Method and drive train for performing a gear shift in a vehicle

Method for performing a gearshift in a vehicle provided with a manual or automated manual transmission (130), wherein a drivetrain incorporating the automated manual transmission comprises a combustion engine (100), connected via a clutch (110) to the manual or automated manual transmission (130), and an electric motor/generator (120) drivingly connected to said drivetrain and arranged between said clutch and said transmission or between said combustion engine and said clutch, and where the electric motor/generator (120) is further connected to an energy storing means and/or an energy consumer, the method being characterised by the steps of:

• i. controlling the motor/generator (120) to absorb a torque equalling or almost equalling the torque provided by the combustion engine (100), such that the manual or automated manual transmission (130) transfers a only minor, or no, torque,
• ii. disengaging a gear with a first gear ratio,
• iii. controlling the torques absorbed by the motor/generator (120) and provided by the combustion engine (100) such that a rotational speed of said combustion engine correlates or almost correlates to a rotational speed necessary for propelling the vehicle at a new selected gear with a second gear ratio, and
• iv. engaging said new selected gear.