PURPOSE: To perform shift control by the same shift control method regardless of power on or off condition of an engine, in the down shift of an automatic transmission for vehicle by which a clutch for a low speed step for settling the low speed side shift step is engaged while releasing engagement of a clutch for a high speed step for settling the high speed side shift step, so as to increase turbine rotating speed toward low speed step synchronous rotating speed.
CONSTITUTION: A target turbine rotating speed changing rate (Nir) of a clutch for a high speed step and a target turbine rotating speed changing rate (Nia) of a clutch for a low speed step are set, further a turbine rotating speed changing rate (Nt) is detected, the transmitting torque of the clutch for the high speed step is feedback controlled so as to conform the detected changing rate (Nt) to the changing rate (Nir), meanwhile the transmitting torque of the clutch for the low speed step is feedback controlled so as to conform the changing rate (Nt) to the changing rate (Nia), and hence down shift is performed.
USUKI KATSUTOSHI
HATTA KATSUHIRO
