Metering valve for metering a fluid

Metering valve for metering fluids in a fuel injection system of an internal combustion engines such as direct-injection diesel engines, comprising a valve housing (10) with a metering opening (20), a valve needle (21) which, together with a valve seat (18) surrounding the metering opening (20), controls the metering opening (20), is guided in axially displaceable fashion in the valve housing (10) and is pressed onto the valve seat (18) under the action of a valve-closing spring (22), a piezoelectric or magnetostrictive actuator (25) which displaces the valve needle (21) axially counter to a closing force of the valve-closing spring (22), and a hydraulic displacement amplifier (23) which converts a rapid change in length of the actuator (25) into a larger stroke of the valve needle (21) and, for this purpose, has an operating piston (30) coupled to the actuator (25), a lifting piston (33) coupled to the valve needle (21), and an amplifier chamber (36) enclosed in the valve housing (10) by the operating and lifting pistons (30, 33) with different piston areas that are guided in axially displaceable fashion therein, in which, for its use as a rapid, outward-opening valve with the valve seat (18) arranged on the outside of the housing (10), the lifting piston (33), which is of small-mass design, projects with an end section (331) of reduced diameter into a recess (32) in the operating piston (30), and a first compression spring (31), which presses the operating piston (30) against the actuator (25) and is designed as a flat spring, is supported on the operating piston (30) and on the valve housing (10), and a second compression spring (34), which presses the lifting piston (33) against the valve needle (21) in the opposite direction and is supported on the lifting piston (33) and on the bottom of the recess (32) in the operating piston (30), are arranged in the amplifier chamber (36).