Control system for automatic transmission

摘要

A control system for an automatic transmission includes a clutch for transmitting the rotation of an engine to the transmission and a hydraulic servo for applying/releasing the clutch. A starting state is determined by satisfaction of at least one of the following conditions: the throttle opening is not fully closed; the brake pedal is released; and/or the vehicle speed is substantially above zero. Sensors detect the throttle opening of the engine and the applied/released state of the clutch and send signals to a control unit. A hydraulic controller controls the oil pressure fed to the hydraulic servo. When the starting state is detected, the control unit detects the actual applied/released state of the clutch to determine the difference between the applied/released state and a predetermined ideal applied/released state to set an oil pressure correction according to that difference. Next, a predetermined oil pressure for achieving the ideal engaging characteristics of the clutch is read, oil pressure correction is added to the read oil pressure, and the sum is output to the hydraulic controller. As a result, even if an error occurs in the output of the control valve of the hydraulic controller or if the clutch has aged, the oil pressure is corrected by the oil pressure correction according to the difference between the actual applied/released state and the ideal applied/released state so that the engaging characteristics obtained can approximate the ideal.