Zf Friedrichshafen Ag

Philipp Kölbl

Ruben Cueppers

Christoph Hess

Jonas Knör

Michael Miller

A method for operating a friction-locking shift element of a transmission of a motor vehicle includes actuating the friction-locking shift element for engagement according to a pressure versus torque characteristic curve. The pressure versus torque characteristic curve has a first characteristic point (a touch point) and a second characteristic point (a contact point), defines a first characteristic curve range between the touch point and the contact point having a first functional dependence, and defines a second characteristic curve range at or after the contact point having a second functional dependence. Once the touch point is reached, the friction-locking shift element begins to transmit torque mainly due to drag torques. Whereas, once the contact point is reached, the friction-locking shift element begins to transmit torque mainly due to friction between shift-element halves of the friction-locking shift element.

Method for operating a friction-locking shift element of a transmission, and control unit

A method for operating an automatic transmission is provided. The method includes disengaging a shifting element of the automatic transmission and measuring an input speed of the automatic transmission while the shifting element is disengaging. A command pressure of the shifting element is adjusted to a target command pressure based at least in part on the input speed of the automatic transmission while the shifting element is disengaging.

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Friedrichshafen, Germany

Philipp Kölbl