| 摘要 |
<p>PURPOSE: A shift control device of an auto transmission is provided to raise the instruction fluid pressure of a second friction fastening element to the maximum value in a short time, thereby reducing the reduction of shift shock and shortening the shift time at the extremely low car speed which can not be exactly detected by a vehicle speed sensor. CONSTITUTION: At the extremely low car speed which can not be exactly detected by a vehicle speed sensor, a precharge controller raises rapidly the instruction fluid pressure of a second friction fastening element and then drops rapidly the instruction fluid pressure after a shift instruction to a different gear terminal. The precharge controller raises gradually the instruction fluid pressure at a rapid drop point of time to complete the piston stroke of the second friction fastening element. An extremely low car speed controller raises the instruction fluid pressure of the second friction fastening element to the maximum value in a short time when the piston stroke of the second friction fastening element is completed.</p> |
