JP3473211B2 - Solenoid valve drive - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic valve drive device, and is suitable for a fuel injection control device for a diesel engine, for example, which performs pilot injection prior to main injection.

[0002]

2. Description of the Related Art In a fuel injection control device for a diesel engine, by injecting fuel twice from a fuel injection valve (injector) during one cycle of intake, compression, explosion and exhaust, engine noise is reduced and exhaust gas We are making improvements. These two injections are first a pilot injection that explodes the fire in the cylinder with a small amount of injection and a main injection that corresponds to the amount of fuel necessary for the original work. In the main injection, fuel burns after the pilot injection. By suppressing rapid combustion during one cycle by such combustion, explosion noise and reduction of nitrogen oxides (NO _x ) at the time of combustion are realized. However, it is necessary to operate the fuel injection valve (injector) at a high speed in order to realize the injection in one cycle in which the time is extremely short and further the injection under a high pressure.

As a method of driving a fuel injection valve, that is, a solenoid valve at high speed, there is a method of discharging energy charged in a capacitor in advance to a drive solenoid of the solenoid valve at the timing of operating the solenoid valve. This is because the magnetic flux (=
Force) rises slowly and cannot meet the control, but stores a high voltage higher than the battery voltage in the capacitor, discharges the capacitor from the capacitor to the drive solenoid, and rapidly raises the magnetic flux to open the solenoid valve at high speed. Is. More specifically, in the fuel injection control device, the injection interval between the pilot and the main may be shortened to about 1 msec. Therefore, after discharging the energy of the capacitor used for driving the pilot injection, charging of the capacitor used for driving the main injection is completed. Since it is difficult to put it in time, prepare two charging capacitors, one for pilot and one for main,
The energy of the two charging capacitors is used during one cycle to complete the recharge by the time of fuel injection in the next cycle.

FIG. 5 shows a concrete configuration example. In FIG. 5, a pilot injection booster circuit 70, a main injection booster circuit 71, and a disconnection circuit 72 are provided. Then, the boosting transistors 70b and 71b are turned on / off by the oscillation signals from the oscillation circuits 70a and 71a to generate electromotive force due to mutual induction (flyback) in the secondary coils of the transformers 70c and 71c, and the capacitor 70d. , 7
Charge is stored in 1d. Also, the comparators 70e and 71e
When a predetermined voltage value is reached while monitoring the capacitor charging voltage by the above method, the output of the oscillation signal to the transistors 70b and 71b is prohibited and the charging is terminated. In addition, the microcomputer 7
By turning on the solenoid valve drive transistor 74 in accordance with the command of No. 3, electric power is supplied to the solenoid valve 75 from the capacitor 70d charged in the pilot injection booster circuit 70 to perform pilot injection, and disconnection is performed by the command of the microcomputer 73. When the circuit 72 is turned on and the solenoid valve drive transistor 74 is turned on, electric power is supplied from the capacitor 71d charged in the main injection booster circuit 71 to the solenoid valve 75 to perform main injection.

[0005]

However, when the circuit configuration shown in FIG. 5 is adopted, the booster circuit 7 for the charging capacitor is used.
Since 0 and 71 were provided independently, the scale had become large. That is, the transformer (7
0c, 71c), boosting transistors (70b, 71c)
b), the oscillation circuits (70a, 71a), and the charge termination circuits (70e, 71e, etc.) for terminating the charging are required in the number of two each, which causes a problem of hindering miniaturization.

Therefore, an object of the present invention is to provide an electromagnetic valve drive device capable of high-speed valve opening operation with a simple structure.

[0007]

According to a first aspect of the invention, a first capacitor and a second capacitor are connected to a common coil means, and a drive solenoid is connected to the first capacitor. Further, a drive solenoid is connected to the second capacitor via a switching element for disconnection.

