JPH10231762A - Distribution type fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sufficient advance phase without being dependent upon a timer device when an engine is started, and enhance an oil feeding rate at the time of middle and low loads while a driving torque at the time of a high load is suppressed not to exceed an allowable value even after starting, in an inner cam mode fuel injection pump. SOLUTION: An inflow/outflow port 31 which sucks and cuts off fuel, is formed in a rotor rotated by being synchronized with an engine, a passing hole 40 which can be communicated with the inflow/outflow port 31 is formed in a control sleeve, and two slant edges which are inclined from a virtual line running parallel with an axial line to an opposite side, are respectively formed at the opening edges of the inflow/outflow port 31 and the passing hole 40. Slant edges 31a, 40a which are crossed each other when the inflow/outflow port 31 and the passing hole 40 are finished to be communicated with each other are formed in parallel with each other, and also slant edges 31b, 40b which are crossed each other when the inflow/outflow port 31 and the passing hole 40 are started to be communicated with each other are formed in parallel with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distribution type fuel injection pump for pumping fuel injected to an engine through a nozzle.
In particular, the present invention relates to a distribution type fuel injection pump in which a plunger is slidably provided in a radial direction on a rotor that rotates in synchronization with an engine, and the plunger is reciprocated by a cam ring to change the volume of a compression chamber formed in the rotor.

[0002]

2. Description of the Related Art An inner-cam type distribution type fuel injection pump is disclosed in, for example, JP-A-59-119056, JP-A-60-79152, and JP-A-3-175143. A concentric inner cam 1 (cam ring) is arranged around the fuel distributing rotary member 4 (rotor), and pressure feed plungers 21 and 22 are applied to cam surfaces formed inside the inner cam 1 via rolling elements and the like.
The pumping plungers 21 and 22 are reciprocated in the radial direction of the fuel distribution rotating member 4. The fuel distribution rotary member 4 includes a pump chamber 2 (compression chamber) whose volume is changed by the pressure-feed plungers 21 and 22, suction holes 51 to 54 for sucking fuel into the pump chamber 2 during the suction step, and a pump chamber 2 during the pressure-feed step. A distribution port 6 for delivering the fuel pressurized by the above and overflow ports 71 to 74 for cutting off the delivery of the fuel are formed. A ring-shaped member 7 (control sleeve) is externally fitted to the fuel distribution rotating member 4 so as to cover the overflow ports 71 to 74.
By moving the shaft in the axial direction, the cutoff time during the pressure feeding step can be changed to change the injection amount.

[0003] In such a distribution type injection pump,
For example, as disclosed in Japanese Patent Application Laid-Open No. 8-270521, there is a well-known device in which a cam ring 26 is rotated by a hydraulic (fuel pressure) timer device to control the advance angle. This is because a timer piston is provided at right angles to the axial direction of the rotor,
The supply pressure of the feed pump is applied to one end of the timer piston, and a timer spring is provided at the other end.The timer piston is positioned at a position where the supply pressure and the spring force of the timer spring are balanced, and a cam ring that works with this timer piston is supplied. It has a basic structure for rotating so as to obtain an advance angle corresponding to the pressure. The timing control valve further adjusts the fuel pressure applied to the tamper piston so that the advance angle can be freely changed.

In the first three publications, a groove 10 is formed inside a ring-shaped member 7 (control sleeve), and one end of the groove 10 is provided to be inclined with respect to the generatrix of the ring-shaped member 7. As a result, the stroke (pre-stroke) from the start of the cam lift to the start of the pressure feeding is set to be constant, but the stroke until the end of the pressure feeding is determined by the axis of the ring-shaped member 7. It is disclosed that the position in the direction changes, that is, the position changes according to the load.

[0005]

However, in the above-mentioned hydraulic timer device, since the supply pressure of the feed pump is basically used, the time from the start of the pump to the increase of the supply pressure is not sufficient. Take it. For this reason, in an engine that requires a large advance angle at the time of starting, it is impossible to obtain an advance angle with a timer device. That is, at the time of starting, an inconsistent state is desired in which a large advance angle is desired even though the timer device does not function sufficiently.

Further, in the above-mentioned prior art, since the fuel pumping is started from an area where the oil feed rate (cam speed × plunger diameter) is small, even in the normal operation after the start, the medium-low load is applied. In order to improve engine performance during operation, it is difficult to ensure a sufficient oil supply rate of the pump. If it is only to improve the oil feed rate at medium / low load, it is sufficient to set the oil feed rate characteristics high overall using a cam profile with a high cam speed. There is an inconvenience that the driving torque of the pump under a very high load, which is given priority, exceeds an allowable value.

