柴油机燃用低比例小球藻生物柴油-柴油混合燃料的试验研究

以野生小球藻生物柴油(Chlorella Biodiesel Fuel,CBF)-柴油作为混合燃料,利用186FA柴油机进行台架试验。在CBF的掺混比例分别为0%,3%,5%(B0,B3,B5)时,对柴油机的动力性、燃料燃用的经济性和燃烧及排放特性进行了比较分析。试验分析表明:柴油机燃用混合燃料时,与燃用纯柴油相比,随着CBF掺混比例的增加,其扭矩和功率略有下降,最大降幅均为4%;柴油机的油耗率和能耗率略有上升,且在高、中负荷时更为明显;柴油机的缸内压力、放热率峰值稍有减小,而压力升高率峰值稍有增大,缸内压力峰值最大降幅为3.4%,放热率峰值最大降幅为12.8%,压力升高率峰值最大增幅为13.7%;柴油机滞燃期缩短了0.5~1.0°CA、燃烧持续期延长了1.0~2.0°CA,缸内压力、压力升高率和放热率峰值的出现时刻均提前了1.0~2.0°CA,燃烧速度加快;HC,CO和碳烟的排放均有所降低,而NOX的排放逐渐增多,全负荷时HC和碳烟排放的最大降幅分别为14.1%和31.7%,NOX排放的最大增幅为9.7%,CO排放的降幅为6%~12%。     

柴油十六烷值改进剂的使用性能与应用

主要介绍了柴油十六烷值改进剂的作用机理、种类和应用情况,并详细介绍了不同的十六烷值改进剂的特点。十六烷值改进剂受热分解产生活性自由基,使得柴油的自燃活化能大大降低,从而缩短发动机燃烧的滞燃期,改善发动机的燃烧性能。     

A survey of the automotive diesel quality in the Athens area

One of the most fuel‐efficient engines available is the diesel engine. It is the engine of choice for the commercial and heavy‐duty transportation industry. Increasingly stringent legislated exhaust emission levels are driving improvements in both engine technology and fuel quality around the world. This paper presents the results of a survey in automotive diesel samples obtained from service stations in the Athens area. For this purpose 112 fuel samples were randomly collected from several service stations during the period from April 1998 until June 1999. These samples are representative of the automotive diesel distributed in the Athens area from all the oil companies operating in Greece. The laboratory examination involved the analysis both for any adulteration with the cheaper domestic heating diesel or marine diesel, and for some key properties of the automotive diesel. The ASTM standard methods were applied for the determination of the sulphur and nitrogen content, the density at 15°C, the Cetane index, the kinematic viscosity at 40°C and the distillation properties of initial boiling point of the fuel (IBP), 10 per cent volume of the fuel (D₁₀), 50 per cent volume of the fuel (D₅₀), 90 per cent volume of the fuel (D₉₀) and the final boiling point (FBP). The results indicate that there is a large fluctuation in the fuel properties among the oil marketers. Forty‐six samples were found to be adultered with the cheaper diesel (domestic heating or marine diesel fuel) during the sampling period. This means that more than 40 per cent of the automotive diesel distributed in Athens, suffers from some degree of adulteration. One sample was found to be outside the current specifications of density maybe due to contamination with white spirit. The fuel adulteration problem is associated with environmental pollution, problems in engine performance and tax losses. It is a common problem not only to the European countries but practically for every nation in the world. The European Union expressed recently its concern on this issue, mandating that by the year 2002 all the member states will promote the development of a uniform system for fuel quality monitoring. Copyright © 2001 John Wiley & Sons, Ltd.     

Effects of cetane number improvers on diesel fuel from direct coal liquefaction

Diesel from direct coal liquefaction possess low sulfur content and good cold flow properties. Nevertheless, its cetane number is only 44, which is much lower than 51 set by EN 590. In this study, the cetane numbers of this diesel and its blends with isooctyl nitrate, tert-butyl peroxybenzoate, acetone, 2-ethoxyethanol, and dibutyl oxalate were measured. Results showed that 0.5% isooctyl nitrate and acetone could increase cetane number from 44 to 53.2 and 52.8, respectively; isooctyl nitrate mixed with 66.7% acetone exhibit positive synergistic effects. The mechanism of these improvers based on the thermal decomposition principle was also explored.     

