Patent ID: 6530857
Filing Date: 2003-03-11
Classification: F16H

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 operation conditions of the vehicle and the engine, comprising;input shaft rotational speed detecting means for detecting an input shaft rotational speed inputted to the transmission; supply time determining means for determining a supply time to supply a preparatory pressure to one of the friction engaging elements of the target gear to be shifted to, based on at least the detected input shaft rotational speed; oil amount estimating means for estimating an oil amount in the one of the frictional engaging elements; supply time correcting means for correcting the supply time based on the estimated oil amount; preparatory pressure calculating means for calculating the preparatory pressure to be supplied to the one of the frictional engaging elements within the determined supply time; and hydraulic pressure control circuit for supplying the preparatory pressure to the one of the frictional engaging elements based on the calculated preparatory pressure, wherein the oil amount estimating means includes: residual oil amount estimating means for estimating a residual oil amount in the one of the frictional engaging elements; and oil decreasing amount estimating means for estimating an oil decreasing amount decreasing from the one of the frictional engaging elements based on at least the estimated residual oil amount and the detected input shaft rotational speed, and estimating the oil amount by subtracting the oil decreasing amount from the residual oil amount.