers of a roller ring supported by the pump casing by receiving spring pressure. . The pump working chamber limited by the pump plunger is directly connected to the inlet controlled by the pump plunger, in which case the pump plunger is usually shifted by the same number of rotations by a number corresponding to the number of pressure conduits. A filling groove or suction slit, which is arranged on the outer peripheral surface and opens toward the pump working chamber, is adapted to coincide with at least one opening of a suction passage leading to the fuel-filled pump inner chamber. . This opening is located directly inside the cylinder sleeve containing the pump plunger, directly facing the pump plunger. In each suction stroke of the pump plunger, one of the suction slits matches the opening, whereas in each discharge stroke of the pump plunger, the suction slit is shielded by the hole wall of the cylinder sleeve. , Said opening is blocked by a pump plunger. Normally, the suction slit is arranged so as to be shielded in the rotation range of the bottom dead center of the pump plunger, that is, the rotation range of the pump plunger when the pump plunger stays at the bottom dead center position. At the start of the stroke, the pump work chamber is closed.

In order to adjust the optimum combustion value of the internal combustion engine, during operation of the fuel injection pump, an injection regulator acting on the roller ring of the cam transmission to rotate the roller ring acts on the axial direction of the pump plunger. The correspondence between the stroke and its rotational position is changed in relation to the rotational speed of the internal combustion engine and the rotational speed of the pump plunger rotating synchronously with the internal combustion engine. In this case, at a high rotational speed, the stroke curve of the pump plunger is shifted in the "early" direction with respect to the rotational position of the pump plunger, and is shifted in the "late" direction when the rotational speed decreases. The possible injection adjustment range is defined by the bottom dead center rotation range of the pump plunger. The inlet must be closed to the pump working chamber at the start of the discharge stroke at all positions of the pump plunger's stroke curve with respect to the rotational position of the pump plunger;
This is because, in order to ensure a sufficient fuel filling of the pump working chamber, the inlet at all possible positions of the stroke curve must not already be closed within the descending edge of the stroke curve. Especially in the case of fuel injection pumps used in 5- or 6-cylinder internal combustion engines, the injection adjustment range is often too small in order to obtain the optimum combustion value of the internal combustion engine. Therefore, a compromise is made by reducing the cam length of the cam provided in the cam transmission. However, in this case, the cam parameters "speed progress" and "stroke"
Is exacerbated by the injection adjustment range.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve a fuel injection pump of the type mentioned at the outset to increase the injection adjustment range in a constant cam geometry without deteriorating the cam parameters. Another object of the present invention is to provide a fuel injection pump in which an optimum combustion value of the internal combustion engine can be obtained by increasing the cam length in a constant injection adjustment range.

[0005]

In order to solve this problem, in a first configuration of the present invention, a space between an inlet controlled by a pump plunger and a pump working chamber is provided from the pump working chamber to the inlet. A check valve having a shut-off direction is arranged, and a control mechanism of the inlet by a pump plunger closes the inlet within the range of the bottom dead center position of the pump plunger at a position where the stroke of the stroke is delayed. The inlet is closed at an early position of the stroke curve within the rising edge of the stroke curve.

Further, in order to solve the above-mentioned problem, in a second configuration of the present invention, the pump working chamber is directly connected to the inlet, and the control mechanism of the inlet by the pump plunger is such that the pump plunger has its stroke curve. At least in a retarded position, the inlet being closed within the descending side edge of the stroke curve and controlled in relation to the stroke by a pump plunger to fill the pump working chamber with fuel. And a second inlet connected to the pump working chamber via a check valve having a shut-off direction from the pump working chamber to the second inlet. The control of the second inlet by the plunger is such that the stroke between the position of the pump plunger at its bottom dead center and the stroke at which the first inlet closes at a later position of the stroke curve. And so it is configured to maintain the state of being open the second inlet in circumference.

