JP2000145566A - Driving method and driving device for injector for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate the opening action of injectors, and reduce their operating noise and prolong their life by relieving shocks at the end of opening action. SOLUTION: With a capacitor 14 kept off charging by a charging power source 13, an energized thyristor 16 causes the capacitor 14 to discharge via an injector solenoid coil 3a where an oscillating current flows whose first zero- cross point after the first peak is practically timed to the end of opening action of the injector valve. The thyristor 16 is electrically disconnected upon the polarity inversion of the oscillating current, and a transistor 23 is energized after the valve reaches the end-of-opening position so that the solenoid coil 3a receives a holding current from a holding current power source 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injector driving method for driving an injector for supplying fuel to an internal combustion engine, and to an injector driving apparatus used for implementing the driving method.

[0002]

2. Description of the Related Art As means for supplying fuel to an internal combustion engine,
Injectors (electromagnetic fuel injection valves) have been widely used.

[0003] The injector has a valve provided to open and close the injection port, the opening operation completion position of which is regulated by a stopper, and a solenoid coil for driving the valve. A predetermined driving current is supplied to the solenoid coil. Is applied, the valve is opened to inject fuel into the fuel injection space of the internal combustion engine (the space inside the intake pipe or the combustion chamber).

FIG. 10 shows an example of an injector 1. This injector has an injection port 2a at its tip.
An injector body 2 having a fuel connector 2b on the rear end side, a solenoid coil 3a, and the solenoid coil 3
The movable iron core 3 which generates a displacement when a drive current is applied to a
b, the solenoid (electromagnet) 3 housed in the injector body 2 and coupled to the movable iron core 3b of the solenoid 3 to close the injection port 2a with the displacement of the movable iron core 3b. The needle valve 4 is displaced between a position and an open position where the injection port 2a is opened, and a return spring 5 for urging the needle valve 4 toward the closed position via the movable iron core 3b. On the rear end side of the injector body 2, an electrical connector 6 having terminals a1 and a2 connected to one end and the other end of the solenoid coil 3a, respectively, is provided.

The injector 1 shown in FIG. 10 is attached to the engine with the injection port 2a facing a fuel injection space (a space in an intake pipe or a space in a combustion chamber) of the internal combustion engine.
Fuel is supplied into the injector body 2 from the fuel pump (not shown) through the fuel connector 2b at a predetermined pressure. The pressure of the fuel supplied into the injector body 2 is kept constant by the pressure regulator. The solenoid coil 3a is connected to an injector driving device (not shown) through an electric cord connected to the connector 6 via a plug, and is driven from the injector driving device to the solenoid coil 3a when an injection command signal is given from a control device (not shown). Current is supplied.

A control device for controlling the injector 1 uses a microcomputer or the like to control the fuel injection time (fuel injection time) with respect to various control conditions such as throttle valve opening, atmospheric pressure, engine temperature, and engine speed. Is calculated, and a rectangular wave injection command signal having a time width corresponding to the calculated injection time (a time width required for performing the fuel injection during the calculated injection time) is calculated. appear.

The injector driving device includes a switch for turning on and off a drive current supplied to the solenoid coil 3a from a power supply unit using a battery or the like as a power source. The switch is operated while an injection command signal is supplied from the control device. When the drive voltage is applied from the power supply to the solenoid coil 3a in the on state, the solenoid coil 3a is turned on.
Is supplied with a drive current of a predetermined magnitude.

When no drive current is applied to the solenoid coil 3a, the valve 4 is urged toward the closed position by the return spring 5, and the valve port 2 is urged by the valve 4.
a is closed liquid-tight. In this state, when a predetermined drive voltage is applied to the solenoid coil 3a and a predetermined drive current is applied to the solenoid coil, the movable iron core 3b is displaced toward the solenoid coil 3a, and the needle valve 4 is moved to the open position ( (Right side in FIG. 10). When the needle valve 4 is displaced toward the open position, a gap is formed between the valve 4 and the injection port 2a, and fuel is injected through this gap. Injector nozzle 2
The cross-sectional area and cross-sectional shape of the gap formed between the valve core 4a and the valve 4 change with the displacement of the movable core 3b.
Reaches the set opening operation completion position, a predetermined gap having a predetermined cross-sectional area and a cross-sectional shape is formed between the injection port and the valve, and the opening operation of the injector is completed. . A stopper for bringing the valve into contact with the valve is provided at the position where the valve has completed the opening operation, and the valve is brought into contact with the stopper to determine the position at which the valve has opened.

When the injection command signal given to the injector driving device is extinguished and the driving current is reduced, the movable iron core is displaced toward the closed position by the urging force of the return spring, and the valve returns to the closed position. The spout is closed.

In the injector 1 provided with the return spring 5 as described above, the atmospheric pressure in the fuel injection space (the pressure in the intake pipe when injecting into the intake pipe, and the piston pressure when injecting directly into the cylinder) When the valve 4 is pushed back by the pressure in the combustion chamber in a compressed state and the injection port portion 2a is opened, the fuel flows backward. Therefore, the initial load of the return spring 4 (the urging force in a state where the solenoid coil is not excited). ) Must be set to a size that can overcome the atmospheric pressure. When driving the injector, it is necessary to move the movable iron core toward the open position against the urging force of the return spring.

In this type of injector, a large drive current is required to quickly open the injection port 2a when opening the injection port 2a by overcoming the urging force of the return spring. To maintain the open state, a very large drive current is not required, and only the holding current smaller than the peak value of the drive current required in the process of opening the nozzle port 2a is supplied to open the nozzle port 2a. Can be held. For this reason, the injector drive circuit
A large driving current is supplied to the solenoid coil 3a when opening the opening a, and the driving current is reduced to a holding current value after the injection port 2a is opened.

The amount of fuel injected from the injector (the amount of fuel supplied to the engine) is determined by the product of the time during which the injector valve is open and the pressure of the fuel supplied from the fuel pump into the injector body. Since the pressure of the fuel supplied into the injector body is controlled to be constant by the pressure regulator, the fuel injection amount is
It can be controlled by controlling the time during which the injection port of the injector is open (valve opening time), that is, by controlling the time width of the injection command signal.

In the injector, the cross-sectional shape and the cross-sectional area of the gap between the valve and the injection port are important factors for determining the fuel injection amount, the spray angle, the spray particle size, and the spray particle speed. Therefore, in order to properly control the fuel injection amount, it is necessary to keep the cross-sectional shape and the cross-sectional area of the gap between the valve and the injection port at the time of performing the fuel injection constant. The transient state until the valve is displaced from the closed position to the open position is a state in which fuel is not normally injected from the injection port and fuel leaks, and thus cannot be used for controlling the fuel injection amount.

