JPS62276227A - Distribution type fuel injection pump - Google Patents

Abstract

PURPOSE:To simply regulate injection amount characteristics, by a method wherein a position allowing a control spring to be coupled with a tension bar, is regulatable in a direction in which it approaches and is separated from the fulcrum of the tension lever. CONSTITUTION:A notched groove 48, extended in the direction of the fulcrum of a tension lever 24, is formed in the tension lever. A governor spring sheet 45 is coupled to the notched groove 48, and the one end of a control spring 37 is coupled to a hook part 46 of the governor spring sheet 45. A control lever 49 is coupled to the rear end of the governor spring sheet 45, and the governor spring sheet 45 is moved along the notched groove 48 through rotating of the control lever 49. This constitution enables simple regulation of injection amount characteristics.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a distribution type fuel injection pump that distributes and supplies fuel to each cylinder of an internal combustion engine, and relates to a control device for a fuel injection port. .

[Conventional technology]

In general, a distribution type fuel injection pump moves a plunger, which is rotated in synchronization with the engine, back and forth during one revolution according to the number of cylinders by the action of a face cam and a cam roller.
During the compression process of the plunger, the fuel in the pressure pump chamber is pressurized and distributed to each cylinder of the engine.

In order to control the amount of fuel distributed to each cylinder, that is, the amount of injection, a spill port is provided on the plunger, and
A spill ring that opens and closes this spill port is slidably inserted into the plunger in the axial direction, and by moving this spill ring in the axial direction and opening the spill port, the oil is supplied to each cylinder. Fuel is allowed to escape from the spill port to a low pressure fuel chamber.

And to move this spill ring in the axial direction,
One end of each of a control lever and a tension lever, which are rotatably supported by a fulcrum, are connected to the spill ring. The control lever is rotated by the thrust generated in the flyweight that responds to the rotation of the drive shaft, and therefore moves the spill ring in the axial direction according to the engine rotation speed to inject fuel. Control quantity.

In addition, the tension lever is rotated by the amount of operation of the accelerator pedal being transmitted via a control spring, so the amount of fuel injection can also be controlled by operating the accelerator pedal. There is.

In the above distribution type fuel injection pump, the fuel injection amount characteristic generally exhibits the characteristic shown by the solid line in FIG. 4. In this case, in the maximum speed control range H, the pump rotation speed increases, the thrust generated in the flyweight overcomes the tension of the control spring, and the tension lever is rotated about the fulcrum, causing the spill ring to inject fuel. The fuel injection amount is controlled to be moved in the decreasing direction, thereby reducing the fuel injection amount to zero.

Incidentally, in recent years, in order to improve engine performance, there has been a demand for a structure in which the characteristics of the maximum speed control region H can be changed as shown by the dashed line in FIG.

As a technique for changing the characteristics of the maximum speed control region H, there is West German Publication No. DE3137520A1. In this device, the control spring is divided into two parts, and a rotation operation lever is used to connect the two control springs, and the rotation operation lever can be rotated from the outside with the rotation center point in the middle. It is something.

According to this, when the rotation operation lever is rotated, the tension force of the control spring changes, and the balance of the tension of the control spring against the thrust generated in the flyweight changes, so the movement characteristics of the spill ring are controlled. Injection quantity characteristics can be adjusted.

[Problem that the invention seeks to solve]

However, the above structure is composed of two control springs and a rotary operation lever that is rotated from the outside with a midway point as a fulcrum, so the structure is complicated and there is a problem in that it requires a particularly large installation space. .

In this type of pump, additional mechanisms such as a boost pressure compensator or an atmospheric pressure compensator may be installed close to the control spring installation location, and in such cases, the above-mentioned structure that occupies a large space is not suitable. Addition 11 There is a concern about interference with +R.

The present invention aims to provide a distribution type fuel injection pump which has a simple structure and requires a small installation space.

[Means for solving problems]

The present invention is characterized in that the position where the control spring is connected to the tension lever can be adjusted in the direction toward and away from a fulcrum on which the tension lever is rotatably supported.

[Effect]

According to the above configuration, when the position where the control spring is connected to the tension lever is adjusted in the direction toward and away from the fulcrum, the torque acting on the tension lever changes, which causes the tension lever to respond to the thrust generated in the flyweight. Since the rotational characteristics are controlled, the movement characteristics of the spill ring can be adjusted, and therefore the injection amount characteristics can be adjusted.

[Embodiments of the invention]

The present invention will be explained below based on an embodiment shown in FIGS. 1 to 3.

FIG. 3 shows the entire distribution type fuel injection pump, and in the figure, l is a drive shaft, which is driven by a diesel engine. The drive shaft 1 rotates a rotary feed pump 3 installed in a pump housing 2. The feed pump 3 sucks up fuel from a fuel tank 4, regulates the pressure of this fuel with a pressure regulating valve 5, and then sends it to a low-pressure fuel chamber 6. supply

A plunger 8 is connected to the drive shaft 1 via a coupling 7, and the plunger 8 is integrally provided with a face cam 9. The coupling 7 transmits the rotation of the drive shaft l to the plunger 8, and
allows for free movement in the axial direction.

