Thermal lining inside IC engine - consists of thin metal sheet over ceramic insulating material on surfaces subjected to heat

摘要

The engine piston (8) has its upper surface covered with a solld or powdered thermally insulating material (15). This is held in place by a thin sheet (14) of metal which is brought down (16) round the sides of the piston and welded or soldered to it. The insulation (15) e.g. foil or ceramic is sealed by the sheet (14) and is kept at a pressure below the minimum pressure in the cylinder. This ensures that the pressure in the cylinder keeps the metal sheet tight to the piston and insulation. Thin sheet with a low thermal capacity can thus be used. A similar construction is applied to other surfaces in contact with hot gases such as the cylinder walls, exhaust valve and the exhaust passage in the cylinder head.