| 摘要 |
PROBLEM TO BE SOLVED: To provide an EGR cooler that can prevent the deterioration of the flow of cooling water or exhaust gas even if spiral protrusions are formed at the inner peripheries of tubes. SOLUTION: An EGR cooler includes tubes in which spiral protrusions 12 are formed at their inner peripheries by spirally denting outer peripheries thereof, and shells that surround the tubes 3 in each of which cooling water 9 is supplied/discharged to/from the inside of the shell, and exhaust gas 10 is circulated in the tubes 3, so that heat exchange between the exhaust gas 10 and the cooling water 9 is achieved while forming a spiral flow. Two types of the tubes 3 are arranged alternately with torsional directions of the spiral protrusions 12 reversed. COPYRIGHT: (C)2009,JPO&INPIT
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