Therefore, in order to properly control the fuel injection amount, it is necessary to keep the valve of the injector at the opening operation completion position when injecting the fuel. In order to control the fuel injection amount accurately, the minimum management injection amount from the injector (the minimum value of the injection amount that can be accurately controlled) is made as low as possible, and the maximum management injection amount (the injection amount that can be accurately managed) is reduced. It is desirable to increase the dynamic range by increasing the maximum value of the amount as much as possible, and for this purpose, the valve 4 is displaced from the closed position to the set open position as soon as possible when the injection command is given, It is necessary to minimize the valve opening transition time of the injector that cannot be used for control.

As a method for driving the injector, a saturated method and a peak hold method are known.

FIG. 6 shows the structure of an injector driving apparatus employing the saturated method. In FIG. 6, reference numeral 3a denotes a solenoid coil of the injector having an inductance 3a1 and a resistance 3a2. One end of the solenoid coil 3a is connected to the collector of an NPN transistor TR1 whose emitter is grounded, and the base of the transistor is connected to the emitter through a resistor r1.
It is connected to an output terminal of a control device (not shown) through a resistor r2. The other end of the solenoid coil is connected through a resistor r3 to the positive terminal of the battery B whose negative terminal is grounded.

FIG. 7 is a waveform diagram showing the operation of the injector driving device shown in FIG. 6. FIG. 7A shows a voltage VLi applied to both ends of the solenoid coil 3a, and FIG.
Indicates a drive current Id flowing through the solenoid coil. FIG. 7C shows the position P of the valve.
And P2 respectively indicate the closed position of the valve and the open operation completed position where the valve comes into contact with the stopper.

In the injector driving device shown in FIG. 6, when a control device (not shown) generates an injection command signal at time t0 shown in FIG. 7, the transistor TR1 is turned on, so that the voltage across the battery B is applied to the solenoid coil. Is done. At time to, the current flowing through the solenoid coil is zero, so that all the applied voltage is applied to the solenoid coil 3a as shown in FIG.
When a voltage is applied to the solenoid coil, the drive current I flowing through the solenoid coil as shown in FIG.
d increases exponentially, and when this drive current reaches a predetermined level Io, the valve starts to open. When the drive current reaches the peak, the valve is opened to the completion position P2.
And the opening operation of the valve is completed. The drive current saturates after reaching the peak, and the valve is held at the open operation completion position. At time t1, when the injection command signal disappears,
Since the transistor TR1 is turned off, the drive current flowing through the solenoid coil is attenuated, and the valve returns to the closed position.

In this saturated method, the voltage applied to the solenoid coil decreases as the drive current increases in the process of displacing the valve toward the opening-completion completion position. take time.

FIG. 8 shows a configuration of an injector driving device employing a peak hold method. In this driving device, a peak current comprising a PNP transistor TR2 and resistors r4 and r5 is added to the circuit shown in FIG. It has a configuration to which a supply circuit is added. FIG. 9 shows an operation waveform of the injector driving device of FIG. 8, and FIG. 9 (A) shows a waveform of a voltage between both ends of the solenoid coil 3a.
(B) shows the waveform of the drive current Id flowing through the solenoid coil 3a. FIG. 9C shows the operation of the valve, wherein P1 and P2 indicate the closed position and the open operation completed position of the valve, respectively.

In the injector driving device shown in FIG. 8, when an injection command signal is given at time to, a driving signal is first given to the base of the transistor TR2.
The transistor TR2 is turned on. As a result, a drive current Id flows from the battery B through the transistor TR2 and the solenoid coil 3a, and when the drive current reaches a predetermined current value Io, the opening operation of the valve is started. Thereafter, before the drive current Id reaches the peak value, the valve reaches the opening operation completion position P2, and the opening operation of the valve is completed. After the valve reaches the opening operation completion position, at time t1, the drive signal given to the transistor TR2 is extinguished, the transistor TR2 is turned off, and the drive signal is given to the transistor TR1 to give the transistor TR2 a signal. TR1 is made conductive.
As a result, the voltage applied to the solenoid coil 3a is reduced, and the drive current Id is reduced to a holding current value Ih necessary to hold the valve at the open operation completion position. The holding current Ih is supplied to the solenoid coil 3a until the injection command signal disappears at time t2.

In the injector drive device of the peak hold type shown in FIG. 8, when an injection command signal is given,
Since a large drive current flows through the solenoid coil, the time required for the valve opening operation can be reduced. After the valve-opening operation is completed, the drive current is reduced to a holding current Ih necessary to hold the valve at the opening-operation completed position, so that heat generation from the solenoid coil is reduced to suppress a rise in the temperature of the injector. be able to.

[0023]

As described above, when the injector of the saturated type shown in FIG. 6 is used, it takes time until the opening operation of the valve is completed. The dynamic range was inevitably reduced.

In the injector drive device of the peak hold type shown in FIG. 8, the time required for opening the valve can be reduced by increasing the peak value of the drive current flowing at the beginning of the valve opening operation. However, in this method, since the valve reaches the opening operation completion position and comes into contact with the stopper while the driving current Id rises toward the peak value, the peak of the driving current when the valve opening operation is performed is performed. When the value is increased, the impact when the valve comes into contact with the stopper increases, and there is a problem that the operating noise of the valve increases. When the peak value of the drive current flowing during the valve opening operation is increased, the valve bounces after colliding with the stopper and vibrates as shown in FIG. 9C, so that the injection immediately after the valve opening operation is completed. The amount could be unstable. In order to suppress these phenomena, the drive device shown in FIG. 8 has a problem that the peak value of the drive current flowing at the beginning of the valve opening operation is limited, and the effect of shortening the valve opening operation time is reduced accordingly. Was.

An object of the present invention is to provide a method of driving an injector for an internal combustion engine and a method of driving the same, which can reduce the impact when the valve comes into contact with the stopper and shorten the time required for the valve opening operation. An object of the present invention is to provide an injector drive device for an internal combustion engine used for the implementation.

[0026]

An injector driving method according to the present invention includes a valve provided to open and close an injection port, the opening completion position of which is regulated by a stopper, and a solenoid coil for driving the valve. When a predetermined amount of current is applied to the solenoid coil, the valve moves to the opening completion position, and the injector that injects fuel into the fuel injection space of the internal combustion engine receives an injection command signal (fuel injection). (A signal instructing to perform the above operation).

