影响火花点火发动机碳氢排放因素的研究

综述了西安交通大学内燃机研究所在火花点火发动机未燃碳氢排放方面的研究成果，内容包括未燃碳氢的生成机理、影响因素、预测模型、详细提供了燃烧室狭缝、润滑油膜、燃烧室沉积物、燃油对发动机碳氢排放的影响，。建立了冷启动和速发动机缸内未燃碳氢的生成规律以及狭缝与火花点火发动机碳氢排放、动力性和经济性的关系。     

Lubricating oil influence on exhaust hydrocarbon emissions from a gasoline fueled engine

Engine exhaust hydrocarbon emissions have been investigated for different lubricating oils, using gasoline as fuel. Six samples of lubricants have been tested: synthetic SAE 5W30 and SAE 5W40, semi-synthetic SAE 15W40 and SAE 20W50, and mineral SAE 15W40 and SAE 20W50. Experiments were carried out in a production engine mounted on a bench test dynamometer, varying engine load and speed in the range from 1500 to 6000 rev/min. The results demonstrate the influence of lubricant viscosity and base oil on hydrocarbon emissions. The synthetic oils showed the lowest hydrocarbon emission levels, especially in the low engine speed range.     

活塞销偏置对润滑油消耗的影响

基于润滑油消耗机制,以某型12v柴油机为研究对象,建立活塞组件动力学仿真模型,分析活塞销偏置方式和活塞销偏置量对于润滑油消耗的影响.结果表明:活塞销偏置方式总体趋势是使润滑油的消耗减少,窜油和甩油得到明显改善,其中活塞销偏副推力侧(Anti-Thrust Side,ATS)对润滑油的消耗减少的效果最好;活塞销偏置量对润...     

气动发动机的试验研究

为优化气动发动机的设计,提高气动发动机的工作性能,在一台由R175柴油机改装的二冲程气动发动机上进行详细的台架试验研究,并提出两个评价气动发动机性能的新指标--比质量流量和总能量效率.采用变压器机油、冷冻油和特制机油等三种不同的润滑油进行气动发动机的润滑油试验,试验结果表明润滑油对气动发动机的经济性和动力性影响很大.针对水套中无水、注入常温水和开水等三种不同换热条件进行气动发动机的换热试验,试验结果表明加强换热条件对气动发动机的经济性和动力性帮助有限,但多级利用压缩空气可以提高气动发动机的总能量效率.利用三种不同进气提前角的进气凸轮,进行三种不同配气相位的速度特性和负荷特性试验.试验表明:气动发动机在低速阶段拥有较好的经济性和动力性,进气提前角为10 ℃A时,气动发动机性能最好.     

纳米二氧化钛的光催化与减摩性能研究进展

纳米二氧化钛(TiO₂)作为一种环境和能源领域出色的光催化剂以及一种新型的发动机纳米润滑油添加剂,受到越来越多的关注。综述纳米TiO₂复合材料在不同掺杂方式下在光催化方面的研究及应用进展,以及纳米TiO₂及其复合材料作为润滑油添加剂的研究及应用进展;总结了综合考虑纳米TiO₂复合材料光催化与减摩性能的研究现状,指出将纳米TiO₂及其复合材料作为发动机润滑油添加剂时,应综合考虑其光催化与减摩性能,从而实现在减摩的同时降低污染物排放。     

Oil Degradation in a Diesel Engine with Dual-Loop Lubricating System

A common lubricating oil sump is used in most modern internal combustion engines for cooling, wear protection, and friction reduction. This requires compromises during base oil and additive selection as a result of differing needs for lubricant performance in engine subsystems. The use of a dual lubricating loop, providing separate oil sumps for the power cylinder and valve train subsystems, was investigated experimentally to determine the effect of system segregation on oil degradation. A small diesel engine was modified, installed in a commercial generator unit, and operated for one oil drain cycle. Oil sampling was tailored to assess base and acid numbers, oxidation, soot concentration, water content, and viscosity changes. The experiment complemented an earlier study that investigated the fuel economy benefits of such a lubricating configuration. These include longer drain intervals for the cylinder head and power cylinder subsystems, improved wear performance for the valve train, and opportunities for alternative material selection during engine design. The experiment demonstrated protection of the valve train subsystem from soot contaminants in the power cylinder. Lower total acid number and oxidation tendency was also observed in the valve train.     