Then, the charging control means controls ON / OFF of the boosting switching element to generate an electromotive force in the coil means by an inductive action. At this time, the first capacitor and the second capacitor are connected to the coil means, the less charged one of the two capacitors is charged, and both capacitors have substantially the same voltage (with the same capacity). Equivalent energy if available) is stored. In this state, the first energization control means turns on the solenoid valve drive switching element with the disconnection switching element off, and energizes the drive solenoid with the first capacitor to perform the first valve opening operation. To perform. The second energization control means is
Immediately after the first valve opening operation, the solenoid valve driving switching element is turned on with the disconnection switching element turned on, and the drive solenoid is energized by the second capacitor to perform the second valve opening operation. Let

Since only one coil means for charging the two capacitors, the step-up switching element, and the charge control means are required in this manner, the solenoid valve can be driven at a high speed with a simple structure.

According to a second aspect of the present invention, the charging operation inhibiting means is provided only for one of the capacitors, and when the terminal voltage of one of the first capacitor and the second capacitor reaches a predetermined value, The charging operation by the charging control means is prohibited. In other words, although there are two capacitors, the current generated from the coil means flows to the capacitor with the lower voltage, so that the charging state of both capacitors can be detected by monitoring the voltage of one capacitor. As described above, since only one charging operation prohibiting unit is required, simplification is achieved.

According to the third aspect of the invention, the first energization control means causes the pilot injection and the second energization control means causes the main injection immediately after the pilot injection.
As a result, it is preferable as a fuel injection control device for an internal combustion engine that performs a valve opening operation twice at a high speed in one cycle.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is embodied in a fuel injection control device for a multi-cylinder diesel engine.

FIG. 1 shows the overall structure of a fuel injection control device for a diesel engine. A fuel injection control device for a diesel engine includes a pump 1 for pressurizing fuel and a pump 1
Common rail 2 for storing the high-pressure fuel pressurized at 1, a fuel injection valve (injector) 3 for injecting the high-pressure fuel from the common rail 2, a microcomputer 4, and an electromagnetic solenoid for opening and closing the fuel injection valve 3 according to a command from the microcomputer 4. It is composed of a valve drive circuit 5. The fuel injection valve (injector) 3 is provided in each cylinder of a multi-cylinder diesel engine. Further, the microcomputer 4 and the solenoid valve drive circuit 5 constitute an electronic control unit (ECU) 32.

A drive shaft 7 of the pump 1 is rotatably supported in a housing 6, and the drive shaft 7 is drivingly connected to an output shaft of a diesel engine. A cam 8 is eccentrically fixed to the drive shaft 7, and a piston 9 is attached to the cam surface (outer peripheral surface) of the cam 8.
Are contacted by the spring 10. Piston 9 is cylinder 1
It is slidably supported in 1 and slides up and down by the rotation of the cam 8 accompanying the rotation of the drive shaft 7. At this time,
The fuel is introduced from the fuel tank 12 into the cylinder 11 by the downward movement of the piston 9, and the fuel in the cylinder 11 is pressurized by the upward movement of the piston 9, and the pressurized fuel flows through the check valve 13. It is supplied to the common rail 2 via. Further, the microcomputer 4 is a pressure sensor 1 provided on the common rail 2.
While monitoring the fuel pressure in the common rail 2 at 4, the solenoid valve 15 provided in the pump 1 is controlled to open and close to spill the pressurized fuel to the tank 12 side so that the fuel pressure in the common rail 2 becomes constant. I am supposed to keep it.

The fuel injection valve 3 comprises a fuel injection valve body 16 and a three-way solenoid valve 17, and high-pressure fuel from the common rail 2 is supplied to the fuel injection valve body 16 and the three-way solenoid valve 17. The fuel injection valve body 16 has a fuel chamber 18
A needle valve 19 is arranged inside, and the needle valve 19 is connected to a piston 20 and is biased by a spring 21 in a direction to close the injection port. The three-way solenoid valve 17 includes a housing 22, and an outer valve 23 is vertically slidably supported in an inner hole 22a of the housing 22. The housing 22 has a first port (fuel intake port) 24, a second port 25,
A drain port 26 is provided. The first port (fuel intake port) 24 is the common rail 2 and the second port 2
5 is connected to the upper space of the piston 20, and the drain port 26 is connected to the drain tank 27. The outer valve 23 has a port 28 corresponding to the first port 24.
And a port 29 corresponding to the second port 25.

