Cylinder head structure of internal combustion engine

Claim 1

A V-type internal combustion engine comprising an elongated cylinder block having a pair of cylinder banks arranged in a substantially V-shape with a central space defined therebetween, each of said pair of cylinder banks defining a plurality of cylinder bores, each bore having a longitudinal axis; a pair of cylinder head assemblies affixed to said cylinder banks, respectively, each of said cylinder head assemblies having a plurality of combustion chambers, each chamber opening into one of said cylinder bores of its associated cylinder bank, intake and exhaust ports communicating with each of said combustion chambers, said intake port being located on one side of said longitudinal axis of its associated cylinder bore closer to said central space and said exhaust port being located on the opposite side of said longitudinal axis remote from said central space, intake and exhaust poppet valves for opening and closing said intake and exhaust ports, respectively, said intake and exhaust valves each having an upwardly projecting, elongated stem, a spark plug located between said intake and exhaust valves and having a lower end communicating with said combustion chamber, a valve mechanism chamber in said cylinder head assembly above said combustion chambers, valve operating mechanism disposed in said valve mechanism chamber, said valve stems projecting upwardly into said valve mechanism chamber and being connected to said valve operating mechanism for operation thereby, said valve operating mechanism comprising an elongated, rotatable camshaft disposed in the upper portion of said valve mechanism chamber for rotation about an axis extending lengthwise of said cylinder block, the axis of rotation of said camshaft being offset laterally from the longitudinal axis of said stem of said intake valve in a direction toward said central space of said cylinder block, first and second cams mounted on and rotatable with said cam shaft, an exhaust valve rocker shaft disposed in said valve mechanism chamber substantially between the upper ends of said stems of said intake and exhaust valves, said exhaust valve rocker shaft extending generally parallel with said cam shaft, a first rocker mounted at an intermediate part thereof on said exhaust valve rocker shaft, said first rocker having a first arm which projects in a direction toward said central space, said first arm having a free end slidably engaged with said first cam, said first rocker having a second arm which projects in a direction away from said central space and toward said stem of said exhaust valve, said second arm having a free end drivingly coupled to the upper end of said stem of said exhaust valve so that rotation of said camshaft will open and close said exhaust valve, an intake valve adjuster disposed in said cylinder head assembly at a location offset laterally from the longitudinal axis of said stem of said intake valve in a direction toward said central space, a second rocker having a single arm which is pivotally supported at one end thereof on said intake valve adjuster and is drivingly coupled at the other end thereof to the upper end of said stem of said intake valve, said second cam being maintained in sliding engagement with said second rocker between said ends of said arm thereof so that rotation of said camshaft will open and close said intake valve, said exhaust valve and said spark plug being arranged to extend almost parallel to the longitudinal axis of their associated cylinder.