Patent ID: 8226524

Claim:
A method of operating a motor vehicle drivetrain, the drivetrain comprising at least a hybrid drive with an internal combustion engine and an electric motor, a clutch being interposed between the combustion engine and the electric motor, a transmission being arranged between the hybrid drive and a drive output, with which a main hydraulic pump and an auxiliary hydraulic pump are associated, and a transmission-internal or a transmission-external starting element, the method comprising the steps of: initiating, an electric motor start of the motor vehicle, when the combustion engine is at rest, the clutch, interposed between the combustion engine and the electric motor, and the starting element are disengaged, and a brake pedal actuated; operating the auxiliary hydraulic pump, at a first power level, to supply the transmission with a pressure required for retaining a desired gear and operating the electric motor at a speed to provide a creep torque through the desired gear; recognizing a desire to start; changing the auxiliary hydraulic pump from the first power level to a second power level to supply another pressure to the transmission required for transmitting either a starting power or a starting torque through the desired gear; increasing the speed of the electric motor, only after a lapse of a defined time interval which starts upon completion of changing the auxiliary hydraulic pump from the first to the second power level, the increased speed of the electric motor producing either the desired starting power or the desired starting torque.