JPS5838618B2 - Injection amount control device for distribution type fuel injection pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an injection amount control device for a distributed fuel injection pump for a diesel engine.

The purpose of this invention is to provide a distribution type fuel injection pump that can prevent shock during sudden acceleration and instantaneous increase in smoke that occurs during acceleration, has good deceleration response during deceleration, improves fuel efficiency, and does not impair performance during deceleration. The object of the present invention is to provide a quantity control device.

In other words, as an injection amount control device for a distribution type fuel injection pump, in which a high pressure pump is provided with a sliding control slide and the fuel injection amount is controlled by the position of the control slide that changes depending on the operating condition, the injection amount control device shown in FIG. There was something like the one shown in ("Technical Manual Diesel Engine" published by Nissan Motor Co., Ltd. in June 1978)
P84-P94).

The injection amount control device shown in FIG. 1 is in a stopped state, and since the control slide 12 is blocking the governing hole 13 of the high pressure pump 14, this corresponds to the maximum injection amount state.

When the engine starts in this state, the centrifugal governor 1 begins to open due to the action of centrifugal force.

When the engine speed increases to near idling, the centrifugal force of the centrifugal governor 1 overcomes the reaction force of the leaf spring 7, pushing the governor sleeve 3 and lever 9 to the right in FIG.

Since the lever 9 swings about the fulcrum 11, the control slide 12 is moved to the left in FIG. 1, the governing hole 13 is opened, and the fuel injection amount is reduced to maintain a predetermined rotation.

To increase the engine output, turn the control lever 22.

Then, the tension of the spring 4 increases, so that the lever 6 is pulled to the left in FIG.

The lever 6 swings about a fulcrum 11, and by the reaction force of the leaf spring 7 attached to the lever 9, the governor sleeve 3 is moved to the left in FIG. 1, and the control slide 12 is moved to the left in FIG. Move it to the right, that is, in the direction that closes the governing hole 13.

Therefore, the injection amount increases and the engine output increases.

That is, the injection amount is determined by the balance between the centrifugal force of the centrifugal governor 1 (determined by the engine speed), the reaction force of the leaf spring 7, and the tension of the spring 4 (which is proportional to the opening degree of the control lever 22).

In FIG. 1, 5 is a pump chamber, 8 is a lever, 16 is an injection timing mechanism, 17 is an eccentric disk, 18 is a roller, and the feed pump 19 and injection timing mechanism 16 are shown in the drawing for ease of understanding. 90 against
It is shown rotated by °.

19 is a feed pump, and 20 is a pressure regulating valve.

As mentioned above, the control slide 12 slides left and right on the high pressure pump 14 to control the injection amount, but the responsiveness of the control slide 12 is affected by the size of the orifice 15 provided in the governor sleeve 3. receive.

The size of the orifice 15 is provided to adjust the speed of fuel flowing in and out between the governor shaft 21 and the governor sleeve 3.

The faster the fuel flows in and out through the orifice 15, the better the movement of the governor sleeve 3 from side to side in FIG. That's because it's really bad.

However, in the case of the above-mentioned remote injection amount control device, the diameter of the orifice 15 remains unchanged, so if the diameter of the orifice 15 is made sufficiently large for the purpose of improving the responsiveness of fuel increase/decrease, the Karo speed will increase. Sometimes control slide 1
2 suddenly moves to the right in FIG. 1, resulting in occasional overrun, resulting in rapid acceleration and smoke.

On the other hand, if the diameter of the orifice 15 is made smaller in order to prevent the sudden acceleration and the generation of smoke, there is a problem in that the responsiveness of deceleration deteriorates, leading to poor deceleration and deterioration of fuel efficiency.

This invention was made with the aim of solving the above-mentioned conventional problems.

The gist of this invention is to install a one-way valve device on the control slide that increases the resistance to movement in the direction of increasing the injection amount and reduces the resistance to movement in the direction of the decrease in the injection amount; An injection amount control device for a distribution type fuel injection pump is characterized in that the movement responsiveness of the fuel injection pump is delayed and the movement responsiveness in the fuel decreasing direction is not deteriorated.

In this invention, the one-way valve device closes when the control slide moves in the fuel increasing direction to increase the movement resistance, and opens when the control slide moves in the fuel decreasing direction to reduce the movement resistance. It does not matter what the configuration is.

Next, the present invention will be explained in detail.

2A to 2C show an injection amount control device in which a control slide 12 that slides on a high pressure pump 14 is provided with a one-way valve device.

The control slide 12 is provided with a passage 26, 26 passing through the control slide 12, the diameter of which changes in three steps in the direction of movement,
A small diameter passage 23 is located at the maximum diameter part of each passage 26 on the left side in the figure.
The orifice 24 having a
．． A notch 25a is provided at the middle diameter portion of 26.

