车用柴油机燃用棕榈生物柴油的颗粒物排放特性研究

在满足国Ⅳ排放法规的车用柴油机上研究了燃用不同掺混体积比例的棕榈油生物柴油的颗粒物排放特性.试验中棕榈油生物柴油的掺混比例分别为0%、10%、20%、50%和100%,采用DMS500型快速颗粒光谱仪测试分析了发动机在外特性和负荷特性时的颗粒物数量浓度、质量浓度及粒径分布.研究结果表明:随生物柴油掺混比例的增加,颗粒物质量浓度降低.燃用生物柴油后颗粒物的数量浓度在大负荷明显降低,中小负荷呈升高趋势.生物柴油的排气颗粒物呈核态和凝聚态的双峰分布特征,核态数量浓度所占比例高于柴油,凝聚态的质量浓度所占比例略低于柴油.生物柴油颗粒物的几何平均直径小于柴油.

Particulate emission characteristics of vehicle diesel engine fuelled with palm-oil derived biodiesel

Characteristics of particulate emission of engines fuelled with different blend ratios of palm oil derived biodiesel and Ultra Low Sulfur Diesel (ULSD) were studied using a China-IV diesel engine. Five biodiesel-ULSD blends of 0%、10%、20%、50% and 100% were tested. The particle mass (PM) concentration, particle number (PN) density, and particle size distribution were measured by DMS500 particulate spectrometer. The results showed PM concentration decreased with the increase of biodiesel blend ratios. The total PN density decreased significantly at high load,while increased at low and medium loads. Bimodal PN size distribution was observed corresponding to nucleation mode and accumulation mode particles. Comparing with ULSD, biodiesel exhibited higher percentage of nucleation mode PN emissions and lower percentage of accumulation mode PM emission. Also, biodiesel exhibited smaller particulatd mean diameter than that of ULSD.