Abstract: An automatic transmission has an electronic control unit and a hydraulic control unit. The electronic control unit outputs an engagement command pressure to a solenoid disposed in a hydraulic control unit to generate a shelf pressure to upshift the automatic transmission. The engagement command pressure is corrected downwardly when the maximum rate of the gear ratio change is larger than the rate of change of a thrust-up determination gear ratio, and upwardly when the maximum rate of the gear ratio change is smaller than the rate change of a prolongation determination gear ratio. By correcting the engagement command pressure using the maximum rate of the gear ratio change, a proper output shaft torque wave form can be obtained so that a fluctuation of an output shaft torque during a torque phase while upshifting has no strong influence on the acceleration of a vehicle to achieve a comfortable shift feeling.

Abstract: An automatic transmission comprises an electronic control unit and a hydraulic control unit. The electronic control unit commands an engagement command pressure to a solenoid disposed in a hydraulic control unit until the time engagement element pressure generated by the solenoid reaches to a shelf pressure, thereby an upshift of the automatic transmission is achieved. The engagement command pressure is corrected in a decrease direction when a maximum rate of change of a gear ratio is larger than a rate of change of a thrust-up determination gear ratio, and the engagement command pressure is corrected in a rise direction when the maximum rate of change of the gear ratio is smaller than a rate of change of a prolongation determination gear ratio. Thus, by correcting an engagement command pressure using the maximum rate of change of the gear ratio, a proper output shaft torque wave form can be obtained.