ThreeDimensional Model of Lubrication and （润滑和三维模型）.pdf

Three-Dimensional Model of Lubrication and Dynamics for The Piston Ring-Pack in Internal Combustion Engines (Ph.D. Proposal) by Liang Liu Sloan Automotive Lab, MIT Thesis Supervisor: Dr. Tian Tian 1. Motivations Development of engine power cylinder system, namely, piston, piston rings, and liner are driven by three factors. First, power cylinder system directly contributes to engine oil consumption, friction, and gas leakage called blow-by, all of which need to be minimized to meet engine performance requirements. Second, new engine development with a trend of higher specific power and downsizing engines constantly presents challenges to the power cylinder system design for fitting into new environment. Finally, reducing engine development lead time and minimizing amount engine tests are critical to engine and component manufacturers and thus better understanding of the power cylinder system with physically based models becomes necessary. Lubrication and dynamics of piston ring pack are of great importance to the engine performance, as they play determining roles for engine oil consumption and ring friction that is a significant portion of the total engine friction. Most existing models [1-5] are mainly two-dimensional (2D) or quasi three-dimensional (3D) ones with negligence of the structure response of piston rings and they have been proved to be effective in assisting engineers to analyze piston ring overall behavior and to predict the performance of the power cylinder system [6,7]. However,