生物油对发动机缸套摩擦学性能的影响

以生物油为研究对象,利用乳化技术对生物油进行提质改性,在发动机缸套-活塞环摩擦磨损试验机上考察了提质前后生物油的摩擦学性能.利用表面轮廓仪,扫描电镜与X-射线光电子能谱仪表征了发动机缸套摩擦表面的微观形貌及化学元素状态,探讨了相关的摩擦磨损机理.结果表明:小球藻生物油比稻壳生物油对缸套-活塞环具有更好的减摩抗磨性能;通过乳化提质方法,可以快速提升生物油的性能;生物油的减摩润滑作用归因于油品中的有机物在缸套表面吸附、摩擦挤压及摩擦沉积形成润滑油膜,局部摩擦熔融形成的"微滚珠",以及在摩擦表面生成的Fe₂O₃及FeOOH氧化膜.此外,小球藻生物油能在摩擦副表面形成含N有机保护膜,这是其具有更好摩擦学性能的重要原因.

Effect of Bio-oil on the Tribological Performance of Engine Cylinder

As a novel alternative fuel for diesel oil, bio-oil was upgraded by emulsification technology and the tribological performances of bio-oil and upgrade ones were tested on a cylinder liner-piston ring tribometer. The surface profilometer, scanning electron microscopy and X-ray photoelectron spectroscopy were used to analyze the micro-morphology and the valence states of elements on the rubbing surface and the tribological mechanisms were also discussed. The results show that the bio-oil from Chlorella had better friction-reducing and anti-wear properties than those of bio-oil from rice husk. The performances of the bio-oil can be improved significantly by the emulsification method. The lubrication mechanism was ascribed to the formation of lubricative films from adsorption, extrusion, and frictional deposition of the bio-oil organics on the cylinder surface, the rolling of micro-balls caused by local frictional melting and protective oxidation film of Fe₂O₃ and FeOOH on the friction surface during the friction process. Moreover, the bio-oil from Chlorella formed a nitrogen-contained organic film on the frictional surface, which was also an important reason for the better tribological performances.