In the present invention, the peak current supply capacitor is charged before the injection command signal is given,
By discharging the electric charge of the peak current supply capacitor through the solenoid coil in a state where charging of the peak current supply capacitor is stopped when the injection command signal is given, an oscillating current flows through the solenoid coil, and the oscillating current is initially The valve reaches the opening operation completion position at the timing near the first zero crossing point after passing the peak of, and after the oscillating current passes the first zero crossing point and the polarity is reversed, the valve opens the opening operation completion position. During this period, a holding current of a magnitude necessary for holding the valve at the opening operation completion position is supplied to the solenoid coil, and the state where the holding current is supplied is maintained until fuel injection is completed.

As described above, when the charge of the peak current supply capacitor is discharged through the solenoid coil and the switch means while the charging of the peak current supply capacitor is prevented, the oscillating current generated in the closed circuit of the LCR is generated. It flows through the solenoid coil as drive current. If the charging voltage of the peak current supply capacitor is set high enough and the frequency of the oscillating current is raised to make the rising of the oscillating current fast enough, the fast-rising current is opened when the injection command signal is given. The current can flow as a valve current, and the valve can be quickly moved to the open operation completion position. Also, by setting the rising of the oscillating current sufficiently fast, it is possible to set the valve to reach the opening operation completion position at a timing near the first zero crossing point where the oscillating current passes after the first peak. it can.

As described above, if the valve reaches the opening operation completion position near the zero crossing point where the oscillating current passes after the first peak, the valve can be operated in a state where the output torque of the solenoid is small. Can reach the opening operation completion position and abut against the stopper. Therefore, it is possible to reduce the impact generated when the valve comes into contact with the stopper, to promptly perform the valve opening operation, and to reduce the operation sound of the valve. Also, since the impact when the valve abuts the stopper can be reduced,
Vibration of the valve generated when the opening operation is completed can be reduced, and the injection amount immediately after the completion of the opening operation can be stabilized. Furthermore,
Because the shock generated when the valve opening operation is completed can be reduced,
The life of the injector can be extended.

Particularly, in an injector used for in-cylinder injection for directly injecting fuel into a combustion chamber of an engine,
Since it is necessary to increase the urging force of the spring for holding the valve in the closed position, it is necessary to generate a large driving force from the solenoid in order to quickly open the valve. If the charging voltage of the capacitor for supplying the peak current is sufficiently high, the peak value of the valve opening current can be sufficiently increased, so that even the in-cylinder injector can be driven. It can be done easily. Further, according to the above method, the rise of the valve-opening current can be made sufficiently fast, and the time during which a large valve-opening current flows through the solenoid coil can be shortened. Valve time can be shortened.

An injector driving device for an internal combustion engine according to the present invention includes a valve provided to open and close an injection port and having an opening operation completion position regulated by a stopper, and a solenoid coil for driving the valve. The present invention drives an injector that opens a valve to inject fuel into a fuel injection space of an internal combustion engine in response to an injection command signal when a predetermined amount of current is applied to the solenoid coil. , A charging power supply that outputs a constant DC voltage, a peak current supply capacitor that is connected in series to the solenoid coil and is charged by the output voltage of the charging power supply, and a valve that is displaced to the open operation completion position A holding current supply power supply that outputs a holding current that needs to flow through the solenoid coil to hold the
A peak current supply that is connected in parallel to the series circuit of the peak current supply capacitor and solenoid coil, and is connected in parallel between the output terminals of the charging power supply and conducts when an injection command signal is given. When the peak current supply switch is turned on, the output of the charging power supply is short-circuited to prevent charging of the peak current supply capacitor, and the electric charge accumulated in the capacitor is passed through the solenoid coil. A switch circuit that constitutes a closed circuit for discharging, and a switch circuit that is provided between the holding current supply power supply and the solenoid coil and is provided so as to supply a holding current from the holding current supply power supply to the solenoid coil when the power supply is turned on. The holding current supply switch means and the peak current supply switch means are turned on when the injection command signal is given. When the polarity of the oscillating current flowing through the closed circuit has passed the first peak and the polarity has been reversed, the peak current supply switch means is turned off, and a predetermined initial drive period has elapsed since the injection command signal was given. The peak current supply switch means and the hold current supply switch means are controlled so that the hold current supply switch means is sometimes turned on to keep the hold current supply switch means conductive until the fuel injection is completed. And a switch control device.

Then, when the oscillating current flowing through the closed circuit has passed the first peak when the peak current supply switch means is turned on, the valve reaches the opening operation completion position near the first zero crossing point. As described above, the charging voltage of the peak current supply capacitor and the circuit constant of the closed circuit are set, and the initial driving period is set so that the oscillation current reaches the first zero crossing point and the polarity is inverted during the initial driving period. Set the length of

In the above injector driving device,
Before the injection command signal is given, the peak current supply capacitor is charged by the output of the charging power supply. When the injection command signal is given, the peak current supply switch means is turned on to form a closed circuit for discharging the electric charge of the peak current supply capacitor through the solenoid coil, so that the oscillating current flows through the closed circuit. In the present invention, since the valve of the injector reaches the opening operation completion position at the timing near the first zero crossing point where the oscillating current reaches after the first peak, the valve is moved to the opening operation completion position. When it reaches and comes into contact with the stopper, the torque of the solenoid is reduced. Therefore, it is possible to reduce the impact generated when the valve comes into contact with the stopper, to reduce the operating noise of the valve, and to prolong the life of the injector. In addition, since the impact when the valve comes into contact with the stopper can be reduced, the vibration of the valve generated when the opening operation is completed can be reduced, and the injection amount immediately after the completion of the opening operation can be stabilized.

As described above, if the switch means for peak current supply is connected in parallel between the output terminals of the power supply for charging, charging is performed when the switch means becomes conductive in response to the injection command signal. Since the output of the power supply is short-circuited to prevent charging of the peak current supply capacitor, the capacitor can be discharged while the charging of the peak current supply capacitor is prevented.

The switch circuit is arranged so that the voltage at both ends of the peak current supply capacitor charged by the output voltage of the charging power supply and the output voltage of the charging power supply are applied in the forward direction between the anode and the cathode. And a peak current supply thyristor connected in parallel with the series circuit of the peak current supply capacitor and the output terminal of the charging power supply, and an anode and a cathode of the peak current supply thyristor. It can be constituted by diodes connected in anti-parallel.

The holding current supply switch means supplies a holding current from the holding current supply power supply to the solenoid coil when a circuit between the collector and the emitter is inserted between the holding current supply power supply and the solenoid coil and the circuit is turned on. And a holding current supply transistor provided to perform the operation.

