EXHAUST GAS PURIFICATION SYSTEM AND EXHAUST GAS PURIFYING METHOD USING SAME

摘要

An exhaust gas purification system (100) which comprises a NOx purification catalyst (34) for purifying nitrogen oxides, which is arranged in an exhaust gas channel (3), and a HC generator (33, 133) for generating at least one of acetylene, C2-5 hydrocarbons other than acetylene, and aromatic hydrocarbons from hydrocarbons in an exhaust gas, said HC generator (33, 133) being arranged in the exhaust gas channel (3) in the upstream of the NOx purification catalyst (34).  An exhaust gas purifying method using the exhaust gas purification system, wherein the oxygen concentration in the exhaust gas supplied to an HC generation catalyst (33A, 133A) in the system (100) is set at 0.8-1.5 vol% when the air/fuel ratio is theoretical or rich.