The face cam 9 has a cam profile 9a formed on a surface opposite to the surface to which the plunger 8 is connected, and has a cam profile 9a having a number of peaks in the circumferential direction according to the number of cylinders of the engine. The cam roller lO is in rolling contact. As the cam roller 10 rolls into contact with the cam profile 9a, the face cam 9 and the plunger 8 are reciprocated multiple times during one rotation, that is, depending on the number of cylinders of the engine.

Note that the cam profile 9a is set in a shape that allows optimum fuel injection pressure and injection timing to be obtained in order to match desired engine performance.

During the suction stroke of the plunger 8, when one of the suction grooves 11 formed on the circumferential surface of the tip end of the plunger 8 communicates with the suction boat 12, the fuel in the low pressure fuel chamber 6 flows into the introduction passage 1.
3 into the pressure pump chamber 14 formed at the tip of the plunger 8.

During the compression stroke of the plunger 8, the fuel in the pressure pump chamber 14 is pressurized, and this pressurized fuel is pushed out into the vertical hole 15 formed inside the plunger 8. Since the plunger 8 is rotating at this time, when the supply port 1B opened on the circumferential surface communicates with one of the discharge ports 17, the injection passage 18 passes through the delivery valve 19 to the fuel injection valve. 20.

A spill ring 21 is slidably fitted into the plunger 8, and this spill ring 21 is connected to the plunger 8.
The formed spill port 22 is opened and closed.

The spill port 22 communicates with the vertical hole 15.

From the vertical hole 15 to the supply port) 1B and the discharge port 17
While fuel is being force-fed from the injection passage 18 to the fuel injection valve 20 via the spill port 22, the spill ring 21
When the vertical hole 15 is opened, the fuel in the vertical hole 15 escapes from the spill port 22 to the low pressure fuel chamber 6. For this reason, the fuel injection valve 20
Stop fuel supply to. Therefore, spilling 2
1 controls the fuel injection amount.

The spill ring 21 is connected to the control lever 23 and the tension lever 241 via a joint 60.

Both the control lever 23 and the tension lever 24 are rotatably attached to the guide lever 26 via a pin 25, and therefore the control lever 23
The tension lever 24 is rotatable about the bin 25 as a fulcrum. The guide lever 2B is connected to the other bin 27
The guide lever 28 is rotatably attached to the pump housing 2 by the pressure spring 2B.
The guide lever 26 is biased to rotate in one direction so that the upper end of the guide lever 26 comes into contact with a full load stopper 29 for adjusting the maximum injection amount.

In addition, the control lever 23 and the tension lever 24
are urged away from each other by a start spring 30 and an idle spring 31 provided between them. In addition, the tension lever 24 has a protrusion 3.
2 is formed, and when this protrusion 32 comes into contact with the control lever 23, the control lever 23 and the tension lever 24 rotate integrally.

The control lever 23 is pushed by a governor sleeve 33, and the governor sleeve 32 is caused to generate thrust by the operation of a flyweight 34. The flyweight 34 is rotated integrally with the driven gear 35 to generate centrifugal force, and this centrifugal force provides thrust to the governor sleeve 33. The driven gear 35 meshes with the drive gear 3B attached to the drive shaft 1.

Therefore, the rotation of the engine is from drive shaft 1 to drive gear 3.
The centrifugal force generated by the flyweight 34 is transmitted to the flyweight 34 through the drive gear 35 and the driven gear 35, and the centrifugal force generated by the flyweight 34 gives thrust to the governor sleeve 33. For this reason, the control lever 23 is pushed in accordance with the engine speed, thereby moving the spill ring 21 in the axial direction and regulating the fuel injection port.

On the other hand, the upper end of the tension lever 24 is connected to one end of a control spring 37 by means described later, and the other end of this control spring 37 is connected to an operating lever 38. The operating lever 38 is operated by an accelerator pedal (not shown). When the operating lever 38 is rotated by the accelerator pedal, the tension lever assembly 4 is rotated via the control spring 37.
The movement of the spill ring 21 in the axial direction is controlled according to the balance with the rotation of the spill ring 21. Therefore, the fuel injection amount can also be controlled by the accelerator operation amount.

The cam roller IO with which the face cam 9 is in rolling contact is,
It is supported by a roller ring 40, which is connected to a timer piston 42 via a rod 41. The timer piston 42 is housed in a pressure chamber 43, and the fuel pressure in the low pressure fuel chamber 6 is introduced into the pressure chamber 43.

When the fuel pressure in the pressure chamber 43 is changed according to the pressure in the low pressure fuel chamber θ, the timer piston 42 is displaced in the axial direction, and this displacement causes the roller ring 40 to rotate in the circumferential direction via the rod 41. Therefore, since the cam roller IO is displaced in the circumferential direction relative to the face cam 9, the timing at which the peak of the face cam 9 rides on the cam roller 10 changes, thereby controlling the injection timing.