In this case, the switch control device turns on the peak current supply thyristor when the injection command signal is given, and holds the holding current supply transistor when a predetermined initial drive period has elapsed after the injection command signal was given. And the holding current supply transistor is held in a conductive state until the injection command signal disappears.

When the oscillating current flowing through the closed circuit constituted by the peak current supply capacitor, the solenoid coil, the peak current supply thyristor, and the diode has passed the first peak when the peak current supply thyristor is turned on, The charging voltage of the capacitor for supplying the peak current and the circuit constant of the closed circuit are set so that the valve reaches the opening operation completion position at the timing near the first zero crossing point to be reached. The initial drive period is set so that its polarity is reversed after passing through the zero cross point.

In the present invention, when the valve opening current is supplied to the injector, the charging of the peak current supply capacitor is prevented, and the peak current supply is performed through the closed circuit constituted by the capacitor, the solenoid coil, and the switch circuit. It is important to discharge the capacitor for use. Therefore, it is necessary to prevent the output of the charging power supply from being applied to the peak current supply capacitor when flowing the valve opening current.

According to the present invention, when the peak current supply switch is turned on, the current is discharged through a closed circuit including the peak current supply capacitor, the switch circuit including the switch, and the solenoid coil, so that the oscillating current is supplied to the solenoid coil. To cause the valve of the injector to reach the opening operation completion position at a timing near the zero crossing point where the oscillating current passes after the first peak. For this purpose, the injection command is increased by making the rising of the oscillating current sufficiently fast and making its initial peak value sufficiently larger than the peak value of the peak current flowing by the conventional peak hold type injector driving method. At the same time as the signal is given, the valve is displaced at a high speed toward the opening operation completion position, and after the oscillating current passes the first peak and the torque of the solenoid decreases, the valve is moved to the opening operation completion position by inertia. The valve is displaced so that the valve reaches the opening operation completion position near the zero crossing point where the oscillating current first reaches after the first peak.

In order to obtain the valve opening current having the above-described waveform, the circuit constant of the closed circuit is set so that the oscillation of the current flowing through the closed circuit for discharging the peak current supply capacitor becomes a damped oscillation. It is necessary to be. L is inductance, C is capacitance, and R is resistance in a closed circuit.
Then, as is well known, the condition for making the oscillation of the current flowing when the electric charge of the peak current supply capacitor is discharged through the closed circuit into the damped oscillation is R ² <4 L / C.

In the present invention, the timing at which the holding current supply switch is turned on (the end of the intended driving period) is set so as to satisfy the following condition.

A. After the oscillating current flowing through the closed circuit has passed the first peak, it should be near the zero crossing point where it first arrives.

B. The time must be after the valve has reached the opening operation completion position.

C. The time before the time when the torque of the solenoid decreases and the valve leaves the opening operation completion position by the urging force of the return spring.

D. It is a time when the shift from the valve opening operation of bringing the valve of the injector to the opening operation completion position to the holding operation of holding the valve at the opening operation completion position can be performed stably.

In the present invention, since the valve-opening current is always an oscillating current flowing through the closed circuit of the LCR having a fixed constant, if the charging voltage of the peak current supply capacitor is kept constant, the above-mentioned holding current supply The timing for turning on the switch means can be always constant. Therefore,
The timing at which the holding current supply switch unit is turned on (the end of the intended driving period) may be determined in advance by calculation, experiment, or the like, and need not be controlled according to the engine speed or the like.

The charging power supply for charging the peak current supply capacitor needs to have a high output voltage so that the capacitor can be charged to a sufficiently high voltage. The charging power supply unit includes a rectifier circuit for rectifying an output voltage of a power generation coil in a magnet type AC generator driven by an internal combustion engine, and a constant voltage control for controlling the output voltage of the rectifier circuit to maintain a constant value. And a circuit. Also, a charging power supply unit can be configured by a battery and a DC-DC converter that boosts the output voltage of the battery and outputs a constant high voltage.

[0049]

FIG. 1 shows the configuration of an injector driving device used to carry out an injector driving method for an internal combustion engine according to the present invention. In FIG. 1, reference numeral 3a denotes a solenoid coil of an injector whose one end is grounded.
a1 and a resistor 3a2. Reference numeral 10 denotes an injector driving power generation coil provided in a magnet type AC generator driven by an internal combustion engine. The power generation coil generates an AC voltage in synchronization with rotation of the engine. The output of the power generation coil 10 is rectified by a rectifier
Has been entered. The constant voltage power supply circuit 12 includes, for example, a power supply capacitor charged by the output of the rectifier circuit 11 and a control circuit that controls the charging voltage of the power supply capacitor to maintain a constant value. Output as charging voltage. In this example, the power generation coil 10, the rectifier circuit 11, and the constant voltage power supply circuit 12
A charging power supply 13 is configured.

One end of a peak current supply capacitor 14 is connected to the other end of the solenoid coil 3a. The capacitor and the solenoid coil 3a are connected in series, and the peak current supply capacitor 14 and the solenoid coil 3a are connected in series. The output voltage of the charging power supply 13 is applied to both ends of the circuit through the diode 15 having the cathode connected to the other end of the capacitor 14. Therefore, the peak current supply capacitor 14 is charged to the polarity shown in the figure through the diode 15 and the solenoid coil 3a by the output voltage of the charging power supply 13.

A thyristor 16 for supplying peak current is connected to both ends of a series circuit of the capacitor 14 for supplying peak current and the solenoid coil 3a with its cathode facing the ground, and a diode is connected to both ends of the thyristor 16. 17 are connected in anti-parallel. A resistor 18 is connected between the gate and cathode of the thyristor 16, and a trigger signal output terminal 19 a of the switch control device 19 is connected to the gate of the thyristor 16 through the resistor 20.

In the illustrated example, the thyristor 16 and the resistor 18
And 20 constitute a peak current supply switch means. A switch circuit 21 capable of flowing current in both directions is constituted by the peak current supply switch means and the diode 17, and when the thyristor 16 is turned on, the capacitor 14-the switch circuit 21-the solenoid coil 3a-the capacitor 14 is closed. A circuit is configured so that an oscillating current flows through the closed circuit.

