Fuel injection system

Fuel injection system according to one of the foregoing claims, characterized in that the current diagnosis unit searches for the fault only at a predetermined time interval.

Fuel injection system according to one of the foregoing claims, characterized in that the fault includes a short circuit from a piezoelectric element (10, 20, 30, 40, 50, or 60) to ground while driving the piezoelectric element (10, 20, 30, 40, 50, or 60).

Fuel injection system according to one of the foregoing claims, characterized in that the current diagnosis unit comprises a comparator circuit for comparing currents flowing in different parts of the driving circuitry, and a control unit (D) receiving a difference signal from the comparator circuit, the control unit (D) generating an error signal when the difference signal is greater than a predetermined maximum during charging or discharging of the piezoelectric element (10, 20, 30, 40, 50, or 60).

Fuel injection system according to claim , 9, 10, or 11, characterized in that the error signal is recorded as an entry in an error memory.

Fuel injection system according to one of the foregoing claims, characterized in that the current diagnosis unit discharges all piezoelectric elements if an error is detected.

Method for operating a fuel injection system with a piezoelectric element (10, 20, 30, 40, 50 or 60) for controlling an amount of injected fuel, by charging and/or discharging the piezoelectric element (10, 20, 30, 40, 50 or 60) using a driving circuitry, in particular for operating a fuel injection system according to one of the foregoing claims, characterized in that a current flowing in the driving circuitry is checked in such a manner that a possible fault of the current flowing in the driving circuitry is detected within 10 μsec of the fault occurring.