JP2845657B2 - Fuel injection amount adjustment device for fuel injection pump - 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 amount adjusting device for a fuel injection pump for injecting fuel into an internal combustion engine such as a diesel engine, and more particularly to a fuel injection device for restricting movement of a control rack provided in the fuel injection pump. The present invention relates to a fuel injection amount adjusting device for a pump.

[0002]

2. Description of the Related Art Conventionally, as a fuel injection pump for injecting fuel into an internal combustion engine such as a diesel engine, a fuel injection pump capable of adjusting a fuel injection amount by moving a control rack has been known. For example, rotating the plunger by moving the control rack,
There is known an in-line fuel injection pump in which the effective stroke of the plunger can be adjusted.

In this type of fuel injection pump, the amount of movement of the control rack is controlled by a cam plate or the like when the internal combustion engine is driven, and the amount of fuel injection is controlled within a predetermined range. For example, there is a fuel injection amount adjusting device as illustrated in FIGS. This fuel injection amount adjusting device is formed on the side surface of the housing 101 of the row type fuel injection pump, and is configured as follows. First, a long hole 104 is formed in the housing 101 in parallel with the moving direction of the control rack 103. A rack pin 105 protrudes from the control rack 103 and penetrates the elongated hole 104 to protrude from the surface of the housing 101. The rack pin 105 moves in the elongated hole 104 as the control rack 103 moves. Further, a flange portion 107 is formed in the housing 101 in parallel with the elongated hole 104. Further, a first pin 109 is protruded from a side surface of the housing 101 between the elongated hole 104 and the flange 107. The first pin 109 swingably supports the first cam plate 111 for restricting the movement of the rack pin 105 in the direction of increasing the fuel injection amount. The first cam plate 111 is
Long sides 11 perpendicular to each other
3 and the short side 115. On the long side 113,
A contact portion 117 that contacts the rack pin 105 is formed at the center thereof, and a hook 119 that engages with a second cam plate 133 described later is formed at the tip. The above-mentioned first pin 109 penetrates the short side 115 at the center. The short side 115
The tip of the first member abuts on the flange portion 107 to restrict the movement of the first cam plate 111 in the fuel injection amount decreasing direction. Further, the first cam plate 111 is urged by the cylindrical coil spring 121 in the fuel injection amount decreasing direction.

A second pin 131 projects from the side of the housing 101 opposite to the first pin 109 with the long hole 104 interposed therebetween.
3 is swingably supported. Also the second cam plate 133 "
This is a metal plate formed in the shape of a square, and is disposed so as to face the first cam plate 111. At one end of the second cam plate 133, a cutout 135 is formed to engage with the tip of the short side 115. The other end is formed with an engagement end 137 for engaging with the hook 119. The second cam plate 133 is connected to the cylindrical coil spring 13
9 is urged in the direction of increasing the fuel injection amount.

In the fuel injection amount adjusting device configured as described above, the tip of the short side 115 and the notch 135 are engaged during the normal operation of the internal combustion engine as illustrated in FIG. Due to this engagement, the first cam plate 111 cannot move beyond the predetermined position in the fuel injection amount increasing direction. Therefore,
Even if a force in the fuel injection amount increasing direction is applied to the rack pin 105, the first cam plate 111 does not move beyond the predetermined position. That is, the rack pin 105 does not move in the direction of increasing the fuel injection amount beyond the rated position where the rack pin 105 contacts the contact portion 117. Therefore, the fuel injection amount can be controlled to a predetermined amount or less.

When the internal combustion engine is stopped, the control rack 103 moves in the direction of decreasing the fuel injection amount by the action of a solenoid (not shown) or a manual lever. Then, the rack pin 105 moves the second cam plate 133 in the fuel injection amount decreasing direction against the urging force of the cylindrical coil spring 139. As a result, the tip of the short side 115 and the notch 135
Is disengaged. At this time, the engagement end 137 is engaged with the hook 119. For this reason, even if the energization to the solenoid is stopped or the manual lever is returned, the front end of the short side 115 and the notch 135 are maintained in a disengaged state.

Therefore, when the accelerator is depressed at the time of starting,
As shown in FIG. 7, the first cam plate 111 moves in the fuel injection amount increasing direction beyond the predetermined position defined by the engagement between the short side 115 and the notch 135. Therefore, when the internal combustion engine is started, the fuel injection amount can be controlled to a large value exceeding the rating, and a large torque can be obtained.

[0008]

In the fuel injection amount adjusting device having the above structure, the rated position of the rack pin 105 is an important factor for determining the maximum rating of the internal combustion engine. However, at the position where the control rack 103 is attached to the plunger of the fuel injection pump, there is a variation in the correspondence between the rotation angle of the plunger and the fuel injection amount due to the variation of components. Further, the maximum rating may need to be changed depending on the use of the internal combustion engine. Therefore, the rated position of the rack pin 105 has to be adjusted to a different position for each fuel injection pump.

