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| Basic Experimental Research on Nano-SiO2 Lubricants for Improving theLubrication and Friction Properties between Piston Ring and Cylinder Liner ofInternal Combustion Engine |
| DOI：10.13949/j.cnki.nrjgc.2018.03.009 |
| Key Words:nano-SiO2 cylinder liner and piston ring lubrication and friction |
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| Abstract:The lubricants with nano SiO2 of different quantity were prepared by the dispersion method and the suspension stability was analyzed accordingly. The extreme pressure properties and antifriction properties of the lubricants were investigated by a four-ball friction tester, which reproduced the mixed lubrication between piston ring and cylinder liner near top dead center and the hydrodynamic lubrication between piston ring and cylinder liner away from top dead center respectively. Real materials of piston ring and cylinder liner and a contraposition reciprocating test rig were used in order to evaluate the lubrication and friction properties of the lubricants under varying operating conditions(changed temperature, speed and load). The morphology of worn surfaces of the cylinder liner was observed by FE-SEM, and the frictional mechanism of the lubricants was analyzed. The experimental results show that the nano-SiO2 particles can improve the extreme pressure and antifriction properties of the lubricants significantly, the average wear scar diameter and average frictional factor are decreased by 51.9% and 46.7% respectively at the optimum nano-SiO2 concentration. There is a mixed lubrication between piston ring and cylinder liner near top dead center. The nano-SiO2 particles can increase antifriction and antiwear properties of the lubricants at varying operating conditions significantly, and the frictional factor is reduced by 10.5%, 10.3% and 5.9% respectively at high temperature, high pressure and low speed. The nano-SiO2 particles play a role of compound effect of “roller bearing” and polishing on the surfaces of friction pairs during friction process. |
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