| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an EGR cooler in which cooling water passages are extensively arranged near expansion parts of internal gas passages formed by pipes, if inexpensively manufactured, and which can effectively suppress the deviation of a gas flow into the expansion parts, thus sufficiently enhancing heat exchanging efficiency.SOLUTION: The EGR cooler includes a plurality of flat internal gas passages 13 whose cross-section opening sizes are each larger in the width direction and smaller in the thickness direction, and cooling water passages 14, the internal gas passages 13 each having a flat passage part 31, and an expansion part 33 expanded to be thicker than the flat passage part 31. On the further width-direction inside than both width-direction ends 31a, 31b, the flat passage part 31 has a main passage portion 31c of a predetermined width Wp which is thinner than both ends 31a, 31b.</p> |
