ACCELERATION METHOD FOR A HYBRID DRIVETRAIN

An acceleration method for a hybrid drivetrain includes providing the hybrid drivetrain, setting an initial torque transmission ratio of a belt-drive transmission to a lower transmission ratio, and opening a first disconnect clutch to interrupt torque transmission between an internal combustion engine and an electric machine. The method also includes receiving an acceleration command, shifting the torque transmission ratio with a transmission adjustment gradient from the lower transmission ratio towards an upper transmission ratio, increasing a rotor speed of a rotor shaft of the electric machine with a rotor shaft adjustment gradient, and engaging a first disconnect clutch to rotate an ICE shaft to start the internal combustion engine and increase a rotational speed of the ICE shaft towards a current rotor speed.