JPH0674776B2 - Injection amount adjustment device for fuel injection pump of diesel engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection amount adjusting device for a fuel injection pump of a diesel engine, which can eliminate the conventional fuel injection rack and simplify the structure of the device. I will provide a.

<Prior Art> As shown in FIG. 1 or FIG. 3, a basic structure of an injection amount adjusting device of a fuel injection pump of a diesel engine, which is an object of the present invention, is a fuel injection pump 1 of a diesel engine E.
The plunger 2 is inserted into the plunger body 3 to form the plunger chamber 4, the fuel suction port 20 is provided at the bottom dead center side portion of the plunger chamber 4, and the fuel discharge port 22 and the outlet valve are provided at the top dead center side portion thereof. It is of the type configured with 24.

As a conventional technique of this type, there is generally one configured as shown in FIG.

That is, a spiral injection amount adjusting groove 50 is formed on the outer peripheral surface of the plunger 2.
And the plunger 2 is linked to the control pinion 51 so as to be slidable up and down and rotatable together.

Further, the control pinion 51 is engaged with the fuel injection rack 52 of the fuel injection pump 1, and the rack pin 53 protruding forward from the fuel injection rack 52 is fitted with the fork-shaped output portion 54 of the governor lever 6.

As a result, the governor lever 6 which swings in accordance with the load of the engine E rotates the plunger 2 via the rack pin 53, the fuel injection rack 52 and the control pinion 51, and the fuel intake port 20 left in the plunger barrel 3 is opened. The amount of fuel injection is adjusted according to the load of the engine E by changing the effective stroke from the start of injection when the tip ends to the end of injection when the injection amount adjustment groove 50 starts to open.

<Problems to be Solved by the Invention> However, the above-mentioned conventional techniques have the following problems.

(1) Since a mechanism for interlocking the plunger 2 with the control pinion 51 so as to be slidable up and down and rotatable together, the control pinion 51, the fuel injection rack 52, and the injection amount adjustment groove 50 are necessary. The structure of the fuel injection adjusting device becomes complicated and the manufacturing cost becomes high.

(2) When the initial position of the fuel injection pump 1 is set, if the control pinion 51 and the fuel injection rack 52 are misaligned with each other, the initial position of the injection amount adjusting groove 50 is displaced with respect to the fuel intake port 20. Then, the fuel injection amount becomes incorrect, and the engine speed becomes abnormally high or low.

(3) When the fuel injection rack 52 is overdriven and overruns, the raised teeth of the rack may collide with the teeth of the control pinion 51 and lock the control pinion 51. is there.

In this case, the fuel injection amount cannot be adjusted, and the engine E
Goes into abnormally high rotation or engine stall.

An object of the present invention is to simplify the processing of the device, eliminate the setting error of the initial position, and perform accurate fuel injection.

<Means for Solving the Problems> Means for solving the above problems will be described below with reference to the drawings corresponding to the embodiments.

That is, the present invention relates to the injection amount adjusting device of the fuel injection pump of the diesel engine of the basic structure, in which the fuel retreat chamber communicated with the top dead center side portion of the plunger chamber 4 is provided.
10, a pressure-receiving actuating member 12 that is slidably inserted into and retracted from the fuel escape chamber 10 and moves to the side where the fuel escape chamber 10 is expanded by the fuel pressure in the fuel escape chamber 10, and the fuel in the fuel escape chamber 10. A pressure spring 14 that pushes the pressure receiving actuator 12 in a direction against the pressure and a tension adjusting member 15 that receives the output of the governor lever 6 and adjusts the tension of the pressing spring 14 increase the load of the engine E and increase the load of the governor. In the state in which the output of No. 1 is decreased, the tension adjusting member 15 increases the spring force of the pressing spring 14 to increase the counter force against the fuel pressure of the pressure receiving actuator 12, and the load of the engine E decreases to reduce the output of the governor. In the raised state, the tension adjusting member 15 reduces the spring force of the pressing spring 14 so that the counter force against the fuel pressure of the pressure receiving operating tool 12 is reduced.

<Operation> Generally, when the plunger 2 rises past the fuel intake port, the compression of the fuel in the plunger chamber 4 starts, and the fuel pressure continues to rise until it reaches the set discharge pressure of the fuel injection pump 1.

In this case, in this device, since the plunger chamber 4 communicates with the escape chamber 10, part of the fuel escapes from the plunger chamber 4 to the escape chamber 10 as the fuel pressure rises, and the spring force of the pressing spring 14 is increased. The escape stops when the force reaches a predetermined level.

Therefore, only the fuel remaining in the plunger chamber 4 is injected when the set discharge pressure is reached.

