Control method and control system for automatic transmission.

摘要

A system and method for controlling an automatic transmission in a vehicle drive train including an engine (10), the automatic transmission (16) and a fluid coupling (12) for transmitting the rotation of the engine to the transmission. The transmission includes a clutch (C1) applied when a forward running range is selected; a second one-way clutch (F2) which is applied, when the first clutch (C1) is applied, to establish a forward 1st speed; and a brake (B1) for locking the one-way clutch (F2), when applied, to block the reverse rotation of the output shaft of the transmission (16). A first hydraulic servo (C-1) receives a first oil pressure for applying the first clutch (C1) and a second hydraulic servo (B-1) receives a second oil pressure for applying the brake (B1). When a forward running range is selected, with the vehicle stopped, the engine idling and a foot brake engaged, the oil pressure of the first hydraulic servo (C-1) is lowered from the oil pressure at the 1st speed whereas the oil pressure of the second hydraulic servo (B-1) is raised to a modulated pressure. The modulated pressure is set to generate, against the reverse force on the vehicle facing up an incline, a resistance corresponding to the forward driving force generated when the engine is idling in 1st speed.