[0007]

The fuel injection pump according to the present invention has the following advantages over the conventional one. That is, due to the additional check valve, which in this case is regarded as a suction valve, and the corresponding inlet control mechanism of the pump plunger, the injection adjustment range is significantly increased in a constant cam configuration to obtain an optimum combustion value. Or vice versa, it is possible to increase the cam length of the cams provided on the cam transmission in the already sufficiently large injection adjustment range, so that the cam parameters can be improved. The suction valve that is required in both cases has the disadvantage that it may indeed be polluted and become less dense, but the less dense suction valve will continue to run due to the reduced power of the internal combustion engine. The possibility of finding a maintenance shop.

[0008] In the configuration according to the first aspect of the present invention, that is, in the first configuration, the inlet control mechanism and the suction valve are connected in series. The benefit of the injection adjustment range (SPV range) or cam length is due to the fact that the inlet control at the cam is performed at the advance position of the stroke curve (SPV advance position).
That is obtained by the inlet is still open for the rotation angle alpha ₁ in rising edge of the stroke curve of the pump plunger. This rotation angle α ₁ is set at the SPV early position,
In other words, it is large at a high rotation speed and is reduced to 0 at the SPV delay position. However, since the suction valve closes the pump working chamber towards the inlet at the beginning of the discharge stroke of the pump plunger, there is no difference in the fault-free operation from the previously known inlet control mechanisms. When the suction valve is not closed on the basis of the contamination or other defects, fuel not discharged in the rotation angle range alpha ₁ of the pump piston, the inlet is discharged first is closed by the pump piston. If the amount of injection discharged in the remaining residual discharge stroke of the pump plunger is not sufficient for the demand of the internal combustion engine, the rotation speed of the internal combustion engine decreases, and thus the rotation speed of the drive shaft and the rotation speed of the pump plunger of the fuel injection pump. And decrease. As a result, the injection regulator shifts the position of the stroke curve of the pump plunger with respect to the rotation angle of the pump plunger in the "slow" direction. Thereby, the angle range α ₁ is reduced to zero. The injection quantity discharged by the pump plunger increases, and it is possible to continue running at a low rotational speed of the internal combustion engine.

In the configuration according to the third aspect of the present invention, that is, in the second configuration, the inlet control mechanism is connected in parallel with the series connection of the suction valve and the previous stroke control mechanism. The inlet communicates directly with the pump working chamber as before. However, the inlet control is certainly not set at the cam rising process, that is, at the rising edge of the stroke curve of the pump plunger.
However, it is designed such that the cam descends at the late position of the stroke curve, that is, closes at the descending edge of the stroke curve of the pump plunger. The advantage of the injection adjustment range or cam length is obtained on the basis of such a forward shift of the closing timing of the inlet control in the SPV retard position. The remaining fuel filling of the pump working chamber after the closing of the inlet control mechanism takes place via a second inlet leading to the pump working chamber. This second inlet is controlled in relation to the stroke by the pump plunger (pre-stroke control).
For this purpose, a second inlet is provided during the suction stroke during the SPV
In the late position, the first inlet opens in the stroke position of the closing pump plunger and closes again in this stroke position if the same stroke position is achieved by the pump plunger during the discharge stroke. The suction valve connected in series with the second inlet prevents the pump working chamber from being partially discharged through the open second inlet during the discharge stroke over said stroke distance until the second inlet closes. It is blocking.

[0010] Such discharge, however, occurs when the intake valve becomes less dense due to a fault. However, the residual discharge remaining in the pump working chamber after the closing of the second inlet allows the internal combustion engine to continue to operate at a low rotational speed, which still offers the possibility of continuing to the garage. .

