Zf Friedrichshafen Ag

Thomas Lemp

Felix Bühle

Falko Platzer

Bernd Allgaier

Friedrich Tenbrock

Michael Gromus

Alexander Pfau

Anton Fritzer

Christoph Hess

Tobias Zollner

Patrick Peter

Tobias Zöllner

Stefan Gierer

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 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.

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

A method of operating a vehicle hybrid drive-train in which, depending on the operating situation, the engine and electric machine either operate individually or together. The engine and the electric machine can be coupled or separated by a clutch. The engine can be started by the electric machine or a separate starting device. To co-ordinate transmission shifts and required engine starts, during a transmission shifting process, if the engine needs to be started, then based on whether the shift is an upshift, a downshift, a traction shift or an overdrive shift and also depending on the type of engine start required, it is first determined whether the shift should be completed, at least partially completed or discontinued before carrying out the start and, based on this determination, measures for continuing, at least partially continuing or discontinuing the shift process are initiated.

Method for operating a hybrid drive train of a vehicle

A method for operating a hybrid vehicle comprises conducting unfire operation in an internal-combustion engine in a fuel cut-off mode during a hybrid-mode ride in deceleration of the internal-combustion engine, disconnecting the internal-combustion engine from an output while maintaining the fuel cut-off mode, and reducing a transmission capacity of a clutch configured to couple the internal-combustion engine and an electric motor. During a hybrid-mode ride in deceleration of the internal-combustion engine for transition to the purely electric drive, the internal-combustion engine may be disconnected from the output and shut down. When the internal-combustion engine is operated unfired in a fuel cut-off mode, the internal-combustion engine may be disconnected from the output and shut down by reducing the transmission capacity of the clutch that is connected between the internal-combustion engine and the electric motor.

Method and system for operating a hybrid vehicle

A method of accelerating decoupling of the starting clutch () that is able to connect the electric machine () to the transmission input in a hybrid drive-train of a motor vehicle, when a decoupling command is issued, at the same time as the regulation of the starting clutch begins for the purpose of decoupling the starting clutch () or a specified time after the regulation of the starting clutch begins. The electric machine is regulated in such manner that a torque is built up such that the transition to sliding friction, and thus decoupling and the onset of slip, are sped up while maintaining the nominal driving torque.

Method for accelerating the decoupling of a starting clutch, which releasable connects an electric machine to a transmission input, in a hybrid drive train of a vehicle

A method of controlling a hybrid drive train of a vehicle which comprises, in series, an internal combustion engine, a clutch, an electric motor and a transmission with an output connected to the drive axle. During traction operation, the vehicle changes from an electric driving mode into a combination driving mode or a combustion engine driving mode, in that the clutch is engaged and the electric torque is temporarily increased. The method includes regulating engagement of the clutch at least until reaching a starting rotational speed of the combustion engine such that the acceleration of the combustion engine occurs according to a predetermined progression of rotational speed and that the torque of the combustion engine is increased by the same amount as the transferable torque of the clutch is increased by the engagement process.

Method to control a hybrid drive train

A method for controlling a hybrid drivetrain of a motor vehicle such that, during a thrust operation of the vehicle, a change takes place from a combustion-powered driving mode, in which the combustion engine is in a thrust operation, the separator clutch is engaged and the electric machine contributes no force, or from a combined driving mode in which the engine is in a thrust operation, the clutch is engaged and the electric machine operates as a generator, to an electric driving mode in which the engine is switched off, the clutch is disengaged and the electric machine operates as a generator. To efficiently change driving modes, the clutch is partially disengaged to a slip limit; the clutch is then completely disengaged; and when the clutch reaches the slip limit, the generator torque of the electric machine is increased inversely to the torque that can be transmitted by the clutch.

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Langenargen, Germany

Thomas Lemp