Automatic shift-down apparatus for automatic transmission

摘要

An automatic shift-down apparatus for an automatic transmission which comprises vehicle speed detection device for detecting the speed of a vehicle; vehicle-speed variation rate calculation device for calculating the variation rate of the detected vehicle speed; shift-start vehicle speed calculation device for calculating, on the basis of the calculated vehicle-speed variation rate and a time required to complete a shift operation, a shift-start vehicle speed which enables the shift operation to finish before the vehicle speed attains a shift-completion speed; and a shift device which starts a shift operation when the detected vehicle speed attains the calculated shift-start vehicle speed.