A drive solenoid 30 is provided above the housing 22. When the drive solenoid 30 is in the non-energized state, the outer valve 23 is urged downward by the spring 31 so that the first port 24 of the housing 22 and the port 28 of the outer valve 23 communicate with each other and the second port 25 of the housing 22 and the outer valve 23. Communicates with the port 29. Therefore, the high-pressure fuel from the common rail 2 is applied to the upper surface of the piston 20 through the ports 24, 28, 29, 25 and the inner hole 23a of the outer valve 23, and this pressure pushes the needle valve 19 downward to open the injection port. close.

When the drive solenoid 30 is energized, the outer valve 23 is suctioned up, the port 24 is closed, and the port 25 and the port 26 communicate with each other. Therefore, the pressure applied to the piston 20 passes through the port 25 and the port 26, and the drain tank 2
It leaks to the 7 side (low pressure side). Therefore, the needle valve 19
Rises by the high pressure fuel in the fuel chamber 18 and opens the injection port to inject the fuel.

Further, when the drive solenoid 30 is not energized, the high-pressure fuel from the common rail 2 and the biasing force of the spring 31 act downward on the outer valve 23, and the ports 25 and 26 communicate with each other and the inside of the common rail 2 is connected. In order to inject the high-pressure fuel, not only the absorbed energy to overcome the downward force F of the outer valve 23 is required, but also the port 24 and the port 26 communicate with each other unless the operation of sucking the outer valve 23 is performed at high speed. Drain into the drain tank 27. Furthermore, the suction operation of the outer valve 23 must be performed at an extremely high speed in order to precisely control the injection start timing.

Therefore, in order to quickly operate the three-way solenoid valve 17 against the fuel pressure which reaches a maximum of 150 MPa, the solenoid valve drive circuit 5 causes the voltage of the battery (12 volt or 24 volt), which is a direct current power source for the vehicle, to be applied. Drive solenoid 3 of the three-way solenoid valve 17 by generating a high voltage exceeding
When the power is 0, the three-way solenoid valve 17 is discharged to supply a high voltage. Due to the sudden rising current that accompanies the supply of such a high voltage, the magnetic flux rapidly increases, enabling a high response even under a high fuel pressure.

FIG. 2 shows a specific structure of the solenoid valve drive circuit 5, the microcomputer 4 and the three-way solenoid valve 1 in the circuit 5.
7 shows a connection state with the drive solenoid 30 of No. 7. A primary coil 34a of a transformer 34, a transistor 35 as a step-up switching element, and a resistor 36 are connected in series to a battery (battery terminal 33 in FIG. 2) that is a DC power source. A diode 37 and a main injection capacitor 38 as a second capacitor are connected in series to the secondary coil 34b of the transformer 34. In the present embodiment, the transformer 34 constitutes the coil means.

The secondary coil 34b of the transformer 34 has a
Pilot as diode 39 and first capacitor
The injection capacitor 40 is connected in series. Dio
Connection point between the cord 37 and the main injection capacitor 38
a has a diode 42 via a disconnection circuit 41,
The drive solenoid (load) 30 of the three-way solenoid valve 17 and the solenoid
A transistor 43 as a valve driving switching element, and
Are connected in series. Where the transistor 43
Is a fuel injection valve 3 (three-way solenoid valve 1) provided in each cylinder.
It is provided corresponding to 7). And each burn
Turning on the transistor 43 corresponding to the fuel injection valve 3
Thus, a current can be passed through the drive solenoid 30.
That is, the drive solenoid 30 in the first cylinder has an electromagnetic
Valve drive current I ₁But in the second combustion cylinder, the second cylinder
The drive solenoid 30 has a solenoid valve drive current I₂But below
Similarly, the drive solenoid 30 in the nth cylinder has an electromagnetic
Valve drive current I_nFlows.

