Profile Design of a Two-piece Piston Skirt for Internal Combustion Engine

Abstract

Ensuring reliable engine operation with minimal friction losses is one of the primary design tasks for a piston design. One of the effective ways to solve this problem is piston skirt profiling. Profiling is aimed at creating conditions for fluid friction in the “piston skirt-cylinder” interface with minimal mounting clearances. We present a mathematical model for studying the influence on the hydrodynamic characteristics of friction and the dynamics of the movement of the piston of the main parameters characterizing the design of the details of the crank mechanism. This model includes a coupled solution of interrelated problems: determining the characteristics of the transverse movement of the piston, the deformation of the piston skirt under thermal and mechanical loads, and the calculation of the hydrodynamic forces acting from the oil layer in the fit. The results are obtained for a two-piece piston with a diameter of 130 mm. We study the influence of the profile of the two-piece piston skirt on the hydrodynamic characteristics and the transverse movement of the piston is studied and present the results for the considered design. Lastly, we give recommendations for profiling.