Reference numeral 22 denotes a holding current supply power supply. In the illustrated example, the holding current supply power supply 22 is formed of a battery, and its negative terminal is grounded. The positive terminal of the holding current supply power supply 22 is connected to the emitter of a holding current supply transistor 23 composed of a PNP transistor, and the collector of the transistor 23 is connected to the resistor 24 and the diode 2.
5 is connected to a connection point between the solenoid coil 3a and the peak current supply capacitor 14. A resistor 26 is connected between the emitter and the base of the transistor 23,
The base of the transistor 23 is connected to the drive signal output terminal 19b of the switch control device 19 through the resistor 27. The transistor 23 and the resistors 24, 26 and 27 constitute a holding current supply switch means 28.

In the injector driving device for an internal combustion engine shown in FIG. 1, a power supply for charging is supplied through a rectifier circuit 11 and a constant voltage power supply circuit 12 by a voltage generated by a power generation coil 10 in a magnet generator as the internal combustion engine rotates. 13 outputs a constant DC voltage. When the thyristor 16 is in the cut-off state, the peak current supply capacitor 14 is charged to the illustrated polarity by the constant DC voltage output from the charging power supply 13 through the diode 15 and the solenoid coil 3a.

FIG. 2 shows signal waveforms at various points in FIG. 1 and the operation of the valve. In FIG. 2, (A) shows the waveform of the injection command signal Vj, and (B) and (C) show the waveforms. The waveforms of the signals output from the output terminals 19a and 19b of the switch control device 19 are shown. FIG. 2D shows a waveform of the drive current Id flowing through the solenoid coil 3a, and FIG. 2E shows a change in the position P of the injector valve. In FIG. 2E, P1 indicates the closed position of the injector valve, and P2 indicates the open operation completion position.

The switch control device 19 is supplied with an injection command signal Vj from an injector control device (not shown) at the fuel injection start timing. The injector control device includes, for example, a microcomputer, and calculates a fuel injection start timing and an injection time with respect to various control conditions such as the rotation speed of the internal combustion engine, the throttle valve opening, or the atmospheric pressure. The injection command signal Vj of a rectangular waveform having a signal width corresponding to the determined injection time is generated.

As shown in FIG. 2A, the injection command signal V
j is a square wave signal that rises at the time of starting fuel injection, and its signal width is the fuel injection time (fuel injection time)
It corresponds to.

The switch controller 19 controls the injection command signal V
When j is given, a trigger signal Vg having a pulse waveform as shown in FIG. 2B is given from the output terminal 19a to the thyristor 16. The switch control device 19 also sets a fixed initial drive period To from the time when the injection command signal Vj is given.
The potential Vb of the output terminal 19b is changed from a high level to a low level (ground potential) when the injection command signal Vj disappears.
To a high level.

The switch controller 19 differentiates the rise of the injection command signal Vj to generate a pulse signal (trigger signal Vg), for example, and measures the initial drive period To when the injection command signal Vj is generated. And a timer circuit that changes the potential of the output terminal from a high-level state to a low-level state when the measurement of the initial drive period is completed.

When the injection command signal Vj is given at time t 1 and the trigger signal Vg is given to the thyristor 16,
The thyristor 16 to which the voltage across the peak current supply capacitor 14 is applied in the forward direction conducts. When the thyristor 16 is turned on, the output terminals of the charging power supply 13 are short-circuited, so that charging of the peak current supply capacitor 14 by the charging power supply 13 is prevented. Thyristor 1
When 6 conducts, the electric charge of the peak current supply capacitor 14 is discharged through the thyristor 16 and the solenoid coil 3a. When the discharge causes the peak current supply capacitor 14 to be charged to the polarity opposite to the illustrated polarity, the anode-cathode of the thyristor 16 is reverse-biased, so that the anode current flowing through the thyristor 16 becomes less than the holding current value. When this happens, the thyristor 16 is turned off. When the capacitor is charged to the polarity opposite to the illustrated polarity by the first discharge of the peak current supply capacitor 14, the charge of the capacitor 14 discharges the solenoid coil 3a and the diode 17. Thus, the oscillating current Id1 as shown in FIG. 2D flows through the closed circuit including the capacitor 14, the switch circuit 21, and the solenoid coil 3a, and this oscillating current becomes the valve opening current. When the oscillating current Id1 flows through the closed circuit, the valve of the injector is displaced from the closed position P1 to the open operation completion position P2. In the present invention, the valve is in the open operation completion position P2.
Before reaching, the frequency of the oscillating current is set sufficiently high so that the oscillating current Id1 passes through the peak and attenuates toward the first zero crossing point tz, so that its rise is made faster.
In addition, the valve is sufficiently accelerated until the oscillation current Id1 reaches a peak, and the oscillation current is adjusted so that the valve continues to be displaced to the opening operation completion position side even in a process where the oscillation current decays past the peak. Make the peak value of
The circuit constant of the closed circuit (the inductance L and the resistance Minute R,
The capacitance C of the capacitor 14 and the charging voltage of the peak current supply capacitor 14 are set in advance.

Then, after the valve reaches the opening operation completion position, while the valve is held at the opening operation completion position, the potential of the output terminal of the switch control device 19 is lowered (the holding current supply switch). (A drive signal is given to the transistor 23 constituting the means), and the transistor 23 is turned on.
3 between emitter-collector-resistor 24-diode 25-
The holding current Id2 is passed through the solenoid coil 3a through the path between the solenoid coil 3a and the holding current supply power supply 22 to hold the valve at the opening operation completion position. When the injection command signal Vj disappears, the potential of the output terminal 19b of the switch control device 19 is set to a high level to turn off the transistor 23 to stop the supply of the holding current to the solenoid coil and return the valve of the injector to the closed position. Let it.

FIGS. 5A and 5B show the change in the valve position when only the oscillating current of the damped oscillation flowing in the closed circuit of the LCR flows through the solenoid coil 3a.
As shown in FIG. 5, when only an oscillating current is supplied to the solenoid coil, the valve is held at the opening operation completion position at the first zero crossing point of the oscillating current. Then, a phenomenon occurs in which the valve moves away from the opening operation completion position P2. Therefore, the switching to the holding current is preferably performed immediately after the first zero cross point.

As described above, if the valve reaches the opening operation completion position near the zero cross point where the oscillating current passes after the first peak, the output torque of the solenoid is reduced. The valve can be brought to the opening operation completion position and brought into contact with the stopper. Therefore, it is possible to reduce an impact generated when the valve comes into contact with the stopper, to promptly open the valve, and to reduce the operation noise of the valve. Further, since the impact when the valve abuts on the stopper can be reduced, the vibration of the valve generated at the time of the completion of the opening operation can be reduced, and the injection amount immediately after the completion of the opening operation can be stabilized. Further, since the impact generated when the opening operation of the valve is completed can be reduced, the life of the injector can be prolonged.

