【作者】 林漫群；

【导师】 刘书亮；

【作者基本信息】 天津大学 ， 动力机械及工程， 2007， 博士

【摘要】 随石油用量增长,为解决燃油短缺和大气污染问题,我国已决定推广使用可再生的清洁燃料。乙醇作为一种广泛使用的可再生环境友好燃料可与汽油混合使用以缓解不断增长的燃油需求。目前国内约有10个省份正在使用E10乙醇汽油。小型汽油机,如摩托车和非道路小型点燃式发动机（通机）产量巨大但较少引人关注。随着E10乙醇汽油在我国迅速增长,有关小汽油机动力性、经济性、磨损、常规与非常规污染物排放和催化净化等关键技术问题亟待开展系统研究。据此作者选择小型汽油机为研究对象,开展乙醇汽油适用性和排放控制研究工作。非道路发动机排放控制是与道路车辆相对的全新研究领域,特别是非道路小汽油机,欧美近几年方才起步。作者在国内建成首个符合美国环保署要求并通过我国国家实验室认可的通机排放实验室,率先开展了国外非道路发动机排放标准体系研究,通过试验对比测定通机燃用普通汽油和乙醇汽油性能与工况法排放差异。摩托车作为小型道路车辆亦对比测定不同燃油条件下工况法排放与整车性能,其间供油系统未做调整。数据显示,小型汽油机使用乙醇汽油后,CO和HC初始排放有所下降,而NOx有升有降,动力性随乙醇含量提高而有所下降。另外发现随乙醇混合比提高供油系统的供油量呈现降低趋势。乙醇做为含氧添加剂潜在排放更多有毒有机物的危险性,为此开展非常规污染物排放研究,工作包括发动机尾气非常规污染物采集、分离和定量测量等。其间作者除了使用色谱-质谱联用技术以外,针对甲醛含量低难以测定的现状探索了新的方法,成功地利用水吸收法富集甲醛并用紫外-可见分光光度法检定,显著地改善了现有甲醛分析的灵敏度,测量下限达到0.02×10^-6 （体积分数）。另使用涂敷二硝基苯肼（DNPH）的固相萃取柱进行采集,用乙腈洗脱后用液相色谱分析法测量发动机尾气中醛和酮类有毒有机物的新方法。截至目前已经在小汽油机尾气中检出包括醇类、苯系物、醛和酮等二十余种有机物并发现燃用乙醇汽油后高毒性物质——甲醛排放明显增高,值得关注。以工况法排放为指标考察摩托车使用普通汽油和E10乙醇汽油在10,000km道路耐久前后催化器净化率变化情况,对经过耐久考核的催化器进行了失活分析。研究发现摩托车催化器使用乙醇汽油后表面积碳聚合物种类以及部位存在差异,初步探讨了导致同型催化器在不同燃油条件下活性劣化程度存在差异的机理。开发了高精度催化剂活性评价设备,以催化器起燃温度为活性指标,对比测试多种催化器样品分别在燃用普通汽油和乙醇汽油的真实废气环境中活性劣化情况。发现不同催化器样品在乙醇汽油和普通汽油条件下表现各有优劣,应依据使用地区的燃油供应条件开展催化器开发与选配。另外,道路耐久后测试发现摩托车使用E10乙醇汽油后磨损偏大,两台二冲程摩托车发动机均发生了拉缸现象。作者注重科研成果标准化工作,牵头起草了我国第一部通机排放国家标准,以及另外两个关于摩托车催化器评价标准以及二次空气阀性能试验方法的标准。更多还原

【Abstract】 To meet the twin problems of fuel lacking and air pollution caused by the growing use of fossil fuels, Chinese government had determined to promote alternate renewable, clean burning fuels. Ethanol, one of widely used and renewable eco-friendly fuels can be used as a blend with gasoline to meet the growing demand of oil consumption. Presently about 10 provinces are using E10 ethanol-blended gasoline. Small gasoline engines such as motorcycles and off-road small spark ignition engines, so called utility engines, should have attracted attention for huge amount of production. Along with the rapid growth of E10 consumption, it is urgent to study effects brought about by ethanol. Author hereby selected small gasoline engines as research object to investigate applicability and emission control of ethanol-blended gasoline.The first laboratory in China for general utility engine emission tests was estabilished by research division of author following requirements of American EPA and certificated by CNACL. Emission regulations of overseas contries have been studied and the effects of ethanol and gasoline blends on the performance and regulated emissions (CO, HC and NOx) of typical utility engines made in China have been experimentally evaluated. To accomplish this task the engine fuel supply system was not modified. Comprehensive measurements of the performance parameters as well as the emissions using gasoline, ethanol-gasoline blends were performed. Furthermore, similar works executed on typical motorcycles. Detailed test results show that E10 could help small engines to reduce exhaust emission of CO and HC in some degree, but for NOx is half-and-half. Further research indicated that fuel supply decreased along with the increase of ethanol mixture ratio.Ethanol as oxygen additive has potential dangerous that might make poisonous organic compound exhaust more than that from pure gasoline fueled engines. This paper is concern to methods research of sampling, separating and analysis of unconventional exhaust emissions. Not only the method of Gas chromatogram and mass spectrum but also attempt to some new methods. Aim at the difficult problem of formaldehyde measurement, author enrich formaldehyde by water and then measured by means of ultraviolet-visible. The minimum measuring limits of formaldehyde was remarkably promoted to 0.02×10-6 (V/V). Furthermore, selected Solid-Phase Extraction Column with dinitrophenylhydrazone (DNPH) to catch aldehyde and ketone by chemical reaction which is so called ramification, and then wash by C2H3N and measured by Liquid- chromatogram. Up to now, more than 20 different organic have been determined. It shows that formaldehyde as high toxicity exhaust emission is much more than that from gasoline.Selected running mode emission test data to indicate conversion ratio of motorcycle catalytic converters before and after 10,000km road aging tests. Then aged converters were analyzed to investigate reasons for deactivity. Different carbon polymer was found from different fuel as primary explanation for de-active. An evaluation testing equipment for catalytic converters was developed and then took light off temperature to indicate converter’s activity. Some converter samples were aged together under the condition of real engine exhsuat gas which was fueled by gasoline and ethanol gasolines respectively. Performance of those samples show it is necessary to develop and match converters depending on different fuel supplied by regions.Contrasting durability tests show that engines fueled by ethanol gasoline appear more serious abrasion and more quantity of fuel supply characteristics for EFI system. Scraping phenomena happed on both two 2T motorcycles. Author also attached importance to standardization work root in study and research. Up to now, have drafted the first Chinese national standard for multipurpose utility engines emission control and other two standards for motorcycle catalytic converter and SAI evaluation test methods.更多还原