Hydraulic pressure control for reducing engagement shock of automatic transmission

摘要

A hydraulic pressure control system for reducing engagement shock of a frictional element when the transmission effects a change in gear position comprises an electromagnetically operated valve for generating a hydraulic pressure supplied to the frictional element and a control unit. In the control unit, the amount of torque transmitted via a torque converter to a transmission input shaft is determined through operations based on output signals of various sensors and data stored in a memory, and a target value of hydraulic pressure is determined in response to the amount of torque determined. The control unit supplies an output signal to the valve to cause the valve to adjust the level of the hydraulic pressure generated thereby to the target value.