悬浮碳烟微粒对在用柴油机油粘度影响的研究

现代柴油机技术清洁了排放，却使进入机油中的碳烟微粒大量增加，本文研究报道了悬浮碳烟微粒对在用柴油机油粘度的影响；粘度随碳烟浓度提高而增大；二者符合Eilers和reiger-Dougherty粘度方程，分散剂能阻止碳烟微粒发生聚结，进而降低相对粘度，其中碱性分散剂作用性能远优于中性分散剂。     

碳烟对DPF再生中温度梯度的影响分析

研究柴油机微粒捕集器(DPF)再生时碳烟燃烧产生的热冲击对提高载体寿命具有重要的意义。利用AVL FIRE建立DPF模型,并验证模型的有效性。分析了在喷油助燃再生条件下DPF载体内温度梯度的分布,并分析了不同的碳烟密度、初始碳烟量以及碳烟分布对温度梯度的影响。研究结果表明:再生中载体后端温度梯度对碳烟分布及初始碳烟量的变化较为敏感。当碳烟的分布趋于载体后端时,载体内温度梯度分布趋于均匀。较高的碳烟密度再生过程相对温和,有利于载体寿命的提高。     

纳米碳对酚醛树脂碳微结构的影响

采用透射电子显微镜研究碳／酚醛烧蚀碳层中含纳米碳微粒的酚醛树脂碳微结构，结果表明：在碳分布均匀状态的树脂碳中，纳米碳微粒约50nm，为圆球形，碳粒周围的树脂碳结构均匀，属于具有一定石墨化程度的网络结构；碳微粒呈聚集态，或微粒尺寸较大时，树脂碳的微结构比较复杂。     

油液监测与诊断技术（下）

三、油液中不溶性微粒监测与诊断技术 油液中不溶性微粒的来源是磨损微粒和污染物(如砂尘、碎棉纱、油漆剥落碎片、添加剂消耗后的残余物等)。它们随润滑油进入润滑部位,促进磨损,堵塞润滑油路,导致润滑状态恶化,而且油液中磨损金属微粒增多更会加剧油质劣化,劣化了的油液反过来又加速设备的磨损和腐蚀。 油液中的不溶性微粒,尤其是磨损微粒,包含着有关零部件磨损状态、机器工况以及系统污染程度等丰富信息。通过对油液中磨损微粒的监测,不解体、不停机即可推断出设备发生异常磨损的趋势、部位及原因,从而预报并控制故障的发生。     

Ni—P—Si3N4复合镀层的磨损特性

本文通过Ｘ射线衍射分析、电子探针分析和摩擦磨损试验，分析了电沉积Ｎｉ－Ｐ－Ｓｉ３Ｎ４复合镀层的结构性能和磨损特性，并比较了不同弥散微粒的影响。结果表明，在油润滑条件下，复合镀层中的Ｓｉ３Ｎ４微粒在支承载荷的同时，有利于边界润滑膜的形成，避免粘着磨损。同时由于Ｓｉ３Ｎ４微粒本身具有的结构特征，提高了复合镀层的耐磨性能。     

Mo2S水基润滑液的摩擦学性能研究

将球磨法制备的超细Mo2S微粒分散于水中形成水基润滑液．用四球摩擦磨损试验机考察了Mo2S水基润滑液的摩擦学性能，用X射线光电子能谱分析了钢球磨损表面典型元素的化学状态。结果表明，Mo2S微粒水基润滑液具有良好的承载能力和抗烧结能力。     

磨损微粒识别的模糊决策树方法

磨损微粒识别是在磨损工况监控中确定机器磨损类型的关键步骤。本文基于非单调模型推理方法，依据磨粒识别过程中所依赖特征的层次关系，建立了磨粒识别的模糊推理决策树。这一决策树开发的软件试验结果表明，本文所提出的方法在实现磨粒的自动识别方面是有效的。     

表面修饰SiO2纳米微粒作为液体石蜡添加剂抗磨性能的研究

用原位表面修饰法合成了异辛酸修饰SiO2纳米微粒，利用四球摩擦磨损试验机考察了SiO2纳米微粒作为液体石蜡添加剂的摩擦学行为。用扫描电子显微镜（SEM）和X射线光电子能谱仪（XPS）对钢球磨损表面进行了分析。试验结果表明，SiO2纳米微粒作为液体石蜡添加剂具有良好的抗磨损性能，能显著提高液体石蜡的失效载荷；表面修饰SiO2纳米微粒在摩擦过程中发生了摩擦化学反应，形成了含SiO2及有机分解产物等组分的复合边界润滑膜，从而表现出良好的抗磨性和较高的承载能力。     