In order to promptly perform the valve opening operation by the injector driving method of the present invention, the charging voltage of the peak current supply capacitor 14 is made sufficiently high so that the initial value of the oscillating current flowing through the solenoid coil during the valve opening operation is increased. It is necessary to increase the peak value of the current. However, it is better that the current flowing through the solenoid coil when the valve reaches the opening operation completion position is small. May be used.

In this specification, the timing at which the injection command signal is generated is defined as the injection start timing. However, there is a delay from when the injection command signal is given to when the valve of the injector is actually opened. The occurrence time does not exactly coincide with the actual injection start time. Since the amount of fuel injected from the injector is determined by the time during which the injector valve is actually kept open and the pressure of the fuel applied to the injector, the time width of the injection command signal depends on the delay in the opening operation of the injector valve. Calculate considering time.

In order to make the waveform of the valve-opening current Id1 as described above, the circuit constant of the closed circuit is set so as to attenuate the vibration generated when the peak current supply capacitor is discharged through the closed circuit. Need to do that. Assuming that the inductance of the solenoid coil 3a is L, the resistance is R, and the capacitance of the peak current supply capacitor 14 is C, the peak current supply capacitor 14 and the switch circuit 2
As is well known, R ² <4 L / C is a condition necessary to make the vibration generated in the current flowing through the closed circuit formed by the solenoid 1 and the solenoid coil 3a into damped vibration. That is, the closed circuit of the LCR for discharging the peak current supply capacitor 15 needs to be a circuit satisfying at least the condition of R ² <4 L / C.

Since the circuit constant of the closed circuit is constant,
The time at which the holding current supply transistor 23 is turned off (initial drive period To) can be fixed to an appropriate time obtained in advance by experiment or calculation and need not be controlled.

In the present invention, a valve opening current having a large peak value is applied to the solenoid coil at the start of the valve opening operation. Therefore, as the injector, the solenoid coil is wound using a coil conductor having a large wire diameter and the inside thereof is wound. One resistance
It is preferable to use one reduced to about 2Ω. Since the in-cylinder injector generally used for directly injecting fuel into the combustion chamber of the engine satisfies such a condition, the present invention is particularly suitable for driving the in-cylinder injector. Useful.

In the above example, the charging power supply 13 for charging the peak current supply capacitor 14 is provided by the power generating coil in the magnet type AC generator and a circuit for rectifying the output voltage of the power generating coil to make it a constant voltage. Although the configuration has been described, the charging power supply 13 may be configured by a battery and a DC-DC converter (chopper circuit) that boosts the voltage of the battery.

Further, the holding current supply power supply 22 is not limited to the above-described example. The holding current supply power supply 18 may be constituted by a circuit that rectifies the output of the magnet generator and outputs a constant DC voltage. Can also.

FIG. 3 shows a specific configuration example of the switch control device 19 of the injector driving device shown in FIG. In the example shown in FIG. 3, the injector control device is constituted by the microcomputer 30, and the injection command signal Vj is output from the output port of the microcomputer 30. An output port of the microcomputer 30 has a PNP transistor 31 whose emitter is grounded.
Are connected through a resistor 32, and the transistor 3
A resistor 33 is connected between one base emitter.
The collector of the transistor 31 is connected to the positive terminal of a DC power supply (not shown) through a resistor 34 and the resistor 3
5 is connected to the base of the PNP transistor 36. The emitter of the transistor 36 is connected to the positive terminal of a DC power supply (not shown), and a resistor 37 is connected between the emitter and the base. The collector of the transistor 36 is connected to the ground potential through a resistor 38 and to the gate of the thyristor 16 through a differential capacitor 39. In this example, a resistor 18 connected between the differential capacitor 39 and the gate cathode of the thyristor 16 is used.
Constitute a differentiating circuit.

The collector of the transistor 31 is also connected through a resistor 41 to the base of an NPN transistor 40 whose emitter is grounded. A timer capacitor 42 is connected between the base and the emitter of the transistor 40,
A diode 43 whose cathode is directed to the base side of the transistor 40 is connected to both ends of the resistor 41. The collector of the transistor 40 is connected to the positive terminal of the DC power supply circuit through a resistor
It is connected to the base of PN transistor 46. The resistor 47 is connected between the base and the emitter of the transistor 46, and the collector of the transistor 46 and the base of the transistor 23 are connected through the resistor 27. Other points are the same as those of the injector driving device shown in FIG.

FIG. 4 shows signal waveforms at various parts of the injector driving device of FIG. FIG. 4A shows an injection command signal Vj output from the microcomputer 30, and FIG. 4B shows a trigger signal Vg supplied to the thyristor 16. (C) shows the voltage Vc across the capacitor 42, and (D) shows the rectangular wave voltage Vq obtained between the collector of the transistor 40 and the ground potential. FIG.
(E) shows the drive current Id flowing through a closed circuit constituted by the peak current supply capacitor 14, the switch circuit 21, and the solenoid 3a.

In the injector driving device shown in FIG. 3, when the microcomputer 30 does not generate the injection command signal Vj, the timer capacitor 42 is connected with the polarity shown in FIG. Has been charged. At time t1, the microcomputer 30 executes the injection command signal Vj (FIG. 4).
When A) occurs, the transistor 31 conducts,
The transistor 36 is turned on, and a current is supplied to the differentiating capacitor 39 from a DC power supply (not shown) through the emitter-collector of the transistor 36. As a result, a trigger signal Vg having a pulse waveform as shown in FIG. 4B is applied to the gate of the thyristor 16. This allows the thyristor 16
, The charging of the peak current supply capacitor 14 is prevented, and the charge of the capacitor 14 is transferred to the thyristor 16.
And discharge through the solenoid coil 3a. Thereby, the peak current supply capacitor 14 and the switch circuit 2
An oscillating current (valve opening current) Id1 flows through a closed circuit constituted by the solenoid valve 1 and the solenoid coil 3a, and the valve starts to be displaced from the closed position to the open operation completed position.

When the injection command signal Vj is generated and the transistor 31 is turned on, the electric charge of the timer capacitor 42 is discharged through the resistor 41 and the transistor 31. Therefore, the voltage Vc across the both ends of the timer capacitor 42 is as shown in FIG.
As shown. When the voltage Vc across the timer capacitor 42 is equal to or higher than the threshold value Vr, the transistor 40 is conducting, and the voltage Vq between the collector of the transistor 40 and the ground is almost at the level of the ground potential (zero level). At time t2, when the voltage Vc across the timer capacitor 42 falls below the threshold value Vr,
Since the transistor 40 is turned off, the voltage Vq between the collector of the transistor 40 and the ground rises to a high level as shown in FIG. Transistor 4
When 0 is turned off, the transistor 46 that has been turned off is turned on, so that a base current flows through the transistor 23 and the transistor 23 is turned on, and the holding current supply power supply 22 supplies the transistor 23, the resistor 24, and the diode. 25, the holding current Id2 is supplied to the solenoid coil 3a.

