Apparatus and method for controlling gear shift for automatic transmission

A gear shift controlling apparatus for an automatic transmission, the automatic transmission comprising a plurality of frictional elements and the automatic transmission being enabled to make a gear shift by a release-to-clutch control in such a manner that while a first one of the frictional elements is released by a decrease pressure control for a working liquid pressure, a second one of the frictional elements is clutched by an increase pressure control for the working liquid pressure, the gear shift controlling apparatus comprising:

• a release-to-clutch controlling section that controls the working liquid pressure for each of the first and second frictional elements to make the gear shift in the automatic transmission in such a manner that while the first frictional element is released by the decrease pressure control for the working liquid pressure, the second frictional element is clutched by the increase pressure control for the working liquid pressure;
• and
• a release capacity setting section that sets a release capacity during an inertia phase during which the gear shift from a first gear range to a second gear range occurs in accordance with an instantaneous gear ratio during the inertia phase so as to output the release capacity set according to the instantaneous gear ratio.

A gear shift controlling method for an automatic transmission, the automatic transmission comprising a plurality of frictional elements and a pressure controller connecting and disconnecting an actuator working liquid pressure for at least a first one of the frictional elements to make a gear shift from a first gear range to a second gear range, the gear shift controlling method comprising:

• controlling a pressure of the actuator working liquid to vary a torque transmission capacity of the first frictional element;
• and
• setting the torque transmission capacity according to an instantaneous gear ratio which varies in accordance with a gear shift from the first gear range to the second gear range, during an inertia phase during which the gear shift from the first gear range to the second gear range occurs.

A gear shift controlling method for an automatic transmission, the automatic transmission comprising a plurality of frictional elements and the automatic transmission being enabled to make a gear shift by a release-to-clutch control in such a manner that while a first one of the frictional elements is released by a decrease pressure control for a working liquid pressure, a second one of the frictional elements is clutched by an increase pressure control for the working liquid pressure, the gear shift controlling method comprising:

• controlling the working liquid pressure for each of the first and second frictional elements to make the gear shift in the automatic transmission in such a manner that while the first frictional element is released by the decrease pressure control for the working liquid pressure, the second frictional element is clutched by the increase pressure control for the working liquid pressure;
• and
• setting a release capacity during an inertia phase during which the gear shift from a first gear range to a second gear range occurs in accordance with an instantaneous gear ratio during the inertia phase so as to output the release capacity set according to the instantaneous gear ratio.