Method for carrying out a load shift in vehicles with electric drive

A method of carrying out a shift under load in either an electric vehicle having a change-under-load transmission or a hybrid vehicle having a hybrid transmission during purely an electric driving operation in which the vehicle comprises an electric machine and an internal combustion engine with a drive train clutch located between the electric machine and the internal combustion engine, the method comprising the steps of:

• employing an electric machine being operatable in both a speed control mode and a torque regulation mode;
• disengaging the drive train clutch located between the electric machine and the internal combustion engine, during a shift, so as to provide purely an electric driving operation and operating the electric machine in the torque-controlled mode;
• carrying out a shift under load in the transmission during the purely electric driving operation;
• changing the electric machine from the torque-controlled mode to a speed regulation mode once the transmission load of the vehicle is taken up by a new clutch to be engaged;
• and
• adapting a speed of the electric machine, required for synchronization to a new gear, with the electric machine operating during the speed regulation mode.

A method of carrying out a shift under load in either an electric vehicle having a change-under-load transmission or a hybrid vehicle having a hybrid transmission during purely an electric driving operation in which the vehicle comprises an electric machine and an internal combustion engine with a drive train clutch located between the electric machine and the internal combustion engine, the method comprising the steps of:

• employing an electric machine which is operatable in both a speed control mode and a torque regulation mode;
• disengaging the drive train clutch located between the electric machine and the internal combustion engine, during a shift, so as to provide purely an electric driving operation and operating the electric machine in the torque-controlled mode;
• carrying out a shift under load in the transmission during the purely electric driving operation by increasing a transmission capacity of a new clutch to be engaged, in order to take up a transmission load of the vehicle, and, at the same time, reducing a transmission capacity of an engaged clutch to be disengaged;
• changing the electric machine from the torque-controlled mode to a speed regulation mode once the transmission load of the vehicle is taken up by the new clutch to be engaged;
• and
• adapting a speed of the electric machine, required for synchronization to a new gear, with the electric machine operating during the speed regulation mode and simultaneously completely disengaging the engaged clutch (K_alt) to be disengaged.