论文部分内容阅读
由于美国柴油法规、强制标准和规范的变化,美国铁路公司正在使用至多含有5%生物柴油的燃料(B5),并且内燃机车发动机将来可能使用生物柴油(高达20%)的混合燃料。尽管生物柴油已经在汽车燃油市场使用了很多年,但是对于机车发动机常规运行来说经验很少,机车制造商和铁路公司已经明确表达了他们的一系列关注,特别是采用高于B5燃油浓度的情况。文章总结了美国联邦铁路管理局(FRA)运输部提供资助的相关工作,以支持铁路行业评估生物柴油在机车应用的问题。详细阐述了美国调整生物柴油法规的初衷;评估B5和B20燃油对排放影响的试验流程;在机车发动机橡胶组件和燃油过滤组件中生物柴油的傅氏转换红外线光谱(FTIR)特性描述,以及采用傅氏转换红外线光谱对机车发动机燃油喷油器沉积物的特征描述。试验流程的目的在于评估不同生物柴油混合燃料对于机车发动机排放的影响。目前经过系统、可信、严谨设计并执行的机车燃油影响研究,进而形成具有显著统计学意义的结论非常缺乏,并且覆盖的机车类型数量极其有限。绝大多数机车生物柴油相关工作仅限于粗略展示相关项目,而对于铁路公司和法规制定部门的首要着眼点则在于了解使用生物柴油带来的排放影响,特别是NOx的排放。在本研究中,选用两种型号机车进行排放试验:一种是EMD SD70ACe型Tier 2机车;另一种是GE Dash9-44CW型Tier 1机车。采用两种基准燃油,传统EPA ASTM No.2-D S15(通常指超低硫柴油-ULSD)认证柴油燃料,以及商用加州空气资源委员会(CARB)标准ULSD燃油。采用同一批次大豆提炼B100燃油分别与EPA和CARB柴油按体积配比进行混合,制成5%和20%混合燃料。采用随机测试方法对6种试验燃油(EPA0、CARB0、EPA5、CARB5、EPA20和CARB20)的每一种都进行3次测试。对排放试验的结果进行分析以确定不同燃油对于排放影响的统计学关联,在其他研究和其他应用中出现的总排放和燃油经济性趋势在本研究中同样出现。生物柴油占比越大,CO、颗粒物排放越低,氮氧化物排放和燃油消耗越高。采用20%生物柴油混合燃料通常与0%和5%生物柴油有显著统计学区别,0%和5%生物柴油间没有显著的统计学区别。机车间的不同趋势可由不同排放等级、燃烧循环(4冲程、2冲程)以及润滑油消耗进行解释。
Due to changes in US diesel regulations, mandatory standards and codes, the U.S. railways are using fuels up to 5% biodiesel (B5) and diesel engine engines may use biodiesel (up to 20%) in the future. Although biodiesel has been used in the automotive fuel market for many years, it has little experience with conventional locomotive engine operation. Locomotive manufacturers and railroad companies have clearly voiced their concern, especially with fuel concentrations higher than B5 Happening. The paper summarizes the work funded by the Department of Transportation of the United States Federal Railroad Administration (FRA) to support the railway industry in assessing the application of biodiesel to locomotives. Described in detail the original intention of the United States to adjust the laws of biodiesel; B5 and B20 fuel emissions assessment of the impact of the pilot process; Locomotive engine rubber components and fuel filter components biodiesel Fourier transform infrared spectroscopy (FTIR) characterization, and the use of Fu Characterization of the Locomotive Engine Fuel Injector Sediment by Transform Infrared Spectroscopy. The purpose of the pilot process is to assess the impact of different biodiesel blends on locomotive engine emissions. At present, the systematic, credible, rigorous design and implementation of locomotive fuel impact studies that led to the formation of statistically significant conclusions are lacking and the number of locomotive types covered is extremely limited. The vast majority of locomotive biodiesel-related work is limited to a rough display of related projects, while the primary focus for railway companies and regulatory agencies is to understand the impact of emissions from the use of biodiesel, particularly NOx. In this study, two types of locomotives were selected for emission tests: one was an EMD SD70ACe Tier 2 locomotive and the other was a GE Dash9-44CW Tier 1 locomotive. Two base fuels are used, the traditional EPA ASTM No.2-D S15 (commonly referred to as ULSD-ULSD) certified diesel fuel, and the commercial California Air Resources Board (CARB) standard ULSD fuel. The same batches of soyabeans B100 fuel were blended with EPA and CARB diesel at a volume ratio of 5% and 20% respectively. Three tests were conducted on each of the six test fuels (EPA0, CARB0, EPA5, CARB5, EPA20 and CARB20) using the random test method. The results of the emission trials were analyzed to determine the statistical correlation of the different fuels to the impact of emissions and the same trends emerged for total emissions and fuel economy in other studies and other applications in this study. The larger the proportion of biodiesel, CO, the lower the emissions of particulate matter, the higher the nitrogen oxide emissions and fuel consumption. Biodiesel blends with 20% biodiesel typically have a statistically significant difference from 0% and 5% biodiesel with no significant difference between 0% and 5% biodiesel. Different trends in the shop floor can be explained by different emission levels, combustion cycles (4-stroke, 2-stroke) and lubricant consumption.