Patent ID: 8393146

Claim:
An exhaust emission control device wherein comprising: a muffling structure; a catalyst arranged downstream of said muffling structure in a direction of gas flow; and a particulate filter arranged downstream of said catalyst in the direction of gas flow encased in a casing, wherein said muffling structure includes a dispersion plate for dividing an interior of said casing into dispersion chambers upstream and downstream in the direction of gas flow, respectively, and an inner pipe inserted from outside of and into the upstream dispersion chamber and with a tip end fixed to said dispersion plate, a portion of the dispersion plate facing the inner pipe is formed with a plurality of pores; a portion of said inner pipe within said dispersion chamber being circumferentially formed with a plurality of pores with diameters gradually reduced in the order from upstream to downstream direction of the gas flow a portion of said dispersion plate outward of said inner pipe is formed with a plurality of radially-outward-larger-diametered and radially-inward-smaller-diametered pores, and said pores on the dispersion plate facing the inner pipe having uniform diameter smaller than that of the innermost of said pores on the dispersion plate outward of said inner pipe.