The disconnecting circuit 41 comprises a transistor 44 as a disconnecting switching element, a diode 45, a transistor 46 and resistors 47, 48 and 49. A transistor 44 is arranged between the connection point a and the diode 42, and a diode 45 is interposed between the gate terminal and the source terminal of the transistor 44. A resistor 47 and a transistor 46 are connected to the gate terminal of the transistor 44.
Are connected, and a resistor 48 is interposed between the base terminal and the emitter terminal of the transistor 46. The base terminal of the transistor 46 is connected to the microcomputer 4 via the resistor 49. Then, the transistor 44 of the disconnection circuit 41 is turned on / off via the transistor 46 by the main injection permission signal from the microcomputer 4, and in the off state, the main injection capacitor 38 and the drive solenoid 30 are electrically cut off and turned on. In the state, the main injection capacitor 38 and the drive solenoid 30 are electrically connected.

At a connection point b between the diode 39 and the pilot injection capacitor 40, a diode 50, a drive solenoid (load) 30 for the three-way solenoid valve 17, and a transistor 43 are connected in series.

The gate of each transistor 43 for driving the solenoid valve
Is connected to the microcomputer 4 by a drive signal line
It Each transistor 43 drives the solenoid valve from the microcomputer 4.
Signal T ₁, T₂, ..., T_nTo turn on. Also, batte
The constant current circuit 51 is connected to the re-terminal 33,
The constant current generated at 51 is driven through the diode 52.
It is supplied to the dynamic solenoid 30. still,
Reference numeral 64 in FIG. 2 denotes a power supply line for the drive solenoid 30.
It is a diode provided on the ground side of the antenna.

On the other hand, a series circuit (voltage dividing circuit) consisting of resistors 53 and 54 is provided for the pilot injection capacitor 40, and the connection point c between the resistors 53 and 54 is inverted by the comparator 56 via the resistor 55. It is connected to the input terminal. That is, a signal having a level corresponding to the voltage across the terminals of the pilot injection capacitor 40 is sent to the comparator 56 as a voltage monitoring signal. A constant voltage power supply 57 is connected to the non-inverting input terminal of the comparator 56, and the comparator 56 compares the level of the voltage monitoring signal with the constant voltage value (corresponding to the boosting end value) of the constant pressure power supply 57. The output terminal of the comparator 56 is connected to the input terminal of the AND gate 58. An oscillation circuit 59 as a charge control means is connected to the other input terminal of the AND gate 58, and the oscillation circuit 59 outputs an oscillation signal to the AND gate 58 in response to a boosting permission signal from the microcomputer 4. The output terminal of the AND gate 58 is connected to the base terminal of the transistor 62 via the resistor 60. A resistor 61 is provided between the base and emitter of the transistor 62. Transistor 62
The collector terminal of the battery terminal 33 via the resistor 63
The collector terminal is also connected to the gate terminal of the transistor 35.

In the present embodiment, the comparator 5
6, the constant-voltage power supply 57, and the AND gate 58 constitute a charging operation inhibiting means for inhibiting the charging operation. next,
The basic operation of the solenoid valve drive circuit 5 configured and connected as described above will be described with reference to the flowchart executed by the microcomputer 4 of FIG. 3 and the time chart of FIG.

In FIG. 4, (a) the solenoid valve drive current I ₁ in the first cylinder, (b) the solenoid valve drive current I ₂ in the second cylinder, (c) the voltage of the pilot injection capacitor 40, (d). The voltage of the main injection capacitor 38,
(E) Voltage monitoring signal, (f) Gate voltage of transistor 35 which is a switching element for boosting, (g) Main injection permission signal, (h) Electromagnetic valve drive signal T ₁ in first cylinder, (i) Second cylinder Solenoid valve drive signal T ₂ at
(J) A boost permission signal is shown.

