Daimler Chrysler Ag

Udo Walter

Eberhard Kutscher

Reiner Schneider

Joachim Lang

Gerhard Lohrmann

A method is for the leak-tightness and operational testing of a stop valve of a pneumatic suspension of a motor vehicle with gas springs, with at least in each case one active volume capable of being connected via the stop valve, the vehicle including at least one connectable pressure source, at least one connectable pressure sink and, for each axle, at least one measuring device determining the distance to the vehicle body, and also damping elements limiting the stroke of the respective gas spring. For this purpose, in a first step, with the stop valve open, a stroke, during which at least one damping element is compressed, is set on the individual gas spring. In a second step, after the closing of the stop valve, the individual gas spring is set to a part-stroke of its total stroke between the damping elements. In a third step, after the opening of the stop valve, the distance which is established between the axle and the vehicle body is determined with the aid of the measuring device and is compared with a predetermined desired value. Thus, a method for leak-tightness and operational testing is provided, which is performed, without the dismantling of components, by the devices already present in the vehicle.

Leak-Tightness and operational test of a stop valve in a pneumatic suspension

In a method for monitoring the functioning of a compressor, which charges a gas-filled accumulator chamber with a working pressure, the actual pressure prevailing in the accumulator chamber is measured and compared to a setpoint pressure. In response to a deviation in the actual pressure from the setpoint pressure, an error signal is produced. The comparison of the actual pressure and the setpoint pressure is carried out during the charging operation when the accumulator chamber is charged.

Method and device for monitoring the functioning of a compressor

It is proposed that a pneumatic suspension leveling system for vehicles with pneumatic suspension leveling elements assigned to the vehicle axles and/or vehicle wheels, with a compressor and a central pressure accumulator fed by it for the compressed air supply of the pneumatic suspension leveling elements, with an accumulator pressure sensor which detects the air pressure in the central pressure accumulator and generates a signal value correlating thereto, and with an electronic control device which processes the signal values of the central pressure accumulator and induces a pressure charging of the central pressure accumulator by the compressor, when the signal value of the accumulator pressure sensor reaches a predetermined lower threshold signal value and terminates this pressure charging when the signal value of the accumulator pressure sensor reaches a preset upper threshold signal value be improved with respect to its functional capacity. This is achieved by providing an ambient pressure sensor which detects the air pressure in the atmosphere surrounding the vehicle and generates a signal value correlating thereto, whereby the control device processes the signal values of the ambient pressure sensor and varies the upper threshold signal value in function thereof.

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Geislingen, Germany

Udo Walter