JPH01290959A - Control method for fuel injection valve - Google Patents

Abstract

PURPOSE:To make constant the crank shaft rotating angle at which fuel is injected in all speed ranges of an engine by setting the number of reversals of a reciprocative valve body prior to the fuel injecting timing larger in the low speed revolving range and smaller in the high speed revolving range. CONSTITUTION:Fuel from a fuel pump 4 is supplied to a fuel injection valve 1 via a throttle 61. Prior to the fuel injecting timing, a valve body 35 is reciprocated in a short time so that the injection valve body 13 does not move. Therein a control device 62 controls current supply to a solenoid 32, and the number of reversals of the valve body 35 shall be made larger in the low speed revolving range and smaller in the high speed revolving range. This drops the fuel pressure gradually at every reciprocative motion, so that the fuel injection pressure can be controlled so as to be lower in the low speed revolving range and higher with increasing revolving speed. This enables injection of a specified amount in a short time in the high speed revolving range and in a long time in the low speed revolving range, which can make constant the crank shaft rotating angle at which the fuel is injected in all speed ranges.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of controlling a fuel injection valve used, for example, in a high-speed diesel engine.

[Conventional technology]

In recent years, there has been a widespread demand for electrical control of fuel injection in diesel engines in order to reduce fuel consumption in the -layer and purify exhaust gas.

In response to this, the applicant of the present invention previously proposed a high-pressure fuel injection device that can be electrically operated by an electromagnet in Japanese Patent Application No. 192577/1983. This is a so-called balanced type that applies fuel pressure before and after the injection valve body that opens and closes the fuel injection port, and the valve body that is operated by an electromagnet closes the valve port that releases the pressure inside the small chamber. The fuel injection port is controlled to close the fuel injection port by pressing the injection valve body with the fuel pressure of 200.degree., and to inject fuel from the fuel injection port by opening the valve port and retracting the injection valve body.

[Problem to be solved by the invention]

However, with this control method, the fuel pressure in the pressure accumulation chamber is kept constant, so when the engine speed changes, the rotation angle of the crankshaft at which fuel is injected also changes. was there. That is, although it takes a predetermined amount of time to inject a predetermined amount of fuel under certain conditions, the crankshaft rotation angle relative to the required time varies depending on the engine rotation speed. The present invention was made in view of the above circumstances, and provides a fuel injection valve control method that can make the crankshaft rotation angle at which fuel is injected constant from a low engine speed range to a high engine speed range. It is something.

[Means to solve the problem]

The control method according to the present invention supplies fuel to the fuel injection valve through the throttle, and also moves the valve body back and forth in a short time so that the injector valve body does not move before the fuel injection timing, and this reciprocating movement The number of times is increased in a low engine speed rotation range and decreased in a high speed rotation range, and the valve body is reciprocated so that the injection valve body moves at the fuel injection timing.

[Effect]

In the present invention, before the fuel injection timing, the fuel pressure in the pressure accumulation chamber is lowered according to the engine rotation speed, and the fuel is injected at that pressure at the fuel injection timing.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a fuel injection valve used in the fuel injection valve control method according to the present invention. The fuel injection valve, which is indicated by the reference numeral 1 in the same figure, is formed into a generally cylindrical shape as a whole.

A fuel injection port 2 is opened at the front end of this fuel injection valve 1,
A fuel supply port 3 is opened at the rear end. A fuel pump 4 is connected to the fuel supply port 3 , and fuel pressurized to a high pressure (for example, about 5001 ur/cwl) is pumped from the fuel tank 5 by the fuel pump 4 .

6 is a body which has a generally cylindrical shape with a small diameter at the front and a large diameter at the rear, and is screwed into a hollow front box 8 having a pressure accumulation chamber 7 inside, and a female thread provided at the rear opening of this front box 8. It consists of a rear section 10 that covers the rear of the front box 8 and the outside of the electromagnet 9, and is attached to the engine body (not shown) using a male screw 11 provided on the outer peripheral surface of the front box 8. A disc-shaped inner lid member 12, which defines the inside of the body 6 from front to back and forms the rear wall of the pressure accumulation chamber 7, is clamped and fixed between the front box 8 and the rear section 10. This inner lid member 1
An injection valve body 1 for opening and closing the fuel injection port 2 is located in the center of the fuel injection port 2.
A cylinder 14 is provided which holds the rear part of the 3. The rear part of the injection valve body 13 is formed to have a larger diameter than the front part, and is provided with a pressure receiving part 20 facing the pressure accumulation chamber 7. On the other hand, the front part of the injection valve body 13 is held by having a front end part 13a inserted into a nozzle tip 15 screwed onto the front end of the front box 8. A shim 16 is interposed between the nozzle tip 15 and the front box 8 to adjust the lift amount of the injection valve body 13. 17 is a small chamber formed by the bottom of the cylinder 14 and the rear end surface of the injection valve body 13 and having an extremely small volume. That is, the injection valve body 13 is housed in the body 6 and is held movable in the axial direction so that the front part faces the pressure accumulation chamber 7 and the rear part faces the small chamber 17. A flange portion 13b is protruded approximately at the center, and the injection valve body 13 is always placed between the spring receiver 18, which is locked by the flange portion 131), and the front surface of the inner lid member 12. A compression coil spring 19 is elastically mounted to bias the injection port 2 in a direction to close it.

