Shift control system for automatic transmission

摘要

A shift control system for a vehicle automatic transmission (2) includes a vehicle speed sensor (10) for detecting a vehicle speed, and a first control means (12) normally performs a shift control of the transmission so that a target speed ratio of the transmission is achieved, which is determined based at least on a vehicle speed detected by the vehicle speed sensor. The shift control system further includes a second control means (13) that properly performs shift control of the transmission when the vehicle speed sensor is in trouble, by generating a command for holding or changing a current speed ratio based on an input rotation speed of the transmission and/or driver's accelerating or decelerating operation of the vehicle.