The advantage of the second configuration over the first configuration of the invention is that not all of the filling volume for the pump working chamber flows through the suction valve, but at high rotational speeds the filling by the suction valve is completely complete. It's gone. Therefore, this suction valve is hardly loaded and the risk of contamination is relatively small. However, there is a disadvantage in that a suction valve that is not dense cannot obtain a sufficient injection amount even at a low rotation speed.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

A fuel injection pump of a distribution type structure used in a four-cylinder internal combustion engine shown in a longitudinal sectional view in FIG.
A cylinder sleeve or a pump cylinder 11 is inserted into a pump casing 10. A pump plunger 12 is inserted in a cylinder hole provided in the pump cylinder.
Are driven by a drive shaft 13 synchronized with the camshaft of the internal combustion engine and a known cam transmission 14 in a reciprocating and simultaneously reciprocating motion. The pump plunger 12 and the pump cylinder 11 define a pump working chamber 15 which, during the suction stroke of the pump plunger 12, communicates via a suction passage 16 with a fuel-filled pump inner chamber or a pump suction chamber 17. Is filled with fuel.
Fuel is supplied to the pump suction chamber 17 from a fuel storage container 19 by a fuel feed pump 18. The fuel in the pump suction chamber 17 is under a pressure which is related to the rotational speed, which pressure is additionally regulated by a pressure control valve 20.

The end of the pump plunger 12 which faces the pump working chamber 15 protrudes into a pump suction chamber 17, at which point via a cam transmission 14,
It is connected to a drive shaft 13 supported on the pump casing 10. The cam transmission 14 is of a known type,
1 is supported by the pump housing 10 so as to be rotatable by a defined angle. An end cam plate 23 is fixed to the pump plunger 12, and the end cam plate is a surface having an end cam 24, and rolls on the roller 21 by receiving an axial spring pressure. In this case, a pawl clutch 25 is provided in an inner bore provided in the roller ring 22, which is shown twisted by 90 ° in the plane of the drawing, in which a drive coupled to the drive shaft 13 is provided. Side pawl 26
Are engaged inwardly and outwardly with a driven side pawl 27 provided on the pump plunger 12, in which case the pump plunger 12 can perform its stroke motion during rotation independently of the drive shaft 13. it can.

The roller ring 22 is connected via an adjusting pin 28 to an injection adjusting piston 29 provided in the injection adjuster 30.
And the injection regulator is shown in FIG. 1 also twisted in the plane of the drawing by 90 °. An injection adjustment piston 29 slidable axially in a tangential direction with respect to the roller ring 22 is loaded by a return spring 31 in one movement adjustment direction and is provided in the injection adjuster 30 in the other movement adjustment direction. The pressure in the control room 32 is loaded. The pump suction chamber 17 via the throttle 58
As the pressure in the control chamber 32 connected to
The injection adjusting piston 29 moves against the action of the return spring 31 to rotate the roller ring 22. In this case, the end cam 24 of the end cam plate 23 moves with respect to the rotational position of the pump plunger 12 or the drive shaft 13. As a result, the pump plunger 12 engages with the roller 21 earlier, whereby the start of the stroke of the pump plunger 12 and, consequently, the start of the discharge of fuel are performed earlier than the rotational position of the pump plunger 12. Pump plunger 1
The stroke curve h performed by this pump plunger in relation to a rotation angle α of 2 is shown in FIG. 5, where the curve a, shown as a solid line, is slow for each rotational position of the pump plunger 12. A curve b indicated by a dash-dot line in the stroke position at the first position represents a stroke curve at the early position. In the retard position of the stroke curve h, also called the SPV retard position, the injection adjusting piston 29 of the injection adjuster 13 is located at the basic position under the action of the return spring 31, whereas the SPV advance position Here, the adjusting piston is shifted by a defined distance against the force of the return spring 31.

Inside the pump suction chamber 17, a ring slider 33 for controlling the injection amount is slidably mounted on the pump plunger 12 in an axially slidable manner. ), Which is actuated in a known manner via an associated control lever 34, in which case the outlet opening of a transverse bore 35 provided in the pump plunger 12 is controlled. This transverse hole 35 is connected to a longitudinal hole 36 provided in the pump plunger 12 which enters the end face of the pump plunger 12 which limits the pump working chamber 15 and ends as a blind hole. ing. A radial hole 37 further branches off from the longitudinal hole 36, and this radial hole communicates with a distribution groove 38 provided on the outer peripheral surface of the pump plunger 12. This distribution groove 38
At the same height, four pressure conduits 39 are opened in the cylinder bore of the pump cylinder 11 at the same rotational angle, and these pressure conduits are
And is connected to the injection valve 41 via the. Of the plurality of pressure conduits 39 provided with the check valve 40 and the injection valve 41, only one pressure conduit 39, the check valve 40 and the injection valve 41 are respectively recognized in FIG. During each compression stroke or each discharge stroke of the pump plunger 12, the fuel under injection pressure in the pump working chamber 15 is filled with longitudinal holes 36, radial holes 37 and distribution grooves 3.
The fuel is discharged into one of a plurality of pressure conduits 39 through 8 and the fuel is injected into the combustion chamber of the internal combustion engine via an injection valve 41 from this location. After one complete rotation of the pump plunger 12, all four pressure conduits 39 are controlled once in turn for each discharge stroke.

