煤间接液化柴油碳烟颗粒摩擦特性

Friction characteristics of soot particles on Fischer-Tropsch synthesis diesel

煤间接液化柴油(F-T柴油)可直接应用在汽车发动机中,但其不完全燃烧产生的碳烟颗粒对发动机润滑系统的影响有待研究。本文在长时四球摩擦磨损试验机上研究F-T柴油碳烟(F-T DS)和0;柴油碳烟(DS)对10;白油摩擦学性能影响及其与传统抗磨添加剂的作用,并通过扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)等分析F-T DS、DS对10;白油的摩擦磨损机理。结果表明:随着10;白油中F-T DS与DS添加量的增加,平均摩擦系数(AFC)与钢球的平均磨斑直径(AWSD)均先降低后增加,当F-T DS添加量为1.0%(wt)时降到最低,此时AFC为0.071,AWSD为0.442 mm, DS也在浓度1.0%(wt)时AFC达到最小值0.075,AWSD达到最小值0.448 mm。当F-T DS与DS为2.5%(wt)时,AFC和AWSD急剧增加,并且都高于10;白油。在添加硫磷双辛伯烷基锌盐(T204)后,含2种碳烟的油品AWSD均明显减少,T204添加浓度为0.4%(wt)时,2种碳烟的AFC和AWSD均达到最小,此时AWSD分别降低为0.292、0.288 mm,分别减少35.4%和37.1%。机理分析表明:T204与碳烟形成复杂、具有抗磨减摩作用的摩擦膜,T204加量超过0.8%(wt)时,碳烟会和T204分解产生的磷酸盐在摩擦过程中形成磨粒,使磨粒磨损变得严重。

Fischer-Tropsch synthesis diesel can be directly used in automobile engines, but the effect of its soot particles produced by incomplete combustion on engine lubrication system remains to be studied.A long time four-ball tribological test was used to investigate the effects of F-T synthesis diesel soot(F-T DS) on the tribological performance of 10;white oil and the effects on traditional anti-wear additives.All experiments were contrastedwith 0;diesel soot(DS).The mechanism of friction and wear for F-T DS and DS were investigated by a range of analytical techniques, such as scanning electron microscopy with energy-dispersive spectroscopy(SEM/EDS),X-ray photoelectron spectroscopy(XPS),etc.Results showed thatthe average friction coefficient(AFC) and the average ware scar diameters(AWSD)firstly slightly decreased and then increased with the addition of F-T DS and DS increased.When the F-T DS content was 1.0%(wt),the AFC and AWSD all dropped to the lowest.TheAFC was attained 0.71.The AWSD including DS content 1.0%(wt)was 0.442 mm.TheAFC including DS content 1.0%(wt) was reached the minimum, its 0.75.The AWSD was 0.448 mm.When the F-T DS and DS mass fraction reached 2.5%(wt),the AFC and AWSD showed a sharp increase.The AFC and AWSDwereall higher than the white oil.After addingzinc dialkylphosphorodithiloate(T204),the AWSD of oil containing two kinds of soot wereall significantly reduced.When the T204 added amount was 0.4%(wt),the AFC of 1%(wt) F-T DS+white oil and 1%(wt) DS+white oil reached the minimum.At this time, the AWSD was reduced to 0.292 and 0.288 mm, respectively, decreased by 35.4% and 37.1%.The wear mechanism analysis showed that T204 interacts with soot to form a complex friction film that played an anti-wear and anti-friction role.If T204 additive content was ultrahigh 0.8%(wt),soot and the phosphate produced by the decomposition of T204 would form abrasive particles in the friction process, making the abrasive wear become seriously.