Electromagnetic load control apparatus having variable drive-starting energy supply

摘要

In an electromagnetic injector control apparatus for an engine, a capacitor (C10) is connected to a power supply (+) and a solenoid (101a) of an injector (101) for accumulating electric charge at a voltage (Vc) higher than that of the power supply. A driving circuit (120) controls transistors (T10, T11) to supply energy from the power supply to the solenoid during an operation period of the solenoid. The driving circuit also controls a transistor (T12) so that a timing to start supplying the accumulated energy from the capacitor to the solenoid is delayed from a timing to start the operation of the solenoid as the voltage of the capacitor increases. Thus, the accumulated energy is used to speed up the operating response of the solenoid. The supply of the accumulated energy to the solenoid is stopped when a current (I) flowing in the solenoid reaches a predetermined cut-off level (I0). The capacitor is set to retain an offset of at least a predetermined quantity to be left therein when energy of a counter-electromotive force of the solenoid is recovered at the end of operation of the solenoid. <IMAGE>