JPH0329658Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a circuit configuration for extinguishing back electromotive force generated in a drive device for a solenoid valve means, such as a solenoid valve drive coil.

[Conventional technology]

Conventionally, a plurality of electromagnetic valves used for fuel injection in an internal combustion engine are driven by individual output transistors as electromagnetic valve means, and in this case, the back electromotive force generated in the drive coil of each electromagnetic valve is Arcs were extinguished separately using multiple arc extinguishing circuits installed for each valve.

[Problem that the invention attempts to solve]

Therefore, arc extinguishing circuits are required for the number of solenoid valves, which increases the circuit portion, increases the space of the control device, and increases costs.

The present invention solves the above-mentioned drawbacks, and aims to provide a driving device for a solenoid valve means that can combine a plurality of arc extinguishing circuits into one, has a simple configuration, and is low in cost.

[Means for solving problems]

Therefore, the present invention includes a plurality of solenoid valve means,
a plurality of output transistors that individually drive these electromagnetic valve means; and a plurality of diodes each having one end of the same polarity connected to each connection point of the electromagnetic valve means and the output transistor and the other end commonly connected. , is characterized by comprising an arc extinguishing circuit connected in series to a common connection point of these diodes.

Further, according to an embodiment of the present invention, the arc extinguishing circuit includes a parallel circuit of a CR time constant circuit and a Zener diode.

〔Example〕

An embodiment of the present invention will be described below. The figure shows an example of a solenoid valve means in which a fuel injection solenoid valve is arranged near the intake port of each cylinder of a four-cylinder internal combustion engine, and each solenoid valve is controlled to open at an independent timing. Note that air is used as the solenoid valve means.
Valve means for controlling various fluids such as fuel are applicable. Reference numerals 1, 2, 3, and 4 indicate fuel injection electromagnetic valves disposed near the intake ports of each cylinder, which include drive coils for electromagnetically operating a mechanical valve opening/closing mechanism. In this case, 5 is an on-vehicle battery power supply, and 6, 7, 8, and 9 are output transistors connected in series to each drive coil built into each solenoid valve to drive each solenoid valve 1 to 4. Reference numeral 10 denotes a control circuit that controls the operation of each output transistor 6 to 9, and is composed of, for example, a digital circuit including a microcomputer, and receives signals S1, S2,...Sn from sensors that detect various operating states of the internal combustion engine. , calculates the required fuel injection amount, outputs a signal with a corresponding pulse width to each output transistor 6-9 at a predetermined crank angle timing, and drives each transistor 6-9 sequentially or simultaneously. 11, 12, 13, and 14 are diodes that connect the drive coils of each electromagnetic valve 1 to 4 and the output transistor 6.
The anode side is connected to the connection point with ~9, and the cathode side is commonly connected. 15 and 18 are resistances,
16 is a capacitor, 17 is a Zener diode, and these elements 15 to 18 constitute an arc extinguishing circuit that extinguishes the back electromotive force generated in each drive coil. The diodes 11 to 14 and the resistor 18 constitute a basic closed loop, and the high voltage component of the back electromotive force is absorbed by the Zener diode 17, and the transient component is absorbed by the CR time constant circuit consisting of the resistor 15 and capacitor 16. It is designed to absorb.

Therefore, each solenoid valve 1 to 4 is driven in response to a pulse signal from the control circuit 10, and the back electromotive force generated immediately after being stopped is absorbed in each path via each diode 11 to 14 and extinguished. That will happen.

[Effect of idea]

As described above, according to the present invention, the conventional necessity for a plurality of arc extinguishing circuits corresponding to the number of solenoid valve means can be simplified to one, and a space-saving and low-cost circuit can be provided.

[Brief explanation of drawings]

The accompanying drawing is a circuit diagram showing an embodiment of the present invention. 1-4... Solenoid valve, 6-9... Output transistor, 10... Control circuit, 11-14... Diode, 15, 16, 17, 18... Resistor, capacitor, Zener diode forming the arc extinguishing circuit, respectively. ,resistance.

Claims (1)

[Scope of utility model registration request] A plurality of electromagnetic valve means, a plurality of output transistors that individually drive these electromagnetic valve means, one end of the same polarity is connected to each connection point of the electromagnetic valve means and the output transistor, and the other end is common. The arc-extinguishing circuit includes a plurality of connected diodes and an arc-extinguishing circuit connected in series with a common connection point of these diodes, and the arc-extinguishing circuit includes a solenoid valve means including a parallel circuit of a CR time constant circuit and a Zener diode. Drive device.