Patent ID: 7533754

Claim:
A motor vehicle having an engine, two pairs of wheels, a driveline to connect the engine to the wheels such that one pair of wheels is driven by the vehicle engine when the vehicle is in a two wheel drive mode and the other pair of wheels is additionally connected to the engine when the vehicle is in a four wheel drive mode, the driveline including an auxiliary driveline which includes a first clutch means to connect to the engine, a differential downstream of the first clutch means, a propshaft connected between the first clutch means and the differential, and releasable torque transmitting means operable to connect and disconnect drive from the propshaft to said other pair of wheels, the vehicle further including an electric motor coupled to the auxiliary driveline, and control means operable to switch the vehicle between the four wheel drive and the two wheel drive modes such that in the two wheel drive mode the propshaft is disconnected from both the engine and said other pair of wheels and when switching the vehicle from the two wheel drive mode to the four wheel drive mode while the vehicle is moving the control means firstly activates the electric motor causing it to spin the propshaft up to a predetermined speed, and subsequently operates the first clutch means and the releasable torque transmitting means to connect the auxiliary driveline to the engine and to said other pair of wheels.