Investigation of the effect of different thermal barrier coatings on performance and emission characteristics of di diesel engine

Abstract

The automotive industry today focuses on reducing the effects of global warming, supposedly caused by engine exhaust emissions. The release of greenhouse gases into the atmosphere due to the combustion of fossil fuels is associated with global warming. The increased fuel costs, a rapid depletion of fossil fuel reserves, increasing demand and environmental issues are the main reasons to lead the engine manufacturers towards diverse design concepts. Higher fuel consumption, higher emissions and poor component life are the major limitations of the diesel engine. The thermal insulation of the combustion chamber of the engine can overcome these limitations. At high temperatures, the piston can expand and will lead the engine to seize. These phenomena can be reduced by applying ceramic coatings on the piston. The Thermal Barrier Coatings (TBC) on the piston surface can significantly reduce the heat transfer and use the heat energy for maximum work output. TBC are applied on the piston crown to minimize the in-cylinder heat loss to cooling systems which enhances the higher energy conversion without significant changes in the engine. It can extend the ability of the engine to operate at high temperatures. It also enhances the efficiency of the engine by operating at higher temperatures with significant reduction in harmful exhaust emissions. For this purpose, this study developed two different types of coatings in order to apply on the engine piston crown using the plasma spray technique. The first piston utilized for this study is coated with bond material (first layer) of 200 and#956;m thickness of AT13 (87 % Al2O3 and 13 % TiO2). The second layer is made with 300 and#956;m thickness of MgZrO3 (92 % ZrO2 and 8 % MgO) over the first layer. newline