| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust gas purification device that can suppress the deterioration in a NO<SB POS="POST">X</SB>purification ratio in an internal combustion engine where fuel and a reduction agent are added. <P>SOLUTION: An exhaust passage 26 of an engine 1 includes: a reduction agent supply mechanism 200 for supplying an oxidation catalyst 31, an SCR catalyst 41, and the reduction agent to the exhaust passage 26; a fuel addition mechanism for adding the fuel to the exhaust passage 26; and a first NO<SB POS="POST">X</SB>sensor 130 for detecting the NO<SB POS="POST">X</SB>concentration before purified by the SCR catalyst 41. A control device 80 suppresses the additive amount of the reduction agent based on the NO<SB POS="POST">X</SB>concentration detected by the first NO<SB POS="POST">X</SB>sensor 130. The control device 80 adds the reduction agent after the period from when the fuel addition is stopped by the fuel addition mechanism until NO<SB POS="POST">X</SB>reduction reaction is suppressed in the oxidation catalyst 31 passes. <P>COPYRIGHT: (C)2013,JPO&INPIT |