Then, the operation of this device will be described as follows: (1) When the load of the engine E increases, the governor lever 6
The swinging force of the pressure spring 14 increases the spring force of the pressure spring 14 via the tension adjusting member 15, and the counter force against the fuel pressure of the pressure receiving actuator 12 increases. Therefore, the escape amount of the fuel escaping from the plunger chamber 4 to the fuel escape chamber 10 is reduced. The amount of fuel that is suppressed and remains in the plunger chamber 4 when the set discharge pressure is reached increases, and the fuel injection pump 1
The amount of injection from is relatively increased.

(2) When the load on the engine E decreases, the governor lever 6
The swinging force reduces the spring force of the pressing spring 14 via the tension adjusting member 15 and reduces the counter force against the fuel pressure of the pressure-receiving actuator 12, so that the amount of fuel escaped from the plunger chamber 4 to the fuel escape chamber 10 is reduced. When the set discharge pressure is reached, the amount of fuel remaining in the plunger chamber 4 is accelerated, and the amount of fuel injected from the fuel injection pump 1 is relatively reduced.

<Effects of the Invention> (1) In the present invention, since the fuel reserving chamber is communicated with the plunger chamber, and the pressure receiving operation tool interlocking with the governor lever is fitted in the retreating chamber so as to be able to move forward and backward, the fuel injection pump. A simple process of forming a fuel escape chamber in the main body of the above is sufficient, and then the present device can be configured simply by accommodating a pressure receiving operation tool in the escape chamber.

Therefore, as in the prior art, a mechanism for interlocking the plunger to the control pinion so that it can slide up and down and accompany it, and a spiral injection amount adjusting groove formed on the control pinion, fuel injection rack, and plunger. Is unnecessary, and complicated processing work such as lead processing of the injection amount adjusting groove is eliminated, and the manufacturing cost can be reduced by simply configuring the entire apparatus.

(2) According to the present invention, the fuel injection amount can be adjusted only by selecting the spring constants of the pressing spring and the governor spring, and the rotary meshing structure by the combination of the fuel injection rack and the control pinion is not necessary. As in the prior art, the misalignment of the initial position and lock of the control pinion due to overrun of the rack are eliminated, and the fuel injection amount can be adjusted accurately.

<Example> An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of a main part of a fuel injection amount adjusting device showing a first embodiment, in which a plunger barrel 3 is formed in the center of a fuel injection pump 1 and a plunger 2 is slid up and down on the plunger barrel 3. Freely fit inside.

A fuel intake port 20 is provided in the middle part of the plunger body 3 in the vertical direction.
To form a fuel storage chamber 21 along the periphery thereof and to upwardly discharge the fuel from the upper end of the plunger barrel 3.
22 is opened, and an outlet valve 24 biased to be closed by a valve closing spring 23 is accommodated in the discharge port 22.

A columnar fuel retreat chamber 10 is formed laterally on the upper part of the plunger body 3 through a communication hole 25, and the other end 10a of the retreat chamber 10 is opened to the outer side portion 1a of the pump 1 so as to face the communication hole 25. The cup-shaped pressure receiving operation valve 12 and the other end opening 10a are faced, and the tension adjusting members 15 are fitted in the fuel retreat chamber 10 so as to be able to move forward and backward.

An O-ring 26 is provided around the side wall of the pressure receiving valve 12 to keep it oil-tight, and the fuel receiving valve 10 receives the fuel pressure flowing into the escape chamber 10 through the communication hole 25.

Further, the tension adjusting member 15 is a flat cylindrical guide portion.
15a and an input portion 15b projecting from the guide portion 15a toward the opening portion 10a, the tension adjusting member 15 and the pressure receiving valve 1
A pressure spring 14 is interposed between the pressure receiving valve 10 and the pressure receiving valve 10, and the pressure receiving operating valve 10 is configured to bias the communication hole 25 by the pressure spring 14.

Reference numeral 27 is a fuel return path from the evacuation chamber 10 to the fuel storage chamber 21, and reference numeral 28 is a stopper for preventing the tension adjusting member 15 from coming off.

On the other hand, a governor lever 6 is swingably supported around a fulcrum 29 on a cylinder block of the engine E, a lower end portion 6a of the governor lever 6 is interlocked with an engine speed governor 8, and a governor spring 7 is provided at an upper end portion 6b thereof. And the governor lever 6 is swung by an unbalanced force between the tension S of the governor spring 7 and the governor force F from the engine speed governor 8.

