Zf Friedrichshafen Ag

Felix Bühle

Thomas Lemp

Falko Platzer

Frank Deprez

Christoph Hess

A method for operating a power shiftable transmission of a motor vehicle, the transmission including a control unit, an input shaft, an output shaft, a gear set, and multiple shift elements, the method including transmitting, with the control unit, a request for a reduction of a drive torque acting on the input shaft for carrying out an upshift, and determining, with the control unit, whether the reduction is completely possible, partially possible, or impossible based on a signal. When the reduction is completely possible, the method includes controlling, with the control unit, a torque transmission rate of a shift element of the multiple shift elements to be engaged during the upshift according to a first way. When the reduction is partially possible or impossible, the method includes controlling, with the control unit, the torque transmission rate according to a second way, the second way differing from the first way.

Method and control unit for operating a power-shift transmission

A method for operating a drive train of a motor vehicle, the drive train having at least one transmission () for carrying out different transmission gear ratios between an input shaft () and an output shaft () of the transmission () by selectively engaging hydraulically actuatable shift elements of the transmission (G), the drive train further having an electric machine as a drive source (), and a hydraulically actuatable or bridgeable starting component () in the power path between the drive source () and the output shaft (). The method includes performing a starting process of the motor vehicle driven solely by the drive source () with an engaged or bridged starting component (). The method further includes limiting a drive source torque () during the starting process to a maximum value dependent on a current system pressure () of a hydraulic system of the transmission ().

Method for operating a drive train of a motor vehicle, and drive train module of a motor vehicle of this type

A method for operating a drive train of a motor vehicle includes selecting between first and second operating strategies for controlling a starting component (A,B) during a stopping process of the motor vehicle, and carrying out a downshift of the transmission (G) during the stopping process after implementing the first operating strategy or the second operating strategy. In the first operating strategy, the starting component (A,B) is engaged or locked up and/or remains engaged or locked up at least until the motor vehicle comes to a standstill. In the second operating strategy, the starting component (A,B) is disengaged or the lock-up of the starting component (A,) is released before the motor vehicle come to the standstill. The downshift of the transmission (G) is triggered at a different rotational speed limit value upon implementation of the first operating strategy than upon implementation of the second operating strategy.

Method to control a vehicle drivetrain, and drivetrain-module for such a vehicle

A method for operating a drive train of a motor vehicle includes, for a starting process according to a first operating strategy, completely engaging a torque converter lockup clutch (WK) and, according to a second operating strategy, not completely engaging the torque converter lockup clutch (WK). A hydraulic pressure gradient for filling a piston chamber of the torque converter lockup clutch (WK) is selected to be higher upon selection of the first operating strategy than upon selection of the second operating strategy. A drive train module of a motor vehicle includes a control unit () for controlling, by way of an open-loop control system, the method.

Method for operating a vehicle drivetrain, and drivetrain module for such a vehicle

A method for operating a drivetrain of a motor vehicle, includes, when the motor vehicle is at a standstill and upon demand for a drive torque of the motor vehicle, increasing power () supplied to a separate electric pump drive () such that a pressure chamber whose pressurization effects a complete closure or lock-up of a launch element () is fast charged with hydraulic pressure from a pump (). The method also includes performing a launch process of the motor vehicle with the drive source () and with a closed or locked-up launch element () and reducing the power () supplied to the separate electric pump drive () after fast charging the pressure chamber. A related drive train module is also provided.

Method for operating a drivetrain of a motor vehicle, and drivetrain module of motor vehicle of said type

A method for operating a motor vehicle originates from a condition in which a torque converter lockup clutch () or a master clutch () is engaged and the transmission () is friction-locking. The torque converter lockup clutch () or the master clutch () is then brought into a slip condition on a control side, and a prime-mover rotational speed is decoupled from a driven-end rotational speed. The torque converter lockup clutch () or the master clutch () is brought into the slip condition without reducing a pressure control of the torque converter lockup clutch () or the master clutch () and by specifying a target rotational speed or a target torque for the prime mover () such that a torque or a target torque is greater than a power transmission capacity of the torque converter lockup clutch () or the master clutch () and slip is built up.

Method and control unit for a motor vehicle

A method for operating a drive train of a motor vehicle includes performing a startup operation of the motor vehicle or a stopping operation of the motor vehicle. A starting component () is engaged or bridged during the startup operation or the stopping operation of the motor vehicle. The startup operation is driven by a drive source (). The method also includes comparing an actual value of an output shaft () based variable with a target value of the output shaft () based variable during the startup operation or the stopping operation and, on reaching or exceeding a specific deviation of the actual value from the target value, moving the starting component () into a slipping state. The starting component () transmits torque in the slipping state. A related drive train module for a motor vehicle is also provided.

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Eriskirch, Germany

Felix Bühle