SPEED CHANGE PRESSURE CONTROLLER OF AUTOMATIC TRANSMISSION

摘要

PURPOSE:To improve the effect of speed change shock reduction by controlling the pressure to operate a friction element at a torque phase separated from an inertia phase in the speed change by an automatic transmission. CONSTITUTION:When an automatic transmission performs up-shift speed change to a higher speed stage from a lower speed stage by engaging a certain friction element, a torque phase time measuring means measures the torque phase time to the moment when the speed change ratio begins to change at the beginning of speed changing. An optimum torque phase time calculating means determines optimum torque phase time favorable for reducing the shock caused by speed change according to the input to the automatic transmission. A speed change pressure learning controlling means performs learning control of the operation pressure of a certain friction element in the torque phase so that the actual torque phase time measured by the torque phase time measuring means may coincide with the optimum torque phase time.