| abstract |
An exhaust gas purifier for internal combustion engine, having a lean NOx catalyst on metal honeycomb substrate capable of removing NOx, CO and HC from exhaust gas generated by fuel combustion conducted at an air fuel ratio higher than theoretical air fuel ratio, which exhaust gas purifier is designed so as to enhance the thermal durability of catalyst through suppression of the sublimation phenomenon and noble metal masking phenomenon of alkali attributed to high-temperature heat load. The catalyst unit of the exhaust gas purifier for internal combustion engine comprises at least a catalyst active component containing an alkali metal, an alkali metal reservoir part capable of stocking the alkali metal and a base of metal material capable of supporting at least the catalyst active component and the alkali metal reservoir part. |