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。     

润滑油性质对汽油机排放的影响及汽油机润滑油的发展趋势

用试验数据说明了汽油机润滑油的性能和质量对排放、节能的影响，分析了国内外汽油机润滑油的现状和发展趋势，提出了今后我国汽油机润滑油的发展方向。     

润滑油性质对汽油机排放的影响及汽油机润滑油的发展趋势

近年来在我国汽车发动机研究的过程开始认识到,只通过改造发动机结构、强化废气处理已经无法满足降低发动机排放的标准,应强化汽油清洁化标准、润滑油质量标准的研究力度,通过改善润滑油性质降低汽车的排放量。针对于此,下文分析润滑油性质对汽油机排放产生的影响,提出汽油机润滑油的未来发展趋势,旨在为降低汽油机排放量提供帮助。     

二冲程润滑油与发动机的排气系统堵塞

因二冲程润滑油直接参与燃烧，使发动机的燃烧室及排气系统产生大量沉积物。本文通过在不同排量发动机上的大量试验，研究了沉积物对发动机性能的影响，并提出了二冲程润滑油抗排气系统堵塞性能的评价方法。大量的试验表明该方法是准确可靠的。     

如何选用发动机润滑油

介绍汽油、柴油发动机润滑油的选用和注意事项,以汽车的使用有一定的指导意义。     

采用纳米铜改善二冲程油润滑性的试验研究

本文研究了加入纳米铜添加剂的润滑油在二冲程发动机标准试验程序下的润滑性。试验结果表明，纳米铜添加剂加入润滑油后，对二冲程发动机润滑性能有改善作用，并可降低发动机的摩擦损失功。     

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。     

小型二冲程汽油机气缸扫气道的设计与造型

介绍在小型二冲程汽油机气缸扫气道设计与三维造型过程中采用的一些处理方法。     

Valvetrain Friction and Wear Performance with Fresh and Used Low-Phosphorous Engine Oils

Continued legislative pressure to reduce automotive exhaust emissions requires an automotive catalyst to operate at its peak efficiency up to 120,000 miles. Catalyst life is shortened by the poisoning of active sites by glazing caused by the deposition of phosphorous. The primary source of phosphorous is zinc dialkyldithiophosphate, an antiwear and antioxidant additive in engine oil. Therefore, the reduction of the phosphorous level in engine oils raises concern for increased wear of engine components. In an engine equipped with a direct acting mechanical bucket-type valvetrain, high contact stress coupled with sliding action at the cam and tappet contact makes it particularly vulnerable to wear. Motored single cam lobe valvetrain experiments were conducted to evaluate the wear protection capability of several 0.05 wt% P containing engine oils while the oil is fresh. The wear protection capability of vehicle drain samples was also evaluated to ensure adequate protection up to the point of oil change. It was observed that used oils provided significantly improved wear protection capability coupled with reduced friction. An analysis of the tappet shim surface showed that the composition of lubricant-derived protective films formed with used oils is very different than that formed with fresh oil, which may very well explain improved wear characteristics and reduced friction with used oils.     

柴油发动机油对烟炱的处理能力要求及评定

为适应排放法规要求的发动机新技术增加了柴油机中烟炱的负荷水平。本文讨论了高烟炱含量对柴油机油的分散性能、抗磨损性能等方面的要求及其测定方法。     

汽油机涡轮增压与废气排放控制

涡轮增压技术与废气排放控制系统的结合,使汽油机的动力性能和燃油经济性能提高到一个新水平,废气涡轮增压技术在提高汽油机动力性能的同时,可以降低排放废气温度,降低排气噪音,改善燃油经济性,减少排放污染。结合目前采用废气涡轮增压技术的小排量汽车日益增多,维修中时常遇到涡轮增压器与废气排放系统相关联的故障,要解决这类问题就必须清楚其工作原理。     

Development and Significance of the Phosphorus Emission Index of Engine Oils

This paper reports the author's effort to verify some of the present assumptions regarding causes and relationships in the volatility of engine oil phosphorus. Using Selby‐Noack volatility data from 1300 engine oils collected by the Institute of Materials in three areas of the world, volatilised phosphorus showed very low statistical dependence on either oil volatility or phosphorus concentration in the fresh oil. Rather, the data seemed to indicate that the chemistries of the phosphorus‐containing additives and their formulation with other additives were the controlling cause of phosphorus volatility and, by extension, emission level. The study permitted the development of a phosphorus emission index that predicts the emission potential of a formulated oil based on the amount of phosphorus found in the volatilised oil collected in the Selby‐Noack test.     

