ENGINE

To efficiently transfer and recover heat generated in a combustion chamber to an axial direction of a cylinder bore wall.SOLUTION: An engine 1 includes a cylinder block 5 having a cylindrical cylinder liner 51 (cylinder bore wall). A water jacket 65 (heat recovery part) is provided on an outer periphery of an upper end of the cylinder liner 51. The cylinder liner 51 includes an outer peripheral part 61 having thermal conductivity anisotropy in which thermal conductivity in an axial direction is larger than thermal conductivity in a radial direction, and an inner peripheral part 60 adjacent to an inner side of the outer peripheral part 61 and facing a combustion chamber 10 and having thermal conductivity in the radial direction larger than the thermal conductivity in the radial direction of the outer peripheral part 61.SELECTED DRAWING: Figure 2 【課題】燃焼室で発生する熱をより効率良くシリンダボア壁の軸方向に輸送し回収する。【解決手段】エンジン１は、円筒状のシリンダライナ５１（シリンダボア壁）を有するシリンダブロック５を備える。シリンダライナ５１の上端部の外周にはウォータジャケット６５（熱回収部）が備えられる。シリンダライナ５１は、軸方向の熱伝導率が径方向の熱伝導率よりも大きい熱伝導異方性を有する外周部６１と、この外周部６１の内側に隣接して燃焼室１０に臨み、径方向の熱伝導率が外周部６１の径方向の熱伝導率よりも大きい内周部６０とを含む。【選択図】図２