Vehicle powertrain has accumulator with spring or compressed gas loaded piston, that is controlled by electronic controller to discharge fluid to fluid passage when engine is restarted

摘要

A transmission is operatively connected to an engine (13) that is selectively turned ON and OFF. A hydraulic control system (10) has a fluid pump (12) that is operatively connected to an engine (13) for supplying fluid to transmission (11) when the engine is ON. The pump is maintained idle when engine is OFF. An accumulator (18) comprising a spring or compressed gas loaded piston (20) is controlled by an electronic controller (44) to accumulate fluid when the engine is ON, to retain fluid when engine is OFF and to discharge fluid to fluid passage (14) when engine is restarted. An independent claim is included for method for controlling hydraulic system of vehicle powertrain.