Patent ID: 7171956
Filing Date: 2007-02-06
Classification: F02M,F28D,F28F

Abstract:
1. An EGR cooler comprising a multipicity of round in section tubes which are juxtaposed spaced apart from each other, with both ends of the tubes leading to a pair of headers, with exhaust gases to be cooled circulating within the tubes, and with a cooling fluid circulating around outer surfaces of the tubes, wherein the round in section tubes are plastically deformed in one plane crossing centerlines of the tubes such that corrugated exhaust gas flow paths are formed inside the tubes; and wherein the centerlines of the tubes are aligned with each other, with a multiplicity of recessed portions being formed inward from the outer surfaces of the tubes apart from each other in the longitudinal direction, with the multiplicity of recessed portions being arranged such that inner and outer surfaces of cross sections on the one plane are formed in mountain shapes and that ridgelines of top portions of the mountains are orthogonal to the one plane, wherein adjacent recessed portions are formed at positions differing from each other by 180 degrees in the circumferential direction, and wherein both longitudinal-direction end portions of the tubes are such that round portions are formed whose cross sections orthogonal to axial lines are round.