When the injection command signal Vj disappears at time t3, the transistor 31 is turned off, so that the transistor 36 is turned off and the peak current supply capacitor 14 is charged. When the transistor 31 is turned off, the timer capacitor 42 is charged. The voltage across the timer capacitor 42 is equal to the threshold Vr
As a result, the transistor 40 is turned on, the transistors 46 and 23 are turned off, and the holding current is cut off. Since the threshold value Vr is set sufficiently low, the holding current is cut off almost at the same time when the injection command signal Vj disappears.

As shown in the examples shown in FIGS. 1 and 3, a thyristor 16 is used as a peak current supply switch means, and the thyristor 16 is connected between the output terminals of the charging power supply 13 and between the peak current supply capacitor 14 and the solenoid. When connected in parallel with the series circuit with the coil 3a, when the thyristor 16 is turned on, the charging of the capacitor 14 can be automatically stopped and the discharging of the capacitor 14 can be started, thereby simplifying the circuit configuration. be able to. However, the present invention provides that when opening the injector valve,
In a state where charging of the peak current supply capacitor 14 is prevented, a closed circuit for discharging the electric charge of the capacitor through the solenoid coil may be formed.
However, for example, another switch is inserted between the charging power supply 13 and the capacitor 14, and the switch is turned on while the injection command signal is extinguished. When the injection command signal is generated, the switch may be turned off to disconnect the charging power supply from the capacitor 14, and the peak current supply switch may be turned on to discharge the capacitor 14.

In the above example, the thyristor 16 is used as the peak current supply switch. However, other switch such as a transistor can be used as the switch. When a switch means having bidirectionality such as an FET is used as the peak current supply switch means, a switch circuit is provided only by the peak current supply switch means without using a diode 17 for flowing a reverse current. 21 can be configured. However, when a transistor or FET is used as the peak current supply switch means, the switch means cannot be automatically cut off when the polarity of the oscillating current flowing through the closed circuit is reversed. It is necessary to control both the conduction timing and the cutoff timing of the means.

In the above example, the thyristor 16 is used as the switch for supplying the peak current, the thyristor is turned off when the polarity of the oscillating current flowing through the solenoid coil is reversed, and then the switch for holding the current is supplied. In the above example, the transistor 23) is set to the conductive state. However, when a switch element for controlling both the conductive time and the cut-off time by a signal from the outside, such as a transistor or an FET, is used as the peak current supply switch means. Alternatively, control may be performed so that the switch means for supplying peak current is turned off while the switch means for holding current supply is turned off.

In the above example, the injection command signal Vj is
Although a rectangular wave signal having a time width corresponding to the injection time was used, a trigger signal (a signal having a pulse waveform shown in FIG. 2B) to be supplied to the peak current supply switch means at the start of injection and the holding current supply switch means were conducted. A drive signal (the signal in FIG. 2C) for causing this to occur may be used as the injection command signal.

In the above example, a battery was used as the holding current supply power supply 22. However, as with the charging power supply 13 used in the above example, a magnet attached to the internal combustion engine was used as the holding current supply power supply. It can be constituted by a circuit that rectifies the output of the generator to obtain a constant DC voltage. When both the charging power supply 13 and the holding current supply power supply 22 are configured to use a magnet generator as a power supply, the injector driving method according to the present invention can be applied to an internal combustion engine having no battery.

When a battery is provided,
The charging power supply 13 may be constituted by the battery and a DC-DC converter that obtains a high DC voltage by boosting an output voltage of the battery.

[0083]

As described above, according to the present invention, a peak current supply capacitor that is charged before fuel injection is started is provided, and when an injection command signal is given, the capacitor is charged. In the stopped state, the electric charge of the capacitor is discharged through the solenoid coil and the switch means to cause an oscillating current to flow through the solenoid coil, and at a timing near the first zero crossing point where the oscillating current reaches after the first peak. Since the valve is made to reach the opening operation completion position, the valve can be made to reach the opening operation completion position in a state where the output torque of the solenoid is small. Therefore, it is possible to reduce an impact generated when the valve reaches the opening operation completion position and abuts on the stopper, so that the operation sound of the valve can be reduced.

Further, according to the present invention, since the impact when the valve comes into contact with the stopper can be reduced, the vibration of the valve generated at the completion of the opening operation can be reduced, and the injection amount immediately after the completion of the opening operation can be stabilized. In addition, the life of the injector can be extended.

According to the present invention, the valve opening operation of the injector can be quickly performed by increasing the first peak value of the oscillating current flowing through the solenoid coil.

As described above, according to the present invention, the valve opening operation of the injector can be quickly performed, and the impact when the valve comes into contact with the stopper can be reduced. This has the advantage that the dynamic range of the injector can be increased by reducing the pressure, and the operating noise of the valve can be reduced and the life of the injector can be extended.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration example of an injector drive device for an internal combustion engine according to the present invention.

FIG. 2 is a waveform chart showing signal waveforms and current waveforms of respective parts in FIG. 1 and operation of a valve.

FIG. 3 is a circuit diagram showing a specific configuration example of a switch control device used in the injector driving device of FIG. 1 together with the overall configuration of the driving device.

FIG. 4 is a waveform diagram showing a signal waveform and a current waveform of each section in FIG.

FIG. 5 is a diagram showing a current waveform and an operation of a valve when only an oscillating current of an LCR closed circuit is applied to a solenoid coil of an injector.

FIG. 6 is a circuit diagram showing a configuration example of a conventional saturated injector drive device.

FIG. 7 is a waveform chart for explaining the operation of the driving device of FIG. 6;

FIG. 8 is a circuit diagram showing a configuration example of a conventional peak hold type injector driving device.

FIG. 9 is a waveform chart for explaining the operation of the driving device of FIG. 8;

FIG. 10 is a sectional view showing an example of an injector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Injector, 3a ... Injector solenoid coil, 10 ... Injector drive generating coil, 13 ... Charging power supply, 14 ... Peak current supply capacitor, 16 ...
Thyristor for peak current supply (switch means for peak current supply), 17: diode, 19: switch control device, 21: switch circuit, 22: power supply for holding current supply,
23: Holding current supply transistor (holding current supply switch means).

