Patent ID: 7055765

Claim:
A fuel injector for a fuel-injection system of an internal combustion engine, comprising: one of a piezoelectric actuator and a magnetostrictive actuator; a valve needle; a valve-closure member; an actuator; and an hydraulic compensation chamber; wherein the one of the piezoelectric actuator and magnetostrictive actuator, by way of the valve needle, actuate the valve-closure member arranged on the valve needle, the valve-closure member cooperating with a valve-seat surface to form a sealing seat, the hydraulic compensation chamber cooperating with a pressure piston and being filled with hydraulic fluid via an hydraulic fluid inlet, the actuator is arranged between the pressure piston and the valve needle and is displaceable in the axis of the valve needle and the pressure piston, and wherein a chamber spring is arranged on the side of the hydraulic compensation chamber of the pressure piston and acts on the pressure piston with a prestressing force that presses the pressure piston out of the compensation chamber.