| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device that has proper purification performance by preventing wasteful exhaust of reducing gas such as ammonia produced from an urea aqueous solution and achieving acceleration of ammonia decomposition reaction and reductive reaction in an SCR catalyst.SOLUTION: An exhaust emission control device of an internal combustion engine (10), which has an NOx selective-reduction catalyst (36) provided in an exhaust passage (18), includes: an exhaust air reflux passage (44) which communicates between an upstream-side reflux gas exhaust port (46) and a reflux gas introduction port (42) provided on a downstream side of the NOx selective-reduction catalyst; a reflux control valve (48) for opening and closing the exhaust air reflux passage; and straightening means (40, 50 and 52) for straightening reflux gas in the exhaust air reflux passage. |
