Simulation algorithm for piston ring dynamics

Abstract

Piston ring dynamics play important roles on the lubricant characteristic of reciprocating engines which lead to the consequences of engine wear and vast amount of lubricating oil consumption. Due to the complexity of motion, a study of motions and effects of the piston ring is mostly conducted in a simulation program. This paper shows a theoretical work and a new simulation algorithm of the 3D piston ring motions. The simulation concept is to determine the positions of the piston ring, which are the solutions of the Newton and Euler equations. Well known models like mixed lubrication model, asperity contact model, and blow-by/blow-back flow model were used in this study. The new simulation algorithm consists of four processes: construction of calculation nodes, use of finite different method, determination of the non-linear equation system, use of parallel computational technique. Two sets of the experimental studies were conducted for simulation verification. First, the gas flows through the static rectangular piston ring pack. Second, the blow-by/blow-back gas flow through the piston ring pack of a single cylinder diesel engine. The good agreement between the experimental and simulation results indicates that the developed simulation program can illustrate the piston ring motions and blow-by/blow-back flow. Since there is no algebraic equation in the ring profile, the presented simulation technique is suitable for the complicated surface of the piston and piston rings.