Abstract: A piezo-actuator is actuated in a first operating mode (B1) by pulsed supply of a first electrical variable for charging or discharging of the piezo-actuator taking into account at least one actuation parameter (P) for the piezo-actuator. The piezo-actuator is actuated in a second operating mode (B2) by non-pulsed introduction of the first electrical variable for charging or discharging of the piezo-actuator, to be precise with the first electrical variable having a predetermined profile which is substantially independent of any load change on the piezo-actuator (1). A profile of a second electrical variable of the piezo-actuator is recorded during at least one measurement time period while the predetermined profile of the first electrical variable is being applied. The at least one actuation parameter (P) of the piezo-actuator is determined as a function of the recorded profile of the second electrical variable.

Abstract: A piezo-actuator is actuated in a first operating mode (B1) by pulsed supply of a first electrical variable for charging or discharging of the piezo-actuator taking into account at least one actuation parameter (P) for the piezo-actuator. The piezo-actuator is actuated in a second operating mode (B2) by non-pulsed introduction of the first electrical variable for charging or discharging of the piezo-actuator, to be precise with the first electrical variable having a predetermined profile which is substantially independent of any load change on the piezo-actuator (1). A profile of a second electrical variable of the piezo-actuator is recorded during at least one measurement time period while the predetermined profile of the first electrical variable is being applied. The at least one actuation parameter (P) of the piezo-actuator is determined as a function of the recorded profile of the second electrical variable.

Abstract: A measured current, voltage or capacity characteristic is subtracted from an idealized characteristic line of the same size stored in the system. The maxima, minima and reversal points are identified in this calculated difference curve, since these values correlate to the valve opening timepoints. In another step the values determined in the first step are approximated in respect of a target value situated on the difference curve with the aid of a mathematical method, in order to ascertain a more exact determination of these values.