Wabco Gmbh & Co Ohg

Norbert Lissel

Andreas Teichmann

Gerd Eden

Eike Lustfeld

J&uuml;rgen Fr&uuml;h

Andreas Sch&auml;l

For a valve arrangement of a pneumatically actuated, spring-loaded control cylinder, a non-return valve in pneumatic communication with the control cylinder piston chamber. At very low backpressures in the control cylinder piston chamber caused by leaks of the valve responsible for pressurization of the piston chamber, the chamber is vented by passage of a very small air stream via the non-return valve. In this way, leaks cannot cause a very slow pressure buildup in the control cylinder piston chamber, followed at some time by undesired shifting of the control cylinder. In contrast, in the case of normal pressure buildup, i.e., during switching of the pressurizing valve, the non-return valve is promptly closed and the pressure in the control cylinder piston chamber is not influenced.

Valve device for a control cylinder

An evaluation method for an inductive displacement sensor first temperature-compensates a measured sensor value, and then calibrates same. The temperature compensation is carried out iteratively, utilizing two temperature dependent functions. The first function is based on the temprature-dependency of the measured sensor value, and the second function is based on the dependency of the temperature coefficient of the sensor model used. For a clutch sensor application, a calibration line is defined by two calibration points, which represent a completely engaged state and a just disengaged state, respectively. Continuous measurement of the displacement of an engaged clutch indicates the wear status of the clutch, so that a warning can be transmitted to the driver when the clutch lining has reached a predetermined thickness.

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Barsinghausen, Germany

Norbert Lissel