Patent ID: 7765987

Claim:
An apparatus for actuating at least one piezoelectric actuating drive of an injection nozzle for an internal combustion engine, comprising a control device which cyclically actuates a charging circuit and a discharging circuit of the piezoelectric actuating drive, wherein a capacitive equivalent load ( 9 ), which is connected to a charging stage ( 13 ) and electrically simulates the piezoelectric actuating drive ( 1 ), and an additional discharging stage ( 7 ) for piezoelectric actuating drive ( 1 ) and a changeover switch ( 8 ) which can be actuated by a control circuit ( 11 ) are provided, which switch connects the equivalent load ( 9 ) or the piezoelectric actuating drive ( 1 ) to the discharging circuit ( 3 ) which is controlled via the control device ( 6 ), and that after it has been decoupled from the discharging circuit ( 3 ) the piezoelectric actuating drive ( 1 ) can be discharged with a delay, via the additional discharging stage ( 7 ) which can be actuated by the control circuit ( 11 ), depending on at least one parameter which changes with the loading of the internal combustion engine.