Delphi Technologies, Inc.

Delphi Technologies Holding S.arl

Peter Griffin

Joseph Walsh

Daniel Jeremy Hopley

Martin A P Sykes

Martin A Sykes

Martin Sykes

Daniel Hopley

A method for controlling the displacement of a stack of a piezoelectric actuator for use in a fuel injector comprises determining a desired amount of charge (&#x394;Q) to be added or removed from the stack. The method further comprises determining an operating parameter of the fuel system and selecting a drive current level (PO, SO) and a drive time (t, t) in accordance with the desired amount of charge (&#x394;Q) and the operating parameter, and driving the drive current through the stack for the drive time (t, t) in order to add or remove the desired amount of charge (&#x394;Q).

Method of controlling a piezoelectric actuator

A fuel injector control method comprises determining a required separation time between a termination of an on signal associated with a first injection event and an initiation of an on signal associated with a second injection event. The method comprises calculating an overlap time between the separation time and the time to charge the piezoelectric stack to a first level; dividing the overlap time into first and second time periods as a function of the charge and discharge currents; applying the charge current to the piezoelectric stack for a charge time; and applying the discharge current to the piezoelectric stack for a discharge time so as to discharge the stack to a second level, wherein the discharge time is calculated on the basis of the second time period of the overlap time. Thus, first and second injection events are merged in a pulse mode of operation.

Fuel injector control method

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Maidstone, United Kingdom

Peter Griffin