Study of piston thermo-elastic behaviour under thermomechanical solicitations

Abstract

The piston material choice is a major factor in the design stages of internal combustion engines for its importance to improving the durability and the operation reliability during the piston life cycle. Indeed, even as many researches have been conducted for a long time to improve the piston performances in the diesel engine, considerable numbers of piston damages still significantly occur. This research work is an assessment by the finite element method (FEM) of a set of piston materials for the purpose of being used in a direct injection diesel engine. The main objective is to predict stresses concentrations and the clearance between the piston and the cylinder (to avoid metal-metal adhesion) from thermomechanical solicitations. The stresses and deformations are evaluated in a 3D piston model by using ABAQUS software. A first assessment step is performed in heat convection/conduction modes to determine the temperature distribution. Then, this last one is coupled to the pressure field resulting from the gas combustion in order to compute stresses and the magnitude displacement. The obtained results show that the austenitic steel AS12UNG with fibre-reinforced possess low thermomechanical stress values compared to other material types. This material allows a minimum failure risk and therefore contributes to the enhancement of the piston design.