| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately estimate the level of remaining oxygen in a NOx catalyst in NOx reduction control intermittently supplying reducer to the NOx catalyst provided in an exhaust gas passage of an internal combustion engine. <P>SOLUTION: Fluctuation width of temperature difference between catalyst bed temperature and flow-in exhaust gas temperature when additional fuel is intermittently supplied to the NOx catalyst is calculated (S103), and oxygen consumption quantity consumed by oxidation reaction of additional fuel is calculated based on temperature fluctuation width (S104) in NOx reduction control of the NOx catalyst. The level of remaining oxygen is estimated based on quantity of oxygen contained in exhaust gas flowing in the NOx catalyst and oxygen consumption quantity (S105). <P>COPYRIGHT: (C)2009,JPO&INPIT |
