Skip downshift control apparatus for automatic transmission

摘要

A control apparatus for an automatic transmission of twin clutch type, in which a skip downshift is executed with a light gearshift shock and in a short gearshifting time period. As illustrated in FIG. 1, after the release of a clutch C2, a command for switching over a synchro mechanism is issued at a time t3. When the r.p.m. NT of a turbine has reached the synchronous r.p.m. NT3 of the intermediate stage of the skip downshift, the oil pressure of a clutch C1 is raised in order that the rising rate of the turbine r.p.m. (speed) NT may become a predetermined value d/dt(NT1) or d/dt(NT2). Thereafter, the oil pressure of the clutch C1 is controlled in order that the turbine r.p.m. NT may maintain a value NT2 (synchronous r.p.m. of the lower speed stage of the skip downshift)+ DELTA NT4. After the completion of the switchover of the synchro mechanism, the oil pressure of the clutch C2 is gradually raised, and that of the clutch C1 is gradually lowered. Thus, the skip downshift in a power-ON state is executed.