| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a shift control system of an automatic transmission capable of making both compatible in reduction in a speed change shock and shortening of a speed change time, at an extremely low vehicle speed unable to perform accurate detection by a vehicle speed sensor. <P>SOLUTION: This shift control system of the automatic transmission has a shift control means (Fig.4) for changing a speed to the other gear stage by releasing a first frictional fastening element and fastening a second frictional fastening element, and controls command hydraulic pressure of the second frictional fastening element based on the detected gear ratio. The shift control means (Fig.4) has a precharge control part (S52 and S53) for completing a piston stroke of the second frictional fastening element when being an extremely low vehicle speed unable to perform accurate detection by an output shaft rotating speed sensor 5 (YES by S43), and an extremely low speed time control part (S54-S59) for increasing the command hydraulic pressure of the second frictional fastening element up to a maximum value in a shorter time than a vehicle speed capable of accurate detection by the output shaft rotating speed sensor 5 after determining completion of the piston stroke of the second frictional fastening element by the precharge control part. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