Therefore, conventionally, the contact portion 1 has
A large number of first cam plates 111 having different lengths L (FIG. 6) reaching the 17 side edges are prepared in advance, and when the internal combustion engine is driven, the first cam plates 111 are replaced and the most suitable first cam plate 111 is replaced. The plate 111 has been selected. Also, in order to replace the first cam plate 111, it is necessary to take steps such as once removing the fuel injection pump from the internal combustion engine, replacing the first cam plate 111, and attaching the fuel injection pump to the internal combustion engine again. It was very time-consuming.

For this reason, when manufacturing this kind of fuel injection pump, it is necessary to prepare a large number of first cam plates 111, so that the material cost increases, and furthermore, as described above, it is necessary to take steps that are cumbersome. As a result, the working efficiency deteriorates and the manufacturing cost of the fuel injection pump increases.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a fuel injection amount adjusting device for a fuel injection pump which can easily adjust a rated position of a rack pin without having to prepare a large number of first cam plates. Was.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a control rack provided in a fuel injection pump for adjusting a fuel injection amount according to a moving position, and a control rack protruding from the control rack. The first cam plate provided on the fuel injection amount increasing side of the rack pin engages with the first cam plate during a normal operation of the internal combustion engine, and the first cam plate moves in the fuel injection amount increasing direction of the control rack. In addition to prohibiting movement beyond the predetermined position, after the internal combustion engine is stopped, the engagement is released, and the first cam plate moves beyond the predetermined position in the fuel injection amount increasing direction of the control rack. A second cam plate that permits movement;
A third cam plate disposed on the first cam plate and abutting against the rack pin from the side of increasing the fuel injection amount to define a rated position of the rack pin; and a third cam plate and the first cam plate. An urging member provided between the first cam plate and the first cam plate for urging the control rack in the fuel injection amount decreasing direction; and a biasing member for urging the third cam plate in the fuel injection amount decreasing direction. A fuel injection amount adjusting device for a fuel injection pump, comprising: an adjusting member that regulates movement and adjusts the rated position of the rack pin.

[0013]

According to the present invention, the second cam plate is engaged with the first cam plate during normal operation of the internal combustion engine.
The first cam plate is prohibited from moving beyond a predetermined position in the fuel injection amount increasing direction of the control rack. At this time, the urging member urges the third cam plate with respect to the first cam plate in the fuel injection amount decreasing direction of the control rack. As a result, the third cam plate is urged against the control rack in the fuel injection amount decreasing direction. Further, the adjusting member is a third
The movement of the cam plate in the fuel injection amount decreasing direction is restricted. Therefore, the third cam plate is held at a position where the movement is regulated by the adjusting member.

The third cam plate contacts the rack pin from the side of increasing the fuel injection amount and defines the rated position of the rack pin. Therefore, the rated position of the rack pin can be adjusted by the adjusting member. Therefore, the rated position of the rack pin can be easily adjusted without replacing the first cam plate.

After the internal combustion engine is stopped, the second cam plate is disengaged from the first cam plate, and the first cam plate moves beyond the predetermined position in the direction of increasing the fuel injection amount of the control rack. Allow to move. Therefore, at the time of starting, the first cam plate moves beyond the predetermined position. Again, the third
The cam plate is urged in the fuel injection amount decreasing direction with respect to the first cam plate. However, since the first cam plate moves, the rack pin moves beyond the rated position in the fuel injection amount increasing direction.
For this reason, the fuel injection amount becomes a large value exceeding the rating,
A large torque can be generated in the internal combustion engine.

[0016]

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing the appearance of a fuel injection pump 1 according to an embodiment to which the present invention is applied. This fuel injection pump 1 is a so-called row type fuel injection pump having three cylinders 3 arranged in parallel. A plunger (not shown) in each cylinder 3 moves up and down with rotation of a cam 7 to supply fuel. Inject.
The fuel injection amount can be adjusted by moving the control rack 13.

A first cam plate 21 and a third cam plate 21 are provided on a first pin 19 protruding between a long hole 14 formed in parallel with the moving direction of the control rack 13 and a flange portion 17 of a housing 15. The cam plate 31 is swingably supported.
The first cam plate 21 has a long side 2 disposed on the fuel injection amount increasing side of a rack pin 25 protruding from the control rack 13.
6 and a short-sided 27 through which the first pin 19 passes through the center. Further, a hook 2 that is engaged with a second cam plate 41 described later is provided at a tip portion of the long side 26.
9 are formed. Further, the first cam plate 21 is urged by the cylindrical coil spring 30 in the fuel injection amount decreasing direction.

