DEVICE FOR CLARIFYING EXHAUST GAS FROM INTERNAL COMBUSTION ENGINE

摘要

An exhaust emission control system for an internal combustion engine is provided. The exhaust emission control system (4) includes a monolith catalyst (MC) that includes an oxygen storage agent and a noble metal-based three-way catalyst including Pd, Rh, and Pt disposed at an upstream location in the exhaust gas flow in the internal combustion engine (2), and a perovskite-type double oxide having a three-way catalytic function disposed at a downstream location in the exhaust gas flow. The amount C1 of Pd carried is 0.97 g/L≤C1≤1.68 g/L, the amount C2 of Rh carried is 0.11 g/L≤C2≤0.2 g/L, the amount C3 of Pt carried is 0.06 g/L≤C3≤0.11 g/L, the amount C4 of the oxygen storage agent carried is 25 g/L≤C4≤75 g/L, and the amount C5 of the perovskite-type double oxide carried is 5 g/L≤C5≤15 g/L. It is thereby possible to provide an exhaust emission control system that can reduce the production cost by reducing the amount of noble metal-based three-way catalyst used and at the same time can maintain a high exhaust emission control rate.