Patent ID: 7318789

Claim:
A hydraulic control system for an automatic transmission, comprising: an input shaft drivable by a rotational power of an engine; an output shaft for outputting a rotational power to a drive wheel of a vehicle; a hydraulic control unit for supplying hydraulic pressure; an engagement element for performing a shift to a higher speed gear from a lower speed gear, wherein the engagement element is placed in engaged state with hydraulic pressure supplied from the hydraulic control unit and; an electronic control unit for outputting to the hydraulic control unit a hydraulic pressure value of hydraulic pressure supplied to the engagement element; and a gear ratio detecting unit for detecting an inertia phase from a change of a gear ratio corresponding to a speed ratio between the input shaft and the output shaft and detecting a gear ratio at the time of the inertia phase, wherein the electronic control unit outputs the hydraulic pressure value as an engagement command pressure to the engagement element until the time the start of the inertia phase is detected, corrects the engagement command pressure on the basis of the gear ratio detected by the gear ratio detecting unit, and sets the corrected engagement command pressure as a next engagement command pressure at a next shift to the higher speed gear from the lower speed gear.