Operation-Cylinder Head
WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.
The cylinder head closes the combustion chamber allowing the pistons to compress the air fuel mixture to the correct ratio for ignition. The valves located in the cylinder head open and close to either allow clean air into the combustion chamber or to allow the exhaust gases out, depending on the stroke of the engine.