Delphi Technologies Holding S.arl

Delphi Technologies Holdings Sarl

Peter J Spadafora

Daniel Jeremy Hopley

Adrian R Tolliday

Alain Wesquet

A method of operating a fuel injector including a piezoelectric actuator having a stack of piezoelectric elements, and wherein in use the injector communicates with a fuel rail, the method comprises: applying a discharge current to the actuator for a discharge period so as to discharge the stack from a first differential voltage level across the stack to a second differential voltage level across the stack; maintaining the second differential voltage level for a period of time; and applying a charge current to the actuator for a charge period so as to charge the stack from the second differential voltage level to a third differential voltage level; wherein the third differential voltage level is selected in dependence on at least two engine parameters, the at least two engine parameters selected from: rail pressure; the electric pulse time; and the piezoelectric stack temperature.

Injection control system

A method of operating a fuel injector having a piezoelectric actuator that is operable by applying an electrical drive pulse thereto to activate and deactivate the injector. The method includes monitoring an electrical characteristic of the actuator during a predetermined time period, determining a time-domain data sample corresponding to the monitored electrical characteristic during the predetermined time period, determining a frequency spectrum signature corresponding to the time-domain data sample, and comparing the frequency spectrum signature of the monitored electrical characteristic to a predetermined frequency spectrum signature indicative of an injector event.

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Leudelange, Luxembourg

Peter J Spadafora