On the other hand, the third cam plate 31 is a U-shaped metal plate composed of a short side 33 through which the first pin 19 passes through the center and a contact portion 35 contacting the rack pin 25. A tension coil spring 37 as a biasing member is suspended between the contact portion 35 and the long side 26 of the first cam plate 21. The tension coil spring 37 is used to connect the third cam plate 31 to the first cam plate 2.
1 is urged in the fuel injection amount decreasing direction. In addition, a tip portion of the short side 33 contacts an adjustment bolt 51 described later.

A second pin 39 is provided on the side of the housing 15 opposite to the first pin 19 with the elongated hole 14 interposed therebetween. The second pin 39 allows the second cam plate 41 to swing. It is supported. The second cam plate 41 is connected to the first cam plate 21.
A notch 43 that engages with the short side 27 and an engagement end 47 that engages with the hook 29 are urged by a cylindrical coil spring 49 in the fuel injection amount increasing direction.

Further, an adjusting bolt 51 as an adjusting member is screwed to the flange portion 17. Adjustment bolt 51
Is brought into contact with the short side 33 of the third cam plate 31 so that
The movement of the third cam plate 31 in the fuel injection amount decreasing direction is restricted. The adjustment bolt 51 has a head 51a and a flange 1
7, a fastening nut 53 is screwed. Therefore, the adjustment bolt 51 rotates the head 51 a to rotate the flange 1.
7 can be adjusted, and the amount of insertion into the flange 17 can be fixed by tightening the fastening nut 53 in the direction of the flange 17.

Next, a force P corresponding to the accelerator operation amount and the engine speed is applied to the control rack 13 by the mechanism illustrated in FIG. That is, the control rack 13
The tip of the speed control lever 61 is engaged with the rack pin 25. The fulcrum 61a of the speed control lever 61 and the rack pin 25
A governor spring 65, the other end of which is connected to the speed control lever 63, is connected between them. The speed control lever 63 swings in conjunction with an accelerator pedal (not shown).

At the other end of the speed control lever 61, a sliding shaft 69 having a pair of opposed heavyweights 67 is provided.
It is provided slidably in one direction. The sliding shaft 69 rotates in conjunction with a camshaft of an internal combustion engine (not shown). When the sliding shaft 69 rotates, a centrifugal force f is applied to the weight 67, and accordingly, a force F in the direction of the speed control lever 61 is applied to the sliding shaft 69.

In the fuel injection amount adjusting device according to the present embodiment having the above-described configuration, the tip of the short side 27 and the notch 43 are engaged during the normal operation of the internal combustion engine as illustrated in FIG. Due to this engagement, the first cam plate 21 cannot move beyond the predetermined position in the fuel injection amount increasing direction. Therefore, even if a large force is applied to the rack pin 25 in the direction of increasing the fuel injection amount by the mechanism described with reference to FIG. 2, the first cam plate 21 does not move beyond the predetermined position.

The third cam plate 31 is provided with a tension coil spring 3.
7 urges the first cam plate 21 in the fuel injection amount decreasing direction. Therefore, the third cam plate 31 is urged in the direction of the rack pin 25, and is held at a position where the tip of the short side 33 is in contact with the adjustment bolt 51. Also, the tension coil spring 3
The urging force 7 is set to be larger than the force applied to the rack pin 25 from the governor spring 65 or the like. Therefore,
The rack pin 25 does not move in the fuel injection amount increasing direction beyond the rated position where the rack pin 25 contacts the contact portion 35. Therefore, in this embodiment, the fuel injection amount can be controlled within a predetermined range.

When the internal combustion engine is stopped, the control rack 13 moves in the direction of decreasing the fuel injection amount by the action of a solenoid (not shown) or a manual lever. Then, the engagement between the tip of the short side 27 and the notch 43 is released, and the engagement end 47 is engaged with the hook 29. For this reason, even if the power supply to the solenoid is stopped or the manual lever is returned, the front end of the short side 27 and the notch 43 are maintained in a disengaged state.

Therefore, when the accelerator is depressed at the time of starting,
A force in the fuel injection amount increasing direction is applied to the rack pin 25 via a speed control lever 63 and a governor spring 65. As a result, the first cam plate 21 moves in the fuel injection amount increasing direction beyond the predetermined position defined by the engagement of the short side 27 and the notch 43 as shown in FIG. Also at this time, the third cam plate 31 is urged against the first cam plate 21 in the direction of decreasing the fuel injection amount, but since the first cam plate 21 moves freely, the rack pin 25 exceeds the rated position. Moving. Therefore, when starting the internal combustion engine,
By controlling the fuel injection amount to a large value exceeding the rating, a large torque can be obtained.

