CONTROL SYSTEM FOR AN AUTOMOTIVE AUTOMATIC POWER TRANSMISSION

摘要

A control system for controlling the line pressure in a hydraulic control system of an automotive automatic power transmission in which a line pressure regulator valve is controlled by a variable back pressure produced by a servo valve which is actuated by an electronic control circuit in accordance with changes in vehicle speed. The voltage to be supplied to the servo valve is increased in proportion to the turbine speed of a value and, when the turbine speed exceeds the predetermined value, the voltage to be applied to the servo valve remains constant. The line pressure is thus regulated in a manner to follow the output torque of the torque converter to thereby control the line pressure to an appropriate level for effecting smooth shifting between the gear ratios.