JP2000002163A - Fuel injection device and electromagnet device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve control circuit which is small, inexpensive, and can achieve high-speed valving motions. SOLUTION: The device comprises a plunger 11b consisting of a magnetic piece fixed to a needle 11 of a fuel injection valve, a spring 4 to energize the plunger 11b in the direction of the valve closing, a first electromagnet consisting of an electric coil 10a and magnetic piece to attract the plunger 11b in the valve opening direction against the force of spring 4 in the valve closing direction, and a second electromagnet consisting of an electric coil 10b and magnetic piece to attract the plunger 11b in the valve closing direction. In the condition that the fuel injection valve is closed, current feed to the electric coil 10b of the second electromagnet is started, and then the start of feeding the current to the other electric coil 10a of the first electromagnet is made, and the current feed to the electric coil 10b of the second electromagnet is stopped at the timing to open the fuel injection valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fuel injection device and an electromagnet device for an automobile engine and the like.

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No. 6-299890 discloses a technique for improving the valve opening response of an engine fuel injection valve.
Japanese Patent Application Laid-Open Publication No. 8-326620 and Japanese Patent Application Laid-Open No. 8-326620.

In the former, a high voltage is generated from a voltage of about 12 V which is a normal power supply for a vehicle by a booster (DC / DC converter) provided in a drive circuit, and the high voltage is applied to a fuel injection valve. When the valve opening operation of the electromagnetic coil is started, the voltage is applied for a short period of time to shorten the time required for the valve opening operation and improve the responsiveness.

On the other hand, in the latter, an electromagnetic coil for driving a fuel injection valve is divided into a plurality of coils, each of which is connected in parallel to a power source, and all coils are energized at the start of valve opening to increase electromagnetic attraction. However, in the state where the movement of the needle valve is accelerated and the valve is kept in the open state, a part of the plurality of coils is de-energized to avoid a decrease in efficiency.

[0005]

However, in such a conventional fuel injection valve, in the former, the drive circuit used among the drive circuits, particularly, the DC / DC converter becomes complicated in forming the circuit, and As a result, it is necessary to switch between two power supplies of a high voltage and a normal 12V, so that the number of parts increases and the cost increases. On the other hand, in the latter case, a coil is required to speed up the valve opening operation. It is necessary to supply a large current to the coil in order to secure sufficient magnetomotive force for the valve opening operation after extremely reducing the number of turns of the coil and lowering the conductance of the coil, and a circuit element for switching this large current is expensive. And it is difficult to reduce the size of the circuit.

The present invention has been made in view of the above problems, and has as its object to provide a fuel injection device capable of realizing a high-speed, high-response valve opening operation at a relatively low voltage.

[0007]

According to a first aspect of the present invention, there is provided a plunger made of a magnetic material fixed to a needle valve of a fuel injection valve, a spring for urging the plunger in a valve closing direction, and generation of the spring. In a fuel injection device having a magnetic body that attracts a plunger in a valve opening direction against a force in a valve closing direction and a first electromagnet formed of an electric coil, the fuel injection device includes a magnetic body that attracts the plunger in a valve closing direction and an electric coil. With the second electromagnet, when the fuel injection valve is in the closed state, the energization of the electric coil of the second electromagnet is started, and thereafter, the energization of the electric coil of the first electromagnet is started, and the fuel injection valve is opened. There is a control circuit for stopping energization of the electric coil of the second electromagnet.

In a second aspect based on the first aspect, the attraction force of the first and second electromagnets is set such that the attraction force of the second electromagnet is larger than the attraction force of the first electromagnet. I do.

In a third aspect based on the first or second aspect, a Zener diode is interposed in parallel with the switching element of the electric coil of the first and second electromagnets.

According to a fourth aspect, in any one of the first and second aspects, a series circuit of a resistor and a capacitor is interposed in parallel with the switching element of the electric coil of the first and second electromagnets.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the time from the start of energization to the electric coil of the second electromagnet until the start of energization to the electric coil of the first electromagnet is set. , At least four times the electrical time constant of the electric coil of the second electromagnet.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the time from the start of energization to the electric coil of the first electromagnet to the stop of energization to the electric coil of the second electromagnet is determined. , At least four times the electrical time constant of the electric coil of the first electromagnet.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the energization of the electric coil of the first electromagnet for attracting the plunger in the valve opening direction is started after the combustion stroke of the four-cycle engine. In addition, it is set to be before the fuel injection start timing.

