Method and device for controlling a piezo-actuator

The method as recited in one of the preceding claims, wherein the absolute value of the electric current, applied to the piezoelectric actuator during charging and discharging, is adjusted, depending on the derivative with respect to time to be achieved.

The method as recited in one of the preceding claims, wherein the engine is a diesel engine.

A control unit for controlling a motor vehicle injection system, comprising at least one piezoelectric actuator for injection of fuel into the combustion chamber of an internal combustion engine via a valve, an electric current which at least partially charges or discharges it being applied to the piezoelectric actuator to change its length, wherein a monitoring unit (150) for determining the operating situation of the internal combustion engine is provided, so that the derivative with respect to time of the voltage during the charging/discharging time, which may be picked off at the piezoelectric actuator (100), can be selected as a function of the operating situation.

The control unit as recited in one of the preceding claims, wherein the absolute value of the electric current applied to the piezoelectric actuator during charging and discharging, respectively, is adjusted as a function of the derivative with respect to time to be achieved.

A fuel injection system having at least one piezoelectric actuator for the injection of fuel into the combustion chamber of an internal combustion engine via a valve, an electric current, at least partially charging or discharging it, being applied to the piezoelectric actuator to change its length, wherein a control unit for determining the operating situation is provided, so that the derivative with respect to time of the voltage during the charging/discharging time, which may be picked off at the piezoelectric actuator (100), may be selected as a function of the operating situation.