Hydraulic control system for powertrain of seven-speed automatic transmission, has clutch control portion supplying operating pressure to clutch based on control of proportional control solenoid valve

摘要

The system has a brake and a clutch control portions controlling and supplying a forward range pressure to a brake (B1) or clutch (C3) based on a control of a proportional control solenoid valve. Another clutch control portion supplies a line pressure to a clutch (C2) based on a control of another proportional control valve. Another brake control portion supplies another forward range pressure to a brake (B2) based on a control of the latter solenoid valve. Third clutch control portion supplies an operating pressure to a clutch (C4) based on a control of a third proportional control valve.