Abstract: In an internal combustion engine, the engine is formed so that an output of an electric motor can be superposed on an output of the engine. An SOX trap catalyst able to trap the SOX contained in the exhaust gas is arranged inside the engine exhaust passage upstream of the NOX storage catalyst. The vehicle drive power from the engine and the vehicle drive power from the electric motor are adjusted so that the SOX trap rate of the SOX trap catalyst is maintained at a predetermined high SOX trap rate.

Abstract: An internal combustion engine in which a front end catalyst (12) and rear end catalyst (14) comprising NOx storing catalysts are arranged in an engine exhaust passage. When these catalysts (12, 14) should recover from SOx poisoning, SOx poisoning recovery proceeding is performed in which the temperatures of the corresponding catalysts (12, 14) are raised to the SOx release temperature and the air-fuel ratio of the exhaust gas flowing into the corresponding catalysts (12, 14) is made rich. In this case, the frequency of performing the SOx poisoning recovery proceeding of the rear end catalyst (14) is made higher than the frequency of performing the SOx poisoning recovery proceeding of the front end catalyst (12).

Abstract: A SOx trap catalyst, an oxidation catalyst, a particulate filter, an aqueous urea supply valve, and a NOx selective reduction catalyst are arranged in order from upstream to downstream in an engine exhaust passage. It is determined whether a discharge concentration of hydrogen sulfide H2S will become equal to or greater than a preset maximum concentration when SOx is released from the SOx trap catalyst. If it is estimated that the discharge concentration of the hydrogen sulfide H2S will become equal to or greater than the maximum concentration when SOx is released, an adsorbed ammonia amount adsorbed on the NOx selective reduction catalyst is reduced before SOx is released so that the discharge concentration of the hydrogen sulfide H2S is less than the maximum concentration when SOx is released.

Abstract: In an internal combustion engine, the engine is formed so that an output of an electric motor can be superposed on an output of the engine. In the engine exhaust passage upstream of the NOX storage catalyst, an SOX trap catalyst able to trap the SOX contained in the exhaust gas is arranged. When regenerating the SOX trap catalyst, the vehicle drive power from the engine and the vehicle drive power from the electric motor are adjusted so that the SOX concentration in the exhaust gas flowing out from the SOX trap catalyst becomes less than a predetermined SOX concentration during the regeneration period.

Abstract: An SOX trap catalyst 12 and NOX purification catalyst 13 are arranged in an engine exhaust passage. A substrate 50 of the NOX purification catalyst 13 is formed with a coat layer comprised of at least the two layers of an upper coat layer 51 and a lower coat layer 52. The lower coat layer 52 is formed from an NOX storage catalyst storing the NOX contained in the exhaust gas when the air-fuel ratio of the exhaust gas is lean and releasing the stored NOX when the air-fuel ratio of the exhaust gas is a stoichiometric air-fuel ratio or rich. The upper coat layer 51 is formed from a material of a weaker basicity than this NOX storage catalyst.