Influence of Base Oil Molecular Structure on the Tribological Performance of Diesel Engine Cylinder Liner and Piston Ring

Abstract Highly intensified diesel engines lead to severe lubricating condition, high performance lubricant is important to solve this problem. Base oil is the main composition of lubricant, which plays important role in lubricating performance. In this paper, three kinds of poly-α-olefin (PAO) base oil were prepared. Different olefin materials were used to produce PAO with different molecular structure. The tribological performance of diesel engine cylinder liner and piston ring lubricated with different base oil were evaluated by reciprocating test rig. Results show that PAO base oil synthesized with long carbon chain olefin has high viscosity index. The P C12 reduced the friction coefficient by 15.4%/19.6% in low speed/high speed friction compared with P C8 . The wear of P C12 reduced 15.8% compared with P C8 . The results were resulted from the long carbon chain of P C12 , which produce high viscosity in high temperature and shear thin effect in high speed friction.