Delphi Technologies, Inc.

Jean-Francois Berlemont

Michael Peter Cooke

Martin Paul Hardy

Christopher Andrew Goat

Andrew John Hargreaves

A method of operating a fuel injector including a piezoelectric actuator having a stack of piezoelectric elements, comprises applying a discharge current (I) to the actuator for a discharge period so to discharge the stack from a first differential voltage level across the stack to a second, lower differential voltage level across the stack so as to initiate an injection event, and applying a charge current (I) to the actuator for a charge period (Tto T') so as to charge the stack from the second differential voltage level to a third differential voltage level so as to terminate the injection event. The method includes determining at least one engine parameter (e.g. common rail pressure) of the injection event prior to applying the charge current (I) to the actuator and selecting the third differential voltage level in dependence on the at least one engine parameter.

System and method for operating a piezoelectric fuel injector

The invention provides a piezoelectric actuator having a stack body comprising a plurality of piezoelectric elements, each element having a positive and negative electrode pair which are electrically isolated from one another by the piezoelectric elements, the electrode pairs being arranged in groups of one or more electrode pairs, each group having a conducting arrangement in electrical connection therewith. The piezoelectric actuator further comprises a distribution electrode arrangement for connecting the conducting arrangement to a power supply, in use, wherein the distribution electrode arrangement includes a fuse arrangement. In the event of a short circuit between electrodes of a pair within one of the groups, the fuse arrangement breaks the electrical connection between the power supply and the conducting arrangement.

Growing community of inventors

Bascharage, Luxembourg

Jean-Francois Berlemont