In order to fill the pump working chamber 15 with fuel during each suction stroke, an inlet 42 controlled by the pump plunger 12 in relation to the rotation angle is provided between the suction passage 16 and the pump working chamber 15; A check valve 43 having a shut-off direction from the pump working chamber 15 to the inlet 42 (hereinafter referred to as a check valve 43).
(Referred to as a suction valve 43). The control mechanism of the inlet 42 by the pump plunger 12 is such that the pump plunger 12 closes the inlet 42 in the range of the bottom dead center when the stroke curve is at the late position (curve a in FIG. 5), and moves the stroke curve to the advanced position (FIG. In curve b) of 5, the inlet 42 is closed within the rising edge of this stroke curve. FIG. 5 shows the rotation angle when the inlet 42 is closed by the pump plunger 12 with the symbol α _S.

As can be clearly seen from the enlarged longitudinal sectional view of the fuel injection pump shown in FIG. 2, the inlet 42 is provided in an annular groove 44 provided on the outer peripheral surface of the pump plunger 12 and also in the pump plunger 12. It is formed by an inlet slit 45 connected to said annular groove and four hole openings 46 provided in the cylinder bore of the pump cylinder 11 (corresponding to the number of cylinders of this internal combustion engine). 4 above
The two hole openings form the outlet openings of four radial holes 47 introduced into the pump cylinder 11 offset by the same angle. All radial holes 47 are pump cylinder 1
1 are connected to each other by an annular groove 48 provided on the peripheral surface. In the annular groove 48, a suction passage 16 connected to the pump suction chamber 17 is opened. Pump plunger 1
The annular groove 44 provided in 2 coincides with the opening 49 of the connection hole 50 extending toward the pump working chamber 15 by the pump plunger 12. The connection hole 50 penetrates a valve body 51 mounted on an end face of the pump cylinder 11 and closing the pump working chamber 15, and forms a valve chamber 53 surrounded by the valve body 51 and the cover cap 52. It is open. A valve seat 54 is formed in a passage penetrating the valve body 51 and extending in a hopper shape from the pump working chamber 15 to the valve chamber 53, and the valve seat cooperates with a valve member 55. This valve seat member is pressed against the valve seat 54 by a valve closing spring 56. Since the valve member 55 supports the pressure receiving surface 57 on the side opposite to the pump working chamber 15, the valve member 55
Can be opened toward the pump working chamber 15 by the pressure in the valve chamber 53. Valve element 51 with cover cap 52
And a valve member 55 having a valve seat 54 and a valve closing spring 56 form the suction valve 43.

During each suction stroke, the pump plunger 12 draws fuel from the pump suction chamber 17 at the open inlet 42 via the suction passage 16 and the open suction valve 43, so that the subsequent pump plunger In the discharge stroke of 12, the pump working chamber 15 is filled with fuel. Since the ring slider 33 closes the outlet opening of the transverse bore 35, the fuel located in the pump working chamber 15 is brought to a high pressure and then the longitudinal bore 36, the radial bore 37 and the distribution groove 38 Via one of a plurality of pressure conduits 39. After the stroke of the pump plunger 12 defined by the position of the ring slider 33, the lateral hole 35 advances from the blocking state, and the pump working chamber 15 is connected to the pump suction chamber 17 via the longitudinal hole 36 and the lateral hole 35. When the pressure is released toward the end, the discharge stroke of the pump plunger 12 ends. The discharge pressure of the pump plunger 12 is
, The high pressure injection is interrupted.

