Analyses of Temperature and Thermal Stresses of a Ceramic-Coated Diesel Engine Valve

Abstract

This work is carried out to detect temperature, thermal strain and stress variation in plasma-sprayed zirconia-coated valve head and further to enhance the function of a diesel engine. Impacts of thermal barrier coating (TBC) thicknesses on engine valve are analyzed, and additionally, examinations with results from an uncoated valve have been prepared. Temperature, thermal strain and stress investigation are performed for different thicknesses of zirconia coating, which varies from 0.2 to 1.0 mm. It was found that the valve head where coating was done is considerably having high temperature as compared to the uncoated valve head surface and also found that the coated surface temperature rises with coating thickness by declining rate. Result shows that the highest temperature expanded up to 33.81% for 1.0 mm thick TBC as compared to the traditional uncoated valve. With the help of TBC, temperature level is increased in combustion chamber, which enhanced the thermal efficiency of the engine and declined the substrate temperature. The average stress on the coated surface increases with increasing coating thickness up to a certain limit. Maximum stress achieves on the top coat surface, and approximately, its value is 1.5 times higher than the substrate. Additional benefits include protection of component metal surface from thermal distortion and reduced cooling necessities.