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The materials commonly employed in the automotive industry are various and depend on the specific application field. For what concern the internal combustion engines the choice is guided by the thermomechanical performance required, technological constraints and production costs. Actually, for high-performance engines, steel and aluminium are the most common materials selected for the piston and the cylinder liner manufacturing. This study analyses the effect of possible material choice on the interaction between piston and cylinder liner, via Finite Element analyses. A motorcycle engine is investigated considering two possible pistons: one (standard) made of aluminium and one made of steel. Similarly, two possible cylinder liners are considered, the original one made of aluminium and a different version made of steel obtained by simply thinning the aluminium component in order to obtain two structurally equivalent components.

Modern high performance engines are usually characterized by high power densities, which lead to high mechanical and thermal loadings acting on engine components. In this scenario, aluminum may not represent the best choice for piston manufacturing and steel may be considered as a valid alternative. In this article, a methodology involving optimization techniques is presented for the design of an internal combustion engine piston. In particular, a design strategy is preliminary investigated aiming at replacing the standard aluminum piston, usually manufactured by forging or casting, with an alternative one made of steel and manufactured via an Additive Manufacturing process. Three different loading conditions are employed for the topology optimizations setup. Optimization results are then interpreted and the various structural features of the steel piston are designed starting from the density distribution contour plots.

Advances in modern engines are becoming more and more challenging. The intense increase of thermal and mechanical loads, as a consequence of a higher power density, requires the improvement of the main couplings encountered between moving engine components. In this scenario, the cylinder liner/piston coupling plays a crucial role in terms of engine performance and durability, especially with regards to pollution emission and friction reduction. In this paper a numerical methodology is proposed, which aims at simplifying the Finite Element evaluation of the cylinder liner bore distortion in an eight-cylinder V-type four stroke turbocharged engine. Finite Element simulations are performed to obtain a virtual approval of the component geometry, in advance with respect to the component manufacturing. In particular, preliminary Finite Element analyses are developed which accurately follow the experimental procedure, where a single engine bank is coupled with a simplified test engine head.