Fuel injector

The injector has two actuator units (1, 2) for operating a nozzle needle (3), and an injection opening closed by stroke movement of the needle. The units are controlled independent of each other and coupled to the needle over a coupling device (5). The coupling device has a hydraulic coupling volume (6) that is limited by two effective surfaces (A-1, A-2). One of the surfaces is formed at a transmission element (7) acting together with the actuator units, such that force intensification is caused in a phase of opening stroke of the needle and path intensification is caused in another phase. An independent claim is also included for a method for controlling a nozzle needle of a fuel injector.