Patent ID: 6554739
Filing Date: 2003-04-29
Classification: F16H,Y10T

Abstract:
A system for controlling an automatic transmission of a vehicle having an input shaft connected to an internal combustion engine mounted on the vehicle and an output shaft connected to driven wheels of the vehicle, the transmission transmitting input torque, through any of frictional engaging elements, generated by the engine and inputted by the input shaft to the driven wheels by the output shaft, in accordance with predetermined shift scheduling defining a target gear based on detected operating conditions of the vehicle and the engine, comprising:operating condition detecting means for detecting the operating conditions of the vehicle and the engine including at least an engine speed; input shaft rotational speed detecting means for detecting an input shaft rotational speed inputted to the transmission; first torque calculating means for calculating a first torque to be inputted to the transmission based on at least the detected operating conditions and the input shaft rotational speed; second torque calculating means for calculating a second torque necessary for advancing shifting in the transmission based on at least the detected operating conditions and the input shaft rotational speed, when the shifting is downshifting; desired value calculating means for calculating a desired value to be supplied to one of the frictional engaging elements now being engaged based on a difference obtained by subtracting the second torque from the first torque; and hydraulic pressure control circuit for supplying hydraulic pressure to one of the frictional engaging elements based on at least the calculated desired value, wherein the first torque calculating means includes: engine speed discriminating means for discriminating whether the detected engine speed is less than a predetermined speed; and when the detected engine speed is discriminated to be less than the predetermined value, calculates the first torque to be a predetermined value.