Water-cooled internal combustion engine

Abstract

A water-cooled internal combustion engine E is provided with a cylinder block water jacket J, a cylinder head water jacket J, and an exhaust manifold passagein which exhaust gas discharged from combustion chambersthrough exhaust portscollects. The exhaust manifold passageis formed only in a cylinder head. The exhaust gas that has collected in the exhaust manifold passageis discharged through an exhaust outlet of the exhaust manifold passagefrom a cylinder headinto an exhaust passageformed in a cylinder block C. The exhaust manifold passageis surrounded by the cylinder head water jacket J, the cylinder block water jacket Jand a discharge water jacketfor carrying cooling water from the cylinder head water jacket Jand the cylinder block water jacket Jto the outside of the engine body. The engine E provided with the exhaust manifold passagedoes not require any assembling work for sealing the exhaust manifold passageand hence the cost of the combustion engine E can be reduced. A wall defining the exhaust manifold passagecan be efficiently cooled by the cooling water that flows through the water jackets.