Abstract: The nozzle body (5) of a fuel injection valve has a central bore (54) in which a nozzle needle (1) is guided. The tip (52) of the nozzle body (5) has a tapered valve seat (55) which forms together with the sealing edge (27) of the nozzle needle (1) a valve (27, 55) which controls the flow of fuel to the injection holes (9) in the nozzle tip (52). Underneath the sealing edge (27) a circumferential groove (33) is disposed in the truncatoconical needle tip (30, 35, 40, 45) at the level of which the injection holes (9) are disposed, so that when the valve (27, 55) opens the nozzle needle (1) is axially stabilized and the shaping of the injected jet is improved.

Abstract: The fuel injector has a housing that is formed from at least one nozzle tension nut, a first injector module and a second injector module. The first injector module and the second injector module adjoin one another and are disposed in the nozzle tension nut. A fuel high-pressure bore is led through the first injector module and the second injector module. A fuel return bore is disposed in the housing. Contact surfaces between the injector modules form a first gap that adjoins the high-pressure bore. Contact surfaces between the nozzle tension nut and the injector modules form a second gap that is connected to the first gap. The return line adjoins the second gap for the discharge of fuel that has entered the second gap from the high-pressure bore via the first gap. The fuel injector is such that the second gap is sealed off relative to the surroundings of the fuel injector.

Abstract: A servo drive includes a piezoelectric actuator contained in a drive housing. The actuator has an actuator stack surrounded by a hollow cylindrical spring element and an actuator casing disposed in the spring element. The spring element is clamped, together with the actuator stack, between an actuator cap and an actuator base. An elastic compound fills gaps between the drive housing and the spring element as well as between the spring element and the actuator casing, and damps an actuator motion. A piezoelectric actuator for the servo drive and a method of producing the piezoelectric actuator are also provided.

Abstract: A device for transmitting a deflection of a piezoelectric actuator to a movable tappet includes a pressure chamber between the piezoelectric actuator and the tappet. The pressure chamber is substantially formed by two mutually parallel diaphragms having effective radii of different lengths. The diaphragm with the longer radius is associated with the piezoelectric actuator and the diaphragm with the shorter radius is associated with the tappet. Therefore, upon a deflection of the first diaphragm by the piezoelectric actuator, the second diaphragm is deflected by a greater distance toward the tappet. A controller with an actuator having a controllable length is also provided.

Abstract: A mechanical force transmitter converts the deformation of a piezoelectric actuator into a linear movement of a final control element. The transmission is via configuration of two mutually inclined working surfaces and a movable mechanical element disposed between the inclined working surfaces.