Siemens Aktiengesellschaft

Continental Automotive Gmbh

Andreas Voigt

Claus Zumstrull

Wilhelm Frank

Günter Lewentz

G&uuml;nter Lewentz

Stefan Kohn

Klaus Plecher

Marcus Unruh

Hakan Yalcin

Michael Denzler

Alwin Perras

Olaf Enke

Carsten Schuh

Hellmut Freudenberg

Gerd Schmutzler

Wendelin Klügl

Martin Neumaier

Dejan Jovovic

Wendelin Kl&uuml;gl

Klaus Rübling

Roland Niefanger

Tim Bohlmann

Matthias Goller

Wolfgang Reisinger

Andreas Farth

Matthias Spickenreuther

An actuator for actuating a fuel injection valve has a piezoactuator, enclosed in an actuator housing unit (). The housing unit has a cylindrical actuator housing () which is elongate in its axial direction (A) and at least partially encased by an extruded plastic coat. The actuator housing unit (), in its encased area, is provided with a ventilation aperture () in which a ventilation element () produced from a microporous material is disposed.

Actuator for actuating a fuel injection valve

A sealing arrangement of a piezoelectric actuator comprises terminal posts () projecting from the piezoelectric actuator and a metallic top arrangement (), provided with openings () allowing the passage of the terminal posts () which is emplaced on the piezoelectric actuator. In order to facilitate reliable sealing in particular also for comparatively thin top plates (), the invention provides for emplacing on terminal post sections () projecting from the openings () a sealing element () which is formed from an electrically insulating and sealing material and which is positioned tight against, on the one hand, circumferential areas () of the terminal post sections () and, on the other hand, the top arrangement (), with an insulating disk () provided with openings allowing the passage of the terminal posts () and made of electrically insulating material being located between the sealing element () and the top arrangement ().

Sealing arrangement for a piezoelectric actuator for a fuel injection valve of an internal combustion engine

In a method for pretreating a piezoelectric ceramic () and a method for adjusting an injection valve (), the piezoelectric ceramic () is exposed to environmental conditions, leading to a reduction of polarization and also a reduction of the length of the ceramic (). The obtained length exhibits a greater long-term stability due to said adjusting phase. Consequently, the injection valve () can be re-adjusted before use. As a result, renewed adjustment thereof is required only after a long period in service.

Method for pretreating a piezoelectric ceramic and method for adjusting an injection valve

A method for producing a tubular spring () in the form of a cylindrical hollow body, especially for pre-tensioning a piezoelectric actuator element () of an actuator unit () of a fuel injector comprises the step of providing a thin-walled, solid-drawn steel tube with a plurality of regularly arranged longish recesses () by means of laser cutting. Thus, an actuator unit () comprises a piezoelectric actuator element () which is arranged in a thin-walled cylindrical hollow body, wherein the hollow body being elastically embodied and pre-tensioning the actuator element (). Furthermore, the hollow body is a solid-drawn steel tube which is provided with a plurality of longish recesses ().

Method for producing a tubular spring and an actuator unit comprising one such tubular spring

A method is described for improving the long-term stability of a piezoelectric actuator encased in a potting compound containing or forming hydrogen atoms. Oxygen is contained in the piezoelectric actuator's piezoelectric ceramic. Appropriate means are employed so that unsaturated bonds of the hydrogen in the potting compound will release less oxygen from the piezoelectric ceramic. One means consists in reducing the concentration of hydrogen in the potting compound, with appropriate thermal processes as a result of which the concentration of hydrogen will be reduced to below a predefined threshold being applied after the piezoelectric actuator has been encased in the potting compound. Means that form bonds with the hydrogen in the potting compound or duct oxygen thereto are provided in further embodiments.

Method for improving the long-term stability of a piezoelectric actuator and a piezoelectric actuator

A piezoelectric assembly, a method for producing a structural unit with a prestressed piezoelectric actuator and a method for producing a hollow body for prestressing the piezoelectric actuator include an actuator pushed into a spring sleeve and force-lockingly and/or form-lockingly connected under prestress to two ends of the spring sleeve. This provides a structural unit in which the prestressing force of the piezoelectric actuator is permanently fixed by the production process.

Piezoelectric assembly

An actuator unit has an elastically configured hollow body in which a piezoelectric actuator is biased, the hollow body being provided with holes which are of a dumb-bell shape and run transversely of the hollow body's axis.

Piezoelectric actuator unit

In order to set the nozzle opening pressure for an injection nozzle, in particular for a diesel injection nozzle, to an accuracy of around &#xb1;1%, the method provides that the injection needle is first pressed against the valve seat with a closing force (Fz), and then when two different test pressures (pU, p, p) are applied to the injection nozzle the test forces (Fz, F, F) effective on the injector needle are measured, with the pressure stage (A) being determined from the measured test forces and the test pressures applied, and finally using the pressure stage (A) a nozzle valve with a suitable valve spring force (Fv) is selected to correspond to the desired nozzle opening pressure (pD).

Method for setting the nozzle opening pressure for an injection nozzle and arrangement for carrying out the method

The injection valve has a housing, a nozzle body and a clamping nut connected to the housing that contacts the nozzle body with first contact surface () acting on a second contact surface (), whereby the clamping nut clamps the nozzle body against the housing. The first or second contact surface has a curvature () towards the second or first contact surface and the both contact surfaces are in contact in the area of the curvature.

Injection valve comprising an optimized surface geometry between a nozzle body and a retaining nut

A device with a piezoelectric actuator () comprises two faces () and two electroconductive contact paths (), each traversing the actuator () starting from at least one face (). The actuator is clamped between two metallic plates (), each arranged against a face (). The piezoelectric actuator further comprises an electroinsulating layer () arranged between each face) and the corresponding metallic plate ().

Device with a piezoelectric actuator

The injection valve has a housing, a nozzle body and a clamping nut connected to the housing that contacts the nozzle body with first contact surface ( ) acting on a second contact surface ( ), whereby the clamping nut clamps the nozzle body against the housing. The first or second contact surface has a curvature ( ) towards the second or first contact surface and the both contact surfaces are in contact in the area of the curvature.

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.

Fuel injector

A method for producing a structural unit with a prestressed piezoelectric actuator includes the steps of inserting a front end of the actuator into a hollow body, form-lockingly or force-lockingly connecting the inserted front end of the actuator to the hollow body, pressing the actuator into the hollow body with a defined force establishing a prestress of the actuator, and force-lockingly or form-lockingly connecting the actuator to the hollow body in the vicinity of a rear end of the actuator, for fixing the prestress of the actuator.

Method for producing a piezoelectric structural unit

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.

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Wuppertal, Germany

Andreas Voigt