Three-Dimensional Multi-phase Physics-Based Modeling Methodology to Study Engine Cylinder-kit Assembly Tribology and Design Considerations- Part I
Understanding cylinder-kit tribology is pivotal to durability, emission management, reduced oil consumption, and efficiency of the internal combustion engine. This work addresses the understanding of the fundamental aspects of oil transport and combustion gas flow in the cylinder kit, using simulation tools and high-performance computing. A dynamic three-dimensional multi-phase, multi-component modeling methodology is demonstrated to study cylinder-kit assembly tribology during the four-stroke cycle of a piston engine. The percentage of oil and gas transported through different regions of the piston ring pack is predicted, and the mechanisms behind this transport are analyzed. The velocity field shows substantial circumferential flow in the piston ring pack, leading to blowback into the combustion chamber during the expansion stroke. Oil initialization and management of a continuous supply of oil throughout the cycle are observed to govern how much oil would be lost to the crankcase and combustion chamber. The calculated blow-by results agree with the results of a quasi-one-dimensional cylinder-kit analysis system of programs known as CASE (Cylinder-kit Analysis System for Engines). Implementing this three-dimensional methodology leads to a better understanding of cylinder-kit fluid flow physics. The findings presented in this work pave the way to further the ongoing development effort of optimum cylinder kit designs with controlled gas leakage, low oil consumption, and low cylinder kit friction.