Patent ID: 8789498

Claim:
An internal combustion engine comprising: a crankshaft; a crankcase supporting the crankshaft; a cylinder block connected to the crankcase and including a cylinder provided therein; a piston connected to the crankshaft via a connecting rod and located inside the cylinder so as to be movable in a reciprocating manner; a cylinder head superposed on the cylinder block so as to cover the cylinder, defining a combustion chamber together with the cylinder and the piston, and including an intake port and an exhaust port in communication with the combustion chamber; a cooling fan rotated together with the crankshaft; a shroud including an inner wall portion located laterally of at least one of a portion of the crankcase, a portion of the cylinder block and a portion of the cylinder head, and an outer wall portion arranged to cover the cooling fan, the inner wall portion, a portion of the crankcase, at least a portion of the cylinder block, and at least a portion of the cylinder head; and a suction port arranged to suction air and located in a region of the outer wall portion facing the cooling fan; wherein the inner and outer wall portions define a duct extending from the suction port to reach at least a portion of the cylinder block and/or at least a portion of the cylinder head; and when a cross section passing through a center of the crankshaft and extending parallel to an axis of the cylinder is viewed in a direction perpendicular to the cross section, a first end of the inner wall portion is located laterally of the crankcase, and a second end of the inner wall portion is located laterally of a region of the cylinder block closer to the cylinder head than a bottom dead center of the piston.