| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust-emission purifying apparatus in which a rich spike condition of NOx trap catalyst is made to be more appropriate. <P>SOLUTION: Even when an amount of NOx adsorption of the NOx trap catalyst exceeds a threshold value, if a NOx adsorption rate of the NOx trap catalyst is higher than a predetermined value, and the NOx concentration in exhaust gases is higher than a predetermined value, a rich spike is prohibited. When the amount of NOx adsorption of the NOx trap catalyst exceeds a threshold value, if the NOx adsorption rate of the NOx trap catalyst is lower than a predetermined value, and the NOx concentration in exhaust gases is higher than a predetermined value, rich spike is performed after changing an operating condition, and reducing NOx concentration in exhaust gases (alternatively, after lowering an exhaust gas temperature, and lowering a temperature of the NOx trap catalyst). <P>COPYRIGHT: (C)2009,JPO&INPIT |
