Piston Design for High Combustion Pressures and Reduced Heat Rejection to Coolant 820505
As an alternative to the standard aluminum piston construction a gallery cooled one piece (so called Monobloc) spheroidal graphite cast iron piston has been developed for use in heavy duty Diesel engines. It allows for 3000 psi (207 bar) combustion pressure. Due to about 180 F (100°C) higher average crown surface temperature it takes less heat from the combustion chamber. A further reduction of the heat loss to the coolant can be obtained by an uncooled, composite piston. Based on a 2-dimensional FEM analysis a reduction of 60% is predicted for a design with metal top. A ceramic top does not promise a significantly greater effect.