Patent ID: 8813481

Claim:
An exhaust emission control device comprising: a selective reduction catalyst for reacting NOx in an exhaust gas with ammonia, urea water adding means for adding a urea water into the exhaust gas upstream of said selective reduction catalyst; and a cylindrical mixing pipe as a connection between said urea water adding means and said selective reduction catalyst, an entry end of said mixing pipe having circumferential opening sections and including guide fins for guiding the exhaust gas to said opening sections tangentially of said entry end to thereby provide a mixer structure, and said urea water adding means being arranged centrally on the entry end of said mixing pipe and directed toward an exit end thereof for addition of the urea water into a swirling flow of the exhaust gas caused by said mixer structure, wherein one side of said respective opening sections is formed along said swirling flow, inclined relative to a direction parallel to an axis of said mixing pipe.