In an eighth aspect based on any one of the first to seventh aspects, the first and second electromagnets are provided with a gap larger than the length of a gap in the magnetic circuit.

According to a ninth aspect, a movable portion made of a magnetic material is provided.
An electromagnet device comprising: a first electromagnet that displaces the movable portion in one direction by a predetermined distance by a magnetic force;
A second electromagnet for moving the movable portion in a direction opposite to the first electromagnet, and energizing the electric coil of the second electromagnet starting a predetermined time before energizing the electric coil of the first electromagnet; A control circuit is provided for controlling the displacement of the movable part by stopping the energization of the electric coil of the second electromagnet after a predetermined time has elapsed after the start of energization of the electric coil of the first electromagnet.

[0016]

According to the first aspect of the present invention, a plunger made of a magnetic material fixed to a needle valve of a fuel injection valve, a spring for urging the plunger in a valve closing direction, and a valve closing generated by the spring A magnetic body and an electric coil that attract the plunger in the valve opening direction against the force in the first direction.
In a fuel injection device having an electromagnet, a second electromagnet made of a magnetic material and an electric coil that attracts the plunger in a valve closing direction, and energization of an electric coil of the second electromagnet is started when the fuel injection valve is in a closed state. Thereafter, the energization of the electric coil of the first electromagnet is started, and the energization of the electric coil of the second electromagnet is stopped at the timing of opening the fuel injection valve.
When both the electromagnets are energized, the energization of the electric coil of the second electromagnet is suddenly cut off, so that the same effect as the attraction force of the first electromagnet acting on the plunger on the step is obtained. As a result, the plunger can perform a high-speed, high-response valve opening operation, and as a result, an electromagnet using an electric coil having a sufficient number of windings to eliminate the need for a booster circuit and a relatively small attractive force. Regardless, high-speed movement of the needle valve, that is, high-speed opening of the fuel injection valve can be enabled.

According to the second aspect of the present invention, the attraction force of the first and second electromagnets is set so that the attraction force of the second electromagnet is larger than the attraction force of the first electromagnet, so unnecessary valve opening is performed. Can be prevented.

According to the third aspect of the present invention, since a Zener diode is interposed in parallel with the switching elements of the electric coils of the first and second electromagnets, an excessive voltage to the switching element on the valve closing side is regulated, and the current is sharply reduced. Can be shut off.

According to a fourth aspect of the present invention, a series circuit of a resistor and a capacitor is interposed in parallel with the switching element of the electric coil of the first and second electromagnets. By the action, the current of the electric coil can be rapidly cut off.

In the fifth invention, the time from the start of energization of the electric coil of the second electromagnet until the start of energization of the electric coil of the first electromagnet is determined by the electric time of the electric coil of the second electromagnet. At least four times the constant, the attraction force of the first electromagnet that attracts the plunger in the valve opening direction acts before the attraction force of the second electromagnet that attracts the plunger in the valve closing direction becomes sufficiently large. Can be prevented, and the closing operation of the valve is stabilized.

In the sixth invention, the time from the start of energization of the electric coil of the first electromagnet until the stop of energization of the electric coil of the second electromagnet is determined by the time when the electric coil of the first electromagnet is electrically operated. Since the constant is at least four times the constant, the energization of the second electromagnet that attracts the plunger in the valve closing direction is stopped before the attraction force of the first electromagnet that attracts the plunger in the valve opening direction becomes sufficiently large. Can be prevented.

[0022] In the seventh aspect of the present invention, the timing for starting the energization of the electric coil of the first electromagnet for attracting the plunger in the valve opening direction is after the combustion stroke of the four-cycle engine and before the fuel injection start timing. Since the energization of the electric coil of the first electromagnet is interrupted when the valve opening pressure due to the in-cylinder pressure of the engine that is at the maximum during the combustion stroke is acting, as a result, the second plunger is attracted in the valve closing direction. The attraction force of the electromagnet can be reduced, and the size and power consumption of the second electromagnet can be reduced.