First, the charging operation of the capacitors 38 and 40 before the fuel injection by the fuel injection valve 3 will be described. When the fuel injection (main injection) is completed in the compression process in a certain cylinder, the microcomputer 4 sets the boost permission signal to the permission side (timing t1 in FIG. 4) and starts fuel injection in the compression process in the next cylinder (pilot). The permitted state is maintained until the injection is started) (timing of t3 in FIG. 4). An oscillation signal is sent from the oscillation circuit 59 to the AND gate 58 in response to this boosting permission signal. Also, the charging voltage of the capacitors 38 and 40 (capacitor voltage)
Is lowered by the discharge operation for the fuel injection operation (the opening operation of the fuel injection valve). Therefore, in the comparator 56, the level of the voltage monitoring signal is lower than the constant voltage value (corresponding to the boosting end value) by the constant voltage power source 57, and the output becomes H level. Therefore, the oscillation signal is output from the AND gate 58 to the transistor 62, the transistor 62 is turned on / off in synchronization with the oscillation signal, and the transistor 35 is turned on / off in synchronization with the on / off operation of the transistor 62. Operate.

When the transistor 35 is turned on,
A primary current flows from the battery to the primary coil 34a of the transformer 34. When the transistor 35 is turned off, the secondary current flows through the secondary coil 34b of the transformer 34 due to the magnetic energy of the transformer primary current that has been flowing, and the capacitors 38 and 40 are charged through the diodes 37 and 39. As a result, , The voltage of the capacitors 38 and 40 rises (the period from t1 to t2 in FIG. 4). This operation is repeated by the on / off operation of the transistor 35, and the voltages of the capacitors 38 and 40 gradually rise. At this time, since the capacitor 38 and the capacitor 40 are connected to the secondary coil 34b of the transformer 34, the two capacitors 38 and 40 are charged on the less charged side, and the capacitors 38 and 40 are substantially equal. Voltage (equal energy with the same capacity) is stored.

When the level of the voltage monitoring signal in the comparator 56 (voltage of the capacitor 40) is compared with the constant voltage value of the constant voltage power source 57 (corresponding to the boosting end value), when the level of the voltage monitoring signal reaches the set voltage Vch. (Timing t2 in FIG. 4), the output of the comparator 56 becomes L level, the output of the AND gate 58 also becomes L level, and the transistors 62 and 35 are turned off.
Charging to 8, 40 will also stop.

In FIG. 3, first and second energization control
The microcomputer 4 as a means operates the accelerator in step 101.
Input the opening signal, engine speed signal, water temperature signal, etc.,
These are used to detect the operating status of the diesel engine
It The microcomputer 4 changes the operating condition of this diesel engine.
The engine calculates the fuel injection amount and fuel injection timing according to
Fuel injection valve 3 pilot injection time according to the operating state of
T_PAnd the main injection time T _MAnd injection stop time T_INTCalculate
To do.

Then, at the pilot injection start timing (timing t3 in FIG. 4), the microcomputer 4 sets the step-up permission signal to the prohibition side in step 102 and also drives the pilot injection time T _P (in FIG. 4). Outputs the solenoid valve drive signal T ₂ ) to H level and outputs it.
At this time, the main injection permission signal is set in step 10 described later.
Due to the process of 5, the transistor 44 of the disconnection circuit 41 is turned off because it is prohibited.