Next, the rated position of the rack pin 25 is as follows.
It is an important factor in determining the maximum rating of an internal combustion engine. This rated position must be adjusted for each individual fuel injection pump 1 due to variations in the parts to be assembled, etc. In this embodiment, this adjustment can be performed easily as follows. That is, in the present embodiment, the above-mentioned rated position is defined by the position where the short side 33 of the third cam plate 31 abuts on the adjustment bolt 51. Therefore, it is only necessary to adjust the insertion amount of the adjustment bolt 51 into the flange portion 17. The above rated position can be easily adjusted.

For example, when the amount of insertion of the adjustment bolt 51 is increased, the position where the short side 33 abuts on the adjustment bolt 51 moves away from the flange 17 as illustrated in FIG. For this reason, the position of the contact portion 35 when the internal combustion engine is driven moves in the fuel injection amount increasing direction, that is, the rated position of the rack pin 25 moves in the fuel injection amount increasing direction. At this time, the long side 26
The length L from the side edge to the side edge of the contact portion 35 is reduced.

As described above, in this embodiment, the adjusting bolt 51 is used.
By changing the amount of insertion into the flange portion 17,
The rated position of the rack pin 25 can be easily adjusted. Therefore, when adjusting the rated position of the rack pin 25, when the internal combustion engine is driven, the insertion amount of the adjustment bolt 51 is changed, and when the maximum rating of the internal combustion engine becomes an appropriate value, the adjustment nut 53 is used to adjust the adjustment position. The insertion amount of 51 may be fixed. That is, in adjusting the rated position of the rack pin 25, a large number of first cam plates 21 are prepared,
It is not necessary to replace the first cam plate 21 many times. Therefore, it is possible to suppress the material cost required for manufacturing the fuel injection pump 1 and improve the work efficiency, thereby reducing the manufacturing cost of the fuel injection pump.

In the above embodiment, the adjustment bolt 51 is fixed by the tightening nut 53.
1 may be fixed by an adhesive or a wire. In this case, rework in the market can be prevented. Further, a dustproof cap may be provided on the fixed adjustment bolt 51.

[0031]

As described in detail above, in the fuel injection amount adjusting device for a fuel injection pump according to the present invention, the adjusting member
The rated position of the rack pin can be easily adjusted without replacing the first cam plate. Therefore, in adjusting the rated position of the rack pin, it is not necessary to prepare a large number of first cam plates or replace the first cam plate many times. Therefore, it is possible to suppress the material cost and labor involved in manufacturing the fuel injection pump, improve the work efficiency, and reduce the manufacturing cost of the fuel injection pump.

[Brief description of the drawings]

FIG. 1 is a front view illustrating an appearance of a fuel injection pump according to an embodiment.

FIG. 2 is an explanatory diagram illustrating a control rack drive mechanism of the fuel injection pump according to the embodiment.

FIG. 3 is a front view illustrating the fuel injection amount adjusting device of the fuel injection pump of the embodiment when the internal combustion engine is driven.

FIG. 4 is a front view illustrating the fuel injection amount adjusting device of the fuel injection pump according to the embodiment when the internal combustion engine is started.

FIG. 5 is a front view illustrating a fuel injection amount adjusting device of the fuel injection pump according to the embodiment in which a rated position is changed.

FIG. 6 is a front view showing a conventional fuel injection amount adjusting device for a fuel injection pump when the internal combustion engine is driven.

FIG. 7 is a front view showing a conventional fuel injection amount adjusting device for a fuel injection pump when the internal combustion engine is started.

[Explanation of symbols]

1. Fuel injection pump 13. Control rack
21: first cam plate 25: rack pin 31: third cam plate
37 ... Tension coil spring 41 ... Second cam plate 51 ... Adjustment bolt
53 ... Tightening nut

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 61-92730 (JP, U) Japanese Utility Model Sho 60-108730 (JP, U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F02D 1/00-1/18

Claims (1)

(57) [Claims] 1. A control rack provided on a fuel injection pump for adjusting a fuel injection amount according to a movement position, a first cam plate provided on a fuel injection amount increasing side of a rack pin protruding from the control rack. During normal operation of the internal combustion engine, it engages with the first cam plate,
The first cam plate is prohibited from moving beyond a predetermined position in the fuel injection amount increasing direction of the control rack, and after the internal combustion engine is stopped, the engagement is released, and the first cam plate is released. A second cam plate for allowing the control rack to move beyond the predetermined position in the fuel injection amount increasing direction; and a second cam plate disposed on the first cam plate and abutting on the rack pin from the fuel injection amount increasing side. A third cam plate for defining a rated position of the rack pin; and a third cam plate provided between the third cam plate and the first cam plate, wherein the third cam plate is mounted on the control rack with respect to the first cam plate. And a regulating member for regulating the movement of the third cam plate in the fuel injection amount decreasing direction to adjust the rated position of the rack pin. Characteristic fuel injection pon Fuel injection amount adjustment device.