CYLINDER BLOCK

Two different systems of cooling water channels are provided in a cylinder block. The cooling water at a relatively low temperature is made to flow through a first cooling water channel, while the cooling water at a relatively high temperature is made to flow through a second cooling water channel. The first cooling water channel includes an exhaust-side water jacket that is located on an exhaust side with respect to a plurality of cylinders juxtaposed in a longitudinal direction of the cylinder block and is provided in the longitudinal direction along the plurality of cylinders. The second cooling water channel includes an intake-side water jacket that is located on an intake side with respect to the plurality of cylinders and is provided in the longitudinal direction along the plurality of cylinders.