| 摘要 |
PURPOSE:To effectively purify NOx over the wide range of exhaust gas temp. from low to high temp. while preventing the deterioration of a NOx purifying catalyst at high temp. CONSTITUTION:A NOx catalyst 4 of low temp. activity having 7 noble metal as an active seed and a NOx catalyst 5 of high temp. activity are arranged on the upstream and downstream sides respectively. The NOx purification at the time of exhaust gas low temp. is ensued by the NOx catalyst of high temp. activity, causing the NOx catalyst 5 of high temp. activity to be arranged so as to be separated from an engine, permitting heat deterioration to be prevented. |
