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Abstract

This study examines the behavior of thermal stress and deformation in piston and cylinder head assemblies of internal combustion engines using numerical simulation techniques. Computational Fluid Dynamics (CFD) is employed to investigate the influence of varying thermal loads on the structural response and durability of these critical engine components. In our numerical investigation, we aimed to understand the role of temperature differences in thermal stresses and deformations within piston-cylinder head setups. These rates are indicative of the severe thermal stresses experienced by the material, which are significantly higher than typical rates observed in standard operating conditions. Results show that peak crown temperatures reach 320–400 °C, producing von Mises stresses of 150–220 MPa, which are concentrated at the ring-land region, leading to localized plastic strains of 0.1–0.3%. Radial skirt expansion of 50–150 μm and a 10–30 % reduction in contact pressure at the liner were also predicted. Parametric studies demonstrated that increasing crown thickness and enhancing cooling can lower peak stresses by 10–20%, while stronger alloys increase the allowable stress margin by 30%. A combination of these temperature variations, the materials’ characteristics, and the gaps in assembly all contribute to hotspots of stress and bending, especially in zones subjected to sharp thermal shifts, such as the top of the piston and the walls surrounding the combustion area. Beyond that, this work lays a solid groundwork for refining future engine layouts and offers practical guidance for extending the lifespan and improving the efficiency of internal combustion engines.

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