摘要 |
While an engine is an idling state and an EGR opening degree is increased stepwise from a specified opening degree, a variation in engine speed (a standard deviation in engine speed) is repeatedly computed. After that, a specified step amount is successively reduced from the EGR opening degree and the variation in engine speed is successively computed until the EGR opening degree becomes less than or equal to a specified value. Then, a maximum value of the EGR opening degrees where the variation in engine speed becomes minimum is learned as the full-close position. |