In view of the above, the present invention provides a distribution type fuel injection pump which can obtain a sufficient advance angle at the time of starting the pump without waiting for the supply pressure of the feed pump to increase and the timer device to function. That is the task. Also, during normal operation, the oil supply rate at medium and low loads is increased, and the drive torque of the pump at high loads is suppressed to the same level as before so as not to exceed the allowable value. It is an object of the present invention to provide a distribution type fuel injection pump capable of ensuring good injection performance with the above.

[0008]

In order to obtain the advance angle by using the timer device, the cam ring is rotated in the direction opposite to the rotation direction of the rotor, whereby the injection timing is advanced. However, the same effect can be realized if the communication end timing (compression feed start timing) between the suction and cutoff holes formed in the rotor and the holes of the control sleeve provided to cover the holes can be changed by the control sleeve. . As described above, if the pressure feeding start timing can be changed by adjusting the position of the control sleeve, it is possible to obtain the advance angle at the time of starting regardless of the timer device. In addition, if the cam use area during the pumping period can be changed successfully in relation to the oil supply rate as the control sleeve is displaced according to the load, the required oil supply rate is obtained according to the load. be able to. Therefore,
The inventor of the present invention has made intensive studies on the configuration for realizing the above, and as a result, completed the present invention.

That is, a distribution type fuel injection pump according to the present invention is provided with a rotor that rotates in synchronization with an engine, and is provided slidably in a radial direction of the rotor, and has a capacity of a compression chamber formed in the rotor. A variable plunger; a cam ring provided concentrically around the rotor to define the movement of the plunger; and a fuel chamber downstream of a feed pump, which is fitted over the rotor and moves axially of the rotor. A control sleeve whose relative position with respect to the rotor is adjusted, wherein the rotor has
A first fuel suction and cut-off port connected to the compression chamber;
And a second hole is formed in the control sleeve so as to communicate with the first hole, and the opening ends of the first and second holes which are close to each other are connected with the axis of the rotor. Two inclined edges are formed, each of which is inclined from the parallel imaginary line to the opposite side, and the inclined edges formed at the start of the communication between the first hole and the second hole are formed in parallel with each other, and the first edge is formed. The inclined edges formed at the end of the communication between the hole and the second hole are formed parallel to each other (claim 1).

Here, the first hole and the second hole have two inclined edges which are inclined from the imaginary line extending in the axial direction of the rotor to opposite sides, respectively. The triangular shape is easy to process, and the first
The hole and the second hole may be formed so that the intersection side of the inclined edge (the side corresponding to the vertex of the triangle) is opposite in the axial direction.

Therefore, a suction step of sucking fuel is performed during a period in which the rotor rotates and the first hole and the second hole communicate with each other, and the first hole is disengaged from the second hole and the next step is performed. A pressure feeding step is performed until one hole communicates with the second hole. Although this pumping step and the timing at which the plunger is lifted by the cam ring are synchronized, the fuel pumping starts after the communication between the first hole and the second hole is cut off after the plunger lift is actually started. Is done. The period from the start of the plunger lift to the time when the communication between the first hole and the second hole is cut off is the pre-stroke period, and the shorter the period, the more advanced the stroke.

Since the timer device uses the supply pressure of the feed pump, it is difficult to obtain an advanced angle at the time of start-up. However, the first and second holes are formed with inclined edges to form the control sleeve. By moving in the axial direction,
Since the end timing of the communication between the first hole and the second hole can be changed, the advance angle can be obtained regardless of the timer device by shortening the pre-stroke period (claim 3). . Therefore, the above-described configuration is particularly useful for an injection pump including a timer device for adjusting the advance angle by rotating the cam ring (claim 2).

Further, in the above pump configuration, the use area of the cam ring for pumping the fuel is increased toward the advance side and the retard side so as to include the intermediate area of the rising area of the cam surface of the cam ring as the load increases. (Claim 4). From this, if the control sleeve is moved so that the pre-stroke period is reduced,
The timing of the start of communication between the first hole and the second hole, that is, the timing of cutoff of the fuel is also delayed, so that the fuel pumping period becomes longer and the injection amount increases. Therefore, at the time of starting, an advanced angle can be obtained and the injection amount can be increased to increase the starting torque, and the injection state exactly meeting the request at the time of starting can be realized.

