The Influence Of Kaolin Lubricating Oil Additive On Friction And Wear Properties Of Piston Ring

Cylinder liner piston ring is a friction part in automobile engine with great friction loss.Its friction lubrication performance directly affects fuel economy,engine performance and life.In recent years,two-dimensional layered silicate mineral materials have been widely used as lubricating oil additives because of their non-pollution to the environment,low price and proved to have a certain anti-friction effect.In this paper,kaolin in silicate mineral is selected as lubricating oil additive,and its surface modification is carried out to improve its suspension stability in lubricating oil.And the influence of kaolin on the friction and wear performance of cylinder liner and piston ring is studied,in order to improve the friction performance of cylinder liner and piston ring.The main research results are as follows:1.After surface modification of micro-nano kaolin with oleic acid,Span80,stearic acid and CTAB active agent,the dispersion stability of micro-nano kaolin oil samples has been improved to varying degrees,and Span80 has the best dispersion stability.The viscosity temperature test showed that the modified nano-kaolin lubricating oil additive could reduce the viscosity of the lubricating oil and improve the viscosity temperature characteristics.Corrosion tests show that the layered micro-nano kaolin additive is non-corrosive.2.Four ball testing machine to carry out the micro-nano kaolin lubricating oil additive of anti-friction and anti-wear experimental study shows that adding different concentration in the base oil,modification method,particle size of micro-nano kaolin particles can reduce friction reducing wear and tear.When adding 5 wt %concentration,Span80 modification methods,2 μm of kaolin,anti-friction and anti-wear performance of lubricating oil additive is best.The temperature influence test results show that the kaolin additive can effectively reduce the friction coefficient and wear of lubricating oil at high temperature,and prolong the service life of lubricating oil.The extreme pressure performance test shows that kaolin additive can improve the Pb value of lubricating oil,and the extreme pressure performance is the best when the concentration is 4 wt%.3.The improved cylinder liner piston ring friction and wear testing machine can simulate the actual working conditions to carry out the friction and wear test of the cylinder liner piston ring.The test shows that with the increase of pressure,speed and temperature,the friction coefficient and surface roughness of the lubricating oil also increase.When the pressure is 0.53 MPa,the speed is 400 r/min,and the temperature is 75 ℃,the friction coefficient and wear of the lubricating oil are the lowest.Under different working conditions,kaolin oil samples are better than base oil in reducing friction and antiwear,that is,nano-kaolin lubricating oil additive can improve the antiwear performance of lubricating oil.4.The lubrication simulation model established by AVL Excite Piston&Ring software can analyze the distribution of the minimum oil film thickness,the distribution of friction force and the friction loss after the lubricating oil is applied to the cylinder liner piston ring.The simulation results show that adding micro-nano lubricating oil additive in kaolin,when crank Angle from 90 ° CA to 630 ° CA,cylinder liner,the minimum oil film thickness between piston ring has increased in different degrees.Asperity ring friction,hydrodynamic ring friction,total friction and friction loss power are reduced in different degrees.Nano kaolin additive can improve lubrication performance and have a good anti-friction and anti-wear effect.