Zf Friedrichshafen Ag

Patrick Riedel

Georg Mihatsch

A method for operating a transmission device, which is transferable into different operating states through the actuation of shifting elements, is described. At least one of the shifting elements is designed as a positive-locking shifting element, which is supplied with operating pressure for presenting a defined operating state of the transmission device. Through a sensor device upstream of a valve device, which is connected to a transmission area essentially featuring ambient pressure, a value of a pressure signal corresponding to the operating pressure can be determined. Upon exceeding a threshold value of the pressure signal, currently in the area of the positive-locking shifting element, a change in operating state is determined, and, upon falling short of an additional threshold value of the pressure signal, the reaching of the requested operating state is established. In a non-actuated operating state of the positive-locking shifting element, the pressure in the transmission area is established by the sensor device. Upon the presence of a request for a change in operating state in the area of the positive-locking shifting element, the threshold value and the additional threshold value are determined from the sum of the pressure calculated in the transmission area prior to the presence of the request for the change in operating state and a pressure offset value.

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Kressbronn, Germany

Patrick Riedel