Patent ID: 6943480

Claim:
A control and operating system for at least one piezoelectric actuator having an impedance of a substantially capacitative type, in particular for a fuel injector for a Diesel engine, including a source of DC supply voltage, at least one control circuit branch connected in parallel to the said source and in which the piezoelectric actuator is connected in series to first and second controlled electronic switches each of which has a respective diode connected in parallel, disposed with its cathode towards the positive pole of the voltage source; at least one energy-accumulating inductor with one terminal connected between said switches and the other terminal connected to a terminal of the voltage source; and electronic command and control means for piloting the said controlled switches so as to cause closure of a first switch while the other or second switch is open, so as to connect the accumulator inductor to the voltage source; opening of the said first switch when the energy accumulated in the inductor has reached a predetermined value, so that the inductor is then connected to the piezoelectric actuator by means of the diode in parallel with the second switch so as to form a resonant LC circuit, and voltage is progressively located on the piezoelectric actuator operable to cause a reversible mechanical deformation thereof; subsequent closure of the second switch while the first is open, so as to allow the voltage located on the piezoelectric actuator to be discharged into the inductor, and the reopening of the said second switch when the voltage on the actuator has fallen to a minimum value, in such a way that the residual energy accumulated in the inductor can then flow back towards the voltage supply source.