Therefor, one end of the multiplying piston (7) is guided into one end of the other multiplying piston (6).

The pressure intensifier (7) comprises a pressure intensifier piston (9) which is assigned a spring element (13) which is supported by way of one side on the injector housing (10) and by way of the other side on the pressure intensifier piston (9).

In said piston (5), an annular collar (18) is configured on the side facing away from the step-up piston (3).

A working chamber (4) of the pressure intensifier (3) is separated from a differential pressure chamber (6) of the pressure intensifier (3) by means of a pressure relay piston (5).

A control piston (5) is displaceably mounted in a step-up piston (3), which is connected to the actuator (2).

A pressure booster (2) provided with a booster piston (5) is arranged between said fuel injector (3) and high-pressure fuel source (21).

Said pressure amplification device comprises a moving pressure amplification piston, which separates a chamber which may be connected to the high pressure fuel source from a high pressure chamber connected to the fuel injector.

The fuel injector (1) comprises a hydraulic coupling chamber (13) which hydraulically connects a transmission piston (10) and the injection valve member (9).

A pressure multiplicator or demultiplicator piston (54) is adjacent on one side to a control chamber (96) and on the other to a high-pressure chamber (76).

Said return spring is arranged in the non-controlled primary chamber which presents a large volume, such that hydraulic oscillations in said primary chamber do not disturb the intensifier piston operation.

The booster piston (5) separates a chamber (9) connected to high-pressure fuel source (21), a high-pressure chamber (11) connected to the fuel injector and a differential pressure chamber (10).

According to said invention, a hydraulic pressure intensifier unit (14), comprising an intensifier piston (16) which can be moved against the effect of a return spring (15) in the compression direction, is provided for producing the injection pressure.

Therefor, one end of the multiplying piston (7) is guided into one end of the other multiplying piston (6).

The actuator (14) acts directly on a converter piston (24) of a pressure converter (100) which pressurizes the conversion chamber (36).

The pressure intensifier (7) comprises a pressure intensifier piston (9) which is assigned a spring element (13) which is supported by way of one side on the injector housing (10) and by way of the other side on the pressure intensifier piston (9).