JPH05263728A - Fuel injection device - Google Patents

Abstract

PURPOSE:To enable optimum fuel injection control without depending on electronic control and attain cost reduction and the like by forming an obliquely extended cutout at the outer peripheral part of a control sleeve, and fitting a timing rod, engaged with the cutout, to the tension lever of a governor. CONSTITUTION:In a governor 1, a timing rod 11 fitted to the upper oscillating end 6 of a tension lever 5 is placed in an initial fixed position at the low rotation time of an engine when a flyweight 3 provided at a rotary shaft 2 is not opened, and a control sleeve is fitted to a plunger 12 is held in a relatively high position so as to position its spill port 14 above. At the same time, the position of a control rack 10 is made invariable so as to obtain the unlimited state of fuel injection quantity. At the high rotation time of the engine, the flyweight 3 is opened, and the tension lever 5 is oscillated. The timing rod 11 is thereby pressed to move a pin 16 along a cutout 15, and the control sleeve 13 is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device provided in an internal combustion engine.

[0002]

2. Description of the Related Art Generally, a fuel injection device for a diesel engine is equipped with a governor for adjusting a fuel injection amount. This governor changes the position of the control rack according to the engine rotation speed in addition to the accelerator pedal opening. By moving the control rack forward and backward, the plunger is rotated and its effective stroke is changed to change the engine rotation speed. The fuel injection amount is limited as the speed increases.

Recently, an electronically controlled injection mechanism (governor actuator) for detecting the state of an engine or a vehicle and controlling the optimum injection amount and injection timing is also used. I am trying to improve.

[0004]

However, since the electronically controlled governor is very expensive, the cost of the fuel injection device becomes high, and there is a risk of disconnection and loss of control. Therefore, it is preferable to obtain the optimum fuel injection by a mechanical mechanism, but there is no mechanical fuel injection device that optimally controls the injection rate and the like.

Therefore, in view of the above circumstances, the present invention was devised to provide a fuel injection device that performs optimum fuel injection without using electronic control.

As a technique to be compared with the present invention, a "fuel injection device for an internal combustion engine" (actually opened) in which the control sleeve is moved up and down according to the engine speed to adjust the injection timing according to the engine speed and load. JP-A-57-196256) has been proposed. However, in this proposal, in order to move the control sleeve up and down, an elongated hole is provided in the link that rotates due to an increase in the number of rotations, and the control sleeve is rotated through this elongated hole. As a result, the relationship between the rotation angle and the moving distance along the slot changes, and the timing cannot be advanced in proportion to the engine speed, which is insufficient to control the optimum fuel injection. it is conceivable that.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a control lever having a spill port has a diagonally extending notch formed in the outer peripheral portion thereof, and a tension lever of a governor that swings due to an increase or decrease in engine speed, The timing rod is attached to engage with the notch to move the control sleeve up and down.

[0008]

With the above structure, the timing rod moves the control sleeve up and down in accordance with the increase and decrease of the engine speed to obtain the advance angle proportional to the speed.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the governor 1 for adjusting the fuel injection amount will be described with reference to FIG. The governor 1 includes a flyweight 3 provided on a rotary shaft 2, a tension lever 5 that is pushed by the opening / closing operation of the flyweight 3 and swings around a support shaft 4, and an upper swing end of the tension lever 5. 6, a torque cam 8 connected via a short rod 7, a sensor lever 9 that engages with the torque cam 8 to swing, and a control rack 10 that moves back and forth due to the swing of the sensor lever 9. .. The control rack 10 is meshed with a pinion (not shown) provided around a plunger of a fuel injection device body (not shown). Therefore, if the engine speed gradually increases,
The tension lever 5 swings according to the relationship between the set number of revolutions and the flyweight lift 3, and the torque cam 8 is rotated by the swing as indicated by an arrow d in the figure. That is, the positions of the torque cam 8 and the sensor lever 9 are determined according to the number of rotations, the tip of the sensor lever 9 moves according to the shape of the torque cam surface, and the full load rack position is controlled.

A timing rod 11, which is a feature of the present invention, is attached to the upper swing end 6 of the tension lever 5 on the side opposite to the torque cam 8 and is held in parallel with the control rack 10. That is, as the tension lever 5 swings, it reciprocates in the rod extension direction.

