Optimization of thermal barrier coatings in a single cylinder diesel engine using thermal analysis and genetic algorithm

Abstract

A significant portion of the energy produced by combustion inside an engine is rejected as heat. Though it is impossible to prevent heat rejection, reducing the amount of heat rejected will help to increase the useful energy. Low heat rejection engine is a solution to these problems as they supply designers with insulation properties. In the design of adiabatic engines, reducing heat rejection in cylinder requires the use of special type of insulation often referred to as thermal barrier coatings in the combustion chamber of the engine. This insulation especially on engine piston is considered as a solution for the reduction of unburned HC emissions caused by incomplete combustion with respect to crevice volume when engines start. The insulation layer in effect reduces the thermal conductivity and raises the oxidation of the unburned charge such that the metallic substrates are exposed to lower peak temperatures, thus reducing the thermal stress in engine components. In this work piston is modelled using CATIA V5R16. For analyzing the effects of insulation layer on the piston, thermal analysis is conducted using finite element method in ANSYS after applying thermal boundary conditions. By changing the coating thickness and performing thermal analysis on each coating thickness followed by the use of mathematical operations enables the optimization of piston coating thickness. This optimized coating thickness is validated using Genetic Algorithm.