| abstract |
[PROBLEMS] To prevent SOx poisoning of a lean NOx catalyst for lean burn exhaust gas purification and maintain NOx purification performance. An SOx trapping material is provided in an exhaust gas flow path, and a lean NOx catalyst is provided in a flow downstream thereof. The SOx trapping material maintains its SOx trapping ability by raising the temperature in a reducing atmosphere. According to the present invention, it is possible to purify lean burn exhaust gas of an internal combustion engine using a fuel containing S. |