EGR COOLER

PROBLEM TO BE SOLVED: To provide an EGR (Exhaust Gas Recirculation) cooler in which the occurrence of crack during temperature rise thereof is suppressed and which furthermore enables the cooling efficiency thereof to be improved.SOLUTION: An EGR cooler (5) includes a metal housing (10), and a ceramic heat exchange body (20) arranged inside the housing. The heat exchange body has: an inclined layer (21) which is a porous ceramic layer having a lower pore density as extending inside and which is arranged in the outer periphery part of the heat exchange body; a dense layer (22) which is a ceramic layer having a pore density lower than that of the inclined layer and which is arranged inside the inclined layer; and a gas passage part (23) through which EGR gas passes and which is arranged inside the dense layer. The housing and the heat exchange body are joined using solder material with which the inclined layer is impregnated. In the inclined layer, a refrigerant passage (24) is provided through which refrigerant passes. 【課題】温度が上昇したときの亀裂の発生を抑制しつつ冷却効率を向上させることができるＥＧＲクーラを提供する。【解決手段】ＥＧＲクーラ（５）は、金属製のハウジング（１０）と、ハウジングの内側に配置されたセラミック製の熱交換体（２０）と、を有し、熱交換体は、内側に向うほど孔の密度が低くなる多孔質のセラミック層である傾斜層（２１）を熱交換体の外周部に有し、傾斜層よりも孔の密度が低いセラミック層である緻密層（２２）を傾斜層の内側に有し、ＥＧＲが通過するガス通過部（２３）を緻密層の内側に有し、ハウジングと熱交換体とは、傾斜層に含浸したロウ材によって接合され、傾斜層には、冷媒が通過する冷媒通路（２４）が設けられている。【選択図】図１