机电信息

柴油机微粒后处理器开发成功　　近日，解放军军事交通学院开发出柴油机微粒后处理器，使柴油车碳烟排放指标明显下降。该处理器由过滤器、微波发生器、旁通阀、二次空气装置等部件组成，大多数柴油车在安装后其微粒排放可以达到欧洲 2号标准。该系统的整体寿命可超过 5万 km，批量生产价格可望在 5000元以下。该系统通过简单匹配就可用于不同排量和用途的柴油机，适用于城市公交车、载重车、工程机械、农用车及固定柴油机等。(湘 镒 )EKB软密封闸阀、蝶阀开发成功　　一种在发达国家城市给排水系统中广泛应用的绿色环保产品—— EKB软密…     

Ni-W-Co/SiC微粒复合材料的磨损规律和机理

研究了Ni-W-Co/SiC微粒复合镀层在润滑渐污条件下的滑动磨损特性,分析了载荷、滑动速度及SiC微粒质量分数对复合镀层磨损机制的影响。试验结果表明：在污染条件下,Ni-W-Co合金的磨损机制主要为显微切削和犁沟;SiC微粒复合相的主要流失形式为撞击脱落。     

Effect of diesel soot contaminated oil on engine wear — investigation of novel oil formulations

Exhaust Gas Re-circulation (EGR) has been found to be very effective in reducing emissions of oxides of nitrogen, for light duty diesel engines. However, EGR results in a sharp increase in particulate matter emissions in heavy-duty diesel engines.The effects of soot contaminated engine oil on wear of engine components was examined using a statistically designed experiment. The three oil properties studied were phosphorous level, dispersant level and sulfonate substrate level. The above three variables were formulated at two levels: High (1) and Low (−1). This resulted in a 2³ matrix (eight oil blends). The effect of soot was also taken into consideration, which resulted in a 2⁴ factorial experiment.A three-body wear machine was designed and developed to simulate and estimate the extent of wear. Ball-on-flat-disk tests were conducted to qualitatively study wear by comparing wear scars due to soot with wear scars due to a known abrasive (alumina). A Scanning Electron Microscope (SEM) was used to study the microstructures of the wear scars. Surface chemical analysis was performed on soot particles and wear scars using Energy–Dispersive X-ray Analysis (EDAX).Results show that diesel soot interacts with oil additives reducing the oil's anti-wear properties possibly by abrasive wear mechanism. Statistical analysis (GLM) showed that the phosphorous level plays a dominant role on oil's wear performance. The effect of dispersant level was not very significant, though on an average, higher dispersant levels reduced wear. The effect of sulfonate was not revealed within the range of these concentrations. Ball-on-flat-disk type tests also revealed the increased wear due to the presence of soot. SEM studies of Wear Scar Diameters suggest that soot is abrasive.     

Soot–additive interactions in engine oils

Soot is known to cause engine wear. In this work, we focus on how engine oil formulation affects soot‐related wear, and how the lubricant‐derived anti‐wear film changes when soot is present. Friction and wear experiments of fully and partially formulated diesel engine oils (containing basestock, dispersants and viscosity modifiers) are conducted with a ball‐on‐disk rig in the presence of carbon black (CB) as a soot surrogate. The friction coefficient was largely unaffected by CB dispersed in the oils, but electrically insulating film formation, an indication of the formation of anti‐wear films, was decreased. Wear on the disk was found to either remain the same or decrease when CB was present, depending on the oil formulation. An examination of the lubricant‐derived films using Raman and Auger electron spectroscopies found that the presence of more abundant amorphous carbon and lesser amounts of anti‐wear film components on the surface was associated with higher wear. Copyright © 2009 John Wiley & Sons, Ltd.     

Soot characterisation and diesel engine wear

The hardness of various types of soot produced by heavy‐ and light‐duty diesel engines of European, Japanese, and North American designs was measured by low‐loss electron energy‐loss spectroscopy (EELS). No clear general trend can be established that shows heavy‐duty diesel engine soot is necessarily harder than light‐duty diesel engine soot. The variation in hardness among individual soot particles produced by the same diesel engine can be as large as differences between the hardest soot particles produced by heavy‐duty diesel engines and the softest soot particles produced by light‐duty diesel engines. There are heavy‐duty diesel engines that can produce soot that is softer than that produced by some light‐duty diesel engines and vice versa. Nevertheless, the hardness of all types of soot studied is close to the range of hardness of metal engine parts. Thus, the results indicate that soot is hard enough to abrade some metal engine parts.     

The Behavior of Diluted Sooted Oils in Lubricated Contacts

An increase in the engine lubricant soot levels has recently been noticed. This increase in soot content of lubricating oils has caused a series of problems in the overall performance of the engine. In a practical context, sooted oils consist of carbonaceous matter suspended in engine oil forming a system commonly known as a colloid sol. The objective of this paper is to better understand the mechanism of action of oil containing soot particles in the lubricated contacts and to identify how the colloidal nature of the sooted oil is related to its performance. This study has shown by means of ultra-thin film interferometry and image analysis techniques that soot colloid particles are entrained in the contact inlet where they can influence the friction and wear characteristics of the base stock. This study shows that soot primary particles are entrained into the contact at slow speeds, affecting the film characteristics of clean engine oils. This entrainment of particles is more pronounced at high temperatures.     

