Research On Friction And Wear Of Diesel Engine Piston-cylinder System Based On Vibration

The piston-cylinder system is one of the most severe systems in the engine,and its state directly affects the life and emissions performance of the internal combustion engine.The friction loss of the piston-cylinder system accounts for a large part of the total mechanical loss of the internal combustion engine,and the vibration has a great influence on the friction and wear characteristics.Therefore,it is very important to study the vibration and friction and wear characteristics of the piston-cylinder system.This paper relies on the school-enterprise cooperation project of the National Key Laboratory of Internal Combustion Engines,"Basic Research on the Lubrication Friction and Wear Mechanism of Diesel Engine Piston-Cylinder System Materials",and studies the vibration and friction and wear characteristics of the piston-cylinder system.The main work contents of the thesis are as follows:First,design the two-dimensional and three-dimensional testing machine model of the piston-cylinder system and its power system,measuring system and loading system,and complete the design and construction of the vertical friction and wear testing machine.The finite element simulation analysis was carried out on the main components of the testing machine.Second,the friction and wear experiments were carried out using a designed vertical friction and wear tester.The orthogonal test was designed to explore the friction characteristics of the three factors of speed,load and vibration frequency.Through the range analysis and variance analysis of orthogonal experiments,the relationship between velocity,load,vibration frequency and friction coefficient under specific conditions is obtained.Thirdly,the three-dimensional modeling software is used to establish the threedimensional model of the piston-cylinder system,and the stiffness simulation of the piston is carried out to prepare for the multi-body dynamics analysis of the system.The finite element simulation software ANSYS is used to simulate the friction and wear of the piston-cylinder system under ideal conditions.The deformation,stress distribution and friction stress of the piston liner without vibration excitation and vibration excitation are calculated respectively.The vibration and friction are explored.The relationship of wear and tear.Finally,the multi-body dynamics simulation software EXCITE is used to establish the multi-body dynamics model of the piston-cylinder system,and the piston side thrust,piston radial displacement,piston friction loss and piston ring friction under certain working conditions are calculated.Then the local structural improvement of the piston was carried out to investigate the vibration-based friction and wear changes of the piston-cylinder system.