Modeling And Experimental Study On Friction Reduction Of Internal Combustion Engine Liners By Vibrations

The piston-cylinder system is one of the key friction pairs of internal combustion engine,and the improvement of its friction lubrication performance is of great significance for the whole internal combustion engine.Therefore,it is an important issue to reduce the friction of the piston-cylinder system in the development of internal combustion engine.At present,the domestic and foreign scholars on the piston-cylinder friction reducing system research mainly focused on the improvement of lubricants,cylinder liner surface texture processing and other conventional means.Although there have been many advances in theory and experimental research on friction reduction by vibration,its research and application in the field of internal combustion engines is less.This paper introduces the research of vibration reduce friction into the piston-cylinder liner field,and studies the vibration reduce friction of cylinder liner by modeling and experimtal.Based on the two-dimensional averaged Reynolds equation,considering the inlet and outlet boundary conditions and the change of lubricant film between piston ring-cylinder liner friction pair,a two-dimensional hydrodynamic lubrication model between piston ring and cylinder liner friction pair is established.The vibration deformation of the cylinder surface were obtained by modeling and calculation.After considering the dynamic deformation factors of cylinder liner caused by vibration,the lubrication model was improved,and the oil film pressure,lubricant film thickness and friction force between piston ring and cylinder liner friction pair were simulated.The effect of cylinder liner vibration on friction behavior between friction pairs was analyzed through simulation.From the simulation point of view,the feasibility of reducing friction by cylinder liners vibration and the mechanism of reducing friction of piston-cylinder liner assembly by vibration were demonstrated.In order to further study the feasibility of reducing friction by vibration of cylinder liner,based on the piston-cylinder assembly,the experimental research on friction reduction by vibration is carried out.In this paper,the theoretical basis of friction reduction by vibration of cylinder liner is studied.The mechanism of reducing friction by vibration is analyzed in detail.The reduction of friction of piston-cylinder liner assembly under high frequency excitation is explained reasonably from three aspects of cylinder liner dynamic deformation,cavity effect and ultrasonic cavitation.A high frequency vibration reduction test bench for piston cylinder assembly under relative motion is set up,and the basic experimental research on friction reduction between piston-cylinder assembly by vibration is carried out.By means of experiment,the feasibility of reduce friction by vibration in piston-cylinder liner field is preliminarily proved.Finally,based on the friction tester of the internal combustion engine,the ultrasonic vibration anti-friction test bench for the internal combustion engine was built,and the reverse drag test of the internal combustion engine was performed under high-frequency excitation.The change of friction between the piston and liner was measured by the floating cylinder method.The influence of high frequency vibration on the friction and lubrication of piston cylinder assembly in internal combustion engine is experimentally studied,and the relationship between excitation frequency,exciting power and effection of friction reduction by vibration of cylinder liner is found.The experimental results show that the application of high-frequency excitation makes the surface of the cylinder liner appear dynamic deformation close to the roughness level,and the friction force of the piston-cylinder liner assembly decreases with different amplitude.It shows that the ultrasonic excitation under reasonable working conditions can reduce the friction of piston ring-liner,thereby reducing the total friction loss of internal combustion engine,it explores a new direction for the application of high frequency excitation and friction reduction in the field of internal combustion.