Patent ID: 6510374
Filing Date: 2003-01-21
Classification: F16H,Y10T

Abstract:
A road surface gradient detecting apparatus for use in a vehicle in which wheels are driven by an engine through a power transmission device having interposed therein a torque converter containing therein a lock-up clutch, said road surface gradient being calculated by a wheel driving force and a vehicle acceleration, said apparatus comprising:a first driving force calculating means for calculating, while the lock-up clutch is not in operation, the wheel driving force based on that fluid transmission torque of the torque converter which is obtained by a speed ratio of the torque converter and an input rotational speed of the torque converter; a second driving force calculating means for calculating, while the lock-up clutch (2a) is in operation in a direct-coupled state, the wheel driving force based on an engine output torque; and a third driving force calculating means for calculating, while the lock-up clutch is in operation in a slipping state, the wheel driving force based on a total torque of: that fluid transmission torque of the torque converter which is obtained by the speed ratio of the torque converter and the input rotational speed of the torque converter; and that transmission torque of the lock-up clutch which is calculated by an engaging force of the lock-up clutch, whereby the road surface gradient is calculated by the wheel driving force which is calculated by the driving force calculating means corresponding to the state of the lock-up clutch.