| 摘要 |
A control system for an automatic transmission operates a clutch for disengaging a transmission mechanism when a vehicle is stopped and idling with the brake pedal depressed while the gear shift is in a forward gear. The clutch is maintained at a drag state (friction elements disengaged but oil causing some torque transmission) bordering a slip state (friction elements engaged) When a neutral control is started, the clutch is released until the retraction of the piston of the hydraulic servo is started. When the rate of change in a rotational difference does not exceeds a reference rate of change even after a set time has elapsed, booster means of specific release state holding means decides that the clutch is in a drag region, and raises an oil pressure to be fed to the hydraulic servo, by a set pressure. On the other hand, when the rate of change exceeds the reference rate and the rotational difference increases, irrespective of the lapse of a set time, the first pressure reducing means of the specific release state holding means decides that the clutch is in a slip region, and lowers the oil pressure to be fed to the hydraulic servo, by a set pressure. As a result, the clutch is always held in a state which is immediately before the transfer from the drag region to the slip region. |