基于灰色时序组合模型的油液光谱分析预测

以某型发动机油液光谱分析数据为基础,分别利用GM模型、AR模型和灰色时序组合模型,对实测数据进行动态建模,并对发动机润滑油中Fe元素的变化进行预测,结果对比表明,灰色模型能够模拟数据的宏观变化趋势,时序模型能够描述数据的细微随机变化,灰色时序组合模型综合两种模型的优点,达到更高的预测精度。     

Effect of different lubricating oil on the adsorption/desorption process of fuel in oil layer in an SI engine

A diffusion equation given by Fick's law is used to study the effect of different lubricants on adsorption/desorption process of fuel in oil layer that contributes to about 25–30% of total engine‐out hydrocarbon emissions in spark ignition engine. A comparative study is carried out between the six lubricants, namely, squalane (C₃₀H₆₂), SAE0W20, SAE10W30, SAE10W40, SAE10W60 and SAE15W60. The Henry's constant and diffusion coefficient are found to be the two most important parameters that affect the amount of fuel in oil layer. The Henry's constant dominates the adsorption/desorption process at high temperatures of oil, whereas at low temperatures, diffusion coefficient effect prevails. The percentage of fuel adsorbed/desorbed into oil layer is found to be dependent on engine speed, equivalence ratio and engine load. The results are found to be in good agreement with experimental trends of hydrocarbon emissions when tested on a single cylinder SI engine using the lubricants SAE10W30 and SAE10W40. Copyright © 2016 John Wiley & Sons, Ltd.     

内燃机活塞裙部-缸套间润滑油输送状况*

活塞裙部-缸套间的润滑油输送情况对内燃机活塞组件摩擦副润滑状态、润滑油消耗、排放和润滑油性能退化等都有重要的影响。结合活塞二阶运动模型、流体润滑模型和润滑油流动模型等,进行不同内燃机工况下活塞裙部-缸套间润滑油输送状况的计算,主要分析活塞向下运动行程中活塞裙部运动后气缸套表面润滑油的滞留量。结果表明,在不同工况下对应行程中润滑油滞留量的变化规律基本相同,不同时刻的润滑油滞留量不相同,活塞上下止点处的润滑油滞留量基本相同。内燃机负荷相同时,随转速增加,进气行程中和膨胀行程中后期的润滑油滞留量减少,膨胀行程前期的润滑油滞留量增加。内燃机转速相同时,膨胀行程前期的润滑油滞留量一般随负荷增加而增加,膨胀行程中后期的润滑油滞留量基本不随负荷变化,不同转速下进气行程中润滑油滞留量随负荷的变化规律不一致。     

Effect of lubricating oil additives on particle size distribution and total number concentration in diesel engine

This paper investigates the characteristics of particle size distribution in exhaust gas of engine fuelled with pure diesel and with diesel mixed with base oil or with oil additives. The experiments are conducted on a turbocharged diesel engine with fast particulate spectrometer DMS 500 connected to the exhaust pipe. Base oil and two kinds of commonly used lubricating oil additives, antioxidant additives and antifoaming additives, are chosen to be added into the fuel, with the concentrations being 0.5%, 1.0% and 1.5% of fuel weight individually. The particle size distribution is measured under medium load (100 Nm) and full load at different speeds. The results indicate that the existence of base oil or oil additives shows great influence on particle size distribution. Copyright © 2012 John Wiley & Sons, Ltd.     