Statistical Analysis of HTHS Viscosity Rating of Present-Day Engine Oils

The article describes the processes of degradation of five engine oils offered by different manufacturers but belonging to the same SAE class of viscosity. The direction and intensity of changes in high-temperature high-shear (HTHS) viscosity have been analyzed. As part of the experiment, the changes in engine oils occurring during actual operation have been observed. All engine oils were operated in passenger cars of a uniform fleet of 25 vehicles. The curves of changes in these engine oils are of similar shape, and the HTHS viscosity in the oil groups after 12 months, relative to the HTHS viscosity of fresh oil, increased by ～10%. The limit values were exceeded in two cases. Statistical analysis assisted in confirming the significance of changes in viscosity between measured oils. The obtained results have led to the development of a statistical model to calculate average predictive values of HTHS viscosity for a given mileage. The results may facilitate decision making regarding the service life of engine oils.     

采用文曲利管降低柴油机NOx排放

废气再循环(EGR,Exhaust Gas Recirculation)是大幅降低整机排放污染物的有效办法,也是目前较为常用和有效的措施.废气再循环(EGR)就是通过将柴油机排出的废气重新引回到气缸内参与燃烧的装置,可更好地控制和减少其尾气中NOx的排放量.文中介绍了柴油机工作时产生NOx的机理和文曲利管降低柴油机NOx排放的原理,通过对安装有文曲利管的柴油机进行试验,分析废气再循环率对柴油机动力性能和NOx排放的影响.     

Effects of Ethanol Contamination on Friction and Elastohydrodynamic Film Thickness of Engine Oils

The use of ethanol as engine fuel has increased for environmental reasons, both in flex-fuel engines and as increasing amounts of ethanol blended with gasoline in conventional engines. This article describes an investigation into the effects of ethanol contamination of lubricants during engine use with ethanol fuel. To facilitate this, a new technique was developed to measure small amounts of ethanol in lubricants. Elastohydrodynamic film thickness measurements and Stribeck curves were obtained for Group I base and formulated oils containing small added amounts of ethanol. The effect of the water present in hydrated ethanol was evaluated by carrying out tests using both hydrated and anhydrous ethanol. Measurements were also carried out using a Group II base oil with added ethanol. These measurements showed that in the low entrainment speed region, where the elastohydrodynamic film is very thin so that boundary lubrication prevails, the addition of ethanol produced a boundary film, which was not present for the base oils. By contrast, the addition of ethanol to formulated oil reduced film thickness in all lubrication regimes. The friction tests showed friction reduction due to addition of ethanol to the base oil, in particular at low speeds. For the formulated oil, ethanol reduced friction at high speeds, which was associated with a reduction in the viscosity of the lubricant, but at low speeds, ethanol reduced the formation of a boundary layer, increasing friction. The presence of water in hydrated ethanol did not significantly change the film thickness and friction when compared with anhydrous ethanol.     

BP神经网络在双燃料发动机排放预测中的应用

运用BP神经网络(Back Propagation Network)的自学习以及非线性逼近能力,对双燃料发动机排气中CO、HC、NO_x和碳烟的浓度进行拟合和预测。搭建神经网络模型,通过采集双燃料发动机排气浓度数据对神经网络模型进行训练和验证。当BP神经网络训练过程中样本和模型计算值的线性相关系数R大于0.9,且用于验证的数据和模型运算值误差在可忽略范围内,则所建的神经网络模型能够有效预测双燃料发动机的排气浓度。训练结果显示,CO、HC、NO_x和碳烟浓度的模型计算值和实测值线性相关系数R都大于0.9,说明神经网络具有较强的拟合能力;验证结果显示,预测值和实测值的相对平均误差都小于10%,能够满足实际需求。结果表明,运用神经网络模型能够有效预测双燃料发动机的排放。