US Patent 7398933 Injection valve

An injector, in particular an injector for a combustion engine, includes at least one nozzle module which has an injection nozzle and a supply line for a fluid under a supply pressure, and a valve-control module, which is in operative connection with the nozzle module, and at least one valve-closure member on which the supply pressure acts, and includes a piezoelectric actuator which is used to activate the valve-closure member and which is prestressed by a spring in the direction facing away from the valve-closure member, the piezoelectric actuator being activated by a valve-control unit which specifies a control gradient. The control gradient is a variable that is dependent upon the supply pressure.