After the engine is started, the supply pressure of the feed pump increases, and the timer device functions. Therefore, the advance angle control during normal operation may be performed by the timer device, and the injection amount control is performed. The operation of the control sleeve is performed in the same manner as the conventional injection device. In the configuration of the present invention, the pre-stroke amount changes when the control sleeve is moved because it is necessary to change the injection amount even during the normal operation, but this change is corrected by a timer device. It is possible to drive without any trouble.

Further, the use region of the cam ring for pumping the fuel uses only the cam speed region where the cam speed becomes equal to or higher than the predetermined speed when the load is equal to or lower than the predetermined load.
When the load becomes larger than the predetermined load, it may be configured to use the cam speed range lower than the predetermined speed. With such a configuration, even in the normal control after the start, at a medium to low load, a region where the cam speed is high (a region where the oil supply rate is large) can be used. The oil supply rate can be increased as compared with a conventional pump of a fixed pre-stroke type which has been forced to be used from a low region. On the other hand, at the time of a high load, the driving speed can be suppressed to about the same level as that of the conventional pump because the driving speed is used up to the low cam speed region.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an inner-cam type distribution type fuel injection pump.
The drive shaft 3 is inserted into the pump housing 2, one end of the drive shaft 3 protrudes outside the pump housing 2, receives drive torque from an engine (not shown), and synchronizes with the engine (half the engine speed). At the number of rotations). The other end of the drive shaft 3 is connected to the pump housing 2
The drive shaft 3 is connected to a feed pump 4. The feed pump 4 supplies fuel supplied through a low-pressure fuel region 5 a to be described later to the fuel chamber 6.

The pump housing 2 includes a housing member 2a into which the drive shaft 3 is inserted, and a housing member 2b mounted on the housing member 2a and provided with a delivery valve 7.
And a housing member 2c provided on an extension of the rotor 8 by closing the opening of the housing member 2b. The fuel chamber 6 includes a rotor support member 9 provided in a pump housing, It is formed by a space surrounded by a wall member 10 holding the rotor support member 9 and an adapter 11 described later, and communicates with a governor storage chamber 13 defined by a governor housing 12. Further, the rotor support member 9 is inserted into an insertion hole 14 formed in the housing member 2b having the delivery valve 7.

The rotor 8 is supported in an oil-tight and rotatable manner in an insertion hole 15 formed in the rotor support member 9, and its base end is connected to the drive shaft 3 via a coupling 16 to drive the rotor 8. Only rotation is allowed with rotation of the shaft 3. Further, a spring 19 is elastically mounted between the housing member 2c and a spring receiver 18 disposed at a tip end portion of the rotor 8 via a thrust bearing 17, and the spring 19 urges the rotor 8 toward the coupling side. The play in the axial direction is eliminated.

At the base end of the rotor 8 connected to the drive shaft,
As shown in FIG. 2, the plunger 20 is slidably inserted in the radial direction (radial direction). In this configuration example, four plungers 20 are provided at intervals of 90 degrees on the same plane, and the distal end of each plunger 20 closes a compression chamber 21 provided at the center of the base end of the rotor 8. And the base end of the plunger 20 is connected to the ring-shaped cam ring 2 via a shoe 22 and a roller 23.
4 is in sliding contact with the inner surface. The cam ring 24 is provided concentrically around the rotor 8 and
Cam surfaces corresponding to the number of cylinders of the engine are formed on the inside, and when the rotor 8 rotates, each plunger 20 reciprocates in the radial direction (radial direction) of the rotor 8 to change the volume of the compression chamber 21. ing.

That is, if the cam ring 24 is formed corresponding to four cylinders, a convex surface is formed inside the cam ring 24 at every 90 degrees. Therefore, the four plungers 20 are formed in the compression chamber. The cam ring 21 is moved so as to be compressed simultaneously while being pinched, and is simultaneously moved away from the center of the cam ring 24.

An annular adapter 11 is rotatably fitted to the rotor 8, and a part of the peripheral edge of the adapter 11 is locked by the cam ring 24 to restrict the rotation.
It rotates with the cam ring 24. The adapter 11 is rotatably fitted to the rotor support member 9.

