NUMERICAL ANALYSIS OF THERMAL DISTRIBUTIONS IN ALUMINUM ENGINE CYLINDERS INFLUENCED BY ALUMINA CERAMIC COATINGS

Alumina ceramic coatings deposited on cylinder bores can achieve weight reduction of automobile engine blocks and improve wear resistance. However, they also attenuate the heat transfer from engine blocks to coolants due to their low thermal conductivities. A two-dimensional transient finite element thermal model has been developed to analyze the effect of the heat transfer on the temperature distributions of the cylinders. Also, the temperature differences induced by the alumina ceramic coatings were predicted, where the oxide coatings were produced by the plasma electrolytic oxidation process. It was found that the higher the engine in-cylinder temperature, the larger the temperature difference.