Zf Friedrichshafen Ag

Clemens Kuhn

Franz-Josef Schuler

Bernd Allgaier

Tobias Zollner

Holger Bacher

Patrick Peter

Lorenz Fehrenbach

Norbert Müller

A method of operating a drive-train of a hybrid vehicle which comprises at least a hybrid drive with an internal combustion engine and an electric machine, an automatic or automated change-speed transmission connected between the hybrid drive and a drive output, and a clutch connected between the internal combustion engine and the electric machine. When starting the internal combustion engine from a purely electric driving mode, the clutch is initially disengaged. To start the internal combustion engine, the clutch is at least partially engaged and the internal combustion engine is drag-started by the electric machine, and, in parallel with starting the internal combustion engine, a downshift in the transmission is initiated once a rotational speed of the internal combustion engine reaches or exceeds an applicable threshold value.

Method and control unit for operating a drive train of a hybrid vehicle

A method for controlling a vehicles drivetrain including an engine and automatic transmission, such that transmission ratios are shifted within a range of transmission ratios in a continuous and/or stepped manner as function of preset target speeds that are adjustable via a vehicle speed control and actual vehicle inclinations in relation to the vehicles longitudinal axis. When the actual speed of the vehicle differs from a preset threshold speed, a request to change an actual ratio of the transmission is generated, if it has been determined that the output torque is smaller than a threshold value or an output torque required to adjust the preset threshold speed of the vehicle. The ratio of the transmission is shifted so the torque applied to the output is modified toward the output torque required to adjust the threshold speed.

Method for controlling a drivetrain of a vehicle, with a drive motor and a gearbox

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Eriskirch, Germany

Clemens Kuhn