Patent ID: 8117830
Filing Date: 2012-02-21
Classification: F01N,Y02T

Abstract:
1. An exhaust purification device for an engine comprising: an after-treatment device interposed in an exhaust passage of an engine for purifying exhaust gas of the engine by using a reducing agent; a reducing-agent supply device that supplies a reducing agent into the exhaust passage on an upstream side of the after-treatment device; and a fin device interposed in the exhaust passage to be located upstream from the after-treatment device that agitates the exhaust gas of the engine by changing a flow direction of the exhaust gas that is passing through the fin device; wherein the fin device includes a base plate having a plurality of through holes that are defined by radially extending spoke portions and a ring-like rim portion connecting outer ends of the spoke portions, and are arranged in a circular pattern in a circumferential direction of the base plate, the base plate being fixed in the exhaust passage by the rim portion being jointed to the exhaust passage via welded portions, a plurality of fins that expand in one arranging direction of the through holes from base ends that are first edges of the spoke portions in the one arranging direction on a slant with respect to the base plate, and change a flow direction of the exhaust gas passing through the through holes to agitate the exhaust gas, and connecting portions that connect outermost circumferential edges of the fins to the rim portion over predetermined regions expanding from the base ends of the fins in extending directions of the fins; and wherein the welded portions are each disposed in an area between respective two adjacent spoke portions in the circumferential direction of the base plate, an outer edge of the rim portion in extending directions of the spoke portions is located next to the exhaust passage with a gap provided therebetween, the connecting portions are formed away from the welded portions in the circumferential direction of the base plate, and the distance between each of the connecting portions and the corresponding closest welded portion in a circumferential direction of the base plate is set equal to or less than 26 percent of the length of the welded portion in the circumferential direction of the base plate.