| 摘要 |
An electro-hydraulic control system is intended for the kind of automatic power transmission which comprises at least three forward gear ratios and in which ratio changes are effected under power by releasing one clutch interconnecting the transmission input and output through one engaged gearset simultaneously with engaging another clutch interconnecting the input and output through another engaged gearset. The control system comprises hydraulic gear actuators each for engaging and disengaging a separate gearset. Electro-hydraulic valves control the supply of hydraulic fluid to the actuators in response to ratio selection signals derived in an electronic control. One set of electro-hydraulic valve states is arranged to engage first and second gearsets while a second set of electro-hydraulic valve states is arranged to engage both second and third gearsets. Operation of the transmission in only one of the ratios associated with the two engaged gearsets is effected by holding one of the clutches disengaged while the other clutch is engaged, thus establishing drive through one and only one of the two engaged gearsets.
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