Patent ID: 7381151

Claim:
A shift control system of an automatic transmission, comprising: at least one sensor, including at least one of a transmission output shaft rpm sensor, a throttle opening angle sensor, an engine rpm sensor, and a turbine rpm sensor; a hydraulic pressure control actuator for hydraulic pressure control of friction elements of the automatic transmission; and a transmission control unit controlling the hydraulic pressure control actuator to perform a gear shifting on the basis of signals from the at least one sensor, wherein the transmission control unit performs a duty control for controlling hydraulic pressures for an on-coming friction element and an off-going friction element during a power-on 2-3 upshift, such that hydraulic pressures for the on-coming friction element and the off-going friction element are simultaneously controlled based on a turbine torque; and wherein the transmission control unit controls a hydraulic pressure control duty of the off-going friction element, and outputs the hydraulic pressure control duty of the off-going friction element as 0% at a point when a current turbine rpm is lower than a second gear synchronous turbine speed by a predetermined value, and at the same time gradually increases the hydraulic pressure control duty of the on-coming friction element to 100%.