EGR COOLER

摘要

PROBLEM TO BE SOLVED: To improve efficiency in heat exchanging of an EGR cooler by bringing exhaust gas into even-contact with the inner peripheral surface of a tube. SOLUTION: An EGR cooler is provided with a tube 3 and a shell 1 for surrounding the tube 3, and heat-exchanges exhaust gas 10 and cooling water by allowing the exhaust gas 10 to flow in the tube 3. A plurality of spiral protrusions 11, 12 are formed on the inner peripheral surface of the tube 3.