Fuel injector for an internal combustion engine

摘要

A method of driving a valve in an injector for an internal combustion engine which intermittently injects liquid fuel by the valve reciprocally moving by attraction force of a solenoid coil and repulsive force of a spring and an apparatus for carrying out the method. An armature secured to the valve to be attracted by the solenoid coil and/or an iron core of the solenoid coil is made of a permanent magnet. The pulse shape of an electric current to be applied to the solenoid coil is made in the form of a stepped wave in which the electric power in the initial stage of application is larger than that in the later stage. An inverse pulse for inversely exciting the solenoid coil is formed to give the permanent magnet of the armature repulsive force upon fall of the pulse wave of the electric current applied to the solenoid coil.