Design and thermal analysis of aluminium alloy piston using finite element method

Abstract

Piston is one of the most important moving components in an internal combustion engine. Because of its proximity to the burning flames in the engine, its material must be able to withstand the high temperature in the engine. There are some known materials which are used for piston design of which aluminium alloy is part. The known aluminium alloys for piston design have been classified into three main categories, namely: eutectic, hypereutectic and special eutectic aluminium alloys. The main objective of this research was to examine the suitability of an aluminium alloy which is not part of the three classifications to design a piston for an internal combustion engine. The piston was modelled using Autodesk Inventor 2017 software. The modelled piston was then imported into Ansys for further analysis. Static structural and thermal analysis were carried out on the piston of four different materials namely: Al 413 alloy, Al 384 alloy, Al 390 alloy and Al332 alloy to determine the total deformation, equivalent elastic strain, equivalent Von Mises stress, maximum principal stress and the safety factor. It was found that, aluminium 332 alloy piston deformed less compared to the deformations of aluminium 390 alloy piston, aluminium 384 alloy piston and aluminium 413 alloy piston. The induced Von Mises stresses in the pistons of the four different materials were found to be far lower than the yield strengths of all the materials. Hence, all the selected materials including the implementing material have equal properties to withstand the maximum gas load. All the selected materials were observed to have high thermal conductivity enough to be able to withstand the operating temperature in the engine cylinders. It was found that the thermal conductivitie of the materials were far higher than the induced total heat flux. Hence, all the pistons made with the four different materials will be able to withstand the operating temperature in engine cylinders. It was therefore concluded that, all the pistons made with the four different materials have equal qualities to withstand the fatigue stress induced in the pistons.