| 摘要 |
PROBLEM TO BE SOLVED: To optimize shift control of a continuously variable transmission. SOLUTION: A target primary pressure (Ppmin) where no slippage of belt occurs and a target transmission gear ratio can be accomplished is calculated [B(1)] and a basic line pressure (Plprs st) is calculated [B(2)]. A line pressure correction coefficient (GainPL) at the time of transition of shifting is calculated at B(4) in reference to a ratio (GainPP) between an actual primary pressure (Ppsen) calculated at B(3) and the target primary pressure (Ppmin) is calculated. After this operation, the value Plbrs st is corrected by GainPL at B(5) to calculated a final output line pressure (Plprs) and then a solenoid valve 9 is feed-back controlled [B(6)], [B(7)]. With such an arrangement as above, since the line pressure control can be made most suitable at the transition time of shifting in reference to a hydraulic pressure of the primary pressure where a slippage of the belt actually occurs, and deteriorations in durability and fuel consumption caused by excessive tension of the belt can be positively restricted while a slippage of a belt is being positively prevented. |