Oxidation of mineral base oils of petroleum origin: The relationship between chemical composition,thickening, and composition of degradation products

The aim of this study was to improve understanding of high-temperature oxidation of base oils used in automobile engine oil formulations. Various oils were investigated: oils from the Middle East and the North Sea, with high and low aromatic and sulphur contents respectively; a hydro-isomerised polyalphaolefin oil with no aromatic or sulphur content; and a hydrocracked oil of intermediate composition. The influence of the aromatic and sulphur content and composition of the oils on thermo-oxidative degradation is investigated. These compounds give base oils natural protection from oxidation, but, under severe oxidation conditions, in the presence of a catalyst such as iron, which is always present in an engine, they become precursors of deposits. The action of two types of additive, radical inhibitors and hydroperoxide decomposers, was studied through oxygen consumption and thin-film oxidation tests. The oxidation products were identified; these provide insight into the degradation processes of the compounds during oxidation. They show too the influence of these processes on the formation of oxidised volatile species, on the increase in viscosity of the oil, and on the formation of oxidised species of high molar mass which, as they condense, contribute to the formation of insoluble compounds and deposits.     

大功率密度柴油机主轴承混合润滑分析

针对某型柴油机功率提升后主轴承润滑性能出现恶化的现象,计及表面形貌和弹性变形等因素影响,建立12V150柴油机主轴承润滑分析模型。运用弹性流体润滑、轴承动力学及Greenwood-Tripp微凸峰接触理论,分析功率提升后的主轴承润滑性能,提出需要改进的参数。分析表明:主轴承润滑性能变差的原因主要是功率提升后,曲轴和主轴承承受载荷加剧,油膜压力增加,引起轴颈弯曲或倾斜,导致主轴最小油膜度减小。研究曲轴平衡率、轴承宽度和润滑油黏度等参数对主轴承润滑性能的影响,提出了将曲轴平衡率由70%增大至90%,轴承宽度由46 mm增大至48 mm,并合理增加润滑油黏度的改进方案。结果表明:曲轴平衡率能有效地减小主轴颈倾斜角度,而轴承宽度和润滑油黏度对轴颈倾斜几乎没有影响;改进后主轴承最小油膜厚度提升了16.08%,峰值粗糙接触压力减小了37.11%,平均摩擦损失总功减小了13.08%。     

表面粗糙度和润滑油黏度对活塞裙-缸套摩擦副润滑性能的影响

以一多缸内燃机为对象,研究表面粗糙度和润滑油黏度对活塞裙-缸套摩擦副润滑性能的影响。建立活塞二阶运动方程与平均Reynolds方程相结合的活塞裙-缸套摩擦副润滑分析模型。活塞二阶运动方程采用Broyden方法求解,应用有限差分法进行活塞裙-缸套摩擦副的润滑分析。结果表明,表面粗糙度对活塞裙-缸套摩擦副润滑性能影响不明显,而随润滑油黏度增加,活塞裙-缸套摩擦副的最小油膜厚度、摩擦力和摩擦功率增加,最大油膜压力在进气和排气行程随润滑油黏度变化比较明显,在其他行程变化较小。     

基于低摩擦的柴油机节能新方法研究

针对车用柴油机节能问题,提出一种基于低摩擦技术的柴油机综合节能方法。研究柴油机摩擦副低摩擦技术,采用涂层技术与润滑技术减少摩擦副磨损;搭建柴油机节能综合试验台,通过油耗仪和尾气分析仪检测节能减排效果。实验研究表明,采用涂层技术与耐磨润滑油,具有较好的节能效果,实现柴油机的节能,这为车用柴油机的节能减排提供了新的方法与思路。     

Comparison of the Effects of Biodiesel and Mineral Diesel Fuel Dilution on Aged Engine Oil Properties

Dilution of engine oil occurs when fuel is injected late in the combustion cycle to regenerate the diesel particulate filter used for trapping particulate emissions. Fuel dilution reduces oil viscosity and the concentration of engine oil additives, potentially compromising lubricant performance. Biodiesel usage may compound these issues due to its oxidative instability, and its higher boiling point compared to mineral diesel potentially causes it to concentrate more in the oil sump.

In this work, different amounts of mineral diesel and biodiesel (soy methyl ester, SME) were combined with 15W-40 CJ-4 diesel engine oil in laboratory oil aging experiments. Fuel was added and oil samples were withdrawn at periodic intervals. The oils were analyzed using typical oil analysis procedures to determine their condition, and wear evaluations under boundary lubricating conditions were determined using a high-frequency reciprocating rig (HFRR). Results showed that fuel dilution accelerated engine oil degradation, with biodiesel having a larger effect. However, friction remained unchanged with dilution, and wear actually decreased for fuel-diluted oils after 48 h of aging compared to aging without fuel dilution. Examination of the tribofilms by ultraviolet (UV) and visible Raman spectroscopy as well as Auger electron spectroscopy showed that additional carbon-containing components were present on tribofilms formed from fuel-diluted oils. These fuel-derived components may be responsible for the decreased wear observed.     

