INTERNAL COMBUSTION ENGINE INCLUDING COOLANT PASSAGE

PROBLEM TO BE SOLVED: To provide an internal combustion engine including a coolant passage having a simple structure.SOLUTION: An internal combustion engine 1 includes: an internal combustion engine body 2; an exhaust pipe 21 fastened to the internal combustion engine body; a body coolant passage 31 having a coolant inlet 36 and a coolant outlet 37 and provided at the internal combustion engine body; an exhaust pipe coolant passage 38 provided at the exhaust pipe; a supply passage 33 connecting the body coolant passage with the exhaust pipe coolant passage and in which a coolant flows from the body coolant passage to the exhaust pipe coolant passage; and a reflow passage 34 connecting the body coolant passage with the exhaust pipe coolant passage and in which the coolant flows from the exhaust pipe coolant passage to the body coolant passage.SELECTED DRAWING: Figure 9 【課題】冷却水路の構成が簡素な内燃機関を提供する。【解決手段】内燃機関本体２と内燃機関本体に締結された排気管２１とを備える内燃機関１において、冷却水注入口３６及び冷却水排出口３７を有し内燃機関本体に設けられた本体冷却水路３１と、排気管に設けられた排気管冷却水路３８と、本体冷却水路と排気管冷却水路とを接続し冷却水が本体冷却水路から排気管冷却水路へ流れる供給路３３と、本体冷却水路と排気管冷却水路とを接続し冷却水が排気管冷却水路から本体冷却水路へ流れる還流路３４とを備える。【選択図】 図９