In the eighth invention, the first and second electromagnets are:
Since the gap is larger than the length of the gap in the magnetic circuit, it is possible to prevent the generation of unnecessary magnetic force and the accompanying generation of unnecessary attraction.

According to a ninth aspect of the present invention, in the electromagnet apparatus comprising a movable portion made of a magnetic material and a first electromagnet for displacing the movable portion in one direction by a predetermined distance by a magnetic force, the first electromagnet is opposed to the first electromagnet. A second electromagnet for moving the movable portion in the direction, and energization to the electric coil of the second electromagnet is started a predetermined time before energization of the electric coil of the first electromagnet, and thereafter, to the electric coil of the first electromagnet. After the start of energization, a control circuit for controlling the displacement of the movable portion by stopping the energization of the electric coil of the second electromagnet after a predetermined time has elapsed is provided. (2) Since the energization of the electric coil of the electromagnet is suddenly cut off, an effect equivalent to that of the attraction force of the first electromagnet acting on the step on the plunger is obtained. The valve opening operation is possible, and as a result, the moving part moves at high speed despite the fact that it is an electromagnet that uses an electric coil that has a sufficient number of turns to secure a booster circuit and that can be secured with a relatively small attractive force. Can be made possible.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a fuel injection valve for an automobile will be described below with reference to the accompanying drawings.

In the first embodiment shown in FIG. 1, a first outer peripheral yoke 2 is fixed to an outer periphery of a valve opening core 1 made of a magnetic material having a cylindrical hollow portion 1a. An electric coil 10 a constituting a first electromagnet together with the valve-opening core 1 is wound between the first outer magnet 1 and the first outer yoke 2. A spring 4 is disposed in the hollow portion 1a of the valve opening core 1,
One end of the spring 4 is positioned on the end face of the spring receiver 3 fitted into the hollow portion 1a of the valve-opening core 1, and the other end of the spring 4 abuts on a plunger 11b molded integrally with the needle valve 11. It is urged in the valve closing direction by the spring force of the spring 4.

A second outer yoke 5 is coupled coaxially below the first outer yoke 2 through an annular magnetic flux shielding member 6 made of a nonmagnetic material. Inside the second outer yoke 5, an electric coil is provided. A valve-closing core 7 having 10b wound around the outer periphery is fixed, and these constitute a second electromagnet. When the first electromagnet is energized, it pulls the plunger 11b upward and drives the needle valve 11 in the valve opening direction, while the second electromagnet draws the plunger 11b downward and drives it in the valve closing direction.

A nozzle 9 is fixed to the distal end of the second outer yoke 5, and the needle valve 11 is slidably disposed therein. An injection hole 9 a is provided at the tip of the nozzle 9, and a ball valve body 12 fixed to the tip of a needle valve 11 penetrating the valve closing core 7 and the stopper member 8 is tapered at a position where the ball valve body 12 contacts the nozzle 9. Part 9b is provided, and the ball valve element 1
The nozzle hole 2a is closed by the contact of 2 with the tapered portion 9b.

The needle valve 11 is provided with a flange 11a at a predetermined axial distance between the needle valve 11 and the stopper member 8. When the needle valve 11 moves in the valve opening direction, the collar 1a is moved.
1 a regulates the maximum lift amount of the needle valve 11 by contacting the stopper member 8. Internal space 9 of nozzle 9
Pressurized fuel is supplied to c through a passage (not shown), and fuel is injected from the injection hole 9a with the lift of the needle valve 11.

On the other hand, one end of each of the electric coils 10a and 10b is connected to a 12V power source which is a battery voltage for a vehicle, and the other end is grounded via switching elements 14 and 15 for controlling the energization of the electric coils 10a and 10b. The switching elements 14 and 15 are ON / OFF controlled by a CPU (controller) 13 as described later. Further, the switching element side ends of the electric coils 10a and 10b are connected to a Zener diode 1 for limiting a voltage to a switching element in parallel with the switching elements 14 and 15.
Grounded via 6 and 17.

Next, the operation of the first embodiment will be described with reference to FIG.