As a result, when the fuel injection valve 3 is opened after the capacitor is charged, the transistor 43 corresponding to the specific cylinder is turned on by the drive signal (drive pulse) from the microcomputer 4 and stored in the pilot injection capacitor 40. The discharged electric charge is discharged all at once through the diode 50 and the drive solenoid 30 of the three-way solenoid valve 17 as an inductive load (the period from t3 to t4 in FIG. 4). In this way, the transistor 43 is turned on and the drive solenoid 30 is energized. At this time, since the applied voltage is boosted higher than the battery voltage, it is possible to realize a high-speed response even under a high fuel pressure by passing a large current through the drive solenoid 30. That is, when the valve for pilot injection is opened, the pilot injection capacitor 4
The valve opening operation is promptly performed by the current from 0.

After the discharge, a constant current flows from the constant current circuit 51 to the drive solenoid 30 through the diode 52 (the period from t4 to t5 in FIG. 4). As described above, during the valve opening operation of the fuel injection valve 3, the valve open state is maintained by the constant current from the constant current circuit 51.

Further, at the pilot injection end timing (timing t5 in FIG. 4), the microcomputer 4 sets the electromagnetic valve drive signal to the L level for the injection stop time T _INT and outputs it at step 103. Therefore, t5 to t6 in FIG.
During the period of, the transistor 43 is turned off.

At the main injection start timing (timing t6 in FIG. 4), the microcomputer 4 sets the main injection permission signal to the permission side in step 104 to turn on the transistor 44 of the disconnection circuit 41, and at the same time, perform the main injection. The electromagnetic valve drive signal is set to the H level and output for the time T _M. That is, when the fuel injection valve 3 is opened after charging the capacitor, the drive signal (drive pulse) from the microcomputer 4
As a result, the transistor 43 corresponding to the specific cylinder is turned on, and the electric charge stored in the main injection capacitor 38 is discharged at once through the transistor 44, the diode 42, and the drive solenoid 30 of the three-way solenoid valve 17 as an inductive load (Fig. 4 period from t6 to t7). In this way, the transistor 43 is turned on and the drive solenoid 30 is energized. At this time, since the applied voltage is boosted higher than the battery voltage, it is possible to realize a high-speed response even under a high fuel pressure by passing a large current through the drive solenoid 30. That is, the main injection capacitor 3 is opened when the valve is opened for main injection.
The valve opening operation is promptly performed by the current from 8.

After discharging, a constant current flows from the constant current circuit 51 to the drive solenoid 30 through the diode 52 (the period from t7 to t8 in FIG. 4). As described above, during the valve opening operation of the fuel injection valve 3, the valve open state is maintained by the constant current from the constant current circuit 51.

After that, the microcomputer 4 sets the main injection permission signal to the prohibition side and sets the boosting permission signal to the permission side in step 105 (timing t8 in FIG. 4). As described above, the process of FIG. 3 is sequentially executed for the fuel injection valve 3 provided for each cylinder in accordance with the combustion order, and the fuel injection control is performed.

As described above, in the present embodiment, the main injection capacitor 38 and the pilot injection capacitor 40 are connected to the secondary coil 34b in the common transformer 34, and one oscillator circuit 59 is provided. The transistor 35 is turned on / off by the oscillation signal output from 59 to generate an electromotive force in the transformer 34 due to the mutual induction (flyback), and the less charged side of the two capacitors 38 and 40 is charged. , I tried to store approximately the same energy in both capacitors. Therefore, the transformer 34 for charging the two capacitors 38, 40,
Since only one transistor 35 as the step-up switching element and one oscillation circuit 59 as the charge control means are required, the solenoid valve can be driven at high speed with a simple configuration.

Further, the comparator 56 as the charging operation inhibiting means, the constant voltage power source 57 and the AND gate 58 are provided only in the capacitor 40 of the capacitors 38 and 40, and the charging operation is performed when the terminal voltage of the capacitor 40 reaches a predetermined value. Banned. In other words, although there are two capacitors, the current generated from the secondary coil 34b of the transformer flows to the capacitor having the lower voltage, so that the charging state of both capacitors can be detected by monitoring the voltage of one capacitor. In this way, the charging operation prohibiting means (56, 57,
58) requires only one, which simplifies.

