CONTROL SYSTEM FOR VEHICULAR AUTOMATIC TRANSMISSION

摘要

An automatic transmission for a vehicle comprises a torque converter TC equipped with a lock-up clutch 4. This automatic transmission further comprises FIRST ~ FOURTH speed clutches 31 ~ 34 for a shift control executing a shift from an off-going speed ratio to an on-coming speed ratio by controlling the release of the hydraulic pressure from the off-going clutch and by controlling the supply of the hydraulic pressure to the on-coming clutch. A control system comprises first and second off-going pressure releasing valves 70 and 80, which release the hydraulic pressure from the off-going clutch during the shift, a lock-up control valve 40 and a lock-up timing valve 50, which control the engagement of the lock-up mechanism, and a linear solenoid valve 60, which supplies a control pressure to these valves and controls the operation of these valves.