Fuel properties and exhaust emissions of low blending rate soybean oil methyl esters blended with diesel fuel

The main properties and engine emissions of low blending rate soybean oil methyl ester blended with diesel from 5 to 30 wt% were compared and analyzed. The experimental results show that, compared with diesel fuel, with an increase in the soybean oil methyl ester percentage in the blends, distillation temperature at 50%, flash point, kinematic viscosity, specific gravity, gelatine content, carbon residue, acidity and ash increase while a cold filter plugging point, solidifying point and copper corrosion keep constant, sulfur content decreases, smoke density and HC decrease while NO_x emission increase, CO increases at 2,200 r/min but decreases at 3,400 r/min.     

供油提前角对柴油/水煤浆混合燃料燃烧排放性能的影响

通过柴油机台架试验,分析了供油提前角变化对柴油/水煤浆混合燃料燃烧排放的影响.试验结果表明:当供油提前角调定为18 ℃A时,柴油/水煤浆混合燃料的有效燃油消耗率降低,热效率升高,燃烧持续期最短,增加或减少供油提前角都将延长燃烧持续期;供油提前角变化对柴油/水煤浆混合燃料的排放有较大影响,逐步增大供油提前角(由17到18 ℃A,再到19 ℃A),混合燃烧的烟度排放降低,Nox的排放先降低再升高,CO的排放先升高再降低,HC排放升高.     

柴油醇混合燃料在小型柴油机上应用的研究

文章就柴油醇在应用中存在的相分离和十六烷值低等问题提出了一种复合添加剂，它主要由醇、醚和酯等成分构成。试验表明，添加1％～2％的复合添加剂可以提高柴油醇的稳定性和抗水性，并可以使柴油醇的十六烷值接近于50。在S1105柴油机上的台架试验表明，与纯柴油相比较，使用20％柴油醇后，发动机的比油耗有较明显的增加，而有效热效率却略有提高；排气烟度在各种负荷下都大幅度降低，NOx排放量在低负荷时降低，在高负荷时却有所升高。     

柴油添加剂降低燃油消耗率及排放的试验研究

在Y4100Q自然吸气柴油机试验台架上使用0#柴油及加入6种不同添加剂的0#柴油,对两者进行比较。给出了柴油机排放物CO,HC,NOX,PM及燃油消耗率的测试结果。分析了排放物的生成机理及不同成分或不同量的添加剂对柴油机排放和燃油消耗率的影响。     

新型多碳醇-柴油燃料对柴油机性能及排放的影响

试验在一台S195柴油机上进行,试验结果表明,新型多碳醇-柴油混合燃料的油耗率比纯柴油高,但随负荷的增大,差距呈下降趋势。新型混合燃料在较大工况范围都保持较低的CO排放量。新型混合燃料中,小比例多碳醇油料的加入有利于混合燃料的HC排放状况的改善,大比例多碳醇油料的加入,对改善混合燃料的HC排放影响不明显;新型混合燃料的NOx排放均比纯柴油低,并且小比例多碳醇-柴油混合燃料的NOx排放比其大比例混合燃料的NOx排放量低;新型混合燃料的碳烟排放均比纯柴油低,并且随着多碳醇掺混比例的增大,改善效果越好。     

基于线性神经网络与柴油十六烷值预测发动机NOx排放

分别以柴油的十六烷值、十六烷值和十六烷改进剂、十六烷值和柴油的含氮量作为输入量,以发动机排放的NOx作为输出量,建立了发动机的NOx排放的线性神经网络模型,利用该模型预测了发动机排放的NOx的值,分析了十六烷改进剂和柴油的含氮量对发动机的NOx排放的影响,得到了较为满意的结果。     

