Method of recognizing the impingement of a reciprocating armature in an electromagnetic actuator

摘要

A method of recognizing armature impingement in an electromagnetic actuator having an electromagnet including a solenoid, an armature movable toward and away from the electromagnet and return means for exerting a force on the armature. The method includes the steps of maintaining a solenoid current at a predetermined magnitude Imax during a predetermined period TA for capturing the armature at the electromagnet; switching off the solenoid current at a moment t1 upon lapse of the period TA; upon lapse of a period T1 running from moment t1, oscillating the solenoid current between a lower holding current threshold IH1 and an upper holding current threshold IH2; detecting a current course from moment t1; and deriving a signal from such current course.