Diagnostic method for checking operating state of piezoelectric actuator of combustion engine fuel injector, in which capacitance associated with actuator is checked against reference or other actuator values

摘要

A capacitance associated with the actuator (16) of e.g. a combustion engine fuel injector (14), is checked against a nominal value or against the capacitances of other actuators. Independent claims are also included for the following; (1) computer program; (2) control and regulation unit; (3) combustion engine.