| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust gas cleaning method capable of effectively cleaning NOx in an oxygen excess area discharged from an internal combustion engine and of effectively removing NOx even if exhaust gas temperature changes in a wide range. <P>SOLUTION: This exhaust gas cleaning method is as follows: An exhaust gas cleaning catalyst including a NOx adsorbent is disposed in an internal combustion engine or its exhaust flow passage. Using an exhaust gas temperature detection means, an oxygen concentration detection means, and an oxygen concentration control means, oxygen concentration in exhaust gas flowing into the catalyst is increased at lean operation when a temperature T<SB>1</SB>of an exhaust gas flowing into the catalyst is above a preset temperature T<SB>2</SB>. <P>COPYRIGHT: (C)2004,JPO |
