JP2000265920A - Electromagnetic fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stable injection amount in a low pulse area by combiningly utilizing coils for opening a valve, keeping it open, and closing the valve. SOLUTION: A coil in an electromagnetic fuel injection valve 30 which opens and closes a valve body for supplying fuel to an internal combustion engine due to magnetic force has followings. A valve opening coil 2 shows remarkable temporal variation ratio of magnetizing force. A valve open keeping coil 3 shows temporal variation ratio of the magnetizing force less than that of the valve opening coil 2. A valve closing coil 4 is prepard by widing a coil in the direction opposite to those of the valve opening coil 2 and valve open keeping coil 3. Magnetic flux generated in the closed or opened state of the valve is forcibly and speedily eliminated. Responsive characteristics at the closing time is improved for reducing closing delay, so that a stable injection amount can be obtained in a low pulse area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection device for an internal combustion engine, and more particularly to an electromagnetic fuel injection device effective for low voltage driving.

[0002]

2. Description of the Related Art An electromagnetic fuel injection valve, that is, an injector energizes a coil inside the injector, and attracts a plunger to which a ball valve is fixed by generated magnetic force.
When the valve is opened and fuel is injected and energization is stopped, the magnetic force is attenuated, and the return spring attached to the plunger closes the bump.

In order to achieve a stable injection amount in a low pulse range, which is a performance standard of the injector, it is necessary for the ball valve to follow a valve opening command and a valve closing command without delay. Conventionally, a high voltage is generated by a booster circuit and injected into the injector to flow current in a short time to improve the valve opening rise characteristics.When the valve is closed, this high voltage is applied in the opposite direction to when the valve is opened (Back-boost boost circuit) A method has been taken to improve the valve closing characteristics.

As another method, a conventional injector described in Japanese Patent Application Laid-Open No. 8-326620 is provided with a plurality of coils, and energizes more coils when the valve is opened than when the valve is kept open. A method of making a structure is disclosed. This increases the suction force for opening the valve and shortens the valve opening time delay, and also reduces the valve closing delay by reducing the suction force in the valve-open holding state.

[0005] Japanese Patent Application Laid-Open No. Hei 6-1117312 discloses an injector provided with a valve opening coil and a holding coil. Further, Japanese Utility Model No. 2582212 discloses an injector provided with a valve opening coil and a valve closing coil.

[0006]

However, the back-starting booster circuit of the prior art is expensive, and in order to reduce the system cost, which is the total cost of the injector and its driving circuit, the back-starting booster circuit is required. It is desirable that the injector have that function without using it.

Therefore, in order to inexpensively achieve a stable injection quantity in a low pulse range, which is a performance standard of the injector, it is necessary to open the valve from the closed state, hold the valve open, and then close the valve again. It is necessary to change the desired coil characteristics for each state. In particular, in order to improve the response characteristics at the time of closing the valve, it is necessary to forcibly and rapidly remove the magnetic flux generated from the closed state of the valve in the open state.

An object of the present invention is to provide an electromagnetic fuel injection device that can obtain a stable injection amount in a low pulse range by using a combination of coils for valve opening, valve opening holding, and valve closing. Is to do.

[0009]

In order to achieve the above object, an electromagnetic fuel injection device according to the present invention is characterized in that a coil for opening and closing a valve body for supplying fuel to an internal combustion engine by a magnetic force is provided. With respect to a valve opening coil having a large rate of change in magnetomotive force with time, a valve opening holding coil having a small rate of change in magnetomotive force with time, and a valve opening coil and a valve opening holding coil, And a valve closing coil wound in the opposite direction.

Specifically, the present invention provides the following devices. The present invention provides an electromagnetic fuel injection valve having a plurality of coils constituting a magnetic circuit, a valve element that opens and closes with a magnetic force generated by each coil, and each of the above-described respective valves in response to a valve opening / closing command from the outside. A control circuit for controlling a voltage applied to the coil, wherein each coil operates based on the state of the applied voltage to operate the valve body to supply fuel to the internal combustion engine. A coil for valve opening having a large rate of change over time in magnetomotive force given by the product of the number of turns of the coil and the current value when a steady voltage is applied;
A valve opening / holding coil having a smaller temporal change rate of the magnetomotive force than the valve opening coil; and a valve closing coil in which a coil is wound in a reverse direction to the valve opening / holding coil. And an electromagnetic fuel injection device characterized in that:

Preferably, the valve closing coil has a larger rate of change of the magnetomotive force with time than the valve opening holding coil.

Preferably, in the initial stage of the opening operation of the valve element, the control circuit applies a voltage to the valve opening coil and the valve opening holding coil so that a magnetic flux is generated in the same direction, and opens the valve. When the state is maintained, the voltage is continuously applied to the valve-opening holding coil.

Preferably, in response to the valve closing command, the control circuit stops applying a voltage to the valve opening holding coil and applies a voltage to the valve closing coil.

Preferably, the valve closing coil cancels a magnetic flux generated in the valve opening holding coil when the voltage is applied.

