Simulation And Experimental Research On Friction Performance Of Piston Cylinder Liner Based On Fluid-Solid Coupling Heat Transfer

Piston cylinder liner assembly is an important part of reciprocating internal combustion engine,its frictional power consumption is one of the most important sources of internal combustion engine,accounting for more than half of the total engine friction loss.Due to the high temperature and high pressure gas and residual gas pollution of lubricating oil makes piston cylinder friction pair extremely poor working environment,and the temperature have a very important impact on the piston liner thermal deformation and lubricant film thickness and viscosity.Therefore,based on the distribution of temperature and the laws of heat transfer,the research on the influence of friction and lubrication on piston-cylinder liner assembly is a great significance.The research object of this paper is a type of single cylinder diesel engine.Firstly,the research status of friction and lubrication characteristics of piston and cylinder liner at home and abroad are summarized and introduced,the basic theory of friction lubrication is introduced.The numerical calculation equations of friction is discussed,in order to measure the temperature field caused by friction under the experimental conditions of motor,a test bench was set up;A constant temperature lubricating oil system to achieve the control of lubricant temperature;Piston liner temperature field is measured by the T-type solder joint thermocouple and oil temperature of the oil pan is measured by the armored T-type.Cylinder liner thermocouple installation along the axial direction of the uniform arrangement of the circumferential direction is divided into two columns,the angle between the two columns is 90°;and then the acquisition system is accessed into experimental system for data acquisition and recording.On the basis of the experiment,the simulation calculation software was further used to simulate the friction and lubrication characteristics of the piston-cylinder liner assembly.The first is the modeling process,modeling is divided into three-dimensional solid modeling,meshing processing,and dynamic model modeling,respectively,the dynamic model establishment process needs to set up the solvers of each body unit and connection unit.The influences of experimental conditions,axial temperature distribution of cylinder liner and axial thermal deformation of cylinder liner on the friction and lubrication characteristics of piston-cylinder liners were considered respectively.Further studies were made on the effect of axial temperature distribution of different liners on reducing the frictional power consumption impact.It is found that in the three calculation conditions of experimental conditions,adding cylinder liner deformation and adding cylinder liner temperature distribution,adding cylinder liner temperature distribution has the greatest influence on the friction and lubrication characteristics of piston cylinder liner assembly.Adding cylinder liner temperature distribution has an important impact on piston.cylinder liner heat transfer,which makes the temperature and viscosity of the oil film change,which will affect the friction and lubrication characteristics of the piston and cylinder liner;In the further optimization of axial temperature distribution of cylinder liner,the first increase and then decrease from temperature distribution is the most beneficial to reduce the frictional power consumption,friction force,Improve the friction and lubrication characteristics of piston cylinder liner.The average frictional power loss in the condition of first increase and then decrease from temperature distribution is lower than that of the decreasing axial temperature distribution of cylinder liner 8.97%,lower than the experimental conditions 4.10%.