Modeling for Design Optimization of Piston Crown Geometry Through Structural Strength and Lubrication Performance Correlation Analysis

Abstract

Piston subsystem is subjected to very complex but dynamic forces. Such forces include combustion gas force, inertial dynamics forces, lubricating action/damping forces, contact friction forces to name a few. Further, piston ring mounted in piston in addition to these forces experiences out ward springing action inside engine mounting due to inherent elasticity. To evaluate the strength of reciprocating piston, the simultaneous effect of all these forces should be considered, while simulating through finite element method. With effect of all these forces, the currently considered piston of Gray Cast Iron, aluminum alloy and Metal-Metric-Composite (Si-C) are given four different crown shapes for optimization of material and crown geometry for better strength. The rings mounted are considered to be coated with Nickasil. The combined numerical simulation for contact and finite element simulation of structural strength and their correlation suggest many important outcomes. Von-Misses stress is maximum in case of type-B Al-alloy crown, while it is minimum in case of type-C SiC metal matrix piston.