When both the electric coils 10a and 10b are not energized, the needle valve 11 is urged in the valve closing direction by the spring force of the spring 4, so that the ball valve body 12 at the tip of the needle valve 11 is The nozzle 9 contacts the tapered portion 9b of the nozzle 9 and closes the injection hole 9a.

At this time, the pressurized force of the spring 4 pressing the needle valve 11 in the valve closing direction is Fs, and the fuel pressurized at a predetermined pressure is actually supplied to the injection valve internal space 9c. In addition to the urging force Fs of the spring 4, a urging force Ff in the valve closing direction due to the pressurized fuel acts on the valve 11.

When the fuel injection valve is applied to an in-cylinder direct injection engine, when the in-cylinder pressure is maximized during the combustion stroke of the engine, the pressure exerts a force pushing the ball valve body 12 in the valve opening direction. Since Fe (max) acts, the sum of Fs and Ff must be greater than this. That is, the set load Fs of the spring 4 as the urging force and the fuel pressure acting force Ff by the pressurized fuel must be determined so that Fs + Ff> Fe (max) (1).

In this state, when the CPU 13 turns on the switching element 15 at the timing of t1 in FIG. 2 to start energizing the electric coil 10b of the second electromagnet, the power supply voltage of 12 V is applied to the electric coil 10b. Therefore, current flows according to a time constant determined by the resistance value and the inductance. By the action of this current,
A magnetic flux is drawn in a loop that returns to the valve closing core 7 through the valve closing core 7, the plunger 11b, and the outer yoke 5, and a suction force acts between the suction surface 7a and the plunger surface 11e of the valve closing core 7. I do. Assuming that a force acting between the valve-closing core 7 and the plunger 11b when a sufficient time has elapsed from the start of energization and the current value of the electric coil 10b has reached a steady state is F2, the needle valve 11 has a spring 4 The closing force Ff due to the spring force Fs and the fuel pressure, and the force F2 due to the action of the second electromagnet.
Will act in the valve closing direction. Since the force F2 has acted on the needle valve 11 in the valve closing direction in addition to the forces Fs and Ff in the valve closing direction that have been applied so far, there is no change in the valve closed state.

Here, when the CPU 13 turns on the switching element 14 at the timing of t2, 12V is applied to the electric coil 10a of the first electromagnet, and the current flows from the valve-opening core 1 to the plunger 11b to the outer periphery. A magnetic flux that returns to the valve-opening core 1 via the yoke 2 is generated, and a suction force is generated between the suction surface 1a and the plunger surface 11d of the valve-opening core 1. Assuming that a suction force between the suction surface 1a and the plunger surface 11d of the valve-opening core 1 after a sufficient time from the start of energization of the electric coil 10a is F1, the needle valve 11 has a valve closing direction Fc in the following equation. The force will act.

Fc = Fs + Ff + F2-F1 (2) In this case, as is apparent from the above equation, when the force F1 generated by the first electromagnet becomes larger than a certain value, Fc becomes negative and the needle becomes It is conceivable that a force in the valve opening direction acts on the valve 11 and the injection valve opens. Even when Fc in the above equation does not become negative, when the in-cylinder pressure of the engine is maximized, Fc <Fe (max) (3), and as a result, the valve opening force Fe (max) due to the in-cylinder pressure is obtained. )
It is conceivable that the injection valve will open.

Therefore, at the plunger position when the injection valve is in the closed state, the force F2 generated by the second electromagnet is larger than the force F1 generated by the first electromagnet, that is, F2> F1. By determining the number of turns of the electric coils 10a and 10b and the value of the flowing current so as to satisfy (4), Fc> Fs + Ff (5) always holds when both electric coils are energized. Unnecessary valve opening can be prevented. Specifically, when the injection valve is in the closed state, the position of the plunger 11b is on the second electromagnet side, so that both electromagnets have substantially the same characteristics, such as the size related to the magnetic circuit and the number of coil turns, for example. If designed in such a manner, the above conditions will be satisfied.

