Techniques for Engine Cooling Using Supercritical Fluids and a Combustion Engine System Implementing the Same

Combustion engines, and more particularly, integrating a supercritical fluid passageway into a cylinder head and/or cylinder block of an engine, and preferably, a combustion engine. Both a combustion engine system and a method of cooling a cylinder head in an internal combustion engine, utilizing supercritical fluid, are disclosed.