Abstract: A method for determining a drag torque coefficient of a transmission includes performing rotational speed synchronisation involving application of synchronisation torque to a first transmission component, and obtaining an initial rotational speed of the first transmission component before the rotational speed synchronisation, and a final rotational speed of the first transmission component after the rotational speed synchronisation, and time period for performing the rotational speed synchronisation. Also, obtaining information relating to a level of the synchronisation torque applied to the first transmission component during the rotational speed synchronisation, and information relating to a total moment of inertia associated with the first transmission component.

Abstract: A method for operating a vehicle drivetrain having a dog clutch and an initial phase shift identifying mode and a normal operating mode. The method includes providing a dog clutch for selective torque transmission, wherein the dog clutch has a first clutch portion with a first set of teeth and a second clutch portion with a second set of teeth, and wherein the first clutch portion is axially moveable for enabling shifting of the dog clutch between an engaged state, in which the first and second clutch portions are operable to transmit torque between first and second clutch portion via the first and second set of teeth, and a disengaged state, in which the first and second clutch portions are rotatable with respect to each.

Abstract: A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.

Abstract: A method for determining a drag torque coefficient of a transmission includes performing rotational speed synchronisation involving application of synchronisation torque to a first transmission component, and obtaining an initial rotational speed of the first transmission component before the rotational speed synchronisation, and a final rotational speed of the first transmission component after the rotational speed synchronisation, and time period for performing the rotational speed synchronisation. Also, obtaining information relating to a level of the synchronisation torque applied to the first transmission component during the rotational speed synchronisation, and information relating to a total moment of inertia associated with the first transmission component.

Abstract: A method for performing rotational speed synchronisation of a first transmission component having a first initial rotational speed with a second transmission component having a second initial rotational speed, so that they rotate with the same final rotational speed during a gear switch from an initial driving gear to a final driving gear in a stepped gear transmission for a hybrid electric or electric drive train having an electric traction motor. The method including calculating a total frictional work resulting from performing the total rotational speed synchronisation by means of a mechanical synchroniser of the stepped gear transmission only, and if the calculated total frictional work exceeds a maximal frictional work of the mechanical synchroniser, performing the rotational speed synchronisation by means of both the electric traction motor and the mechanical synchroniser.