Patent attributes
An exhaust gas purification system for an engine includes an exhaust passage extending from the combustion chambers of the engine, and an exhaust purifying unit disposed in the exhaust passage and configured to purify exhaust gas in the exhaust passage. The exhaust purifying unit includes a carrier disposed in the exhaust passage, a first purifier having at least a function of oxidizing components in the exhaust gas. The first purifier covers, as an underlayer, an outer surface of the carrier, and a second purifier having a function of purifying the exhaust gas by reducing, using occluded ammonia, the components in the exhaust gas that have been oxidized in the first purifier. The second purifier includes a superposed portion covering, as an upper layer, an outer surface of the first purifier.