Note that although the timer piston 42 and the pressure chamber 43 are actually provided in a direction perpendicular to the plane of the paper, they are shown as shown in the figure for convenience of drawing.

The connection between the upper end of the tension lever 24 and the control spring 3B will now be described with reference to FIGS. 1 and 2.

The control spring 37 is connected to the tension lever 24 via a governor spring seat 45. That is, a hook portion 46 is formed in the governor spring seat 45 so as to pass through the tension lever 24, and this hook portion 4B is connected to one end of the control spring 37. A governor spring 47 is provided between the governor spring seat 45 and the tension lever 24.

In this case, the tension lever 24 is formed with a cutout groove 48 that extends in the direction of the pin 25 described above, and the hook portion 46 of the governor spring seat 45 is inserted along this cutout groove 48, that is, as shown in FIG. It is inserted so that it can be moved up and down.

An operating lever 49 is located at the rear end of the governor spring seat 45.
are connected to each other, and the operating lever 49 is connected to the operating screw 50 by an operating screw 50 inserted into the pump housing 2.
It is designed to rotate around 0 as the rotation center. When the operating lever 49 is rotated by the operating screw 50, the governor spring seat 45 is moved along the notched groove 48.

Note that the operating screw 5o is fixed by a lock nut 51 after adjusting the position of the governor spring seat 45.

According to such a configuration, when the operating screw 50 is turned from the outside of the pump housing 2, the operating lever 49 is rotated.
Therefore, the governor spring seat 45 is moved along the notch groove 48. Changing the position of the governor spring seat 45 means that the point of action of the control spring 37 on the tension lever 24 changes.
In other words, the pin 2 serves as the center of rotation of the tension lever 24.
5 to the connection point of the control spring 37, the torque from the control spring 37 applied to the tension lever 24 is adjusted.

As a result, when the tension lever 24 is rotated based on the operation of the accelerator pedal, the balance with the rotation of the control lever 23 changes, and therefore the movement of the spill ring 21 in the axial direction changes. It is possible to finely adjust the fuel injection amount characteristics as shown by the chain line, that is, the slope of the maximum speed control range.

Moreover, according to the above configuration, the notch groove 48, the operating bar 4
9 and the operation screw 50, the structure is simple and does not require a large space to install them, so other additional equipment (not shown), such as a boost pressure compensator or an atmospheric pressure compensator, can be installed. It does not get in the way when arranging things such as.

In the above embodiment, the position of the governor spring seat 45 is adjusted by turning the operating screw 50 from the outside of the pump housing 2, but this adjustment is not necessarily performed from the outside.

〔Effect of the invention〕

As described above, according to the present invention, since the position where the control spring is connected to the tension lever is adjusted in the direction of approaching and separating from the fulcrum, the torque acting on the tension lever from the control spring side changes. This changes the balance with the control lever operated by the thrust generated in the flyweight, and adjusts the movement characteristics of the spill ring, thereby making it possible to adjust the injection amount characteristics. Moreover, since this device only requires adjusting the position where the control spring is connected to the tension lever, it has a simple structure and requires less space.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 and 2 are enlarged views of part A in FIG. A perspective view, FIG. 3 is a sectional view showing the entire distribution type fuel injection pump, and FIG. 4 is a diagram showing fuel injection amount characteristics. ■... Drive shaft, 7... Coupling, 8... Plunger, 9... Face cam, 10... Cam roller, 14... Pressure pump chamber, 20... Fuel injection nozzle, 21 ... Spill ring, 22... Spill port,
23... Control lever, 24... Tension lever, 25... Pin (fulcrum), 34... Fly weight, 37... Control spring, 45...
・Governor spring seat, 48...notch groove, 49・
...operation lever, 50...operation screw.

Claims (2)

[Claims] (1) A cam roller rotated by the internal combustion engine and a face cam in rolling contact with the cam roller convert the plunger into reciprocating motion multiple times during one rotation of the engine, and the reciprocating motion of the plunger causes the fuel in the pressure pump chamber to move. In addition to pressurizing and supplying it to each cylinder of the internal combustion engine,
By moving a spill ring that is slidably attached to the plunger, the spill port is opened to control the fuel injection amount, and the spill ring is actuated by a control lever and a tension lever that are rotatably supported by a fulcrum, In the distribution type fuel injection pump, the control lever is rotated by the centrifugal force of the flyweight, and the tension lever is rotated by the actuation of the accelerator operator being transmitted via a control spring. A distribution type fuel injection pump characterized in that the position where the control spring is connected to the tension lever can be adjusted in a direction toward and away from the fulcrum. (2) The adjustment structure for the position where the control spring is connected to the tension lever is an external adjustment operation means provided in the pump housing, which moves the governor spring seat that connects the control spring to the tension lever toward and away from the fulcrum. 2. The distribution type fuel injection pump according to claim 1, characterized in that the fuel injection pump is configured such that: