Gear shift control system for automatic transmission

摘要

A gear shift control system for vehicles is provided which mathematically calculates a rate of deceleration of the vehicle equipped an automatic transmission upon start of deceleration of the vehicle and inhibits the automatic transmission from upshifting or changes a permissible gear shift range of the automatic transmission as a function of the rate of deceleration of the vehicle, thereby ensuring a desired degree of braking force including an engine braking force while the vehicle is decelerating.

主权项

1. A gear shift control system for an automatic transmission mounted in a vehicle to transmit torque, as produced by a power source, to a wheel of the vehicle, comprising:
a speed determiner which works to determine a speed of the vehicle; a deceleration detector which detects deceleration of the vehicle when a braking force is being applied to the wheel; a braking force determiner which determines the braking force applied to the wheel when the deceleration detector is detecting the deceleration of the vehicle; a deceleration determiner which determines a deceleration of the vehicle as a function of the speed of the vehicle, as determined by the speed determiner, and the braking force, as determined by the braking force determiner; a gear shift controller which determines whether the deceleration of the vehicle, as determined by the deceleration determiner, is greater than a given deceleration threshold, and when the deceleration of the vehicle is determined to be greater than the given deceleration threshold, the gear shift controller inhibits the automatic transmission from upshifting gears thereof; and wherein the given deceleration threshold is variable with vehicle speed and the gear shift control system determines a higher value for the given deceleration threshold at a higher vehicle speed and a lower value for the given deceleration threshold at a lower vehicle speed.