| 摘要 |
1. Device for controlling a stepwise automatic transmission with three forward drive ratios with changeover under torque, damped by a hydrokinetic torque converter (1), and one reverse drive, of the type comprising a train of epicyclic gears (2) operated by two clutches (E1, E2) and two brakes (F1, F2) hydraulically controlled, which device comprises a hydraulic selector unit (22) controlled by two electrically operated valves (EL1, EL2) so as to selectively feed the two clutches and the two brakes on the basis of information relating to the operation of the vehicle fitted with the transmission, characterized in that the means of controlling the electric valves (EL1, EL2) are so arranged as to use, in addition to the three different states of the two electric valves for a selective feed corresponding respectively to each of the three forward drive ratios, a fourth possible state for the transition between the third and second forward drive ratios. |
