Zf Friedrichshafen Ag

Christoph Hess

Thomas Lemp

Ruben Cueppers

Jörg Arnold

Falko Platzer

Felix Bühle

Jens Weller

Philipp Kölbl

Philipp Koelbl

The invention relates to the actuation of a converter lock-up clutch () of a hydrodynamic torque converter () in a vehicle drive-train by means of a safety function where, in addition to a driving strategy function, the safety function can actuate the converter lock-up clutch () by issuing a clutch actuation command. For this purpose, at least one rotation speed at the torque converter () is monitored. If the monitored rotation speed is below a rotation speed threshold, the safety function commands an actuation of the converter lock-up clutch () in its opening direction.

Actuation of a converter lock-up clutch of a hydrodynamic torque converter by means of a safety function

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 drive train of a motor vehicle is provided, the drive train featuring a first drive assembly formed as an internal combustion engine a second drive assembly formed as an electric motor, a start-up element and a transmission). The start-up element features a converter and a lock-up clutch and is connected between the electric motor and the transmission. The electric motor is connected between the internal combustion engine and the start-up element. If a decoupling of the lock-up clutch is requested, the lock-up clutch of the start-up element is initially brought into slip. If the slip at the lock-up clutch of the start-up element reaches a threshold or is greater than the threshold, a target rotational speed is subsequently predetermined for the electric motor and the rotational speed of the electric motor is adjusted to such target rotational speed.

Transmission control method

Within of the method for improving the shifting quality at the start of the commissioning of a new automatic transmission or an automated transmission of a motor vehicle, a filling pressure adaptation is carried out by individual gearshifts. At least one adaptation counter is monitored, which indicates the number of the carried out filling pressure adaptations of at least one shifting element with one individual gearshift from the commissioning of the new automatic transmission or automated transmission. As long as the value of a specified number of monitored adaptation counters falls below a specified threshold value, no D-R and R-D reversing operations are permitted by the transmission control.

Method for improvement of the shifting quality at the start of the initial operation of a new automatic gearbox or an automatized gearbox of a motor vehicle

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.

Method for operating an automatic transmission

A method of carrying out coasting downshifts that involve an interlocking shifting element in an automatic transmission having a torque converter lockup clutch. At the beginning of the coasting downshift, positive action is taken on the torque. The method including the steps of, at the beginning of the coasting downshift, the torque converter lockup clutch is fully or partially disengaged so that the drive-train is fully or partially decoupled from the drive aggregate, and action upon the torque is carried out in such manner that the engine rotational speed only falls below the turbine rotational speed once the synchronous point for the interlocking shifting element is reached.

Procedure for operating decelerating downshifts with the participation of a form-locking shift element of an automatic transmission comprising a torque converter lockup clutch

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Eriskirch, Germany

Christoph Hess