Patent ID: 6883725

Claim:
A fuel injector for a fuel-injection system of an internal combustion engine, comprising: a valve-seat surface; a valve-closure member forming a sealing seat with the valve-seat surface; a valve needle, wherein the valve-closure member is positioned at the valve needle; a hydraulic coupler having a pressure cylinder, a pressure-cylinder support joined to the pressure cylinder and including a coupler valve-closure member, and a pressure piston guided in the pressure cylinder, wherein a pressure chamber is formed inside the pressure cylinder; an actuator for actuating the valve-closure member via the hydraulic coupler, wherein the actuator is one of a piezoelectric and magnetostrictive actuator; a coupler spring element positioned between the pressure piston and the pressure cylinder, the coupler spring element generating an initial stress that drives the pressure piston out of the pressure cylinder; a coupler valve-seat surface cooperating with the coupler valve-closure member by the spring force of the coupler valve-spring element to form a coupler valve-sealing seat, a cross-sectional surface of the coupler valve-sealing seat being smaller than a cross-sectional surface of the pressure piston; and a fuel inflow connected to the pressure chamber by an inflow bore in the pressure-cylinder support, and by the coupler valve-sealing seat.