润滑油水侵对动压可倾瓦推力轴承润滑性能的影响*

针对核主泵、船用轴系等特定工况下推力轴承润滑油的进水问题,以46润滑油和68润滑油为例研究润滑油水侵对推力轴承润滑性能的影响。通过黏度测试获得润滑油中水分质量分数为0、0.5%、1.0%时的运动黏度,采用黏温曲线对润滑油含水前后的动力黏度进行表征。将润滑油的黏温关系代入推力轴承的润滑计算当中,获得不同含水量下轴承的最小油膜厚度、温升、流量及功耗等静态特性参数,并分析含水量对推力轴承起飞转速的影响。研究结果表明：润滑油含水后对最小油膜厚度和功耗影响较大,对温升和流量影响较小;随着润滑油含水量的增加最小油膜厚度和功耗均降低,而温升增大,流量减小;使用2种润滑油在不含水和水分质量分数为0.5%时的起飞转速都在50 r/min以下,水分质量分数为1.0%时起飞转速都在50 r/min以上,表明随着含水量的增加起飞转速增大。     

柴油机排放标准对润滑油发展的影响

阐明了柴油机润滑油的性能和质量对排放、节能的影响，分析了国内外柴油机润滑油的现状和发展趋势，提出了今后我国柴油油机润滑油的发展方向。     

二冲程油的润滑与沉积对摩托车运行的影响

本文论述了二冲程油的润滑特点，涉及润滑性及清净性的质量级别及其发展，通过发动机台架试验和摩托车道路试验，研究了不同二冲程油对发动机性能及有害排放的影响，并对用户使用不同质量的二冲程油进行了经济性分析。     

Characterization of Tribofilms Generated from Serpentine and Commercial Oil Using X-ray Absorption Spectroscopy

The chemical and tribological properties of serpentine particles suspended in lubricating oil were investigated using a pin-on-disk high frequency friction machine at 100 °C. The wear scar width of the upper steel pins was measured by an optical microscope. The tribofilm was characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) elemental mapping, and X-ray absorption near-edge structure (XANES) spectroscopy. It was found that the addition of serpentine to commercial engine oil improves its tribological properties. The SEM and EDX elemental mapping shows that a tribofilm formed by the commercial oil with serpentine contains silicon, magnesium, oxygen, phosphorus, sulfur, zinc, calcium, and carbon on the worn surface, which is different from the tribofilm formed by the commercial oil without serpentine. The results of the XANES analysis show that the addition of serpentine to the commercial oil changes the chemical compositions of the tribofilms. This change may account for the better tribological properties of the lubricating oil containing serpentine. The formation mechanism of the tribofilm is discussed.     

新型减摩润滑剂改善汽油/柴油发动机动力性能的研究

利用合成和复配技术制备了新型减摩润滑剂，采用WD615型柴油发动机和C698QA型汽油发动机进行了全速全负荷的加速强化台架试验和300摩托小时的可靠性台架试验，考察了该润滑剂作为CD15W／40和SF10W／30机油添加剂对发动机功率、扭矩、机械损失、油耗等外特性的影响。结果表明：研制的减摩润滑剂在改善车辆发动机的动力性能和延长使用寿命方面具有良好的效果．与CD15W／40机油相比，该润滑剂能够使柴油发动机的功率、扭矩分别提高2．1％、2．0％．降低机械损失4％，节省油耗达1．8％；与SF10W／30机油相比，使用新型减摩润滑剂后的汽油发动机最人功率和最大扭矩分别升高了6．1％和2．0％，油耗降低了6．0％。这是由于该润滑剂充分利用了配方中多种功能添加剂的单剂特性和复合协同功效，提升了传统润滑油的减摩润滑性能和整体性能。