Abstract: For diagnosing coupled piezo-mechanical systems, methods are used which utilize electrical characteristic curves of the piezo-element that is contained in the piezo-mechanical systems. These electrical characteristic curves contain information about the mechanical condition of the overall piezo-mechanical system, which can be interpreted by suitable evaluating methods. It is thus possible to perform a diagnosis in which malfunctions and failures of the piezo-mechanical system can be detected (e.g. wear or failure of particular components). An important field of application is the diagnosis of fuel injectors which are controlled via piezo-actuators.

Abstract: A wobble motor has at least one shaft guided in a rotatably and axially displaceable fashion, and at least one drive ring which surrounds the shaft and can be tilted with respect to a longitudinal axis of the shaft. The at least one guide ring can be displaced in a frictionally locked fashion and free from rotation.

Abstract: A stroke transmission apparatus includes a displaceable stroke element, a drive element and at least one lever, which is respectively seated on the drive element and can be applied to the stroke element and to a bearing, so that with a simultaneous seating of the lever on the stroke element, on the drive element and on the bearing, a primary stroke (xp) can be transmitted to the stroke element via a lever effect of the lever, and with a changing primary stroke (xp), a stroke factor (II) can be modified by modifying at least one contact point.

Abstract: A wobble motor has at least one shaft guided in a rotatably and axially displaceable fashion, and at least one drive ring which surrounds the shaft and can be tilted with respect to a longitudinal axis of the shaft. The at least one guide ring can be displaced in a frictionally locked fashion and free from rotation.

Abstract: A fluid metering device that employs a sealing element for delivering a metered dose of a pressurized fluid. The sealing element includes a metal bellows sealing element or metal bellows that attaches to a valve needle and a housing. The metal bellows includes a number of corrugated elements for sealingly guiding said valve needle as the valve needle moves to deliver the metered dose of pressurized fluid.

Abstract: A piezoelectric multilayer actuator made of at least two individual piezoelectric layers which can be driven electrically by at least one electrode, wherein the actuator exhibits a hexagonal cross-sectional geometry.

Abstract: In a plate valve, particularly a cone spray valve, the valve gap, or respectively, seal gap (6) which is present in the open condition is not designed with parallel faces, but with cross-sectional areas which remain the same given increasing radius. This approach applies to a set from the interior outward. The advantage consists in the avoidance of cavitation and in the achievement of a low closing force for sealing the valve.

Abstract: The compensation element is compensating for temperature-conditioned length changes of an object. An injection valve that is fully functional in the entire range of the operating temperatures of a motor requires a device that compensates thermally conditioned length changes of the mechanical components (piezo-electric actuator, valve lifter, housing, etc.). This device should be capable of absorbing great forces and allow a stiff bearing of the actuator. The compensation element (3) has an oil-filled chamber (21) is composed of an actuator-side upper part (18), of a lower part (19) supported on a stiff bearing (valve housing 17), and of a structure (annular seal element 20) sealing the chamber (21) and yielding in an axial direction.

Abstract: A device and method for dosing fluid has a housing enclosing a lifting element and a primary drive hydraulically operable on the lifting element via a hydraulic chamber. The lifting element is disposed within a borehole with a leakage permitting fit. A fluid chamber in communication with the borehole contains a fluid to be dispensed in a dosed manner by controlled axial movement of the primary drive and lifting element.

Abstract: A wall-controllable primary drive, for example a piezo actuator, guided in a first bore transfers its stroke motion-commutated onto a secondary-side lifter element guided in a second bore, transmitting said stroke by a piston-hydraulic stroke transmission on the basis of a hydraulic chamber. The pressure in a valve chamber is controlled via secondary-side lifter element.

Abstract: An electrohydraulic drive is provided. High-speed injection valves of hydraulic lift transformers have, for example, a pressure piston driven by a piezoelectric actuator and a reciprocating piston mounted in an axially displaceable fashion in a pressure piston bore and connected to the valve needle. The electrohydraulic drive has a piezoelectric actuator and a hydraulic force/travel transmission of compact design. To ensure the required axial symmetry of the drive despite production-induced tolerances, a balance element supported in a frustoconical depression of the pressure piston is arranged between the piezoelectric actuator and the lift transformer. During assembly of the hydraulics, the element having the form of a spherical segment and produced from high-grade steel can slide freely on the piezoceramic and thus compensate a nonconcentric alignment of the actuator and pressure piston.

Abstract: An easily controllable primary drive (5) guided in a first bore (3), for example a piezo actuator, transmits its stroke by a piston-hydraulic stroke transmission with a hydraulic chamber (2) onto a stroke element (70) of the secondary side guided in a second bore (4). The pressure in a valve chamber (9) is controlled via the stroke element (7) of the secondary side.

Abstract: A electrohydraulic stop device contains a piezoelectric actuator (P) which acts on two coupled hydraulic stroke transformers having identical transmission ratios. Essential components of the stop device are the pressure piston (DK) driven by the actuator (P), the lifting piston (HK) mounted axially displaceably in a cylindrical bore (ZY) of the pressure piston (DK), and a chamber (KB), into which open inflow and outflow ducts (B2, G2, B3, G3) for the medium to be shut off. By activating the actuator (P), the dumbbell-shaped lifting piston (HK) can be displaced virtually without delay in the pressure piston bore (ZY) and the inflow or outflow ducts (B2, B3) be closed.

Abstract: Drive elements whose physical volume is considerably smaller than piezoelectric actuators for comparable mechanical characteristics and actuation travels can be developed on the basis of the magnetostrictive material Tb.sub.x Dy.sub.1-x Fe.sub.2 (Terfenol). Despite these characteristics, magnetostrictive actuators have until now been used only where no rapid switching processes or actuation movements are required. An actuator of compact construction responds to an electrical drive signal very quickly and can produce large actuation forces. The actuator typically contains N.apprxeq.100 drive elements (1, 1') which are arranged one above the other in the form of a stack, are each of layered construction, and are provided with electrical connections. The drive elements (1, 1') each have a small metal plate (4, 4'), which is arranged between two insulators (2, 2', 3, 3'), and an actuator element (5, 5') which is manufactured from Terfenol.

Abstract: In order to avoid measurement signal drift, a gas sensor has a gas sensitive layer which is provided on its upper side with a measuring electrode structure and on its lower side with an electrically conductive layer.

Abstract: An ultrasonic atomizer includes an electrically excitable piezoceramic and a coupling body being operatively connected to the piezoceramic. The coupling body has a surface coming into contact with a liquid to be atomized and the surface is in the form of a cap-shaped protuberance. The cap-shaped protuberance and the coupling body are formed of a metallic solid material.

Abstract: A device is provided which allows exact apportioning and controllable atomization of fuel as necessary for various operating conditions of an internal combustion engine. The apportioning ensues with an apportioning aperture that can be closed via a valve needle. Separately therefrom, the atomization ensues with a piezoelectrically driven nozzle having an atomizer orifice placed into vibration. The shape of the atomizer aperture can be round, triangular, quadrangular or cross-like.

Abstract: Integrated design of a combustion pressure sensor (11, 12, 13, 14) and combustion heat-flow sensor (21) which is suitable for determining a physical variable of the combustion process of an engine.