EXHAUST PURIFIER OF INTERNAL COMBUSTION ENGINE AND METHOD OF EXHAUST PURIFICATION

摘要

SOX trap catalyst (11) having at least either an alkali metal or an alkaline earth metal dispersed and supported therein is disposed in an exhaust passage of internal combustion engine. During engine drive, the temperature of the SOX trap catalyst (11) is maintained at one at which a nitrate of at least either an alkali metal or an alkaline earth metal becomes a molten form to thereby promote the action of nitrate migration coagulation inducing the migration to the surface of the SOX trap catalyst (11) and coagulation of the nitrate within the SOX trap catalyst (11). By virtue of this action of nitrate migration coagulation, SOX is removed while attaining recovery of SOX trap ratio.