In order to improve the combustion value of the internal combustion engine, the stroke curve of the pump plunger 12 is reduced by the injection regulator 30 with respect to its rotational angular position, in the direction of "early" (SPV advance position) at higher rotational speeds. The rotation speed is shifted in the direction of “late” (SPV delay position).
This is illustrated in FIG. 5 by the rotation angle α of the pump plunger 12.
And curves h and a drawn in relation to the stroke progress h. The reference SPV indicates the effective injection control range, which is sufficient for obtaining optimum combustion values at optimum cam parameters (speed profile and pump plunger stroke). .
As can be clearly seen from FIG. 5, in the SPV early position, the inlet 42 is still open at the beginning of the discharge stroke of the pump plunger 12 (the rising side edge of the stroke curve h).
In this range, the suction valve 43 controls the pump working chamber 1
5 prevents backflow into the suction channel 16 again through the inlet 42 which is still open. Suction valve 4
Based on such a structural design of the inlet control mechanism in conjunction with 3, the injection adjustment range SPV is increased by the range α ₁ (FIG. 5) compared to the conventional inlet control mechanism under a constant cam configuration. be able to. Without inlet valve 43, while the discharge stroke of the pump piston 12 does not start, that is, in the bottom dead center rotational range of the pump piston 12 which is defined by the scope SPV minus alpha ₁ in Figure 5, the pump plunger 12 to inlet 42 It will be closed.

FIG. 5 shows, by means of a curve c, the stroke h in a conventional inlet control without an additional suction valve 43 connected in series, which is also of the same magnitude. The fuel injection adjustment range SPV is realized. It can be clearly seen that the end cam 24 provided on the end cam plate 23 has to be made shorter, but this results in a smaller stroke and a smaller stroke speed of the pump plunger. Cam parameters are degraded. In the same injection adjustment range SPV, the inlet control mechanism of the fuel injection pump according to the invention using the additional suction valve 43 allows the cam length to be increased by Δα. With a larger cam length, the cam parameters are better in the constant-size injection adjustment range SPV.

The fuel injection pump shown in FIG.
It works satisfactorily unless the function of 3 is faulty. If the suction valve 43 no longer reliably closes due to contamination or other defects, no fuel is discharged in the rotation angle range α ₁ during the discharge stroke of the pump plunger 12 and the inlet 42 is closed by the pump plunger 12. , The fuel is discharged for the first time. If the residual discharge amount remaining in the residual discharge stroke of the pump plunger 12 is insufficient for the demand of the fuel injection pump, the rotation speed of the fuel injection pump decreases, and thus the rotation speed of the drive shaft 13 also decreases. Would. The pressure in the pump suction chamber 17 decreases. As a result, the injection regulator 30 shifts the stroke curve of the pump plunger 12 to a later position. As a result, the angle range α ₁ is reduced to zero. The fuel injection amount discharged by the pump plunger 12 increases, and it becomes possible to continue running at a low rotational speed of the internal combustion engine. Vehicles can find a garage without getting stuck.

FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2, showing a variation of the inlet 42 shown in FIG. In this case, the inlets 42 ′ are provided in four inlet slits 45 ′ arranged on the outer peripheral surface of the pump plunger 12 at the same rotation angle and a radial hole 47 ′ provided in the pump cylinder 11. It is formed by only one hole opening 46 'which coincides with the entrance slit 45'. In this case, the inlet slits are each connected to an annular groove 44, and the radial holes are connected to the suction passage 16. An annular groove 44 is likewise provided in the pump cylinder 1 in a connection hole 50 leading to the pump working chamber
It matches the opening 49 provided in one cylinder hole. FIG.
Is controlled in the same manner as described above.