The engine speed governor 8 is a fly that pushes the governor sleeve 31 that slides back and forth along the governor shaft 30 and the governor sleeve 31 that rotates in the direction of arrow A about the fulcrum 32 when the engine speed increases. The governor sleeve 31 is a centrifugal speed governor including a weight 33 and a lower end portion of the governor lever 6.
It is attached to 6a.

The input portion 15b of the tension adjusting member 15 is brought into contact with the middle portion 6c between the upper end portion 6b of the governor lever 6 and the fulcrum 29 so that the unbalanced force acting on the governor lever 6 can be transmitted to the tension adjusting member 15. It Therefore, the function of the present fuel injection amount adjusting device will be described.

(1) When the load of the engine E increases, the engine speed decreases, the tension S of the governor spring 7 overcomes the governor force F of the governor 8, and the governor lever 6 pushes the tension adjusting member 15 in the direction of arrow P. .

The advancing of the tension adjusting member 15 compresses the pressing spring 14 to increase the spring force, and the counter force against the fuel pressure of the pressure receiving operating valve 12 increases.

As a result, when the plunger 2 rises above the fuel intake port 20 and the fuel pressure in the plunger chamber 4 increases, part of the fuel tries to flow from the plunger chamber 4 into the evacuation chamber 10, but the pressure is received. Since the counter force of the actuating valve 12 is strong, the amount of fuel withdrawn when the outlet valve 24 reaches the valve opening set pressure is small,
A large amount remains in the plunger chamber 4, and the injection amount of the fuel injection pump 1 increases.

(2) When the load of the engine E decreases, the engine speed increases, the governor force F of the governor 8 overcomes the tension of the governor spring 7, and the tension adjusting member 15 causes the tension adjusting member 15 to move in the direction of arrow Q due to the reciprocating swing of the governor lever 6. Change direction.

Withdrawal of the tension adjusting member 15 causes the pressing spring 14 to expand and the spring force to decrease, so that the counter force against the fuel pressure of the pressure receiving operating valve 12 decreases.

As a result, since the opposition force of the pressure receiving actuating valve 12 is weak, as the fuel pressure in the plunger chamber 4 increases, the amount of fuel saved in the save chamber 10 increases, and when the outlet valve 24 reaches the set opening pressure. In this case, the residual amount in the plunger chamber 4 is reduced and the injection amount of the fuel injection pump 1 is reduced.

On the other hand, FIG. 2 shows a second embodiment of the present invention, in which the pressure receiving valve
12 is a ball valve instead of the cup-shaped valve of the first embodiment, and the inner diameter of the cylindrical evacuation chamber 10 is adjusted to the outer diameter of the ball valve. It can be done easily.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is a longitudinal sectional view of a main portion of a fuel injection amount adjusting device showing the first embodiment, and FIG. 2 is a first embodiment showing the second embodiment. FIG. 3 is a schematic perspective view of a fuel injection amount adjusting device showing a conventional technique. 1 ... Fuel injection pump, 2 ... Plunger, 3 ... Plunger barrel, 4 ... Plunger chamber, 10 ... Fuel retreat chamber, 12
...... Pressure receiving actuator, 14 ...... Pressing spring, 15 …… Tension adjusting member, E …… Engine.

Claims (1)

[Claims] 1. A fuel injection pump 1 for a diesel engine E.
The plunger 2 is inserted into the plunger body 3 to form the plunger chamber 4, the fuel suction port 20 is provided at the bottom dead center side portion of the plunger chamber 4, and the fuel discharge port 22 and the outlet valve are provided at the top dead center side portion thereof. In the injection amount adjusting device of the fuel injection pump of the diesel engine configured by providing 24, the fuel retreat chamber communicating with the top dead center side portion of the plunger chamber 4
10, a pressure-receiving actuating member 12 that is slidably inserted into and retracted from the fuel escape chamber 10 and moves to the side where the fuel escape chamber 10 is expanded by the fuel pressure in the fuel escape chamber 10, and the fuel in the fuel escape chamber 10. A pressure spring 14 that pushes the pressure receiving actuator 12 in a direction against the pressure and a tension adjusting member 15 that receives the output of the governor lever 6 and adjusts the tension of the pressing spring 14 increase the load of the engine E and increase the load of the governor. In the state in which the output of No. 1 is decreased, the tension adjusting member 15 increases the spring force of the pressing spring 14 to increase the counter force against the fuel pressure of the pressure receiving actuator 12, and the load of the engine E decreases to reduce the output of the governor. In the ascended state, the tension adjusting member 15 reduces the spring force of the pressing spring 14 so that the counter force against the fuel pressure of the pressure receiving actuator 12 is reduced. Quantity adjustment device