A fuel inlet 25 for guiding fuel from a fuel tank (not shown) is provided in the upper part of the housing member 2b, and the fuel flowing from the fuel inlet 25 is formed in the housing member 2b. From the fuel supply passage 26 to the suction side of the feed pump 4 through the space formed around the wall member 10 and the adapter 11, the space formed between the cam ring 24 and the rotor 8, the periphery of the coupling 16, and the like. The space and the passage form a low-pressure fuel region 5 a extending from the fuel inlet 25 to the feed pump 4.

The fuel compressed by the feed pump 4 is supplied to a passage 2 formed in the upper part of the pump housing.
7 and a gap 28 formed between the pump housing 2 and the governor housing 12 assembled to the pump housing 2 and to the fuel chamber 6, and also to the overflow valve 29 via the governor storage chamber 13 and communicate with each other. A high-pressure fuel region 5b is formed by the part that performs this operation.

As shown in FIG. 3, the rotor 8 has
A vertical hole 30 formed in the axial direction and communicating with the compression chamber 21;
The vertical hole 30 communicates with the vertical hole 30 and an inflow / outflow port 31 opened on the peripheral surface of the rotor 8 and a fuel delivery passage 32 formed in the rotor support member 9 and the housing member 2b. A distribution port 33 is formed. The inflow / outflow ports 31 are formed with phases shifted by equal intervals corresponding to the number of cylinders, and each outflow / inflow port 31 is formed in a substantially triangular shape. More specifically, the edge 31a that determines the end timing of communication with the inflow / outflow port 31 is formed to be inclined at a predetermined angle with respect to the axial direction of the rotor 8, and the start of communication with the inflow / outflow port 31 is started. The edge 31b for determining the timing is formed so as to be inclined to the opposite side to the edge 31a with respect to the axial direction of the rotor 8.

The inflow / outflow port 31 opens at the surface of the rotor 8 at a position located in the fuel chamber 6, and this opening is covered by a control sleeve 34 which is fitted over the rotor 8 in an oil-tight manner. . An engagement groove 35 is formed in the control sleeve 34 over a range of a predetermined angle in a circumferential direction of the upper surface, and a ball 38 formed on a tip of a shaft 37 of an electric governor 36 is engaged with the engagement groove 35. Have been combined. The ball 38 is provided eccentrically with respect to the shaft 37, and when the shaft 37 is rotated by an external signal, the control sleeve 34 moves in the axial direction of the rotor 8.

The control sleeve 34 has a through hole 40 which can communicate with each of the inflow / outflow ports 31 as shown by a broken line in FIG. This through hole 40
Has a substantially triangular shape formed in a direction symmetric to the inflow / outflow port 31, and an edge 40 a that determines a communication end timing with the inflow / outflow port 31 is formed to be inclined with respect to the axial direction of the rotor 8. An edge 40b that is parallel to the edge 31a of the inflow / outflow port 31 and that determines the communication start timing with the inflow / outflow port 31 is formed so as to be inclined to the opposite side to the edge 31a with respect to the axial direction of the rotor 8. It is parallel to the edge 31b of the inflow / outflow port 31.

Edges 31a, 4b formed in the inflow / outflow port 31 and the through hole 40 for determining the end timing of communication.
0a and the inclination angles of the edges 31b and 40b that determine the communication start timing
Since the movable range of the control sleeve 34 in the direction of the rotor axis is determined by the relationship with the governor, the amount of change in the pumping start timing or cutoff timing per unit movement of the control sleeve 34 is determined, and each is determined based on this amount of change. That is, it is not always necessary to set the same.

An engagement groove 41 extending in the axial direction is formed in a lower portion of the control sleeve 34. The protrusion 11a of the adapter 11 is engaged in the engagement groove 41, and the adapter 11 and the control sleeve 34 are connected to each other. Is always kept constant.

The timer device 40 houses a timer piston 41 slidably in a cylinder provided at the lower portion of the pump housing 2, and connects the timer piston 41 to the cam ring 24 via a lever 42. The movement is converted into the rotation of the cam ring 24 to adjust the injection timing.

