Method for reducing performance variation of an electromagnetically-activated actuator

A method for reducing performance variation of an electromagnetically-activated fuel injector including an electrical coil and an armature, comprising:

• providing injector activation signals to the electromagnetically-activated fuel injector comprising driving a first current through the electrical coil in a first direction;
• subsequent to each injector activation signal, sensing a respective voltage inflection in the electrical coil indicative of the armature reaching a rest position;
• detecting variable timing among the respective voltage inflections, wherein unacceptable response variations correspond to unacceptable variable timing;
• and
• subsequent to detection of unacceptable response variations, driving a second current through the electrical coil in a direction opposite that of the first direction and following injector activation signals.

A system for controlling actuation of a fuel injector, comprising:

• a fuel injector comprising an electrical coil and an armature;
• an injector driver responsive to an injector command signal for driving current through the electrical coil;
• and
• a control module configured to:
• actuate the injector by providing the injector command signal to the injector driver effective to drive a first current through the electrical coil in a first direction;
• subsequent to the first current through the electrical coil, sense a voltage inflection in the electrical coil indicative of the armature reaching a rest position;
• determine a timing of the voltage inflection,
• detect a timing variation between the timing of the voltage inflection and a timing of a prior voltage inflection corresponding to an immediately prior injector actuation;
• determine an unacceptable injector response variation based on an unacceptable timing variation;
• and
• subsequent to detection of the unacceptable injector response variation, provide the injector command signal to the injector driver effective to drive a second current through the electrical coil in a direction opposite that of the first direction.