Fuel injection apparatus for internal combustion engines

A fuel injection apparatus for internal combustion engines, having at least one pump work chamber (7), defined by a pump piston (5) in a bore (3) of a cylinder liner (1), said work chamber is made to communicate with an injection valve (33) via a line (29) which is supplied with fuel from a low-pressure fuel chamber (15) and is relieved via a fuel line (13) having a control valve (23) electrically actuated by a control unit (51), wherein a fuel quantity injected at the injection valve (33) and the instant of injection are controllable by the electrically actuated control valve (23) during a pumping stroke of the pump piston (5) in such a manner that the injection quantity is split into a successive preinjection quantity and a main injection quantity, a sensor (61) is disposed on the injection valve (33), said sensor detects the injection onset and injection end of said injection valve (33) and directs a signal to the control unit (51) that triggers the electric valve (23) said control unit compares this signal, representing an actual value, with a set-point value derived from a performance graph and if the actual value deviates therefrom readjusts the triggering for the opening and closing motion of the electrically actuated valve (23), the sensor (61), is embodied as a needle stroke transducer, and does not transmit the signal for the opening or closing motion of the nozzle needle to the control unit (51) until a certain limit value beginning at the onset of motion of the nozzle needle in the opening and closing direction is exceeded or fails to be attained.