Aisin Aw Co., Ltd.

Haruki Sato

Hiroshi Tsutsui

Masatake Ichikawa

Nobuhiro Iwai

Shoichiro Araki

Takahiro Morimoto

A shift controller controls a downshift to a low shift speed, spaced apart from a high shift speed by two or more steps, through an intermediate shift speed, by first releasing first and second shift release elements, then engaging a first shift engagement element, and finally engaging a second shift engagement element, while controlling the torque capacity of the second shift release element by feedback control. As a result of releasing the first and second shift release elements before engaging the first shift engagement element, it is possible to rev up an input rotation at maximum performance of an engine to reduce the time for shifting. As a result of the feedback control of the torque capacity of the second shift release element after engaging the first shift engagement element, a torque fluctuation at the intermediate shift speed can be reduced to avoid occurrence of an uncomfortable shift shock.

Shift control apparatus for automatic transmission

A shift control apparatus that disconnects and connects respective pairs of friction engagement elements during downshift to a speed spaced apart by two or more steps through an intermediate shift speed. A shift controller controls a hydraulic pressure of a second shift release element by feedback control, and in accordance with the increase in the torque capacity of the second shift release element, also controls the torque capacity of a first shift engagement element so as to be sufficiently higher than the amount of change in the torque capacity of the second shift release element. The occurrence of adverse consequences in which a shift shock is generated is effectively suppressed because a sufficient reaction force cannot be ensured during engagement switching due to insufficient torque capacity of the first shift engagement element, and since the second shift release element cannot be appropriately feedback-controlled, difficulty in control of rotation change results.

Growing community of inventors

Anjo, Japan

Haruki Sato