Temperature and Thermal Stress Analyses of a Ceramic-Coated Aluminum Alloy Piston in A Diesel Engine

The aim of this work is to determine both temperature and thermal stress distributions in a plasma sprayed magnesia-stabilized zirconia coating on an aluminum piston crown to improve the performance of a diesel engine. The coating is done on the piston crown to the extent of 0.2 to 1.6 mm coating thickness with magnesia zirconia excluding the bond coat layer. Effects of the coating thickness on temperature and thermal stress distributions are investigated, including comparisons with results from an uncoated piston by means of the finite element analysis. Temperature and thermal stress analyses are performed for various coating thicknesses from 0.2 to 1.6 mm excluding the bond coat layer. In the analysis a quarter of the piston model is used for various conditions an uncoated piston crown and a ceramic-coated piston crown and the boundary conditions are applied to solve the field equations using ANSYS WORKBENCH15 FEA software. Temperature at the coated surface is significantly higher than that of the uncoated piston. It is observed that the coating surface temperature increases with coating thickness by decreasing rate. The higher combustion chamber temperature provided by means of coating results in the better thermal efficiency of the engine. It also provides for a reduction in the substrate surface temperature. The normal stress on the coated surface decreases with increasing coating thickness. Maximum normal stress occurs on the bond coat surface.