EXHAUST GAS PURIFYING DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To simultaneously purify HC, CO and NOx regardless of the air-fuel ratio of air-fuel mixture. CONSTITUTION:An NOx absorbent 20 for absorbing NOx when the airfuel ratio of exhaust gas to flow in is lean and discharging absorbed NOx when the oxygen density in exhaust gas to flow in is decreased is arranged in an engine exhaust gas passage. The air-fuel ratio of exhaust gas is made lean by supplying secondary air into the engine exhaust gas passage on the upstream side of the NOx absorbent 20 from a secondary air supplying device 22 when the air-fuel ratio of air-fuel mixture to be supplied into an engine cylinder is made rich or the stoichiometric air-fuel ratio.