Driving circuitry for electromagnetic fuel injection valve

Abstract

Driving circuitry for an electromagnetic fuel injection valve in which the holding current value is made variable to obtain a minimum necessary holding force from the holding current according to the fuel pressure includes a solenoid for driving the fuel injection valve, a capacitor charged by a high-voltage charge control part, a switch circuit for on-off controlling a high-voltage current supplied from the capacitor to the solenoid in response to an injection command signal, and a holding current supply circuit for supplying a holding current from the power supply to the solenoid. When the holding current is supplied, a comparator circuit compares a voltage obtained by converting the value of electric current flowing through the solenoid by a resistor for detection and a voltage corresponding to a fuel pressure sensor signal, and the value of the holding current is varied according to an output signal from the comparator circuit.

Dependencies are inferred from the claim text.