PURPOSE: To reduce the driving loss of an oil pump by providing such a constitution as detecting the output torque of an automatic transmission and the change gear ratio in the present shift position, and setting line oil pressure according to the above output torque and change gear ratio in the steady state.
CONSTITUTION: During a period where the input and output shaft rotating speed ratio is not coincident with the change gear ratio of the shift position at that time and a guard period determined by a determined value of a timer from the start of shifting, flag is maintained at 0, so that line oil pressure is calculated according to motor output, as a simple example, depending on only throttle opening. When the input and output shaft rotating speed ratio is coincident with the change gear ratio of the shift position after shifting, shifting termination is judged, and the line oil pressure is set according to a net load torque of a frictional engaging device necessary for formation of the shift position after shifting. Therefore, the line oil pressure is set lower, compared with the case where the line oil pressure is determined according to only the motor output, and according to this, the necessary driving energy of an oil pump generating the original pressure of the line oil pressure is reduced.
TAKADA MITSURU
TAKAHASHI NORIYUKI