At one end of the timer piston 41, a high-pressure chamber for introducing high-pressure fuel in the high-pressure fuel zone 5b is formed, and at the other end, a low-pressure chamber communicating with the low-pressure fuel zone 5a is formed. Further, a timer spring is elastically mounted in the low-pressure chamber, and the timer piston 41 is constantly biased toward the high-pressure chamber by the timer spring. Therefore, the timer piston 41 stops at a position where the spring pressure of the timer spring and the fuel pressure in the high-pressure chamber are balanced, and when the high-pressure chamber pressure increases, the timer piston 41 moves toward the low-pressure chamber against the timer spring. The cam ring 24 is rotated in a direction to advance the injection timing, and the injection timing is advanced. When the high-pressure chamber pressure decreases, the timer piston 41 moves to the high-pressure chamber side, and the cam ring 24 is rotated in a direction to delay the injection timing, and the injection timing is delayed. The pressure in the high-pressure chamber of the timer is adjusted by a timing control valve (TCV) 43 so as to obtain a required timer advance angle.

In the above configuration, when the rotor 8 rotates, the inflow / outflow ports 31 corresponding to the number of cylinders sequentially communicate with the through holes 40 of the control sleeve 34, and the plunger 20
In the suction step in which the gas moves in the direction away from the center of the cam ring 24, the inflow / outflow port 31 and the through hole 40 of the control sleeve 34 are aligned, and the fuel in the chamber 6 is sucked into the compression chamber 21.

Thereafter, the plunger 20 is moved to the cam ring 24.
In the pumping step of moving toward the center of the control sleeve, communication between the inflow / outflow port 31 and the through hole 40 of the control sleeve 34 is cut off, and the distribution port 33 and one of the fuel delivery passages 32 are aligned and compressed. The fuel is discharged to the delivery valve 7 through the fuel delivery passage 32. The fuel delivered from the delivery valve 7 is sent to an injection nozzle via an injection pipe (not shown), and is injected from the injection nozzle into a cylinder of the engine.

When the inflow / outflow port 31 and the through hole 40 of the control sleeve 34 communicate with each other again in the course of the pressure feeding process, the compressed fuel flows out into the chamber 6, the delivery to the injection nozzle is stopped, and the injection ends. I do. Then, such a process is sequentially repeated, and four times per one rotation of the rotor.
Cycle.

Here, since the inflow / outflow port 31 and the through hole 40 of the control sleeve 34 are formed in a triangular shape as described above, the timing at which the inflow / outflow port 31 ends the communication with the through hole 40, and the communication. The start timing can be changed by the control sleeve 34. In other words, the pressure feeding start time and the pressure feeding end (cutoff time) can be adjusted by adjusting the position of the control sleeve 34, and the pressure feeding start time is increased as the control sleeve 34 is moved to the left (the base end side of the rotor 8) in FIG. And end the pumping operation earlier,
The end of the pumping can be delayed and the end of the pumping can be delayed as it moves to the front end side of the pump.

Hereinafter, this relationship between the start of the engine and the idling will be specifically described with reference to FIGS. 4 and 5. FIG. FIG. 4 shows a state in which the inflow / outflow port 31 and the through hole 40 of the control sleeve are developed on the same plane, and the inflow / outflow port 31 gradually shifts downward with respect to the through hole 40 as the rotor rotates. Hole 4 indicated by a solid line
0 indicates a position at the time of starting, and a through hole indicated by a broken line indicates a position at the time of idling. Further, the cam angles (I) to (IV) in FIG. 4 are in a section where the cam lift gradually increases from zero, and are, for example, shown in FIG.
Each corresponds to the position (IV).

Since the edges between the inflow / outflow port 31 and the through hole 40 for determining the communication end timing and the communication start timing are inclined as described above, the following injection characteristics are obtained during idling. That is, at the time of the cam angle (I), although the cam lift has been started, the inflow / outflow port 31 and the through hole 40 are still in communication, and the fuel leaks to the fuel chamber. Thereafter, at the time of the cam angle (II), the communication between the inflow / outflow port 31 and the through hole is cut off, the compression of the sucked fuel is started, and the compressed fuel is pressure-fed to the fuel delivery passage. This pumping state depends on the cam angle (II
Continue to the point of I), and at the time of (III), the next outflow / inflow port 3
1 and the through hole 40 start communicating, and the fuel is cut off. At the cam angle (IV), although the volume of the compression chamber is further reduced, the fuel leaks to the fuel chamber because the inflow / outflow port 31 communicates with the through hole.

Therefore, as shown in FIG. 5, the pressure is fed in the middle area of the cam in the sections (II) to (III), and the injection amount is reduced due to the shortened pumping period, and the cam lift is started. The pre-stroke amount from the start to the start of pressure feeding increases.

