Patent ID: 7784273
Filing Date: 2010-08-31
Classification: B01D,B01F,F01N,Y02A,Y02T

Abstract:
1. An exhaust emission purifying apparatus for an engine, comprising: a reduction catalytic converter disposed in an exhaust passage of said engine, for purifying nitrogen oxides contained in the exhaust gas by reduction through reacting with a reducing agent; an injection nozzle for injection-supplying the reducing agent at a position in said exhaust passage on an exhaust upstream side of said reduction catalytic converter; and a swirl-flow generating means disposed on an exhaust upstream side of an injection position of the reducing agent in said injection nozzle, for generating, in the exhaust gas, a swirling flow which spirally swirls about a center corresponding to a central axis of said exhaust passage, wherein said swirl-flow generating means comprises a plurality of fins which is provided in said exhaust passage in a manner such that said fins extend, respectively, defining a predetermined angle with respect to a linear direction in which the exhaust gas flows from the exhaust upstream side toward an exhaust downstream side, wherein said fins are formed by pulling up a corresponding number of fin-forming portions of a thin plate of a shape substantially the same as a cross section of said exhaust passage, said fin-forming portions being defined by cuts given to said thin plate, wherein said reduction catalytic converter is formed to have a diameter thereof larger than the cross section of the exhaust passage on the exhaust upstream side thereof and on the exhaust downstream side of the swirl-flow generating means, and wherein said passage is formed such that an edge portion thereof is expanded in a bell-mouth shape increasing a diameter thereof toward the exhaust downstream side, at an exhaust gas inlet portion to said reduction catalytic converter.