Simulation of composite titanium nitrite (TiN) coated internal combustion engine exhaust valve using ANSYS

Abstract

In Internal Combustion Engine, valves play a crucial role in the circulation of intake and exhaust gases. Although inlet valve is exposed to higher temperatures during combustion, its failure rate is less when compared with exhaust valve. This is because the inlet valve is cooled by fresh charge admitting into the cylinder. But exhaust valve is heated up by the enormous heat carrying flue gases. Hence it is more prone to failure and has become the focus of study. The exhaust valve undergoes mechanical and thermal loads when gases are circulated from the cylinder. The valve is exposed to these extreme high temperatures subjected to fatigue loads which cause failure of valve. The valves should possess good material properties at high temperatures i.e., higher hardness, hot hardness, higher thermal conductivities and high strength properties. It has been observed that the exhaust valve performance can be appreciably enhanced by using thin film Titanium coatings like Titanium Nitride (TiN), Titanium Carbide (TiC), Titanium Nitride (TiCN) based Titanium coatings. The Titanium based thin film coatings have high corrosion resistance, less wear rates due to cyclic loads, and higher thermal resistance. In the present work, the valve coated with TiN and uncoated IC engine exhaust valves, here poppet valve of four stroke two wheeler engine valve is chosen and simulated under both high temperature loads and mechanical loads using finite element analysis(FEA). The simulated results obtained are then compared for both coated TiN and uncoated valve. It indicates that the Titanium Nitrate (TiN) coated valve has low thermal resistance and less thermal and mechanical failure than uncoated valve. FEA simulated results of TiN coating on the valve and uncoated exhaust valves are analyzed and presented in the research article.