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Daimlerchrysler Ag Stuttgart

Holger Steffen

Thomas Stolk

Alexander Von Gaisberg-Helfenberg

Matthias Gramann

Reinhard Orthmann

Werner Wiedemann

Michael Nagel

Rudolf Wilczek

Robert Schmidt

Hans-Peter Schoener

In an operating system for a hydraulic valve clearance control element of an internal combustion engine, which includes a hydraulic fluid having a pressure that depends on the engine operating state and wherein the hydraulic clearance control element includes a pressure chamber in which a hydraulic fluid volume is maintained for adjusting the length of the hydraulic clearance control element and means for maintaining the fluid volume when, after engine shut down, the pressure of the hydraulic fluid supplied by an engine fluid pressure source drops below a certain value so as to maintain the hydraulic clearance control element at its operating length during engine shutdown, means are arranged on the hydraulic fluid supply line to the hydraulic valve clearance control element for releasing hydraulic fluid to reduce its pressure below the certain value immediately upon engine shut down to safely maintain the hydraulic clearance control elements at their operating length.

Hydraulic valve lifter with operating control system

A method of operating an actuator for electromagnetically controlling a valve in an internal combustion engine involves supplying a heating current to the operating coils of the actuator before starting the internal combustion engine from a cold start condition. Thereby, the operating coils, the components surrounding them, and the lubricant are heated to ensure proper viscosity of the lubricant and thus proper operation of the actuator.

Method for operating actuators for electromagnetically controlling a valve

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Stuttgart, Germany

Holger Steffen