In a fuel injection pump according to another embodiment shown in a longitudinal sectional view in FIG. 4, components corresponding to those in the fuel injection pump shown in FIGS. 1 and 2 have the same reference numerals. In this case, the inlet 60, which is located between the suction passage 16 and the pump working chamber 15 and is controlled in relation to the rotation angle by the pump plunger 12,
It is located just before. The inlet consists of four suction slits 61, which are distributed along the outer peripheral surface of the pump plunger 12 at equal rotational angular distances, each of which has a pump working chamber at the end face of the pump plunger 12. 15 is open. The suction slit 61 is aligned with an opening 62 of the radial hole 63 introduced into the pump cylinder 11 and the cylinder hole of the pump cylinder 11. The radial hole 63 is a large diameter blind hole 64 provided in the pump cylinder 11.
The blind hole is connected to the suction passage 16. The control mechanism of the inlet 60 by the pump plunger 12 is such that the pump plunger 12 closes the inlet 60 within the descending side edge of this stroke curve at the retarded position of the stroke curve with respect to its rotational angle position (SPV retarded position). It is configured. The stroke curve h of the pump plunger is shown in FIG. 6, where the SPV retard position is indicated by the solid line by curve a and the SPV advance position is indicated by the dash-dot line by curve b. The rotation angle of the pump plunger 12 when the inlet 60 closes is denoted by α _S. In the SPV early position (curve b), the closing timing of the inlet 60 is located in the bottom dead center rotation range of the pump plunger 12.

A second inlet 66 is provided parallel to the first inlet 60 and leading to the pump working chamber 15, which is connected between the suction passage 16 and the pump working chamber 15. , Connected in series with the suction valve 43 and controlled by the pump plunger 12 in relation to the stroke. The second inlet 66 has an annular groove 67 provided on the outer peripheral surface of the pump plunger 12, which has a radial hole 69 introduced on the one hand through a blind hole 64 provided in the pump cylinder 11. Of the connection hole 50 on the other hand. This connection hole communicates with the pump working chamber 15 via the suction valve 43 as described in FIG. The suction valve 43 is constructed in the same way as described with reference to FIG. A radial hole 69 having a hole opening 68 is provided in an annular groove 67 provided in the pump plunger 12.
Are arranged as follows. That is, the radial bore is calculated from the bottom dead center position of the pump plunger 12 connected to the annular groove 67 over a stroke distance h _V of the pump piston 12, the second inlet 66 is opened by this stroke distance h After traveling _V , the annular groove 67 advances out of the hole opening 68 so that the pump plunger 12 closes the second inlet 66. The stroke distance h _V is defined so that the pump plunger 12 takes a stroke position such that the first inlet 60 closes during the suction stroke of the pump plunger 12 at the SPV delay position. Based on such a front stroke control mechanism formed by the second inlet 66, with the closing of the first inlet 60 at the descending edge of the stroke curve at the SPV retard position,
The pump working chamber is now completely filled with fuel by the now open second inlet 66 and the suction valve 43. The subsequently discharge stroke to be performed, in the first inlet 60 is closed, the second inlet 66 is open to the pump plunger 12 advances the stroke distance h _V. During this pre-stroke h _V,
Since the pump working chamber 15 is shut off by the closed suction valve 43 against the open second inlet 66, fuel cannot flow out of the pump working chamber 15 and the pump plunger 12 has its bottom Start discharging from the point. With such a configuration, a large injection adjustment range can be obtained. This large injection adjustment range is indicated in FIG. 6 by the symbol SPV. This injection adjustment range is made larger by the rotation angle range α ₁ of the pump plunger 12 than the fuel injection pump having the same cam design of the cam transmission and the conventional inlet control mechanism. Curve c shown by a broken line in FIG.
A pump plunger of a fuel injection pump with a conventional inlet control mechanism, that is to say a cam transmission with a correspondingly short end cam to obtain an injection adjustment range SPV of the same size, is provided. It represents the progress of the process. In the case of conventional inlet control mechanisms, this large injection adjustment range SPV obviously has a disadvantageous effect on the cam parameters. In the fuel injection pump shown in FIG. 4, the same size of the injection adjustment range SPV is obtained by the cam transmission device 14 in which the cam length is formed larger by the angle range Δα and the cam parameters are greatly improved. .

