| abstract |
A device, for purifying exhaust gas of an engine, comprises a SO x storage arranged in the exhaust passage for temporarily storing SO x contained in an exhaust gas inflowing therein, and an auxiliary catalyst arranged in the exhaust passage downstream of the SO x storage, the auxiliary catalyst having an oxidizing ability. When SO x stored in the SO x storage is discharged therefrom with the atmosphere of the auxiliary catalyst being in a sulfate forming atmosphere, the atmosphere of the auxiliary catalyst is changed to an atmosphere other than the sulfate forming atmosphere. When SO x stored in the SO x storage is discharged therefrom with the atmosphere of the auxiliary catalyst being in an atmosphere other than the sulfate forming atmosphere, the atmosphere of the auxiliary catalyst is maintained at an atmosphere other than the sulfate forming atmosphere. |