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 (PB1, PC1, PC2, PC3) of the fourth engageable elements. A control apparatus controls the servo pressure (PC2) in accordance with the servo pressure (PB1, PC1). 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.