Patent ID: 9475485
Filing Date: 2016-10-25
CPC Classification: B60K,B60W,Y02T,Y10S,Y10T

Claim Text:
1. A method for moving off a vehicle the vehicle having a propulsion system, which comprises a combustion engine with an output shaft, an electric machine comprising a stator and a rotor, a gearbox with an input shaft, and a planetary gear comprising three components in the form of a sun gear, a ring gear and a planet wheel carrier; the output shaft of the combustion engine being connected to a first of the components of the planetary gear so that rotation of the output shaft of the combustion engine causes rotation of the first component, the input shaft of the gearbox is connected to a second of the components of the planetary gear so that rotation of the input shaft of the gearbox causes rotation of the second component and the rotor of the electric machine is connected to a third of the components of the planetary gear, so that rotation of the rotor causes rotation of the third component; the propulsion system further comprises locking means transferrable between a locking position in which two of the components are interlocked, such that the three components rotate as a unit with the same rotation speed, and a releasing position, in which the components are allowed to rotate with different rotation speeds; the method comprising: the method starting from an initial state of setting the combustion engine to rotate with idle speed, setting the locking means in the releasing position and engaging an appropriate gear in a gear box for moving off the vehicle and then performing the following steps: (a) controlling the torque of the electric machine so that the electric machine applies a positive torque on the third component of the planetary gear, (b) controlling the rotation speed of the combustion engine towards a constant or an essentially constant rotation speed, performing steps (a) and (b) simultaneously so that a reaction torque acting on the input shaft of the gear box is created and gives rise to a demanded driving torque, whereby the vehicle moves off, preceding steps (a) and (b) by performing the steps of: (i) checking the demanded driving torque, (ii) calculating the torque that the electric machine in step (a) must apply on the third component of the planetary gear in order to reach the demanded driving torque.