| 摘要 |
PURPOSE:To contrive to improve reliability against failures by judging the completion of gear shifting based on a specified time determined by a timer means when a revolution detecting means fails. CONSTITUTION:The completion of gear shifting in order to suspend the back pressure control of an accumulator is judged by detecting the revolution of a member which is changed by gear shifting. The completion of gear shifting is therefore positively judged even if the actual gear shifting time is changeable due to the high or low oil temperature of an automatic transmission, or the variation with the passage of time of a friction engagement device. And a timer means (back-up timer) is provided, which determines a specified time from gear shifting judgement or gear shifting command, so that the back pressure control of an accumulator is suspended by a timer when a revolution detecting means fails. By this constitution, the back pressure control can be brought to an end at an appropriate time even if the detecting means fails, the durability of a solenoid valve can thereby be prevented from being lowered. |
