Design Analysis and Optimization of Piston and Determination of its Thermal Stresses Using CAE Tools

In I.C. Engine, piston is most complex and important part therefore for smooth running of vehicle piston should be in proper working condition. Pistons fail mainly due to mechanical stresses and thermal stresses. Analysis of piston is done with boundary conditions, which includes pressure on piston head during working condition and uneven temperature distribution from piston head to skirt. The analysis predicts that due to temperature whether the top surface of the piston may be damaged or broken during the operating conditions, because damaged or broken parts are so expensive and difficult to replace and generally are not easily available. The main purpose of the preliminary analyses presented in the book is to compare the behaviour of the combustion engine piston made of different type of materials under thermal load. FEA analysis is carried out using ANSYS software. Development of the FEA model is also presented. Geometrical CAD model of the piston is developed based on the actual engine piston of TATA MOTORS four stroke diesel engine. The piston is loaded by a temperature field inside it. Appropriate averaged thermal boundary conditions such as temperatures and heat fluxes were set on different surfaces of the FEA model. In this study, firstly, thermal analyses are investigated on a conventional diesel piston, made of structural steel for design 1. Secondly, thermal analyses are performed on optimized piston, made of aluminium alloy and titanium alloy material by means of using a commercial code, namely ANSYS. The proposed new material is characterized by a low density, high thermal conductivity, easy machinability, high reliability and very good recycling characteristics. The results obtained for the piston made of a new material are compared with those for the current standard material. The analysis is carried out to reduce the stress concentration on the upper end of the piston i.e. (piston head/crown and piston skirt and sleeve) so as to increase life of piston.