On the other hand, when the engine is started,
At the time when the cam angle (I) is reached, the communication between the inflow / outflow port 31 and the through hole is cut off, and at this time, compression of the sucked fuel is started, and the compressed fuel is pressure-fed to the fuel delivery passage. This pumping state continues until the cam angle (IV), and at the time (IV), the next inflow / outflow port 31 starts communicating with the through hole, the fuel is cut off, and the pumping ends.

Therefore, at the time of starting, as shown in FIG. 5, the wide range of the cams in the sections (I) to (IV) is used during the pumping period, so that the pumping period becomes longer, and the injection period becomes longer. The amount increases. Further, the pre-stroke amount from the start of the cam lift to the start of the pressure feeding is reduced.

In the conventional injection device, when it is desired to change the injection timing (advance control), the cam ring is rotated by a desired amount by the timer device, thereby shifting the cam characteristic itself in FIG. Thus, the phase of the cam with respect to the rotor 8 (or the drive shaft 3) is changed. However, such advance control is based on the premise that the timer device 40 functions sufficiently. At the start, as described above, the feed pressure of the feed pump is low. It is impossible to do at 40.
In this regard, in this configuration example, the control sleeve 3
The injection timing can be advanced by operating the valve 4 to shift the through hole 40 in the axial direction so as to be separated from the inflow / outflow port 31, and the required advance angle can be substantially obtained without shifting the cam ring 24 at the time of starting. it can.

As described above, at the time of starting, the timer device 40
Lead angle that cannot be obtained by the control sleeve 34
In the stage where the pump is started once, the supply pressure (= chamber pressure) of the feed pump 4 is increased, and the advance angle can be sufficiently adjusted by the timer device 40, the advance angle control is performed by the timer device 40. Is performed. Further, the control sleeve 34 is operated to change the injection amount during the normal operation, but in the above configuration example, when the control sleeve is moved to obtain a desired injection amount, the injection timing is simultaneously changed. There is an inconvenience. However, since the timer device functions normally during normal operation, the change in the injection timing may be corrected by rotating the cam ring 24 by the timer device.

Further, from the viewpoint of controlling the injection rate during normal operation, changing the use area of the cam by the control sleeve without moving the cam ring (without shifting the cam characteristics) depends on the operation of the control sleeve. The possibility of injection rate control remains. Certainly, in the above configuration, the use area of the cam is changed while changing the pumping period as a result of moving the control sleeve for controlling the injection amount, and the pumping period is the same as in the conventional injection pump. While the area of use of the cam is not changed, control similar to the conventional injection rate control is also possible depending on how the cam surface is formed.

Further, as a result of the provision of the above configuration, the following operation and effect can be obtained during normal operation after starting. Hereinafter, this point will be specifically described with reference to FIGS. Here, the solid characteristic lines shown in FIG. 6 to FIG. 8 are schematic characteristics representing the oil feeding rate (cam speed × punjaja diameter), and are extremely small in which the oil feeding rate becomes maximum in the middle region of the rising region of the cam. This shows the characteristics of a normal injection pump.

At the time of low load () including idling, as described above, the intermediate region of the cam lift is used as shown by the broken line in FIG. 5, so that it can be understood from FIGS. The fuel is pumped in a small section of the maximum area of the oil transfer rate, the pre-stroke amount is large, and the effective stroke amount, that is, the cam lift amount from the start to the end of the pumping is small (Amm). In the figure, Uαist
Is the voltage applied to the actuator that drives the control sleeve.Since the movement of the control sleeve is linked to the load, Uαist is used as a parameter that expresses the load. Is represented.

Also, at the time of medium load (), the middle area of the cam lift used during the injection period becomes wide, so that as shown in FIGS. Since the injection is performed in a wide range, the pre-stroke amount is somewhat shortened, and the effective stroke amount is somewhat increased (Bmm).

At the time of high load (), the area of the cam lift used during the injection period is further widened and becomes as shown in the starting pumping period of FIG.
As can be understood from FIG. 5, the injection is performed in a wider section including the region where the oil supply rate is low from the region where the oil supply ratio is low, so that the pre-stroke amount becomes short and the effective stroke amount becomes the largest (Cmm). .

The above injection characteristics are described in JP-A-59-11905.
No. 6, JP-A-60-79152, JP-A-3-
Compared to the conventional product shown in 175143 gazette and the like,
In the conventional product, the pre-stroke is constant and small irrespective of the load unless the cam ring is rotated. When the load increases and the control sleeve is displaced, only the pumping end stroke increases. Therefore, regardless of the load state, the fuel starts to be pumped from the low oil feed rate region.

