| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technology for generating an efficient intermediate substance in an intermediate substance generating catalyst and efficiently eliminating NOx in exhaust gas in an exhaust emission control system of an internal combustion engine equipped with the intermediate substance generating catalyst for generating a prescribed intermediate substance by reaction between a reducing agent and NOx, and a NOx eliminating catalyst for reducing and eliminating NOx by using the generated intermediate substance. <P>SOLUTION: The exhaust emission control system equipped with an NSR 10 as the intermediate substance generating catalyst, an SCR 11 as the NOx purifying catalyst, and a fuel addition valve 14 for supplying a reducing agent for generating ammonia in the NSR 10 into exhaust gas is focused on. When adding fuel from the fuel addition valve 14, a control valve 15 is opened, a bypass tube 6 is passed in a portion of the exhaust gas, and pressure of the exhaust gas is reduced. Thereby, the added fuel from the fuel addition valve 14 is suppressed from being dispersed, and formation of a local over-rich state in the NSR 10 is made possible. <P>COPYRIGHT: (C)2009,JPO&INPIT |
