US Patent 7559302 Thermally insulating element for an engine valve assembly

A cylinder head assembly for an internal combustion engine including a cylinder head at least partially defining a flow path through the engine, including an intake port, an exhaust port, and a combustion chamber disposed between the intake port and the exhaust port. A valve is coupled to the cylinder head and movable relative to the cylinder head to selectively open the combustion chamber to one of the intake port and the exhaust port. A valve spring is positioned between the valve and the cylinder head and biases the valve to a closed position. A thermally insulating washer is positioned between the cylinder head and the valve spring.