Referring to the range of use of the oil feed rate characteristic line of this conventional product in which the effective stroke is matched with that of the present invention, as shown in FIGS. 6 to 8, when the load is small,
The pumping angle (pumping period) becomes larger in the region where the oil feed rate is small, and as the load becomes larger, it becomes larger in the high oil feed rate region. It will cover the area.

Due to such a difference in characteristics, in the present invention, a high oil feed rate region is used at the time of medium / low load pumping, so that the oil feed rate during the pumping period can be increased as compared with conventional products. On the other hand, the oil supply rate during the pumping period under a high load is substantially the same as that of the conventional product. Since the driving torque is determined in accordance with the oil feed rate, the relationship between the driving torque and the load is as shown by the solid line in FIG. 10, and this characteristic is lower than that of the conventional product indicated by the dashed line. Although the drive torque increases as a result of improving the oil supply rate under load, the drive torque under high load can be suppressed to about the same level as the conventional product.

In order to increase the oil feed rate at the time of medium to low load with the conventional configuration, a cam lobe with a high cam speed is formed to improve the oil feed rate characteristics as a whole, as shown by the broken line in FIG. Although it is conceivable to shift the characteristic line of the drive torque upward as described above, in the design of the injection pump, the drive torque at the time of maximum load (maximum drive torque) is often set to the limit of the allowable value. When the cam shape is changed to a characteristic as indicated by a broken line, the oil supply rate is improved at medium and low loads, but at a high load, the driving torque exceeds the allowable value (FIG. 10). Hatch area), and the drive system structure (drive shaft, bearings, etc.) of the pump must be strengthened. Further, in order to strengthen the drive system structure of the pump, the pump itself may need to be upsized. On the other hand, the present invention increases the oil supply rate at medium and low loads and suppresses the driving torque at high loads to be within an allowable value, so that the drive system structure of the pump is not strengthened. Good injection performance can be ensured in the entire load range during operation.

[0051]

As described above, according to the present invention,
A first hole formed in the rotor and a second hole formed in the control sleeve and communicable with the first hole are respectively inclined from an imaginary line parallel to the axis of the rotor to the opposite side. Since two inclined edges are formed, and the inclined edge formed at the start of communication between the first hole and the second hole and the inclined edge formed at the end of communication are formed in parallel with each other, the control sleeve is moved in the axial direction. By moving, the timing of communication and non-communication between the first hole and the second hole can be adjusted.

As a result, the pre-stroke period from when the plunger lift is started to when the communication between the first hole and the second hole is interrupted can be changed to vary the advance amount. Even in the initial stage of starting when the supply pressure of the feed pump has not yet risen, it is possible to obtain a required starting advance angle only by controlling the control sleeve.

As described above, since the advance angle is changed by the control sleeve, if the control sleeve is adjusted with the intention of changing the injection amount after the engine is once started, the pre-stroke amount changes and the pumping start timing is changed. However, at this time, the supply pressure of the feed pump is also increased, and the advance angle control by the timer device is sufficiently possible, so that the injection amount can be controlled without any trouble by correcting the injection timing by the timer device. be able to.

Further, the configuration of the present invention in which the pre-stroke is changed in conjunction with the load is useful not only at the time of starting but also at the time of normal control. While satisfying the above conditions, the driving torque at the time of a high load can be suppressed to the same level as that of the related art, and good injection performance can be secured in the entire load region.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a distribution type fuel injection pump according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the cam ring shown in FIG. 1 and members inside the cam ring viewed from an axial direction of a rotor.

FIG. 3 is an enlarged sectional view illustrating a rotor and members around the rotor.

FIG. 4 shows an inflow / outflow port 31 associated with rotation of a rotor.
FIG. 5 is a diagram showing a change in the positional relationship between the control hole and the through hole 40 of the control sleeve, wherein a broken line indicates a position at the time of idling, and a solid line indicates a position at the time of starting.

FIG. 5 is a diagram showing a pumping period, an advanced state, and a pre-stroke in relation to a cam angle at the time of idling and at the time of starting.

FIG. 6 is a diagram showing a pressure feeding section (pressure feeding angle) between the present invention and a conventional product at a low load on an oil feed rate characteristic line.

