汽油润滑性研究Ⅲ.汽油模型化合物试验

STUDY ON THE LUBRICITY OF GASOLINE FUELS Ⅲ.Model Gasoline Compound Study

汽油组成比喷气燃料和柴油简单 ,天然极性杂质含量也特别低 ,这对于研究燃料中主体烃组分对燃料润滑性的贡献 ,并与杂质的贡献区分开来是有利的。根据前文归纳的详细汽油组成数据 ,挑选代表汽油不同组分的纯化合物 ,进一步提纯 ,研究其对汽油润滑性的贡献。结果表明 ,由汽油主要成分烷烃、单烯烃和单环芳烃引起的磨损随粘度的增加而下降。尽管这 3类化合物的化学结构不同 ,但只要粘度接近 ,磨损就几乎相同。含氧掺和剂MTBE在商品汽油通常的含量范围下总是增大磨损。纯双环芳烃本身虽然磨损较小 ,但加到基础油中则会增大磨损。双烯的抗磨作用最为显著。

The composition of gasoline is simpler than that of jet fuel and diesel fuel and,in particular,the level of naturally occurring polar impurities in gasoline is very low.This is valuable for studying the contribution of the bulk hydrocarbon components of fuel to lubricity and for differentiating this from the contribution of polar constituents. Some pure model compounds chosen to represent gasoline constituents,based on the data summarized in previous paper,were further purified and used to investigate the individual contribution to lubricity of different hydrocarbons.The results revealed that for paraffins,monoolefins and monoaromatics,wear decreased linearly with the increase of their viscosity.In spite of their different chemical structures of these hydrocarbons,they showed quite similar wear performances as they had close viscosities.Pure diaromatics reduced wear significantly,but when it was added to base fuels at low concentrations,wear increased gradually with the increase of diaromatics concentration.The most significant wear reduction was produced by dienes.Oxygenate MTBE was consistently found to increase wear at the concentrations used in commercial gasolines.