二甲醚用作柴油机燃料的进展

介绍二甲醚作为柴油发动机燃料的进展 ,有关发动机的性能、微粒排放、燃料喷射、磨损和密封、着火延迟及安全性能问题     

Influence of fuel oxygen content on diesel engine exhaust emissions

The aim of this work was to investigate: the intersolubility of mixtures of rapeseed oil methyl esters, diesel fuel and ethanol; to determine the dependence of solubility upon temperature and finally to evaluate emissions of exhaust gases of these stable fuel mixtures.Bearing in mind that the cloud point is an important parameter of diesel fuel, the variation of solubility of a tri-component rapeseed oil methyl ester–diesel fuel–ethanol (RME–D–E) system at temperature (20; 0; −10 °C) was also investigated. It was found that temperature decrease causes the RME–D–E system solubility limits to become narrow. Solubility investigations allowed to determine the optimal solubility limits and select mixtures containing 6.9–25.7% of oxygen for engine tests. The highest oxygen content in biodiesel fuel permitting the engine to work normally at 2000 and 1200 min⁻¹ was 19.5%. The lowest concentration of PAH and smoke index of exhaust gases were determined when fuel mixtures contained 19.5% of oxygen. The CO concentration depended on the rotational speed and varied from 10.7% to 16.8%. Apparently, optimal diesel fuel on this basis will contain from 15% to 19% of oxygen.     

植物油及其衍生物在柴油机上的应用

评述了植物油及其衍生物在柴油机上应用的前景和可行性,讨论了目前纯植物油、生物柴油和它们的混合物在柴油机上使用的最新研究成果。比较了植物油及其衍生物和传统柴油的性质以及柴油机燃用这些燃料时的性能和排放特性。     

Influence of cetane number improver on performance and emissions of a common-rail diesel engine fueled with biodiesel-methanol blend

In this paper, the effect of cetane number (CN) improver on performance and emissions, including particulate number concentration and size distribution, of a turbocharged, common-rail diesel engine fueled with biodiesel-methanol were studied. Two volume fractions (0.3% and 0.6%) of CN improver were added to BM30 (30% of methanol in the biodiesel-methanol blend) in the experiment. The results show that, compared with those of biodiesel-methanol blend, the peak value of cylinder pressure increases, the second peak of heat release rate decreases, the start of second heat release are advanced, and the fuel economy and thermal efficiency are improved when CN improver is added to biodiesel-methanol blend. Besides, CO and HC emissions decrease, NO_x emission varies little and smoke emissions increase slightly. Moreover, exhaust particles of BM30 mainly distribute in nano-size range. Furthermore, particle number concentration decreases and peak of size distribution profile shifts toward large size direction.     

Experimental investigation of the performance and exhaust emissions of a swirl chamber diesel engine using JP-8 aviation fuel

An experimental study is conducted to evaluate the use of JP-8 aviation fuel as a full substitute for diesel fuel in a Ricardo E-6 high-speed naturally-aspirated four-stroke experimental engine having a swirl combustion chamber. The study covers a wide range of engine load and speed operating conditions, comprising measurements of cylinder pressure diagrams, high-pressure fuel pipe pressures, exhaust gas temperatures, fuel consumptions, exhaust smokiness and exhaust gas emissions (nitrogen oxides, unburned hydrocarbons and carbon monoxide). Processing of the measurements provides important performance parameters such as maximum combustion pressure, dynamic injection timing, ignition delay, combustion irregularity and knocking tendency. The differences in the measured performance and exhaust emission parameters are determined for engine operation with JP-8 fuel, against baseline engine operation using diesel fuel. The study shows that the exhaust emission levels are not much different for operation with the two fuels. On the contrary, operation with JP-8 fuel increases combustion pressures, combustion intensity and irregularity. This is caused mainly by high pressure fluctuations present in the fuel injection system due to the different physical properties of JP-8 fuel (compared to diesel fuel), which totally change the injection characteristics. Retardation of the static injection timing is one means of improving this situation, while using the same fuel injection equipment. © 1997 John Wiley & Sons, Ltd.     

Influence of polyoxymethylene dimethyl ethers on diesel fuel properties

Polyoxymethylene dimethyl ethers (PODE_3–8) is a new type of diesel fuel additive that can improve combustion and reduce pollution emissions significantly. In this study, the effect of the different ratios of PODE3-8 to diesel on the properties of diesel fuel was studied. The results showed that 20% of the mixed sample improved the quality of diesel oil, reducing the pour point from to –6℃, enhancing the cetane number from 46 to 53.6, and increasing the flashpoint from 55 to 57℃. All other technical specifications of polyoxymethylene dimethyl ether and 20% blending diesel were in accordance with the Chinese National Standards of 0^#diesel.     

