EXHAUST GAS PURIFIER FOR INTERNAL COMBUSTION ENGINE

摘要

This invention provides an exhaust gas purifier for an internal combustion engine, comprising an SOx collector (25), for collecting SOx contained in an exhaust gas, provided within an exhaust gas passage in the engine. The SOx collector collects SOx when the internal atmosphere in the SOx collector is a lean atmosphere and, at the same time, the temperature of the SOx collector is relatively low. On the other hand, the SOx collecting capability is recovered when the temperature of the SOx collector is relatively high while maintaining a lean atmosphere as the internal atmosphere in the SOx collector. An NOx catalyst (37) is provided within an exhaust gas passage in the engine located downstream of the SOx collector. The NOx catalyst (37) collects and retains NOx when the internal atmosphere is a lean atmosphere. On the other hand, the NOx catalyst (37)reduces and purifies the retained NOx when the internal atmosphere is a rich atmosphere. In recovering the SOx collecting capacity of the SOx collector, control for recovering the NOx collecting capability of the NOx catalyst is started before control for recovering the SOx collecting capability of the SOx collector is started.