21 is a vertical fuel passage that is opened in the fuel supply port 3 and passes through the peripheral wall of the rear section 10 in the axial direction; 22 is a horizontal fuel passage that passes radially between the cylinder 14 and the outer peripheral surface of the inner cover member 12; be. These fuel 1J11 paths 21 and 22 are communicated with each other through a communication passage 23. The lateral fuel passage 22 connects to a central chamber 2 provided at the rear of the injection valve body 13 via a communication hole 24.
It is connected to 5. The central chamber 25 is arranged on the axis of the injection valve body 13 and communicates with the small chamber 17 through an orifice of a brass orifice member 26 press-fitted into the rear end of the injection valve body 13 . 27 is a supply hole opened on the front surface of the inner lid member 12, which connects the horizontal fuel passage 22 and the pressure accumulation chamber 7.
It communicates with Reference numeral 28 denotes a valve port that communicates the small chamber 17 and the inside of the rear section 10 and releases the pressure inside the small chamber 17 into the shallow box 10, and is arranged on the axis of the inner lid member 12. The inside of the shallow box 10 is communicated with the outside through a fuel return port 29. The fuel return port 29 is a tube press-fitted and fixed to the rear end of the rear node 1O, and is formed to open rearward along the axial direction.
It is connected to the fuel tank 5.

The electromagnet 9 has a core γ31 having a shaft hole in the center, an electromagnetic coil 32 fitted into the core 31, and a cylindrical coil fitted so as to cover the outside of the electromagnetic coil 32 and the core 31. The yoke 33 has a cylindrical shape as a whole.

35 is a valve body interposed between the electromagnet 9 and the valve port 28 to open and close the valve port 28. The valve body 35 has a valve stem 35a extending toward the electromagnet 9 and being inserted into the shaft hole of the core 31 to be held movably forward and backward, and has a disc-shaped armature 36 on the outer periphery facing the core 31 and the yoke 33. are integrally provided. Further, the end surface of the valve body 35 on the valve port 28 side is formed into a smooth planar shape. A flat seat 41 is provided at the opening edge of the valve port 28 on the valve body 35 side.

The yoke 33 has a small diameter core holding part 33a that covers the outside of the electromagnetic coil 32 and holds the core 31, and a large diameter fixing part ((3b The front end surface of the fixed portion 33b is in contact with the inner lid member 12 via a shim 43.The portion between the core holding portion 33a and the fixed portion 33b is connected to the armature 36. They protrude inward so that the diameter becomes smaller toward the front so as to face each other.
An armature facing portion 33c is integrally provided here. The armature-facing portion 33 is located between the armature-facing portion 33c and the fixed portion 33b.
A portion close to c is formed to have a smaller cross-sectional area than other portions. Note that the yoke 33 has
A communication hole 44 communicating between the fuel coal inlet 29 and the valve port 28 is provided.

A compression coil spring 45 constantly presses the valve body 35 toward the valve port 28 and compresses and deforms itself in the axial direction. This spring 45 is loaded into a recess 46 provided on the axis of the core 31 on the side opposite to the armature. 47 is valve stem 3
A spring receiver provided at the rear end of 5a, 48 is a concave portion 46
This is an adjustment screw that is screwed onto the edge of the opening from the rear and adjusts the elastic force of the spring 45 depending on the amount of screwing.

51 is an external connection terminal member for connecting the electromagnetic coil 32 of the electromagnet 9 to an external power source. This terminal member 51 is formed in the shape of a screw shaft, and is fixed by a collar portion and a nut 52 so as to pass through the rear wall of the rear section 10, and the terminal 53 is held between the nuts 52 52 stacked in the axial direction. ing. , 54 is a sealing material that seals between the terminal member 51 and the rear section 10.

Next, a method of controlling the fuel injection valve 1 will be explained. Fuel from the fuel pump 4 is supplied to the fuel injection valve 1 through the throttle. In the embodiment, a throttle 61 is provided in the vertical fuel passage 21, and this throttle 61 has the function of separating the vertical fuel passage 21 into a fuel supply side and a pressure accumulation chamber 7 side. Note that the shape of the throttle 61 is such that fuel can be replenished before the next fuel injection timing. Then, before the C1 fuel injection time, the valve body 35 is reciprocated in a short period of time so that the injection valve body 13 does not move, and the number of movements is increased in a low engine speed rotation range and decreased in a high engine rotation speed range. Such control is performed by a control device 62 that controls energization of the electromagnetic coil 32.

