| 摘要 |
PURPOSE:To ensure safety by adding each speed change value for a time set with a timer when an accelerator is in the OFF condition in setting the drive position of an automatic gear, and shifting down the gear when the accumulation of values so added has exceeded a predetermined level. CONSTITUTION:A timer starts to operate when an accelerator pedal 25 is at the OFF position during the running of an automatic vehicle on a downward road with the select lever 29 thereof at the drive position, and a rising vehicle speed is detected with a sensor 33. The vehicle speed gives a rise in succession and though a brake 27 is operated whenever necessary for reducing the speed, is added in turn. When time is up and an accumulated value has exceeded a predetermined level, an electromagnetic valve 18 is operated to actuate an air clutch 16 and a gear change with a valve set 23 for the changeover of a gear position, thereby shifting down a gear. According to the aforesaid constitution, the automatic shift-down of the gear can be done and safety with engine brake operation on a downward road is maintained. |
