ENGINE COMBUSTION CHAMBER STRUCTURE AND METHOD FOR PRODUCING THE SAME

An object of the present invention is to enhance the thermal efficiency of an engine, to provide a film having low thermal conductivity and low heat capacity and being free from separation, drop-off and the like and excellent in durability and reliability. According to the present invention, an engine combustion chamber structure, wherein an anodic oxide film having a thickness of from more than 20 µm to 500 µm and a porosity of 20% or more is formed on the inner surface of the engine combustion chamber, and a manufacturing method thereof are provided.