EXHAUST EMISSION CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINE

摘要

A device (4) for clarifying an exhaust gas from an internal combustion engin e (2), characterized in that it comprises a monolithic catalyst (MC) having a noble metal three component catalyst comprising Pd, Rh and Pt and an oxygen storage agent which are placed on the upstream side of the exhaust gas and a perovskite type double oxide exhibiting the function of a three component catalyst which is placed on the downstream side of the exhaust gas, wherein the carried amounts of Pd (C1), Rh (C2), Pt (C3), the oxygen storage agent (C4) and the perovskite type double oxide (C5) are set in the ranges of 0.97 g/L <= C1 <= 1.68 g/L, 0.11 g/L <= C2 <= 0.2 g/L, 0.06 g/L <= C3 <= 0.11 g/L, 25 g/L <= C4 <= 75 g/L and 5 g/L <= C5 <= 15 g/L, respectively. The device for clarifying an exhaust gas can be used for reducing the amount of the noble metal three component catalyst used and thus reducing the production cost therefor, while maintaining the degree of clarification of an exhaust gas at a high level.