Contemporary challenges of soot build-up in IC engine and their tribological implications

Confronted with the contemporary challenges of maximising energy efficiency with minimal impact on the environment, the automotive industry has developed various technologies to tackle them. Most of these technologies, however, have wider implications on the tribological performance of the automotive engines due to resultant soot build-up. This paper reviews the effects that attempts by stakeholders to satisfy requirements for reduced fuel consumption, reduced emissions and extended service intervals have had on increasing soot levels to an extent that can lead to engine component failure. Three areas have been identified that have either not been explored or not widely explored in the study of automotive soot namely: numerical simulation and modelling of soot wear, soot effects on wear of actual engine components and the wear and friction performance of non-metallic materials used in internal combustion engines. A paper-grading system is also utilised to present an overview of how sooty oil-related research covers various areas.     

烟炱对电接触磨损的影响

选用常见的铜作为电接触材料,将烟炱溶液喷洒于试样表面,进行不同载荷下的电接触微动试验,用3D形貌仪和SEM对磨痕形貌进行分析。结果表明:载荷对材料的电接触性能影响显著,接触电阻与法向载荷成反比,即增加载荷可改善摩擦副的电接触性能;接触区域的有效导电面积是有限的,故载荷达到某一值后,随着载荷的增加,接触电阻不再有明显的下降趋势;小载荷下,烟炱的加入恶化了摩擦副的电接触性能,随着载荷的增加,这种恶化作用逐渐减小;摩擦因数随着载荷的增加而降低,载荷较低时(2～6 N),摩擦因数曲线可见明显的上升期、跑合期、下降期、稳定期;而载荷较高时(8～10 N),只有上升期和稳定期;大载荷下,触头接触区域匹配良好,摩擦副表面迅速达到了平衡点,摩擦因数较稳定。在电化学的作用下烟炱颗粒在摩擦副表面形成固体膜,起到减摩抗磨的作用。     

基于自动磨粒分析技术的直升机在用发动机油界限值的研究

运用自动磨粒分析仪(LNF)测定直升机在用发动机油的切削磨损、滑动磨损、疲劳磨损和非金属颗粒,通过对数据的频数分布直方图的计算分析,研究得到切削磨损、滑动磨损、疲劳磨损和非金属颗粒的界限值,可以作为直升机在用发动机油监测的又一补充,弥补了原子发射光谱不能监测较大磨损金属颗粒的缺陷,为直升机的合理换油提供技术依据。     

Zinc Dialkyldithiophosphate Additive Adsorption on Carbon Black Particles

Soot is known to cause high wear in engine components and this is a problem with engine oils between extended drain intervals. Although several wear mechanisms have been suggested, exact soot-induced wear mechanisms are still not fully understood. This study aims to investigate the additive adsorption mechanism (specifically anti-wear additive) on carbon black (CB) particles (as a soot surrogate). This mechanism is one of the main mechanisms responsible for high wear. Base oil (BO) was used to exclude the effect of other additives that are present in fully formulated oil. Zinc dialkyldithiophosphate (ZDDP) anti-wear additive was added to the BO and then the mixture, which will be referred to as the model oil, was aged with CB particles. The resulting oils were then chemically characterised by using ICP and FTIR analysis techniques. Finally, the CB particles were filtered out and analysed using EDX. The results showed that both zinc and phosphorous which are chemical elements from ZDDP anti-wear additive were adsorbed on CB particles in the oil phase. This additive adsorption mechanism can lead to increased wear in the engine components due to lack of additives in the oil. This study highlights the importance of understanding the additive adsorption on soot particles since this mechanism will reduce the engine oil life and increase frequency of oil changes.     

柴油机油烟炱分散性能研究

通过模拟试验、发动机台架试验以及行车试验,考察柴油机润滑油的烟炱分散性能。结果表明:烟炱模拟试验能区分不同油品的烟炱分散能力;由于发动机技术的不同、试验目的的不同、试验条件设置的不同,台架试验结果会有很大差异,应根据发动机的技术特点,建立与润滑油在车辆实际使用过程中性能相关联的台架试验;质量级别越高的润滑油,其烟炱分散性能越好;不同分散性能、不同类型黏度指数改进剂的润滑油在行车试验中性能差异不大,特别是由烟炱引起的黏度变化基本没有表现出来,而黏度指数改进剂的剪切性能对黏度指标的影响比烟炱含量的影响表现得更为突出。     

基于柴油发动机国六排放应用的氮氧化物传感器碳颗粒堵塞问题研究

针对目前国六柴油发动机应用的氮氧化物传感器被碳颗粒堵塞的问题进行了分析与讨论.为验证影响传感器积碳堵塞的内部和外部条件,采用了发动机台架和整车路试试验方法.通过总时长100 h以上的巴黎循环试验,测试分析了市面上两家主流供应商提供的氮氧化物传感器对于积碳堵塞的鲁棒性差异.试验结果表明:供应商1和供应商2氮氧化物传感器的...