Internal Combustion Engine Piston Ring - Cylinder Liner Lubrication Analysis And Research

The history, research status and trend of the lubrication design of piston ring-cylinder used by internal combustion engines is introduced at the very beginning of this paper. With the increase of the required speed and power of internal combustion engine, higher operating performances of the piston ring-cylinder are required. Meantime, the remarkable differences between the practical working condition of the internal combustion engine piston ring-cylinder and those hypothesis used by the classic hydro-lubrication theories make it necessary to analyze the engine piston ring-cylinder system and rebuild proper and relevant equations. In addition, with the development of computational technology, it turns to be possible to solve accurately the problems that cannot be solved with the analytical methods. However, almost all the design methods and programs used currently for lubrication analysis and design are prepared for some specific working conditions. These methods and programs cannot be used for all different working conditions because many influence factors are neglected. On the other hand, different lubrication design theories and methodology are introduced. It is pointed out that the rapid problem-solving method, which uses existing performance curves and forms for reference to design the lubrication of piston ring-cylinder, is time-consuming because it has lower accuracy and is not universal for all the different working conditions. The mathematic model, corresponding equations and computing methods are presented according to the inner structure and operating principle of the piston ring-cylinder. Based on the investigation of effect of piston ring elastic pressure distribution, it is proved that the lubrication status of piston ring-cylinder is non-uniformity circumferentially. In this paper, by employing the two dimensional Average Flow Model and Asperity Contact Model, and taking the change of lubricant viscosity into account, a new model which can be used to study the lubrication property of piston ring-cylinder is presented, and the three dimensional distribution of oil film thickness between piston ring and cylinder is given. The effect of piston ring elastic pressure distribution and the position of the piston ring gap on the non-uniformity of oil film thickness between piston ring andcylinder is studied quantitatively. A practical computing program, which can be used for analyzing, designing and computing the lubrication status of piston ring-cylinder, is prepared under WIN2K and C environment. As a case in point, the lubrication analysis and calculation for piston ring-cylinder of the diesel engine SD1110 by Shandong Juling Co., Ltd. is studied.