Zf Friedrichshafen Ag

Johannes Brockmann

Peter Schiele

Andreas Schmidt

Jörg Arnold

Philipp Fehr

A method for operating a vehicle having a vehicle drive train () and a vehicle brake () downshifting an automatic transmission () in a coasting condition, during which at least one friction-locking shift element is to be disengaged and one form-fit shift element is to be engaged. An output torque present at a driven end () is at least partially supported at a drive motor () at the point in time of a demand for the coasting downshift. The drive motor () is actuated before the implementation of the coasting downshift in order to reduce the portion of the output torque which is supportable at the drive motor (), and a portion of the output torque is supported in the area of the vehicle brake () by an appropriate actuation of the vehicle brake ().

Method for operating a vehicle with a vehicle powertrain and a vehicle brake

A method for operating a vehicle drivetrain () includes proceeding, in the presence of the demand for activation of the engine start-stop function of the vehicle drivetrain () and a simultaneously shut-down drive machine (), from an operating state of the vehicle drivetrain () during which a sailing operating function of the vehicle drivetrain () is active, during which the drive machine () is decoupled from the drive output (), during which the positively engaging shift element (F) is open and during which a rotational speed (n_ab) of the drive output () is higher than a defined rotational speed at which a rotational speed difference between shift element halves of the positively engaging shift element (F) lies within a rotational speed range within which the positively engaging shift element (F) is transferrable into the closed operating state, and actuating the positively engaging shift element (F) in a closing direction no later than when the defined rotational speed is reached.

Method for operating a vehicle drive train with a drive motor, an output and a transmission which is arranged between the drive motor and the output

A method for operating a vehicle drivetrain () having a drive machine (), an output () and a gearbox () with the gearbox () arranged in power flow between the drive machine () and the output () includes opening, in the presence of a demand for activation of a sailing operating function of the vehicle drivetrain () and a simultaneously activated engine start-stop function, a positively engaging shift element (F) while the drive machine () is left both decoupled from the output () and shut down.

Method for operating a vehicle drive train

A method for terminating a gearshift for an automatic transmission for a motor vehicle is provided, wherein a positive-locking shifting element is involved. After the initiation of the gearshift, there is an evaluation of the continuous signals of at least one control unit of the vehicle, which affect the engine torque and thus the turbine speed gradient. Based on the evaluation of the signals, an upcoming change to the turbine speed gradient that exceeds a first predetermined threshold value or falls short of a second predetermined threshold value is detected, and, upon such detection, the gearshift is terminated.

Method for terminating a gearshift for an automatic transmission for a motor vehicle wherein at least one positive-locking shifting element is involved

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Lindau, Germany

Johannes Brockmann