Line pressure control device for auto gearbox transmitting rotation of engine to output shaft has oil pressure circuit to vary pressure to gearbox, sensors for vehicle and engine speed plus throttle opening and microprocessor

摘要

A line pressure control device for an auto gearbox (200) transmitting the rotation of an engine (100) to an output shaft (250) has: - an oil pressure circuit (210) to vary a line pressure which is supplied to the gearbox, a sensor (63) to detect a vehicle speed, a sensor (68) to detect the speed of the engine, a sensor (62) to detect a throttle opening of the engine and a microprocessor (61). The microprocessor is programmed to calculate an input torque into the gearbox based on the speed of the engine and the throttle opening, calculate a line pressure in accordance with the input torque to the gearbox determine whether or not the vehicle speed is greater than an established vehicle speed execute a line pressure increase process in order to lock the target line pressure onto an established line pressure independently of the input torque of the gearbox when the vehicle speed is higher than an established vehicle speed and control an oil pressure circuit so that the line pressure equals the target line pressure.