Hydraulic circuit used for automatic transmission of vehicle having automatic engine-stop system, and oil-pressure control system and method

Abstract

A hydraulic circuit for controlling the oil pressure supplied to an automatic transmission of a vehicle which has a mechanical oil pump, driven by an engine, for supplying hydraulic oil to the automatic transmission and which has an automatic engine-stop system is disclosed, by which the rise speed of the oil pressure for driving the automatic transmission can be increased when the engine is restarted, and the delay of the response for starting the vehicle can be decreased. In the hydraulic circuit, a bypass passage for connecting the suction side and the supply side of the mechanical oil pump is provided; and an electric oil pump is connected to the bypass passage in a manner such that the mechanical oil pump and the electric oil pump are arranged in parallel.

Dependencies are inferred from the claim text.