Operation control for multiple speed axle assembly of automatic drive train in motor vehicle, involves shifting multiple speed axle assembly at set reduction gear ratio when engine torque is low

摘要

An electronic controller (20) enables a multiple speed axle assembly (14) to shift to a desired reduction gear ratio, when the output to be transmitted to the axle assembly from an engine (11) through the transmission (13) is made low. At low engine torque, a clutch (12) disconnects the engine from the transmission. When the engine torque synchronizes with the estimated angular speed of the output shaft (13a) of the transmission, the clutch connects the engine to the transmission. The engine torque can be then raised.