CATALYST FOR CONTROLLING EXHAUST EMISSION AND EXHAUST EMISSION CONTROL SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a catalyst for controlling exhaust emission and an exhaust emission control system capable of efficiently controlling NOx, dispensing with making the air-fuel ratio of exhaust emission reach the theoretical air-fuel ratio-rich, without making the fuel consumption of an internal combustion engine worse and while removing oxygen poisoning in controlling the absorbed NOx. SOLUTION: This catalyst for controlling exhaust emission includes solid reduced materials capable of being supplied non-periodically, NOx absorption materials and noble metals. This exhaust emission control system comprises the catalyst for controlling exhaust emission employed. The exhaust emission control system is provided with an NOx absorption control section comprising the NOx absorption materials and the noble metals combined and a solid reduced material supply means capable of supplying solid reduced materials non- periodically. Solid reduced materials are supplied to the NOx absorption control section timely to reduce composition derived from NOx for controlling.