Patent ID: 6873895
Filing Date: 2005-03-29
Classification: B60K

Abstract:
1. A method of controlling a four-wheel drive vehicle, the vehicle including an engine, an automatic transmission connected to the engine which is changeable between a forward travel position and a backward travel position, and front wheels and rear wheels, the rear wheels being directly connected to the automatic transmission, the front wheels being connected to the automatic transmission through a rotation transmission device, the rotation transmission device comprising a two-way clutch and an electromagnetic coil, the two-way clutch being adapted to engage when the electromagnetic coil is energized, thereby transmitting engine torque to the front wheels, and being adapted to disengage when the electromagnetic coil is not energized, thereby uncoupling the front wheels from the engine, said method comprising: detecting a traveling direction of the vehicle based on signals from a rotation sensor that picks up the rotational direction of a propeller shaft for the front wheels or for the rear wheels or the rotational direction of at least one of the front and rear wheels; detecting the travel position of the automatic transmission; comparing the traveling direction of the vehicle with the travel position of the automatic transmission; and energizing the electromagnetic coil to engage the two-way clutch if the vehicle is traveling forward while the automatic transmission is in the backward travel position or if the vehicle is traveling backward while the automatic transmission is in the forward travel position.