Sensor with a Piezo-Actuator

Various embodiments may include a method for operating a piezo-actuator in a piezo-operated injector for a fuel injection system comprising: producing a measuring pulse at a position at which the usable signal which is to be measured is expected; then producing a reference pulse which corresponds to the measuring pulse, in the same cycle; subtracting a first actuator voltage measured during the reference pulse from a second actuator voltage measured during the measuring pulse; using a resulting voltage signal difference to calculate a force sensed by the piezo-actuator; and using the force sensed to correct an injection amount for the injector.