Research On Theory And Test Equipment Of Contaminant Solid Particles Influencing Lubrication And Wear Of Piston Ring And Cylinder Liner

Piston ring and cylinder liner are important components in an internal combustion engine due to their crucial effects on internal combustion engine such as dynamic, economical efficiency, reliability and durability. Supported by the project of national nature science fund of china-"Study On Simulation And Mechanism Of Abrasive Wear Process", and meet development demand of mechanical industry and improve quality of engine products in Yunnan province, considered piston ring and cylinder liner of 4100 serial products of internal combustion engine as subject investigated, contaminant Solid particles in lubricant oil influencing lubrication and wear of piston ring and cylinder liner of internal combustion engine was systematically researched in this thesis.In chapter 1, the background and significance of the research are introduced. The development trend and current research situations were expatiated, which included solid particle influencing lubrication and wear, piston ring and cylinder liner tribology, solid particle influencing lubricating and wear of piston ring and cylinder liner, solid particle detection and measuring system and testing equipment of piston ring and cylinder liner, and then the study contents of this dissertation were proposed.In chapter 2, the origin of contaminant Solid particles in lubricant oil existing between piston ring and cylinder liner was explained, and solid particle geometric shape descriptor was studied, the shape descriptor got is according to real geometric shape. Shape measuring of general solid particle in lubricant oil such as SiO₂, Al₂O₃ and Fe₂O₃ was tested to verify the shape descriptor and geometric shape of solid particles come from lubricant oil samples of 4100 internal combustion engine of Yunnan province internal combustion engine company was analyzed and observed based on ferrography analysis experiments. The change trend in quantity of solid particle in lubricant oil, solid particles detecting technology and concentration balance theory were analyzed, model building methods of solid particle concentration change trend, particularly model by support vector machines theory were studied and used successfully to establish particle concentration change trend model of lubricant oil of 4100 internal combustion engine in use.In chapter 3, based on contact analysis, a new contact model of solid particle and friction surface was put forward, which considered three deformation states such as elastic, plastic and elasto-plastic behavior, and deformation continuity law and smooth curve theory in state transition, and then the model of many solid particles was also established according to the quantity of solid particles in lubricant oil for macroscopic view. In order to disclose changing process and state and get intermediate data which are not be attained by current experiment, numerical simulation of solid particle acting on worn surface were researched, which were the finite element methods that were used to analyze micro contact process, impacting process and heat effect of solid particle on worn surface, and which is molecular dynamics simulation that was used to analyze micro cutting process of micro particle.In chapter 4, on the view of two phase fluid due to lubricant oil containing solid particles, two phase effect that changed value of viscosity, flashing point and ignition point under condition of lubricant oil containing three different type solid particles were tested for Yunnan internal combustion engine company special lubricant oil of CD grade No.40. Based on lubrication theories of piston ring and cylinder liner researched mainly, the lubrication model that considered solid particle influencing lubrication of piston ring and cylinder liner was established, and then numerical solution method was introduced to solve the model of second-order partial differential equation. In order to solve the puzzle of convergence and conveniently compare two type lubrication condition of containing solid particles or not, a new simplification and utility lubrication model was established. On condition of lubricant oil containing solid particles lubrication performance of piston ring and cylinder liner in the four stroke of intake, compression, expansion and exhaust were calculated and analyzed for 4100 serial products of Yunnan internal combustion engine company.In chapter 5, based on wear model of mechanical effect that combines micro cutting mechanism and plastic deform mechanism, the piston ring and cylinder liner wear model that considered solid particle influencing was established, and then piston ring wear, cylinder liner wear and wear distribution in cylinder liner on condition of given run time, concentration and size of solid particle were calculated and analyzed for 4100 serial products of Yunnan internal combustion engine company.In chapter 6, the mechanism of adhere wear generated by heat effect was discussed, and the flashing contact temperature mathematical model for solid particle on friction surface and adhere wear volume model generated by solid particle heat effect were established, and then Instantaneous contact temperature mathematical model for solid particle on cylinder liner surface, solid particle on piston ring surface and adhere wear volume model of cylinder liner surface and piston ring surface which are generated by solid particle heat effect were also established. Using the theoretical models the piston ring and cylinder liner of 4100 serial products of Yunnan internal combustion engine company were calculated and analyzed on condition of given run time, concentration and size of solid particle. Instant contact temperature increment of cylinder liner surface and particle on different cylinder liner position generated by heat effect were got, and adhere wear volume distribution in cylinder liner generated by heat effect was got.In chapter 7, micro measuring system for three-dimensional geometric shape measuring of solid particle in lubricant oil was successfully developed based on three dimension rotational stereo measuring theory and was tested that it is feasible. Aim at do special experiments of lubrication performance and wear effected by solid particles, Reciprocating type Piston ring and cylinder liner test machine was designed and developed, which comprises of two exchangeable components and can be use to simulate real movement of piston ring and cylinder liner in an internal combustion engine and do experiments of solid particles influencing lubrication and wear of piston ring and cylinder liner. Based on Likong industrial configuration software made in china the data collection and monitor system of testing machine was also developed, which can be used to measure and monitor experiment data on line and record changing data in experiment process. So shortage of similar test equipment that can not automatically monitor test data was remedied.In chapter 8, simulated real movement of piston ring and cylinder liner of 4100 serial internal combustion engine, friction and wear of piston ring and cylinder liner on condition that lubricant oil containing solid particles or not were compared by experiments. The results show that solid particles influence tribological performance such as friction force, wear of piston ring and cylinder liner and friction loss. The relationship between tribological performance and load, velocity and run time was also investigated by experiments. Based on theory research achievement in advance chapters, applied theoretical models to calculate friction force related to lubrication performance and wear of specimen made from piston ring and cylinder liner under different experiment conditions in test machine, compared with corresponding test data, the theoretical models were proved that they are effective and confidence.In chapter 9, the study contents and conclusions of the dissertation have been summarized and the further research works have been forecast.