| 摘要 |
PROBLEM TO BE SOLVED: To improve heat exchange efficiency in a wide flow range from a low flow rate to the high flow rate by axially forming two-dimensional projections in the inside face of a cylindrical tube member at prescribed intervals, inserting a spiral member in the inside of the tube member, and fitting it to the secondary projections. SOLUTION: A tube member 21 for distributing ERG gas is formed of stainless steel, etc., into a cylindrical shape and two-dimensional projections 23 are integrally formed axially in its inside at prescribed interval apart from each other. A spiral member 25 inserted inside the tube member 21 has a cross-shaped section and formed into a spiral shape at pitches of prescribed intervals in the tube length direction. The spiral member 25 is fitted to the two-dimensional projections by nickel brazing. This constitution can accelerate the EGR gas flow by the spiral member 25, disturb the EGR gas in flowing across the two-dimensional projections 23, and improve the heat exchange efficiency in a wide range from the low flow rate to the high flow rate.
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