| 摘要 |
A method of operating a control system to move an EGR valve (24) toward its seat (32), in which the control system includes an actuator (16) operable in response to an electrical position command signal (84, 86). The method comprises the steps of determining (102) if the valve is being commanded toward a closed position, and determining (106) if the valve is still at least a predetermined distance (X) from a Stage 1 Position. If both answers are affirmative, the valve is commanded toward the Stage 1 Position, then the logic determines when the valve is within a predetermined tolerance (T) of the Stage 1 Position, and when it is, the logic provides a position command signal corresponding to an unchanging position of the valve for a predetermined period of time (Y), while any overshoot of the valve position settles out, and the valve position stabilizes before the logic proceeds with the rest of the closing operations. The result is greatly reduced stress on the valve (24) and the gear train which drives the valve.
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