Thermal Analysis of a Plasma Sprayed Ceramic Coated Diesel Engine Piston

In this paper, we evaluated performance-enhancing modifications of the coating surface for a diesel engine piston. Thermal barrier coatings were applied to insulate the substrate from higher operating temperatures. A top coat (0.4 mm thick) and bond coat (0.1 mm thick) were applied to the aluminum alloy piston crown for analysis. Yttria-stabilized zirconia was used for the top coat and NiCrAl alloy was used for the bond coat. A static thermal analysis was performed to determine the temperature distribution at the top and substrate surface. Holes (2, 3, 4 and 5 mm in diameter) were created on the surface of the coating and the temperature distribution was analyzed. Comparison of the results with those of an uncoated piston revealed that the temperature of the substrate was decreased while temperature of the top surface was increased. Decreasing the temperature of the substrate reduced thermal fatigue while increasing the temperature of the top surface reduced fuel consumption thus leading to an overall improvement in performance. The lowest substrate temperature obtained was for a coated surface with 2 mm diameter holes, whereas the highest top surface temperature obtained was for a coated surface with 5 mm diameter holes.