Common rail injector

In a common rail injector for injecting fuel in a common rail injection system of an internal combustion engine, which system has an injector housing (1) with a fuel inlet (21) that is in communication with a central high-pressure fuel reservoir outside the injector housing (1) and with a pressure chamber (24) inside the injector housing (1), from which fuel subjected to high pressure is injected as a function of the position of a control valve (33) that assures that a nozzle needle (8) movable back and forth and received in a longitudinal bore (6) of the injector housing (1) axially counter to the prestressing force of a nozzle spring (19) that is received in a nozzle spring chamber (20), lifts from a seat when the pressure in the pressure chamber (24) is greater than the pressure in a control chamber (30) that communicates with the fuel inlet (21) via an inlet throttle (31, 38, 39), the improvement wherein the control chamber (30) is defined by a bush (28) that is displaceable, causing a sealing action, on the end of the nozzle needle (8) remote from the combustion chamber located outside the injector housing (1) and kept in contact against the injector housing (1) with the aid of the nozzle spring (19).