Method for operating a drivetrain of a motor vehicle, and drivetrain module of motor vehicle of said type

A drivetrain module of a motor vehicle, comprising:

• at least one drive source (1) in the form of an electric machine;
• an interface to an internal combustion engine (9) of the motor vehicle;
• a control unit;
• a transmission (2) for providing different transmission ratios between a drive shaft (21) and an output shaft (22) of the transmission (2);
• a launch element (3) which is hydraulically actuatable or lockable and which is situated in power flow between the drive source (1) and the output shaft (22);
• and
• a pump (24) which is operable independently of the drive source (1) by a separate electric pump drive (25) and is configured for hydraulic pressure supply to the transmission (2),
• wherein the control unit is programmed for
• when the motor vehicle is at a standstill, and upon demand for a drive torque of the motor vehicle, increasing power (25p) supplied to the separate electric pump drive (25) such that a pressure chamber, whose pressurization effects a complete closure or lock-up of the launch element (3), is fast charged with hydraulic pressure from the pump (24),
• performing a launch process of the motor vehicle with the drive source (1) and with a closed or locked-up launch element (3), and
• during the launch process, reducing the power (25p) supplied to the separate electric pump drive (25) after fast charging the pressure chamber,
• wherein the control unit is programmed such that the internal combustion engine (9) of the motor vehicle is off during the launch process.