Patent ID: 7739989

Claim:
A valve-operating mechanism for an internal combustion engine having a cylinder head, a combustion chamber, and intake and exhaust ports, comprising: intake and exhaust valves adapted to be disposed in the cylinder head for respectively opening and closing the intake and exhaust ports which are designed to communicate with the combustion chamber, each of the intake and exhaust valves being configured as dual valves having an outer valve and an inner valve, the outer valve having an inner valve aperture extending axially thereof, the inner valve being movably fitted in the inner valve aperture, the outer valve having an inner channel that allows communication between the combustion chamber and the intake and exhaust ports, the inner channel being opened and closed by the inner valve; and valve control members for controlling the opening and closing of the outer valve and inner valve, the valve control members, at least during scavenging, simultaneously closing the outer valves of the intake and exhaust valves to produce a non-overlapping state, and simultaneously opening the inner valves of the intake and exhaust valves to produce an overlapping state, wherein the valve control members respectively opening the inner valve and the outer valve of one of the intake and exhaust valves are rotatable on a same shaft.