TRANSMISSION CONTROL UNIT OF AUTOMATIC TRANSMISSION FOR VEHICLE FOR COMBINING FRICTION FACTORS ACTIVELY ACCORDING TO VEHICLE SPEED IN LIFT FOOT UP SHIFTING

摘要

PURPOSE: A transmission control unit of an automatic transmission for a vehicle is provided to prevent shift shock, and to combine second friction factors timely by setting hydraulic pressure to the friction combination factors according to input rpm difference of a fluid coupling. CONSTITUTION: A combination is released by releasing hydraulic pressure of first friction combination factors of a gear shifting mechanism in switching the speed range, and friction combination factors are assembled by supplying hydraulic pressure to the second friction combination factors to shift the speed range. Hydraulic pressure supplied to the second friction combination factor is feedback-controlled, and the input rpm difference of a fluid coupling is calculated in shifting the speed range based on vehicle speed before starting feedback control while up shifting with the engine output below the predetermined value(S51). The initial supply hydraulic pressure to the second friction combination factor is predetermined based on the rpm difference(S52).