Friction and wear response of vegetable oils and their blends with mineral engine oil in a reciprocating sliding contact at severe contact conditions

摘要

Although many studies investigating the tribological performance of pure vegetable oils have been conducted, audbetter understanding of vegetable oil tribological performance at extreme conditions is still needed. Similarly,udlittle work has been carried out to study the influence of the vegetable oils on the performance of a lubricantudformed from a blend of vegetable oil and conventional mineral engine oil. This work presents the tribologicaludperformance of vegetable oils, and their blends with mineral oil, in a high temperature and contact pressureudreciprocating contact. Palm and soybean based vegetable oils were mixed with a commercial mineral engine oiludat a 1:1 ratio by volume. The conventional mineral oil was also tested to provide a benchmark. The pure palmudoil exhibited lower friction than soybean oil, but for wear performance, this was reversed. The frictionudperformance of the palm oil was competitive to that of the mineral engine oil. The mineral engine oil was farudsuperior in wear resistance over both vegetable oils. When blended with mineral engine oil both vegetable oilsuddemonstrated a reduction in coefficient of friction when compared to their pure oil states. An improvement inudwear performance was observed for both a blend of palm oil and mineral engine oil (25% improvement) andudthat of soybean and mineral engine oil (27% improvement). This work shows that for palm oil and soybean oil,udthe performance of a blended oil is influenced by its vegetable oil component and that tribologicaludcharacteristics of vegetable oils are dominant. That said, the significant limitation of these vegetable oils is theirudability to provide a satisfactory level of wear resistance. It is suggested that any future work in this area shouldudhave a greater emphasis on the enhancement of wear resistance. ud