FIG. 7 is a diagram showing a pressure feeding section (pressure feeding angle) between the present invention and a conventional product at a medium load on the oil feed rate characteristic line.

FIG. 8 is a diagram showing a pressure feeding section (pressure feeding angle) between the present invention and a conventional product under a high load on the oil feed rate characteristic line.

FIG. 9 is a diagram showing a relationship among a pumping angle, a pre-stroke, a pumping end stroke, and an effective stroke with respect to a change in load.

FIG. 10 is a diagram showing a relationship between a drive torque and a change in load.

[Explanation of symbols]

 Reference Signs List 4 feed pump 6 fuel chamber 8 rotor 20 plunger 24 cam ring 31 inflow / outflow port (first hole) 31a, 31b edge 34 control sleeve 40 through hole (second hole) 40a, 40b edge

[Procedure amendment]

[Submission date] January 22, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

In the conventional injection device, when it is desired to change the injection timing (advance control), the cam ring is rotated by a desired amount by the timer device, thereby shifting the cam characteristic itself in FIG. Thus, the phase of the cam with respect to the rotor 8 (or the drive shaft 3) is changed. However, such advance control is based on the premise that the timer device 140 functions sufficiently. At the time of starting, as described above, since the supply pressure of the feed pump is low, the advance control is performed by the timer device. It is impossible to do at 140 . In this regard, in the present configuration example, the injection timing can be advanced by operating the control sleeve 34 in the axial direction so as to move the through hole 40 away from the inflow / outflow port 31, and the cam ring 24 is shifted at the time of starting. The required advance angle can be substantially obtained without the need.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

As described above, at the time of starting, the timer device 14
Advancing angle that cannot be obtained by 0
In the stage where the pump is started once, the supply pressure (= chamber pressure) of the feed pump 4 is increased, and the advance angle can be sufficiently adjusted by the timer device 140 , the advance angle is set by the timer device 140 . Control is performed. Further, the control sleeve 34 is operated to change the injection amount during the normal operation, but in the above configuration example, when the control sleeve is moved to obtain a desired injection amount, the injection timing is simultaneously changed. There is an inconvenience. However, since the timer device functions normally during normal operation, the change in the injection timing may be corrected by rotating the cam ring 24 by the timer device.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomohiko Shiraishi 3-13-26 Yayucho, Higashimatsuyama City, Saitama Prefecture Inside of Zexel Higashimatsuyama Plant

Claims (5)

[Claims] 1. A rotor that rotates in synchronization with an engine, a plunger that is slidably provided in a radial direction of the rotor and that varies a volume of a compression chamber formed in the rotor, and that is concentric with the periphery of the rotor. A cam ring that defines the movement of the plunger, and a control that fits over the rotor in the fuel chamber downstream of the feed pump and that adjusts the relative position of the rotor by axial movement of the rotor. A second hole communicable with the first hole is formed in the control sleeve. The first hole is formed in the rotor in communication with the compression chamber to suck and cut off fuel. And two inclined edges, which are inclined from the imaginary line parallel to the axis of the rotor to the opposite side, at the open ends of the first and second holes adjacent to each other. The inclined edges formed at the start of the communication between the first hole and the second hole are formed in parallel with each other, and the inclined edges formed at the end of the communication between the first hole and the second hole are formed together. A distribution type fuel injection pump characterized by being formed in parallel. 2. The distribution type fuel injection pump according to claim 1, further comprising a timer device for adjusting an advance angle by rotating the cam ring. . 3. The distribution type fuel injection pump having the configuration according to claim 1, wherein at the time of starting of the engine, the relative position of the control sleeve is adjusted to start the first through hole and the second through hole from the start of the cam lift. A distribution type fuel injection pump characterized in that a period until communication with the through hole is completed is shortened so as to obtain an advance angle. 4. The distribution type fuel injection pump having the configuration according to claim 1, wherein a use area of the cam ring for pumping fuel is an intermediate area of a rising area of a cam surface of the cam ring as the load increases. The distribution type fuel injection pump is characterized in that it increases to the advance side and the retard side so as to include: 5. The distribution type fuel injection pump having the configuration according to claim 1, wherein a use area of the cam ring for pumping fuel is such that a cam speed is higher than a predetermined speed when a load is lower than a predetermined load. Using only the cam speed range
A distribution type fuel injection pump characterized in that when a load becomes larger than the predetermined load, the camshaft is used up to a cam speed region lower than the predetermined speed.