Speed shift control apparatus of automatic transmission

摘要

At the time of the 6†’3 speed shift, an automatic transmission achieves a 6†’4†’3 speed shift by controlling the servo pressures (P B1 , P C1 , P C2 , P C3 ) of the fourth engageable elements. A control apparatus controls the servo pressure (P C2 ) in accordance with the servo pressure (P B1 , P C1 ). The engagement and release timings are adjusted by determining and controlling the oil pressures of the hydraulic servos, taking into consideration the 6†’4 shift state (torque sharing) during a shift transitional period. Therefore, engine blow and prolongation are prevented during the 6†’3 shift control.