The time between the start of energization of the electric coil 10b of the second electromagnet and the start of energization of the electric coil 10a of the first electromagnet, that is, (t2-t1) in FIG.
The time constant τ2 of the electric coil 10b of the second electromagnet is set to be four times or more. Generally, in an electric coil, it is known that the current reaches a steady state in about four times the time constant determined by the inductance and the resistance value of the electric coil. Therefore, the timing of starting energization is determined as described above. This can prevent the attraction force F1 of the first electromagnet from acting before the attraction force F2 of the second electromagnet becomes sufficiently large.

In this state, when opening the injection valve, the CPU 13 turns off the switching element 15 (state at t3 in FIG. 2). Normally, when the current flowing through the inductive load is suddenly cut off, a high voltage is applied to the switching element 15 by the back electromotive force. In the present embodiment, the switching element 15 is protected from the high voltage by the Zener diode 17. At the same time, the current can be eliminated very steeply. More specifically, this will be described with reference to FIGS.

When the switching element 15 is turned off while the current i2 is constantly flowing through the coil 10b,
Although the voltage at P1 in FIG. 3 rises sharply, its value is regulated by the Zener voltage Vz of the Zener diode 17. Here, by selecting the switching element such that the withstand voltage performance of the switching element 15 is higher than the zener voltage Vz of the zener diode 17, it is possible to avoid applying a voltage higher than the withstand voltage performance to the switching element 15. At the same time, focusing on the voltage between the terminals of the coil 10b, the voltage of P1 is instantaneously changed from 0V to V
By increasing to z, a voltage of (Vz−Vb) V, which is opposite to the previous voltage, is applied to the coil 10b. Therefore, the current of the coil 10b rapidly decreases, and when it reaches 0A, P1 becomes equipotential with Vb.
Stabilize.

The circuit configuration of this portion may be the configuration according to the second embodiment as shown in FIG. 5, and a resistor Rs and a capacitor Cs are connected in series instead of the Zener diode 17 of FIG. In this configuration, when the switching element 15 is cut off, the current i2 of the coil 10b is attenuated vibratingly as shown in FIG. 6 due to the resonance action of the series RLC circuit composed of the coil 10b, the resistor Rs and the capacitor Cs. The current can be reduced quickly.

Thus, the current of the electric coil 10b decreases,
Upon disappearance, the suction force F for valve closing acting on the suction surface 11e of the plunger 11b from the suction surface 7a of the valve closing core 7 is removed.
2 becomes 0, and as a result, the valve closing force F acting on the needle valve 11
c becomes Fc = Fs + Ff-F1 (6).

If F1> Fs + Ff (7), Fc becomes negative, that is, the plunger portion 11b of the needle valve 11 is sucked in the valve opening direction by the action of the first electromagnet, and the ball valve body 12 means that the fuel is injected by separating from the tapered portion 9b of the nozzle 9.

Here, the time from the start of energization of the electric coil 10a of the first electromagnet to the stop of energization of the electric coil 10b of the second electromagnet, that is, (t3-t in FIG. 2).
2) is set to be four times or more the time constant τ1 of the electric coil 10a of the first electromagnet.

Therefore, it is possible to prevent the energization of the second electromagnet from being stopped before the attraction force F1 of the first electromagnet becomes sufficiently large.

When fuel injection is to be terminated, CP
U13 cuts off the current of the switching element 14 to demagnetize the magnetic force of the first electromagnet.
1 is set to 0, and the valve is closed by the action of the valve closing force Fs of the spring 4 or the like.

As described above, according to the present invention, the current of the electric coil 10b of the second electromagnet is cut off very steeply, so that the attractive force of the first electromagnet acts on the plunger 11b in a stepwise manner. The same effect is obtained, compared with the conventional method, in which the force in the valve opening direction gradually increases from 0 and starts the valve opening operation only when the force in the valve closing direction exceeds the force in the valve closing direction, an extremely high speed, High-response operation becomes possible.

The dotted line in FIG. 2 indicating the needle valve displacement indicates a case where the switching element 15 is not used and the switching element 14 is used for driving (ie, only the first electromagnet is used).
Is shown.

FIG. 7 shows a conventional system (Japanese Unexamined Patent Publication No.
299890) is a schematic diagram showing the displacement of a needle valve of a fuel injection valve in relation to elapsed time, in which responsiveness is enhanced by application of a high voltage current. In this case, the needle valve can be displaced at a speed equal to or higher than that shown in FIG.