[0015] Preferably, the valve opening holding coil and the valve closing coil are adjacent to each other.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electromagnetic fuel injection device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of an electromagnetic fuel injection device according to one embodiment of the present invention. The electromagnetic fuel injection device 300 includes an electromagnetic fuel injection valve 30 and a control circuit 130 that controls the electromagnetic fuel injection valve 30.

As shown in FIG. 1, a control circuit 130 is supplied with a battery voltage from a battery 120 and, based on an injection signal from an engine controller 100, a valve opening coil 2, a valve opening holding coil 3, and a valve closing coil. The power supply to the coil 4 is controlled.

The control circuit 130 includes a current control circuit 104 for controlling the energization of the valve opening coil 2 and a current control circuit 114 for controlling the energization of the valve opening holding coil 3.
And a current control circuit 124 for performing current control on the valve closing coil 4.

The respective current control circuits share current information to the respective coils detected by the valve opening coil current detection resistor 103, the valve opening holding current detection resistor 113, and the valve closing coil current detection resistor 123. are doing.

A timer 11 based on the information and the injection signal from the engine controller 100 is used as a reference.
Power transistor 1 for valve opening coil according to output 0
02. An energization signal is sent to the power transistor 112 for the valve opening holding coil and the power transistor 122 for the valve closing coil.

Power transistor 10 for valve opening coil
2. When the power transistor 112 for the valve opening / holding coil and the power transistor 122 for the valve closing coil are turned on, the voltage of the battery 120 is applied to the valve opening coil 2, the valve opening / holding coil 3 and the valve closing coil 4. Applied.

Reference numerals 101, 111 and 121 denote the internal resistance of the valve opening coil 2, the valve opening holding coil 3 and the valve closing coil 4, respectively, and the equivalent resistance of the drive circuit.

FIG. 2 is a schematic diagram showing the configuration of the electromagnetic fuel injection valve of FIG. The electromagnetic fuel injection valve 30 is supplied with pressurized fuel from a fuel pump (not shown).
The ball 10 attached to the tip of the plunger 7 and the seat surface on the nozzle 8 side are sealed. A swirler 9 for atomizing the fuel is provided near the sheet surface.

The electromagnetic fuel injection valve 30 includes a valve opening coil 2, a valve opening holding coil 3, and a valve closing coil 4.

When the valve is opened, a magnetic flux is generated by applying a voltage to the valve-opening coil 2 and the valve-opening holding coil 3, and passes through the core 1, the yoke 5 and the plunger 7 as a magnetic path. A suction force is generated between the plunger 5 and the plunger 7.
Thereby, the plunger 7 and the ball 10 which are the valve
However, in FIG. 2, it is displaced upward and fuel is injected.

When the valve is held open, a voltage is applied only to the coil 3 for holding the valve open, and the plunger 7 and the ball 10 are held open.
However, in FIG. 2, the state is maintained at the upper side, and the fuel is continuously injected.

When the valve is closed, the voltage applied to the valve-opening holding coil 3 is stopped, and a voltage is applied to the valve-opening holding coil 4 to remove the residual magnetic force generated in the valve-opening holding coil 3. Thereby, the suction force is removed, and the plunger 7 and the ball 10 are closed by the return spring 6. Furthermore, the valve opening holding coil 3
And the valve closing coil 4 are adjacent to each other, so that the residual magnetic force generated in the valve opening holding coil 3 can be quickly removed.

FIG. 3 is a diagram showing the state of current flowing through the valve opening coil 2, the valve opening holding coil 3, and the valve closing coil 4 in response to an injection signal from the engine controller 100.

As shown in FIG. 3, the valve opening coil 2, the valve opening holding coil 3, and the valve closing coil 4 have different electrical characteristics. That is, the valve-opening coil 2, the valve-opening holding coil 3, and the valve-closing coil 4 are respectively opened and closed.
This is because the role is different in each stage of valve opening and valve closing.

The valve opening coil 2 is a coil used exclusively in the initial state of valve opening, the valve opening holding coil 3 is a coil used in the valve opening holding state, and the valve closing coil 4 is a coil used when the valve is closed. is there. The differences are described below.

First, the characteristics required for the coil when the valve is opened will be described below. When the valve is opened, the set load by the return spring 6 and the fuel pressure by the pressurized fuel act on the ball 10, so that a larger force is required as compared with the time when the valve is held open. The plunger 7 starts to be displaced only when the electromagnetic force reaches a level that overcomes these forces. Therefore, the time required to generate the force needs to be as short as possible to affect the valve opening delay.

Here, the magnetomotive force is determined by the number of turns N (T) of the coil.
Is multiplied by the inflow current I (A), and is applied to the evaluation of the magnetomotive force that can be reached in a very short time.
When the internal resistance of the drive circuit is zero, as the number of turns is reduced, the inductance component and the resistance component are reduced, a large amount of current flows, and as a result, the magnetomotive force that can be reached in a very short time increases. However, in practice, an internal resistance exists in the drive circuit, and the maximum value of the attained magnetomotive force is limited, and at the same time, the optimum number of turns changes according to the internal resistance of the drive circuit.