That is, the control device 62 energizes the electromagnetic coil 32 so that the valve body 35 releases the pressure in the small chamber 17 and drives the injection valve body 13 at the fuel injection time, and also energizes the electromagnetic coil 32 for a very short time before the fuel injection time. Then, the electromagnetic coil 32 is energized.

The number of times of energization is determined according to the signal output from the engine rotational speed detector 63. This determination can be made by calculating the number of energizations by the control device 62 according to the engine rotation speed, or by calculating the number of energizations by the control device 62 in advance according to the engine rotation speed.
2. When the engine speed is high, the number of energizations is reduced to increase the fuel injection pressure, and when the engine speed is low, the number of energizations is decreased to lower the fuel injection pressure. Do more.

By controlling the fuel injection valve 1 in this way, the valve port 28 is opened before the fuel injection timing, and the pressure inside the pressure accumulating chamber 7 is reduced to the small chamber 1.
Since the fuel can be released through the pressure accumulator 7 and the fuel can be prevented from being supplied to the pressure accumulation chamber 7 by the throttle 61, the pressure inside the pressure accumulation chamber 7 can be lowered.

FIG. 2 is a graph showing the fuel pressure in the pressure accumulating chamber to explain the operation, in which the horizontal axis shows the crankshaft rotation angle θ, and the vertical axis shows the fuel pressure P in the pressure accumulating chamber. 6
5 is a line showing the fuel pressure P in the pressure accumulator 7 in the engine low speed range, 66 is a line showing the movement state of the valve body 35, and the upper part of the line 66 in the figure shows the movement of the valve body 35. Benguchi 2
8 is shown in an open state, and the lower part shows a state in which the valve port 28 is closed. Fuel is stored in the pressure accumulation chamber 7 at the supply pressure Ps, but before the fuel injection timing T near the crankshaft rotation angle O0, the small chamber 17 is closed in order for the valve body 35 to reciprocate in a short time. The fuel then escapes from the valve port 28 and returns to the fuel tank 5 via the fuel return port 29. Therefore, the fuel pressure P gradually decreases every time the valve body 35 moves back and forth, and reaches the fuel injection pressure Pi just before the fuel injection timing T. Here, the number of times the valve body 35 is moved is smaller in the high speed range and increased in the low speed range in accordance with the engine speed, so that the fuel injection pressure Pi is lower in the low engine speed range and the engine speed is lower. It can be controlled to increase as the value increases. - On the other hand, at fuel injection timing T, the opening time of the valve port 28 by the valve body 35 is lengthened, so that the small chamber 1
Since the pressure inside 7 drops significantly and the injection valve body 13 retreats, the fuel injection port 2 is opened and fuel is injected. In addition,
The fuel injection timing T is controlled to always be at a constant angle with respect to the crankshaft rotation angle θ.

Injecting a predetermined amount of fuel over a short period of time by injecting with high fuel injection pressure in the engine high speed rotation range, and injecting the predetermined amount over a long period of time by injecting with low fuel injection pressure in the engine low speed rotation range. Therefore, the crankshaft rotation angle at which fuel is injected can be made constant from a low engine speed range to a high engine speed range.

〔Effect of the invention〕

As explained above, according to the present invention, fuel is supplied to the fuel injection valve through the throttle, and the valve body is reciprocated in a short time so that the injection valve body does not move before the fuel injection timing, The number of reciprocating movements is increased in the engine's low-speed rotation range and decreased in the high-speed rotation range, and the valve body is moved back and forth so that the injector valve body moves at the fuel injection timing, so that the engine rotational speed is Accordingly, the fuel pressure in the pressure accumulation chamber can be lowered and fuel can be injected at that pressure.

Therefore, since the fuel injection pressure can be changed according to the engine rotation speed, the crankshaft rotation angle at which fuel is injected can be kept constant from a low engine rotation speed range to a high engine rotation speed range. In addition, since the fuel injected from the fuel injection port can be directly controlled, responsiveness can be improved, and even if the engine speed changes suddenly, it can be easily followed. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a fuel injection valve used in the fuel injection valve control method according to the present invention, and FIG. 2 is a graph showing the fuel pressure in the pressure accumulation chamber for explaining the operation. 1... Fuel injection valve, 7... Pressure accumulation chamber, 9...
Electromagnet, 13...Injection valve body, 17...Small chamber, 2
1... Vertical fuel passage, 35... Valve body, 61...
- Aperture, 62,...control device. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] An injection valve element for opening and closing a fuel injection port is held in a body having a pressure accumulation chamber and a small chamber to which pressurized fuel is supplied so that its front part faces into the pressure accumulation chamber and its rear part faces into the small chamber,
Fuel is supplied through a throttle to a fuel injection valve whose valve opening for releasing pressure in the small chamber is opened and closed by a valve body operated by an electromagnet, and the injection valve body does not move through the valve body before the fuel injection timing. A fuel injection valve that moves reciprocatingly in a short period of time, increases the number of reciprocating movements in a low engine speed range and decreases it in a high engine speed range, and moves the valve body back and forth so that the injector body moves at the fuel injection timing. Control method.