| 摘要 |
PURPOSE: An automatic transmission 4-3 kick down changing control method is provided to improve shifting performance and driving experience by reducing shift quality occurring in the last stage of shifting. CONSTITUTION: Duty control is performed in first and second pressure control solenoid valves with the start of 4-3 kick down changing due to drive condition. The first pressure control solenoid valve for combining a front clutch is duty-controlled by an initial open loop duty control signal from a TCU(transmission control unit). After third reference time, the duty of the first solenoid valve is increased to the duty(Df). While maintaining the duty for fourth reference time, feed back start duty control point is detected. The initial open loop duty control is finished to perform 4-3 kick down changing feed back duty control with the decrease of the duty to feed back duty start point(Dui).
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