SHIFT CONTROL METHOD FOR TWO-SHAFT AUTOMATIC TRANSMISSION FOR VEHICLE

PROBLEM TO BE SOLVED: To achieve a 6-speed transmission utilizing an existing 5-speed power train having two shafts by simultaneously controlling a main transmission part and an auxiliary transmission part. SOLUTION: This shift control method for a two-shaft automatic transmission having the main transmission part for a first shaft and the auxiliary transmission part for a second shaft includes the following three processes. In the first process, when a shifting command is issued, control starting timing for a friction element is determined in accordance with vehicle operating condition, and when shift control of the second shaft is detected, shifting of the first shaft is started and feedback control target change rates of the both shafts are set. In the second process, the feedback control of the first shaft is performed based on the change rate of a difference in input and output rotational speeds of the first shaft and the feedback control target change rate of the first shaft, and the feedback control of the second shaft is performed based on a turbine rotational speed change rate and the feedback control target change rate of the second shaft. In the third process, when the shifting of the first shaft is completed, the shifting of the second shaft is completed. COPYRIGHT: (C)2004,JPO