Comparison of fuel characteristics of green (renewable) diesel with biodiesel obtainable from algal oil and vegetable oil

To fulfill the need of renewable, sustainable, and cleaner form of fuel, scientists are attracted toward biodiesel and hydrotreated vegetable oil or green (renewable) diesel. Biodiesel is generally obtained from vegetable oil by the process of transesterification while green diesel is obtained by hydrogenation. However, chemically both are completely different and thus their physical properties are highly affected. In present work, authors have compared the important properties of Pongamia biodiesel, algal biodiesel and hydrotreated vegetable oil. It is observed that both the biofuels may be blended for use in diesel engines as this will complement their fuel characteristics.     

柴油机使用EGR后供油提前角对排放特性影响的研究

研究了增压直喷柴油机供油提前角对排放特性的影响规律,分析了在柴油机采用废气再循环（EGR）技术降低NOX排放的同时,不同供油提前角对柴油机排放及油耗的影响情况。依据柴油机EGR控制系统的工作特点和功能,确定了柴油机的最佳供油提前角,并通过负荷特性试验对比分析,证实了在保证此最佳供油提前角的情况下,EGR综合降低排放效果可达到最佳。     

柴油机新型含氧燃料研究现状及进展

柴油机含氧燃料作为柴油的替代品和添加剂,可有效减少机动车尾气排放,缓解对石化燃料的依赖。因此,开发柴油机新型含氧燃料有着环保和节能的双重意义,是近年来研究热点。综述了国内外液态醚类燃料、醚酯类燃料、生物柴油等新型含氧燃料及其研究进展,介绍了它们的排放性能。     

Analysis of performance and emission patterns of novel biofuel feedstock neat coconut fatty acid distillate (CFAD) fuelled single-cylinder diesel engine

This study examined the potential of using coconut fatty acid distillate (CFAD), a by-product of the processing of edible oils, as a diesel engine fuel. The major novelty of this study is to assess the CFAD as a viable feedstock of biodiesel to address global energy demands. CFAD has not been specifically researched as a feedstock for producing biodiesel or as a fuel for diesel engines, despite the fact that numerous studies on the production and performance of biodiesel have already been conducted. Fourier transform infrared (FTIR) spectroscopy, gas chromatography (GC), and FTIR were used to analyze the fuel. According to the results of the GC test, CFAD oil contains 91.53% saturated fatty acids, compared with only 8.47% unsaturated fatty acids. High saturation values can be seen in myristic acid (16.92%) and lactic acid (45.33%). Longer hydrocarbon chain lengths indicate higher energy density and boiling point, which also indicate lesser volatility. At a frequency of 1708.54 cm⁻¹, C─H stretching vibrations have been identified through FTIR investigation. The vibrations of C─C stretching at 1465.47 cm⁻¹ indicate the presence of alkenes/fingerprint phase. The blends used for this investigation include 90% diesel with 10% CFAD (CFAD10), 80% diesel with 20% CFAD (CFAD20), 70% diesel with 30% CFAD (CFAD30), and 100% CFAD. The CFAD 10%, 20%, and 30% blends as well as the CFAD100 had brake thermal efficiency values of 27.24%, 26.23%, 24.88%, and 21.52%, correspondingly, at full load. The average increment in brake-specific energy consumption for CFAD10, CFAD20, CFAD30, and CFAD100 over diesel fuel was 8.23%, 10.88%, 13.77%, and 25.90%, respectively. The behavior of CFAD exhibits reduced cylinder pressure because of the large content of moderate saturated fatty acids in this substance. The net heat release rate (NHRR) and cylinder pressure have a similar relationship in that the NHRR increases with increasing diesel volume. In comparison to diesel, the CO emissions from the CFAD20, CFAD30, and CFAD100 blends increased by 10.79%, 16.66%, and 35.89% at maximum load, respectively. It has been reported that NO_x is reduced more significantly the more CFAD is present in the mixture. The blend CFAD10 had the least amount of smoke. The high viscosity of the CFAD and its blends influences the fuel droplets range and the development of spray in the cylinder, which results in delayed combustion and higher unburned hydrocarbon emissions.