In the above example, the oscillation signal is output from the oscillation circuit 59, but the oscillation signal may be sent directly from the microcomputer 4. Further, in the above example, the voltage is monitored for the capacitor 40, but the voltage may be monitored for the capacitor 38. Further, the voltage of each of the capacitors 40 and 38 may be monitored to permit or prohibit the charging operation.

Although the disconnection circuit 41 is provided only between the main injection capacitor 38 and the drive solenoid 30, the main injection capacitor 38 and the drive solenoid 30 are provided.
In addition to the above, the disconnection circuit 41 may be provided between the pilot injection capacitor 40 and the drive solenoid 30. Then, between the pilot injection and the main injection (the period from t5 to t6) in FIG. 4, the newly added disconnection circuit for the pilot injection capacitor 40 may be turned off to perform the charging operation. In this case, it is more preferable to monitor the voltages of both capacitors 38 and 40.

Although the transformer 34 is used, one winding may be used as the coil means. Furthermore, the present invention can be used not only in the fuel injection control device for a diesel engine, but also in a solenoid valve drive device that continuously performs a valve opening operation in a short time.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a fuel injection control device for a diesel engine.

FIG. 2 is a circuit configuration diagram in the embodiment.

FIG. 3 is a flowchart for explaining the operation.

FIG. 4 is a time chart for explaining the operation.

FIG. 5 is a configuration diagram of a conventional solenoid valve driving device.

[Explanation of symbols]

3 ... Fuel injection valve, 4 ... Microcomputer as first and second energization control means, 33 ... Battery terminal as direct current power source, 34 ... Transformer constituting coil means, 35 ... Transistor as boosting switching element, 38 … Second
For main injection, as a condenser for
Pilot injection capacitor as first capacitor, 43 ... Transistor as solenoid valve driving switching element, 44 ... Transistor as disconnecting switching element, 56 ... Comparator constituting charging operation inhibiting means, 57 ... Inhibition of charging operation Constant-pressure power source constituting means 5,
8 ... AND gate constituting charging operation prohibiting means, 59 ...
Oscillation circuit as charge control means.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI F02M 47/02 F02M 47/02 (58) Fields investigated (Int.Cl. ⁷ , DB name) F16K 31/06-31/11 F02D 41/20 375 F02M 45/10 F02M 47/00 F02M 47/02

Claims (3)

(57) [Claims] 1. A solenoid valve which opens by energizing a drive solenoid, a solenoid valve drive switching element connected in series with the drive solenoid, a DC power supply and a boost switching element connected in series. Coil means, a first capacitor connected to the coil means and the drive solenoid, and a second capacitor connected to the coil means and to the drive solenoid via a switching element for disconnection.
And a charge control means for controlling the step-up switching element to be turned on / off to generate an electromotive force due to an inductive action in the coil means to charge the first and second capacitors, and the switching for separation. First energization control means for turning on the solenoid valve driving switching element with the element off and energizing the drive solenoid with the first capacitor to perform a first valve opening operation; Immediately after the first valve opening operation, the solenoid valve driving switching element is turned on with the disconnection switching element turned on, and the second solenoid is energized by the second capacitor. Second to make valve operation
And an energization control means for the solenoid valve drive device. 2. A charging operation prohibiting means for prohibiting the charging operation by the charging control means when the inter-terminal voltage of one of the first capacitor and the second capacitor reaches a predetermined value. The solenoid valve drive device according to claim 1. 3. A fuel injection control device for an internal combustion engine, wherein the solenoid valve is provided in a fuel injection valve that injects high pressure fuel when the valve is open, and the first capacitor is a pilot. An injection capacitor, the second capacitor is a main injection capacitor, and the first capacitor
3. The electromagnetic valve drive device according to claim 1, wherein the energization control means of 1 performs the pilot injection, and the second energization control means performs the main injection immediately after the pilot injection.