A valve 25.25 having a diameter 25a is axially movably inserted into the passageway 26.

The movement of the valve 25 to the left in the figure is restricted by an orifice 24, and the movement to the right is restricted by a stepped portion 27 with a different diameter.

That is, after the passage 26 is provided in the control slide 12, the valve 25 is first inserted into the middle diameter part thereof, and then the orifice 24 is press-fitted into the maximum diameter part at the left end of the passage and fixed.

The diameter of the small diameter passage 23 of the orifice 24 is smaller than the diameter of the right end minimum diameter portion 26a of the passage 26.

When the valve 25 is in close contact with the orifice 24, the small diameter passage 2
3, but the notch 25a is formed so as not to close the minimum diameter portion 26a even if it comes into close contact with the step portion 27 having a different diameter.

The notch 25a in the valve 25 is formed as a groove with a semicircular cross section that passes through the valve 25 in the axial direction, as an example of which is shown in FIG.

However, the cross-sectional shape and number of notches 25a are not limited to the illustrated example.

Thus, when the valve 25 comes into close contact with the orifice 24, the flow from right to left in the figure in the passage 26 is stopped, and conversely, when the valve 25 comes into close contact with the stepped portion 27 of different diameter, the flow from the right to the left in the passage 26 is stopped.
A one-way valve device is constructed that allows flow from left to right in the figure within 6.

Note that FIGS. 2B and 2C above show a configuration in which two one-way valve devices are installed symmetrically on the control slide 12, but the number of unidirectional valve devices is determined based on the request for adjusting the magnitude of the movement resistance of the control slide 12. and then decide.

Next, the operation of the injection amount control device having the above configuration will be explained.

When the engine accelerates, the control slide 12 is moved in the direction of increasing the fuel injection amount, that is, in the right direction in the figure.

At this time, the valve 25 in the one-way valve device comes into close contact with the orifice 24 due to its inertia and the drag force of the fuel and closes the small diameter passage 23.

For this reason, even though the control slide 12 moves through the fuel in the pump chamber 5, the fuel does not flow through the passage 26, and the resistance to valve movement increases, resulting in a slight delay in response and desired acceleration.

Conversely, when the engine is decelerating, the control slide 12
is moved in the direction of decreasing the fuel injection amount, that is, to the left in the figure, which opens the governing hole 13.

At this time, the valve 25 in the one-way valve device comes into close contact with the step portion 27 having a different diameter due to its inertia and the drag force of the fuel.

However, the small diameter passage 23 and the minimum diameter portion 26a are communicated with each other by the notch portion 25a.

Therefore, the fuel flows through the passage 26, the valve movement resistance is small, the control slide 12 responds quickly, and desired deceleration performance is obtained.

Note that the one-way valve device is configured so that the movement resistance of the control slide in the direction of decreasing the injection amount is the same value as the current one.

For example, the diameter of the orifice 15 of the governor sleeve 3 is made smaller than that of the conventional one, or the control slide 1
It is distantly related by either increasing the drag area (projected area) of 2.

Regarding the initial settings, it can be freely determined whether the resistance is set optimally during acceleration and the resistance is small during deceleration, or whether the resistance is optimally set during deceleration and increased during acceleration.

Next, the effects of this invention will be explained.

As mentioned above, this invention sets a one-way valve device on the control slide, increases the movement resistance of the control slide during acceleration and delays its response, and conversely reduces the movement resistance of the control slide during deceleration. This structure prevents shock during sudden acceleration and the instantaneous increase in smoke that occurs during acceleration, and also provides good deceleration response during deceleration, improving fuel efficiency and impairing performance during deceleration. That is not the case.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a distribution type fuel injection pump, Figure 2A
is a sectional view of the injection amount control device, FIG. 2B is a left side view of FIG. 2A, FIG. 2C is a sectional view of FIG.
The figure is a sectional view of the one-way valve device, FIG. 4A is a sectional view of the valve, and FIG. 4B is a left side view of FIG. 4A. 14... High pressure pump, 12...
... Control slide, 13 ... Governor hole, 26 ... Passage, 25a ... Notch, 25 ... Valve, 23 ...・Small diameter passage, 24...orifice.

Claims (1)

[Scope of Claims] 1. An injection amount control device for a distribution type fuel injection pump in which a high pressure pump is provided with a sliding control slide and the fuel injection amount is controlled by the position of the control slide that changes depending on the operating state. Injection amount control of a distribution type fuel injection pump characterized in that a unidirectional valve device is installed on the control slide to increase the resistance to movement in the direction of increasing the injection amount and to reduce the resistance to movement in the direction of decreasing the injection amount. Device. 2. The one-way valve device according to claim 1, wherein a valve having a notch is interposed in a passage having a step with a different diameter and passing through a control slide in the direction of movement of the control slide. Injection amount control device.