The fuel injection pump shown in FIG.
It works satisfactorily unless the function of 3 is faulty. When the suction valve 43 is no longer closed reliably based on the contamination, the fuel not discharged before the time of the discharge stroke in the stroke range h _V. A portion of the fuel located in the pump working chamber 15 has an open suction valve 43 and an open second inlet 66.
Through the suction passage 16. With the closure associated with the stroke of the second inlet 66 by the pump plunger 12, the remaining fuel quantity is transferred from the pump work chamber 15 to one of the connected pressure conduits 39. This injection amount is sufficient to operate the internal combustion engine at a low rotation speed and a low output, so that the vehicle can continue to travel until it reaches a maintenance shop.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a fuel injection pump according to the present invention in a partially sectional view.

FIG. 2 is an enlarged longitudinal sectional view of the fuel injection pump shown in FIG.

FIG. 3 is a view showing a modified embodiment of the fuel injection pump, which is cut along a line III-III in FIG. 2;

FIG. 4 is a longitudinal sectional view of a fuel injection pump according to another embodiment.

FIG. 5 is a diagram showing a stroke progress related to a rotation angle of a pump plunger in the fuel injection pump shown in FIG. 2;

FIG. 6 is a diagram showing a stroke progress related to a rotation angle of a pump plunger in the fuel injection pump shown in FIG. 4;

[Explanation of symbols]

REFERENCE SIGNS LIST 10 pump casing 11 pump cylinder 12 pump plunger 13 drive shaft 14 cam transmission device 15 pump working chamber 16 suction passage 17 pump suction chamber 18 fuel feed pump 19 fuel storage container 20 pressure control valve 21 roller 22 roller ring 23 end face cam plate 24 end face Cam 25 pawl clutch 26,27 pawl 28 adjustment pin 29 injection adjustment piston 30 injection adjuster 31 return spring 32 control chamber 33 ring slider 34 control lever 35 lateral hole 36 longitudinal hole 37 radial hole 38 distribution groove 39 pressure conduit 40 Check valve 41 Injection valve 42, 42 'Inlet 43 Suction valve 44 Annular groove 45, 45' Inlet slit 46, 46 'Hole opening 47, 47' Radial hole 48 Annular groove 49 Opening 50 Connection hole 51 Valve body 52 Cover cap 53 Valve chamber 54 Valve seat 55 Valve member 56 Valve closing spring 57 Pressure receiving surface 58 Restrictor 60 Inlet 61 Suction slit 62 Opening 63 Radial hole 64 Blind hole 66 Inlet 67 Annular groove 68 Hole opening 69 Radial hole 70 Opening α, α _S rotation Angle α, Δα Angle range h Stroke curve h _V Stroke distance a, b, c Curve

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Helmut Laufer Germany Germany Gerlingen Otto Shepfer Strasse 12 (56) References JP-A-57-212361 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 41/12

Claims (5)

(57) [Claims] 1. A fuel injection pump for use in an internal combustion engine, comprising a pump plunger for limiting a pump working chamber, wherein the pump plunger reciprocates and rotates simultaneously with a cam transmission. Drivable to fill the pump working chamber with fuel during an intake stroke via an inlet controlled by the pump plunger in relation to a rotation angle, and further comprising a pump stroke or a discharge stroke. Then, the fuel under the injection pressure is discharged from the pump working chamber to a plurality of pressure conduits respectively connected to the injection valves, and further, an injection regulator is provided, and the injection regulator is provided. In relation to the rotation speed of the pump plunger, the position of the stroke curve constituted by the pump plunger is determined by the rotation position of the pump plunger. Pumps of the type that is designed to shift relative to the position, and to shift in the "early" direction as the rotational speed increases and in the "late" direction as the rotational speed decreases. Plunger (1
2) a check valve (43) having a shut-off direction from the pump working chamber (15) to the inlet (42) between the inlet (42) controlled by 2) and the pump working chamber (15);
The control mechanism of the inlet (42) by the pump plunger (12) operates the pump plunger (1).
2) closes the inlet (42) in the range of the bottom dead center of the same pump plunger (12) at the late position of the stroke curve, and within the rising edge of the stroke curve at the early position of the stroke curve. A fuel injection pump used in an internal combustion engine, wherein the fuel injection pump is configured to close the inlet (42). 2. The check valve (4), wherein the inlet (42) is connected to the check valve (4).
An annular groove (44) provided on the outer peripheral surface of the pump plunger (12), which coincides with the opening (49) of the connection hole (50) communicating with the pump working chamber (15) through 3); An inlet slit (45) arranged on the outer peripheral surface of (12) and a plurality of the pump plungers corresponding to the number of pressure conduits (39), which are aligned with the inlet slit and are shifted by an equal rotation angle from each other. Or a plurality of said pump plungers (12) corresponding to the number of pressure conduits (39) formed by or with one bore opening (46 ') defined by the bore opening (46). And an inlet slit (45 ') provided on the outer peripheral surface of the pump plunger (45') so as to be shifted by an equal rotation angle to each other. It said annular groove provided in 2) (4
4), and is connected to the hole opening (46; 46 ').
2. The fuel injection pump according to claim 1, wherein the fuel injection pump is connected to a suction passage leading to the fuel supply chamber. 3. A fuel injection pump for use in an internal combustion engine, comprising a pump plunger for limiting a pump working chamber, wherein the pump plunger reciprocates and rotates simultaneously with a cam transmission. Drivable to fill the pump working chamber with fuel during an intake stroke via an inlet controlled by the pump plunger in relation to a rotation angle, and further comprising a pump stroke or a discharge stroke. Then, the fuel under the injection pressure is discharged from the pump working chamber to a plurality of pressure conduits respectively connected to the injection valves, and further, an injection regulator is provided, and the injection regulator is provided. In relation to the rotation speed of the pump plunger, the position of the stroke curve constituted by the pump plunger is determined by the rotation position of the pump plunger. Pumps of the type that is designed to shift relative to the position, and to shift in the "early" direction as the rotational speed increases and in the "late" direction as the rotational speed decreases. The working chamber (15) is directly connected to the inlet (60), and the control mechanism of the inlet by the pump plunger (12) is such that the pump plunger (12) is at least at a later position of the stroke curve. The pump working chamber (1) is configured to close the inlet (60) within the descending side edge.
5) Pump plunger (12) to fill fuel
Second inlet (66) controlled in relation to the stroke by
And the second inlet is connected via a check valve (43) having a shut-off direction from the pump working chamber (15) to the second inlet (66). 1
5), wherein the control mechanism of the second inlet (66) by the pump plunger (12) is such that the pump plunger (12) is in the first position at its bottom dead center position and at the later position of the stroke curve. characterized in that it is configured to maintain the state of being open the second inlet (66) in the stroke range (h _V) between the stroke position when the inlet (60) is closed, the internal combustion engine Fuel injection pump used for 4. The said second inlet (66) coincides with the opening (70) of a connection hole (50) leading to the pump working chamber (15) via the check valve (43). An annular groove (6) provided on the outer peripheral surface of the pump plunger (12)
7) and the fuel supply chamber (1) corresponding to the annular groove (67).
7) and a hole opening (6) connected to the suction passage (16).
8), the annular groove (67) being opposed to the openings (68, 70) located around the pump plunger, to close the first inlet (60) at a position where the stroke curve is delayed. wherein the stroke distance of the pump piston, calculated from the bottom dead center position of the pump plunger, which is defined by the timing (12) (h _V) both openings (68,7
4. The fuel injection pump according to claim 3, wherein the fuel injection pump is arranged to exit from 0). 5. A cylinder sleeve (1) held by a pump plunger (12) in a pump casing (10).
1), a check valve (43) is arranged on a valve body (51) closing the cylinder sleeve (11) on the end face side, and the valve body is disposed on the pump casing (1).
5. The fuel injection pump according to claim 1, wherein the fuel injection pump is fixed to 0).