Control system of automatic transmission

A control system of an automatic transmission, the automatic transmission including a stepwise variable transmission section that includes a plurality of frictional elements and establishes a desired speed by a shift change disengaging one of the plurality of frictional elements and engaging another of the plurality of frictional elements and a continuously variable transmission section that establishes a desired speed continuously, the control system making a speed change control of the continuously variable transmission section cooperate with a change of an input rotation speed of the stepwise variable transmission section,

• the control system comprising:
• means for judging, during the shift change of the stepwise variable transmission section, whether a delivery of a torque from one of a plurality of disengaging side frictional elements to one of a plurality of engaging side frictional elements is completed;
• and
• means for starting the speed change control of the continuously variable transmission section upon judgment that the delivery of the torque is completed and that an inertial phase has started.

A method of controlling an automatic transmission, the automatic transmission including a stepwise variable transmission section that includes a plurality of frictional elements and establishes a desired speed by a shift change disengaging one of the plurality of frictional elements and engaging another of the plurality of frictional elements and a continuously variable transmission section that establishes a desired speed continuously, the continuously variable transmission section being controlled in cooperation with a change of an input rotation speed of the stepwise variable transmission section,

• the method comprising:
• judging, in a transmission controller, during the shift change of the stepwise variable transmission section, whether a delivery of a torque from one of a plurality of disengaging side frictional elements to one of a plurality of engaging side frictional elements is completed;
• and
• starting, in a transmission controller, control of the continuously variable transmission section upon judgment that the delivery of the torque is completed and that an inertial phase has started.