Continued on front page F term (reference) 3G066 AA02 AB02 AD12 BA06 BA19 BA22 BA40 CC06U CC14 CC56 CD26 CE22 CE25 CE29 DC04 DC09 DC17 3G301 HA04 JA14 JA37 LB04 LC10 MA11 MA18 NA05 NB06 NE16 PA09Z PA11Z PG02A PG02Z 3H106 DB02 DB23 DA23 DC06 DC17 DD03 EE05 EE19 EE20 EE48 FA02 FB18 FB21 FB31 FB33 KK18

Claims (6)

[Claims] A valve provided to open and close the injection port and having an opening operation completion position regulated by a stopper; and a solenoid coil for driving the valve, and a current of a predetermined magnitude is supplied to the solenoid coil. Is provided, the valve moves to the opening operation completion position, and the injector for injecting fuel into the fuel injection space of the internal combustion engine is driven in response to an injection command signal. Charge the peak current supply capacitor before the injection command signal is given, and charge the peak current supply capacitor in a state where the charging of the peak current supply capacitor is blocked when the injection command signal is given. By discharging through the solenoid coil, an oscillating current flows through the solenoid coil, and the oscillating current is After the valve has reached the opening operation completion position at a timing near the first zero crossing point, which is reached after passing through the opening, after the oscillating current has passed the first zero crossing point and its polarity has been reversed, the valve is closed. A holding current having a magnitude necessary to hold the valve at the opening operation completion position was passed through the solenoid coil while the valve was at the opening operation completion position, and the holding current was flowed until the fuel injection was completed. A method for driving an injector for an internal combustion engine, characterized by maintaining a state. 2. A valve provided to open and close an injection port, the opening operation completion position of which is regulated by a stopper, and a solenoid coil for driving the valve, and a current of a predetermined magnitude is applied to the solenoid coil. In the injector drive device that drives the injector in response to an injection command signal by opening the valve to inject fuel into the fuel injection space of the internal combustion engine when the valve is opened, a charging power supply that outputs a constant DC voltage A capacitor for peak current supply connected in series with the solenoid coil and charged by an output voltage of the charging power supply; and for holding the valve displaced to the open operation completion position at the open operation completion position. A holding current supply power supply for outputting a holding current required to flow through the solenoid coil; A switch circuit for peak current supply, which is connected in parallel to the series circuit with the inductor coil and is connected in parallel between the output terminals of the charging power supply and conducts when the injection command signal is given. A closed circuit for short-circuiting the output terminals of the charging power supply when the peak current supply switch means is turned on, and discharging the electric charge accumulated in the peak current supply capacitor through the solenoid coil. A holding circuit provided between the holding current supply power supply and the solenoid coil to supply the holding current from the holding current supply power supply to the solenoid coil when conducting. Switch means for supplying current, and the switch means for supplying peak current when the injection command signal is given. At a timing near the first zero crossing point where the oscillating current flowing through the closed circuit passes after the first peak, the peak current supply switch means is turned off, and a predetermined initial drive is performed after the injection command signal is given. The peak current supply switch means and the holding means are arranged to keep the hold current supply switch means conductive until the fuel injection is completed by turning on the hold current supply switch means when a period has elapsed. A switch control device for controlling a current supply switch means, wherein when the peak current supply switch means is turned on, the oscillating current flowing through the closed circuit is set at a timing near the first zero crossing point. The charging voltage of the peak current supply capacitor and the circuit constant of the closed circuit are set so as to reach the open operation completion position. Wherein the length of the initial drive period is set such that the oscillating current reaches the first zero crossing point and reverses its polarity within the initial drive period. apparatus. 3. A valve provided to open and close the injection port, the opening operation completion position of which is regulated by a stopper, and a solenoid coil for driving the valve, and a current of a predetermined magnitude is supplied to the solenoid coil. An injector drive device that drives an injector that opens the valve to inject fuel into the fuel injection space of the internal combustion engine when given, in response to an injection command signal having a time width corresponding to the fuel injection time, A charging power supply that outputs a constant DC voltage; a peak current supply capacitor connected in series with the solenoid coil and charged by an output voltage of the charging power supply; A holding current supply power source that outputs a holding current necessary to hold the valve at the opening operation completion position, and an output voltage of the charging power source. The voltage between both ends of the charged peak current supply capacitor and the output voltage of the charging power supply are applied in a forward direction between the anode and the cathode to form a series circuit of the solenoid coil and the peak current supply capacitor. A thyristor for peak current supply connected in parallel to the output terminals of the charging power supply, and a diode connected in anti-parallel between the anode and cathode of the thyristor for peak current supply, A holding current supply provided to supply the holding current from the holding current supply power supply to the solenoid coil when a collector-emitter circuit is inserted between the holding current supply power supply and the solenoid coil to conduct electricity. Transistor for conducting the peak current supply thyristor when the injection command signal is given. When a predetermined initial drive period has elapsed since the injection command signal was given, the holding current supply transistor is turned on, and the holding current supply transistor is turned on until the injection command signal disappears. A switch control device that controls the thyristor and the holding current supply transistor so as to hold the peak current supply capacitor, a solenoid coil, and the peak current when the peak current supply thyristor is turned on. The peak current such that the valve reaches the opening operation completion position at a timing near the first zero crossing point where the oscillating current flowing through the closed circuit formed by the supply thyristor and the diode passes after the first peak. The charging voltage of the supply capacitor and the circuit constant of the closed circuit are set, and The oscillating current the first internal combustion engine injector driving apparatus according to claim zero that the length of the initial driving period, as its polarity is reversed reached a cross point is set within a dynamic period. 4. The power supply for charging includes a power generating coil provided in a magnet type AC generator driven by an internal combustion engine, a rectifying circuit for rectifying an output of the power generating coil, and a constant output voltage of the rectifying circuit. The injector drive device for an internal combustion engine according to claim 2 or 3, comprising a constant voltage power supply circuit that controls the voltage to be kept at a value. 5. The charging power source includes: a battery; and a D / D converter that boosts an output voltage of the battery and outputs a constant DC voltage.
4. The injector driving device for an internal combustion engine according to claim 2, wherein the injector driving device comprises a C-DC converter. 6. When the inductance existing in the closed circuit is L, the capacitance is C, and the resistance is R,
^The injector drive device for an internal combustion engine according to any one of claims 2, 3, 4, and 5, wherein the closed circuit is configured to satisfy a condition of ² <4L / C.