Cylinder head for an internal-combustion engine with intake ducts having an air-deflecting projection

A cylinder head for an internal-combustion engine comprises, for each cylinder of the engine, at least one intake duct (2) extending from an inlet located at a lateral face (3) of the head down to an outlet cylindrical mouth (5) opening out on a bottom face (4) of the head, and an intake valve (8) associated with each intake duct (2). The outlet cylindrical mouth (5) is coaxial with the valve stem (10). The surface of the intake duct (2) has a longitudinal projection (13) for deflecting the flow of air that flows through the intake duct (2). The projection (13) is configured to provide a deflection of the air flow towards the two sides of the valve stem (10), so as to substantially reduce the quantity of air that hits the valve stem (10) directly. The projection (13) extends down to the outlet cylindrical mouth (5), so as to hinder a flow of air through an angular sector (14) of the cross-sectional area of the outlet mouth (5) which angular sector (14) faces towards the lateral face (3) of the cylinder head.