Blow-by gas recirculation structure for internal combustion engine

摘要

A blow-by gas recirculation structure includes a cylinder head (3) including an intake manifold mounting surface (3d) and a cylinder block mounting surface (3e) with a first intake passage (21A) extending between a first intake opening formed in the intake manifold mounting surface (3d) and a first intake port (10) formed in the cylinder block mounting surface (3e), and a second intake passage (21B) extending between a second intake opening formed in the intake manifold mounting surface (3d) and a second intake port (10) formed in the cylinder block mounting surface (3e). The cylinder head (3) further includes at least one blow-by gas passage (22) for recirculating blow-by gas to the first intake passage (21A). The intake manifold mounting surface (3d) has at least one enlarged recess (25a) fluidly connected between the blow-by gas passage (22) and the first intake passage (21A), the enlarged recess (25a) being disposed between the first and second intake openings and at least partially aligned with centers of the first and second intake openings.