Patent ID: 6885131
Filing Date: 2005-04-26
Classification: F02D,F02M,H02N

Abstract:
1. A method for controlling a piezoelectric actuator that is actuatable to displace an element, wherein the actuator and the element are arranged so that a return stroke comprising a gap exists between the actuator and the element, the size of the return stroke being variable in response to ambient influences, said method comprising the steps of: determining a current size of the return stroke by measuring at least one parameter that is indicative of the current size of the return stroke, the at least one parameter comprising a capacitance of the actuator; and applying a control voltage to the actuator to displace the element, the control voltage being selected such that it is dependent on the determined size of the return stroke to compensate for variations in the return stroke due to ambient influences, the control voltage including a sum of a first voltage and a compensation voltage, wherein only the compensation voltage portion of the sum is dependent on the determined size of the return stroke.