FIG. 8 is an explanatory diagram when the present invention is applied to a 4-cycle, 4-cylinder engine. Although the configuration and operation principle are the same as those of the first embodiment, according to this embodiment,
The signal of the crank angle sensor of the engine not shown
In step U13, the CPU determines which of the four strokes of intake, compression, combustion, and exhaust each cylinder of the engine is in.
The timing at which the valve 13 starts energizing the valve opening coil 10a of the first electromagnet, that is, the timing at which the switching element 14 is turned on, is set after the combustion stroke and before the fuel injection start timing.

For this reason, in the combustion stroke in which the force Fe for pushing the ball valve body 12 in the valve opening direction by the in-cylinder pressure of the engine becomes maximum, the force F1 by the first electromagnet becomes 0, and in the aforementioned equation (2), the needle F1 Force Fc acting on valve 11 in the closing direction
Will not be negative. Therefore, the condition of the expression (4) is eliminated, and instead, it suffices that Fs + Ff + F2> F1 (8).

As a result, the attraction force F2 of the second electromagnet can be smaller than that of the first embodiment, which makes it possible to reduce the size and power consumption of the second electromagnet.

FIG. 9 shows a third embodiment of the present invention.

FIG. 9 schematically shows the lines of magnetic force generated by the current when the valve opening coil 10a is energized while the needle valve 11 is in the closed state. When the plunger 11b and the yoke 5 are not sufficiently separated from the valve-opening core 1 as shown in FIG. 9, the plunger 11b is vertically penetrated from the core 1 as indicated by A2 in FIG. After entering the core 7, the core 1 passes through the yoke 5 and the yoke 2.
The lines of magnetic force are generated as if returning to. The line of magnetic force A2 generates a suction force between the suction surface 1a of the core 1 and the suction surface 11d of the plunger 11b. However, at the plunger position as shown in the drawing, a larger suction force is applied to the suction surface 11e and the valve closing core. Is generated between the suction surfaces 7a, and the valve closing force is generated in spite of the total energization of the valve opening coil 10a, which is not preferable.

Therefore, the thickness d1 of the magnetic flux shielding member 6 is set to a value larger than the total value of the magnetic circuit to be formed by the first electromagnet, that is, the total value of the gaps on the path of the magnetic field lines A1, thereby preventing the generation of the magnetic lines A2. I'm preventing. Specifically, the distance between the core 1 and the suction surface of the plunger 11b is X1,
When the clearance between the outer side surface 11c and the yoke 2 is Xc, d1 is determined such that d1> X1 (max) + Xc (9). Further, since the same can be considered on the valve closing coil side, when the distance between the suction surface 11e of the plunger and the suction surface 7a of the core 7 is X2, d1> X2 (max) + Xc (10) ) Is determined. By determining d1 that satisfies the expressions (9) and (10) at the same time, it is possible to prevent unnecessary suction force from being generated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a timing chart of the switching element, the coil, and the needle valve.

FIGS. 3A and 3B are circuit diagrams illustrating the operation of the electric coil in a current control state, wherein FIG.

FIG. 4 shows the operation of the switching element at the time of current interruption,
5 is a timing chart of the voltage of P1 and the voltage and current of the electric coil of the second electromagnet.

FIGS. 5A and 5B are circuit diagrams illustrating an operation of the electric coil according to the second embodiment in a current control state, in which FIG.

FIG. 6 is a timing chart of the operation of the switching element and the voltage and current of the electric coil of the second electromagnet when the current is interrupted.

7 (a) to 7 (c) are diagrams showing the operation of a conventional needle valve according to the conventional technique, and FIGS. 7 (d) and 7 (e) show the displacement of the needle valve using a high voltage with respect to the conventional technique. (According to JP-A-6-299890).

FIG. 8 is a schematic explanatory diagram when the present invention is applied to a 4-cycle, 4-cylinder engine.

