Patent ID: 7044097

Claim:
A cylinder head for mounting on a cylinder of a combustion engine, the cylinder head comprising a guideway in which is located a rotatable valve comprising a fluid port operable to effect fluid communication between a cylinder and a fluid manifold in the guideway, whereby rotation of the valve effects alignment of the fluid port with the combustion chamber of a cylinder to enable fluid flow between the valve and a cylinder, and wherein the cylinder head further comprises a seal which, in use, is movable from a first, non-sealing position in which the seal is biased away from the valve, and a second, sealing position in which the seal is biased onto the valve by gaseous pressure from within a cylinder, and wherein the seal is located in a port or duct in the cylinder head which at one end opens into a cylinder when the cylinder head is mounted on a cylinder, in use, and at the other end opens into the guideway of the cylinder head.