DOC对柴油机燃用生物柴油颗粒物微观形貌及SOF组分的影响

为研究氧化催化转化器（DOC）对柴油机燃用调合生物柴油（B0，B20）后排放颗粒物微观形貌及可溶性有机组分（SOF）的影响规律，对DOC作用前后的排气颗粒物进行采样，利用透射电镜（TEM）和气相色谱-质谱仪（GC-MS）开展颗粒物理化特性研究.结果表明：未加装DOC时，与B0相比，B20排放颗粒物基本碳粒子粒径减小，分形维数增加，团聚堆积现象加剧；SOF组分中的脂类和酸类物质质量分数增加，烷烃类、芳香烃和酚类物质质量分数减少，C26~C35的质量分数降低.加装DOC后，B0和B20排气颗粒物团簇程度降低，分形维数降幅分别为10.1%和15.5%；SOF组分中芳香烃类和酚类物质质量分数增加，烷烃类、脂类、酸类质量分数减小，C15~C25质量分数下降；B0排放颗粒物SOF中C26~C35质量分数降低41.4%，而B20增加865.8%.

Influence of DOC on the microstructure and SOF components of particulate matters from a diesel engine fueled with biodiesel-diesel blend

In order to analyze the effect of Diesel Oxidation Catalyst (DOC) on microstructure and Soluble Organic Fractions (SOF) components of emission particulates emitted from diesel-biodiesel dual fuel (B0, B20), an experimental study was carried out on a diesel engine. Particulate matters before and after the DOC were collected and their physicochemical properties were characterized with using Transmission Electron Microscopy (TEM) and Gas Chromatograph-Mass Spectrometer (GC-MS). Results show that, increasing biodiesel percentage can minimize the size of basic carbon particles. Moreover, the surface of those tiny carbon particles appears more complicated, and consequently, the fractal dimension of particles were increased when the engine was fueled with B20. With a static analysis of the detailed SOF components from GC-MS analysis, it is revealed that esters and acids account for a larger proportion, while alkanes, PAHs and phenols account for very small proportion. A decline in the mass fraction of C26~C35 was also revealed. For the diesel engine with DOC, the surface of particles is more perceivable, and the fractal dimension of particles for B0 and B20 were reduced by 10.1% and 15.5% respectively. In terms of the SOF content, PAHs and phenols account for a larger proportion while alkanes, esters and acids account for a smaller proportion and also, the results show a decline in the mass fraction of C15~C25. The B0particle emission of C26~C35 mass fraction of SOF decreased 41.4% while B20 increased 865.8%.