| 摘要 |
Electro-hydraulic control system for an automatic power transmission providing forward ratios, neutral and reverse gear ratio in which forward ratio changes are effected under power by releasing one clutch (12 or 13) interconnecting the transmission input and output through one engaged gearset simultaneously with engaging another clutch (13 or 12 respectively) interconnecting the input and output through another engaged gearset. The control system comprises five hydraulic gear actuators (GA1, GA2, GA3, GA4, GAR) each for engaging and disengaging a separate gearset and three electro-hydraulic valves (A,B,C) for controlling the supply of hydraulic fluid from a pump (PP) to the hydraulic gear actuators in response to ratio selection signals derived in an electronic control system (EC). A manually operable mode selector valve (MV) is arranged to supply the electrohydraulic valves with fluid under pressure from pump (PP) when a driving mode is selected thereby but to cut off fluid pressure supply from the electro-hydraulic valves when a non-driving mode such as neutral is selected. Reverse gear actuator (GAR) and first gear actuator (GA1) are selected by the same ratio selection signals (A = 0, B=1,C=1,) and pressure is distributed to the appropriate one of these gear selectors through the mode selector valve in dependence on whether a forward driving mode or reverse is selected thereby. |
