Parameterization and FEA Approach for the Assessment of Piston Characteristics

Elastohydrodynamic lubrication, piston dynamics and friction are important characteristics determining the performance and efficiency of an internal combustion engine. This paper presents a finite element analysis on a production piston of a gasoline engine performed using commercial software, the COSMOSDesignStar, and a comprehensive cylinder-kit simulation software, the CASE, to demonstrate the advantages of using a reduced, parameterized model analysis in the assessment of piston design characteristics. The full piston model is parameterized according to the CASE specifications. The two are analyzed and compared in the COSMOSDesignStar, considering thermal and mechanical loads. The region of interest is the skirt area on the thrust and anti-thrust sides of the piston. The results are compared with the CASE results and a discussion follows on how the piston model simplification approach can help significantly reduce computation time without losing valuable information on piston performance. The piston characteristics are evaluated with the reduced model thus allowing for a faster analysis and optimization than would be possible with a complete FEA piston model. The results demonstrate that the simplified model agrees qualitatively and quantitatively with the full model; the maximum temperature and calculated distortions on the skirt face are comparable. Computation time difference between the full model and simplified model is not significant for a single analysis; however it becomes very significant when a cyclical analysis is performed at every crank angle degree.