FIG. 9 is a schematic diagram of lines of magnetic force when a needle valve according to a third embodiment is in a closed state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Valve-opening core 1a Suction surface of valve-opening core 2 First outer yoke 3 Spring receiver 4 Spring 5 Second outer yoke 6 Magnetic flux shielding material 7 Valve-closing core 7a Suction surface of valve-closing core 8 Stopper member 9 Nozzle 9a Injection hole 9b Taper portion 9c Internal space 10a Valve opening electric coil 10b Valve closing electric coil 11 Needle valve 11a Convex portion 11b Plunger 11c Outer surface of plunger 11d Suction surface of plunger 11e Suction surface of plunger 12 Ball valve body 13 CPU 14 Switching element 15 Switching element 16 Zener diode 17 Zener diode d1 Thickness of magnetic flux shielding material X1 Distance between core 1 and suction surface of plunger 11b X2 Distance between plunger surface 11e and suction surface 7a of core 7 Xc Outside plunger 11b Clearance between side surface 11c and yoke 2

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takayuki Arai, Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Akihiro Sakakida 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa, F Nissan Motor Co., Ltd. Term (reference) 3G066 AA02 AB02 AD12 BA17 BA19 BA61 BA67 CC05U CC06U CC14 CC15 CC51 CD28 CE22 CE24 CE25 CE26 CE29 DA04 DC05 3H106 DA07 DA13 DA25 DB02 DB12 DB23 DB32 DC06 DC17 DD03 EE04 FA02 FA08 FB32 KK18

Claims (9)

[Claims] A plunger made of a magnetic material fixed to a needle valve of a fuel injection valve, a spring for urging the plunger in a valve closing direction, and a plunger against a force generated by the spring in a valve closing direction. A first electromagnet made of a magnetic material and an electric coil that attracts the plunger in the valve opening direction, a second electromagnet made of a magnetic material and an electric coil that attracts the plunger in the valve closing direction, and the fuel injection valve comprises: When the valve is in the closed state, energization of the electric coil of the second electromagnet is started, and thereafter, energization of the electric coil of the first electromagnet is started,
A control circuit for stopping energization of the electric coil of the second electromagnet at a timing when the fuel injection valve is opened. 2. The first and second electromagnets such that the attraction force of the second electromagnet is greater than the attraction force of the first electromagnet.
The fuel injection device according to claim 1, wherein the attraction force of the electromagnet is set. 3. The fuel injection device according to claim 1, wherein a zener diode is interposed in parallel with a switching element of an electric coil of the first and second electromagnets. 4. The fuel injection device according to claim 1, wherein a series circuit of a resistor and a capacitor is interposed in parallel with the switching elements of the electric coils of the first and second electromagnets. 5. An electric coil of the second electromagnet, which is energized, and a time until the energization of the electric coil of the first electromagnet is started is at least 4 times the electric time constant of the electric coil of the second electromagnet. 2. The method according to claim 1, wherein the number is twice or more.
5. The fuel injection device according to any one of items 1 to 4. 6. A time period between the start of energization of the electric coil of the first electromagnet and the stop of energization of the electric coil of the second electromagnet is at least 4 times the electric time constant of the electric coil of the first electromagnet. 2. The method according to claim 1, wherein the number is twice or more.
6. The fuel injection device according to any one of claims 1 to 5. 7. A timing for starting energization of an electric coil of a first electromagnet for attracting the plunger in a valve opening direction is after a combustion stroke of a four-cycle engine and before a fuel injection start timing. 7. The fuel injection device according to any one of claims 1 to 6. 8. The electromagnet according to claim 1, wherein the first and second electromagnets are provided with a gap larger than a length of a gap in the magnetic circuit. The fuel injection device according to claim 1. 9. An electromagnet apparatus comprising: a movable portion made of a magnetic material; and a first electromagnet for displacing the movable portion in one direction by a predetermined distance by a magnetic force, wherein the movable portion is moved in a direction opposite to the first electromagnet. A second electromagnet for moving the part,
The second electromagnet starts energizing the electric coil of the second electromagnet a predetermined time before the energizing of the electric coil of the first electromagnet, and after a predetermined time elapses after the energization of the electric coil of the first electromagnet starts. A control circuit for controlling the displacement of the movable part by stopping the current supply to the electric coil.