Heat exchange device

Abstract

A heat exchange system is provided that includes an evaporator () that carries out heat exchange between exhaust gas discharged from an exhaust port (B) and water, exhaust gas passages () on the upstream side in the direction of flow of the exhaust gas being disposed on the radially inner side, an exhaust gas passage () on the downstream side being disposed on the radially outer side, and an oxygen concentration sensor cooling portion () for cooling a mounting section of an oxygen concentration sensor () facing the exhaust gas passage () on the most upstream side being positioned on the radially outer side of the exhaust gas passage (). Water is supplied separately to a water passage (W) of the evaporator () and a water passage (W) of the oxygen concentration sensor cooling portion (), and the water passage (W) of the evaporator () is arranged so that the direction of flow of the water is opposite to the direction of flow of the exhaust gas. It is thereby possible to improve the waste heat recovery efficiency of the evaporator () that carries out heat exchange between the exhaust gas of an internal combustion engine and water and, in particular, to minimize the escape of heat via the oxygen concentration sensor () for detecting the condition of the exhaust gas.