Next, the characteristics required for the coil when the valve is held open will be described below. In the valve-opening holding operation, the ball 10 and the plunger 7 serving as the valve body can be held in the valve-open state with a smaller magnetomotive force than when the valve is opened. This is because the fuel is injected by opening the valve, the pressure is balanced before and after the ball 10, and the force due to the fuel pressure is reduced, and at the same time, the gap between the core 1, the yoke 5 and the plunger 7 is reduced. This is because the magnetomotive force rises and can be used effectively.

If the magnetomotive force at the time of holding the valve open is too large, the residual magnetic force increases, leading to a delay in valve closing. Therefore, it is necessary to hold the valve with a low magnetomotive force close to the holding limit when holding the valve open.

Finally, the characteristics required for the coil when the valve is closed will be described below. In the valve closing operation, the voltage applied to the valve opening holding coil 3 in the valve opening holding operation is stopped, and a voltage is applied to the valve closing coil wound in the opposite direction to the valve opening holding coil 3. By removing the residual magnetic force existing in the core 1, the yoke 5, and the plunger 7, the magnetomotive force is rapidly reduced, and the magnetic force is reduced. When the load becomes less than the set load of the spring 6, the valve closing operation starts. .

The only characteristic required for the valve closing coil 4 is to remove the magnetizing force existing in the core 1, yoke 5 and plunger 7 in the shortest possible time.

FIG. 4 is a schematic diagram showing a configuration of an electromagnetic fuel injection valve according to another embodiment of the present invention. Placing the valve-opening holding member 13 outside the valve-opening coil 12 and the valve-closing coil 14 makes it possible to generate an electromagnetic force as a whole.

[0039]

According to the present invention, valve opening, valve opening holding,
By using the coil for valve closing in combination, it is possible to improve the response characteristics of the coil particularly when the valve is closed, shorten the valve closing delay, and obtain a stable injection amount in a low pulse range.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an electromagnetic fuel injection device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of the electromagnetic fuel injection valve of FIG.

FIG. 3 is a diagram showing a state of energization of a valve opening coil, a valve opening holding coil, and a valve closing coil.

FIG. 4 is a schematic diagram showing a configuration of an electromagnetic fuel injection valve according to another embodiment of the present invention.

[Explanation of symbols]

1,11 ... core, 2,12 ... valve opening coil, 3,13 ...
Coil for holding valve open, 4,14 ... Coil for closing valve, 5,15
... Yoke, 6,16 ... Spring, 7,17 ... Plunger, 8,18 ... Nozzle, 9,19 ... Swallower, 10,20
... Ball, 30,230 ... Electromagnetic fuel injection valve, 100 ...
Engine controller, 101, 111, 121 ... internal resistance, 102, 112, 122 ... power transistor,
103, 113, 123 ... current detection resistors, 104, 11
4, 124 current control circuit, 110 timer, 120
Battery, 130: control circuit, 300: electromagnetic fuel injection device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhisa Hamada 2477 Takaba, Hitachinaka-shi, Ibaraki Inside Hitachi Car Engineering Co., Ltd. 3G066 AB02 BA09 BA19 BA51 BA61 CC06U CC14 CC15 CC43 CD26 CE25 CE29 DA01 DC00 3G301 JA14 LB01 LC01 LC10 MA11 ND03 PB03A PB03Z PG02A PG02Z 3H106 DA07 DA13 DA23 DB02 DB14 DB15 DB17 DB48 FA08 KK18

Claims (6)

[Claims] An electromagnetic fuel injection valve having a plurality of coils constituting a magnetic circuit, a valve element which opens and closes by a magnetic force generated by each of the coils, and a valve opening / closing command from the outside. A control circuit for controlling a voltage applied to each coil, wherein each coil operates based on a state of the applied voltage to move the valve element to supply fuel to the internal combustion engine. In the above, each coil is a valve opening coil having a large time change rate of a magnetomotive force given by a product of the number of turns of the coil and a current value when a steady voltage is applied, and a time change rate of the magnetomotive force from the valve opening coil. Characterized by comprising a valve-opening and holding coil having a small diameter, and a valve-closing coil having a coil wound in the opposite direction to the valve-opening and the valve-opening and holding coils. Injection device. 2. The valve closing coil according to claim 1,
An electromagnetic fuel injection device, wherein a temporal change rate of the magnetomotive force is larger than that of the valve opening holding coil. 3. The control circuit according to claim 1, wherein in the initial stage of the opening operation of the valve element, a voltage is applied to the valve opening coil and the valve opening holding coil such that magnetic flux is generated in the same direction. The electromagnetic fuel injection device, wherein the voltage is continuously applied to the valve opening holding coil when the voltage is applied and the open state is maintained. 4. The control circuit according to claim 1, wherein the control circuit stops applying a voltage to the valve-opening holding coil and applies a voltage to the valve-closing coil in response to the valve-closing command. An electromagnetic fuel injection device characterized by the following. 5. The valve closing coil according to claim 4,
An electromagnetic fuel injection device, wherein a magnetic flux generated in the valve opening holding coil by application of the voltage is canceled. 6. The electromagnetic fuel injection device according to claim 1, wherein the valve opening holding coil and the valve closing coil are adjacent to each other.