Patent ID: 7131510

Claim:
A method of controlling propulsion in a motor vehicle provided with: an internal combustion engine ( 1 ), a transmission system ( 2 ) comprising a transmission ( 3 ) with discrete ratios, provided with actuator means ( 22 ) for selecting the ratios, a reversible electric machine ( 4 ) which includes a rotor ( 5 ) and a stator ( 6 ), is interposed between the internal combustion engine ( 1 ) and the transmission system ( 2 ), and is suitable for operating as a generator and as an electric motor, a first clutch and a second clutch ( 7 , 8 ) which can be operated selectively to control the connection of the rotor ( 5 ) of the electric machine ( 4 ) to the transmission system ( 2 ) and to the internal combustion engine ( 1 ), respectively, the method comprising the implementation of a stop-start function, including: a stop stage in which the internal combustion engine ( 1 ) is disconnected from the electric machine ( 4 ) and from the transmission system ( 2 ) and is switched off, and a subsequent start stage in which the internal combustion engine ( 1 ) is restarted by the electric machine ( 4 ), operating as a motor, and is then reconnected to the transmission system ( 2 ); the method being characterized in that, during the start stage: the electric machine ( 4 ), operating as an electric motor, is connected to the transmission system ( 2 ), whilst a predetermined ratio, is engaged in the transmission ( 3 ) so that, during the start stage, the vehicle (V) is initially propelled by the electric machine ( 4 ), and a change from the predetermined ratio to a higher ratio is subsequently implemented and, during this change of ratio, while the first clutch is open, the internal combustion engine ( 1 ) is connected to the electric machine ( 4 ), operating as a motor, in order to bring about starting of the internal combustion engine ( 1 ), and then the restarted internal combustion engine ( 1 ) is connected to the transmission system ( 2 ) so that, upon completion of the start stage, the vehicle (V) is propelled by the internal combustion engine ( 1 ).