Hydraulic control system for an automatic transmission

摘要

A controller of an automatic transmission provides gear changes with optimum gear change characteristics under any traveling conditions. The controller of the automatic transmission of the present invention includes an input torque detector for determining input torque to the transmission, an inertia torque estimator for estimating an inertia torque corresponding to the rate of change of rotary speed of a rotary member during a gear change, input torque corrector for calculating a required operating torque by adding the input torque and the inertia torque and an operating pressure controller for controlling operating pressure to correspond to the required operating torque. The operating pressure corresponding to the necessary engagement torque is supplied to a hydraulic servo, to effect a gear change, irrespective throttle opening and driving speed and irrespective of whether the gear change is made step by step or jumped.