HEAT EXCHANGER

摘要

An exhaust gas secondary flow path (20c) is formed between cooling passages (20d, 20e) such that heat exchange can take place between exhaust gas and a cooling medium from both the inside and the outside. The space of this exhaust gas secondary flow path (20c) has wide areas and narrow areas which repeatedly alternate in the circumferential direction. The cross-sectional shape of the exhaust gas secondary flow path (20c) at a wide area is asymmetrical with respect to an axis (Za).