Internal combustion engine for vehicle

Abstract

In an internal combustion engine for a vehicle in which a cylinder unit is arranged such that the axis line thereof is directed toward the substantially front of the vehicle traveling direction, traveling air is guided to a plug hole with a simple structure. An engine 20, in which a cylinder unit 22 accommodating a piston in a reciprocating manner is arranged in such a manner that the axis line C of the cylinder unit is directed toward the substantially front of the vehicle traveling direction, includes a first air intake guide 78 which is provided on the ground surface side of a cylinder head 24 of the cylinder unit 22 and which guides traveling air toward a first plug hole 66, and a second air intake guide 79 which is provided on the ground surface side of a head cover 25 of the cylinder unit 22 and which guides the traveling air toward the first air intake guide 78.