Driveline and control method for hybrid vehicle

摘要

A motor vehicle 11 has an engine 12 driving a transmission 13 which in turn drives a front final drive unit 14 connected to a pair of front wheels 15. The front final drive unit 14 also drives a rear drive take-off unit 17 which is connected to a rear final drive unit 18 by a propshaft 19. The rear final drive unit 18 houses an electric motor/generator 35 which can also drive the rear wheels through an epicyclic reduction gear 39, a pinion 31 and crown wheel 27. A clutch 33 controls the connection from the propshaft 19 to the pinion 31. The motor/generator 35 and an integrated starter generator 29 on the engine 12 are controlled by an electronic control unit (ECU) 51 for drawing power from or supplying power to a traction battery 61 and to an auxiliaries battery 62. The ECU 51 also controls the engine 12 and can also receive signals from a speed set control and ABS sensors associated with the wheels. For high torque off-road driving, the accelerator pedal (52 see fig 3) or speed set control (58 see fig 3) can set a ground speed which the ECU maintains by controlling the outputs of both the engine 12 and motor generator 35. The ECU response is improved by using current to or from the motor generator 35 to provide a motor speed signal which is a better indication of the speed of the rear wheels 21 than may be obtained from the ABS sensors at low vehicle speeds.