On the other hand, as shown in FIG. 2, a control sleeve 13 is slidably fitted in the plunger 12 up and down, and a spill port 14 which is appropriately connected to a known lead groove formed in the plunger 12 is formed. Is dripping Further, an obliquely extending notch 15, which is a feature of the present invention, is formed on the outer peripheral portion of the control sleeve 13. As shown in FIGS. 3 and 4, a pin 16 protruding from the side surface of the timing rod 11 is fitted in the notch 15 so as to be movable along the extension direction of the notch 15. This pin 16
The timing rod 11 is formed so as to be located at the lower end of the notch 15 in the initial position (during low speed rotation).
Further, as shown in FIG. 2B, a guide groove 16 for preventing rotation is formed on the outer peripheral portion of the control sleeve 13.
It is engaged with a convex portion (not shown) formed on the housing.

Therefore, as shown in FIGS. 3 and 4, when the flyweight 3 is not opened and the engine is running at a low speed, the timing rod 11 is in the initial fixed position, and the control sleeve 13 is moved relative to the position shown in FIG. The spill port 14 is positioned above by holding the spill port 14 upward. At this time, the position of the control rack 10 does not change,
There is no restriction on the fuel injection amount. Then, when the engine is rotated at high speed and the flyweight 3 is opened and the tension lever 5 starts to swing, the timing rod 11 is pushed and the pin 16 moves along the notch 15, as shown in FIG. The control sleeve 13 is lowered.

Thus, as shown in FIG. 5, the control sleeve 13 is held in the upper position in the low engine speed region, so that the prestroke of the plunger 12 becomes large and delayed injection timing is obtained, and the cam lift is increased. Due to the characteristics of the curve, it is possible to use a portion with a relatively high injection rate of the cam. Further, in the high rotation region, the control sleeve 13 is set to the lower position, the pre-stroke becomes small, and the advanced injection timing is obtained, and the portion with a low injection rate of the cam can be used (A> B in the figure).

That is, as shown in FIG. 6, in the conventional case (indicated by a broken line in the figure), the pressure in the injection pipe increases in proportion to the engine speed, so that it is impossible to perform high-pressure injection in the entire speed range. However, according to the present invention, it is possible to obtain high-pressure injection in the low-medium speed range and obtain high-pressure injection in the high-speed range in a range that does not lead to pump breakdown. Therefore, a large-scale and expensive pre-stroke actuator becomes unnecessary, which can contribute to the cost reduction of the fuel injection device.

Further, in the present invention, the control sleeve 13 can be moved up and down in proportion to the forward and backward movement of the timing rod 11, and the advance characteristic proportional to the engine speed can be obtained. Further, the advance angle (prestroke) characteristic can be easily changed only by changing the inclination angle of the notch 15 of the control sleeve 13.

[0017]

In summary, according to the present invention, the following excellent effects are exhibited.

Since a notch extending obliquely is formed on the outer peripheral portion of the control sleeve, and a timing rod that engages with the notch is attached to the tension lever of the governor that swings due to an increase / decrease in engine speed, it does not depend on electronic control. The fuel injection can be optimized and cost reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a fuel injection device according to the present invention.

FIG. 2 is a diagram showing a control sleeve of the present invention,
(A) is a side view, (b) is a top view, (c) is another side view.

FIG. 3 is a side sectional view of FIG. 2, in which (a) is a low-speed engine rotation state and (b) is a high-speed engine rotation state.

FIG. 4 is a side view of FIG. 3, in which (a) is a low-speed engine rotation state and (b) is a high-speed engine rotation state.

FIG. 5 is a comparison diagram of a control sleeve position and a cam lift / cam angle relationship diagram for explaining the operation of the present invention.

FIG. 6 is a relationship diagram between the pressure in an injection pipe and the engine speed for explaining the effect of the present invention.

[Explanation of symbols]

 1 Governor 5 Tension lever 11 Timing rod 13 Control sleeve 14 Spill port 15 Notch

Claims (1)

[Claims] 1. A control sleeve having a spill port is formed with an obliquely extending notch on an outer peripheral portion thereof, and a tension lever of a governor swinging according to an increase or decrease in engine speed is used to move the control sleeve up and down. A fuel injection device, characterized in that a timing rod engaged with the notch is attached.