THERMAL INSULATOR OF CYLINDER BORE WALL, INTERNAL COMBUSTION ENGINE AND AUTOMOBILE

PROBLEM TO BE SOLVED: To provide an internal combustion engine which is high in the uniformity of a wall temperature of a cylinder bore wall.SOLUTION: In a thermal insulator of a cylinder bore wall which is arranged in a middle lower part of a grooved cooling water flow passage of a cylinder block of an internal combustion engine, and thermally insulates a part of a bore wall out of the bore walls of all cylinder bores, the thermal insulator is composed of: a thermal insulation rubber member which contacts with a wall face of one cylinder bore out of all the wall faces at the cylinder bore side of the middle lower part of the grooved cooling water flow passage, or contacts with the wall face over the two or more cylinder bores; a metal base body member to which the thermal insulation rubber member is fixed; and an energization/back-face side flow suppression member which is fixed to a back face side of the metal base body member, energizes the metal base body member so that the metal base body member presses the thermal insulation rubber member toward the wall face at the cylinder bore side of the middle lower part of the grooved cooling water flow passage, and suppresses a flow of cooling water between the metal base body member and the wall face at a side opposite to the wall face at the cylinder bore side of the middle lower part of the grooved cooling water flow passage. One or more of the energization/back-face side flow suppression members are arranged in each bore part of the metal base body member.SELECTED DRAWING: Figure 4 【解決課題】シリンダボア壁の壁温の均一性が高い内燃機関を提供すること。【解決手段】内燃機関のシリンダブロックの溝状冷却水流路の中下部に設置され、全シリンダボアのボア壁のうちの一部のボア壁を保温するためのシリンダボア壁の保温具であり、溝状冷却水流路の中下部のシリンダボア側の全壁面のうちの１つのシリンダボアの壁面又は２つ以上のシリンダボアに亘る分の壁面に接触する保温用ゴム部材と、該保温用ゴム部材が固定される金属基体部材と、該金属基体部材の背面側に固定され、該溝状冷却水流路の中下部のシリンダボア側の壁面に向かって、該金属基体部材が該保温用ゴム部材を押し付けるように付勢すると共に、該金属基体部材と溝状冷却水流路の中下部のシリンダボア側の壁面とは反対側の壁面との間の冷却水流れを抑制する付勢兼背面側流れ抑制部材と、からなり、該付勢兼背面側流れ抑制部材が、該金属基体部材の各ボア部毎に、１つ以上付設されていること、を特徴するシリンダボア壁の保温具。【選択図】図４