车用柴油机燃用柴油/乙醇混合燃料进行试验，采用DMS500 快速响应颗粒分析仪进行颗粒物浓度和粒径分布测试，分析乙醇掺混比例、发动机运行工况对颗粒物粒径分布、质量浓度和几何平均直径的影响． 研究表明: 柴油/乙醇排放的颗粒物呈核态、积聚态双峰对数分布; 随掺醇比的增加，小负荷下核态颗粒物数浓度明显降低，中、大负荷下积聚态颗粒物数浓度明显降低，核态颗粒物比例有所增加，颗粒粒径向小粒径方向移动; 柴油/乙醇排放颗粒质量浓度普遍低于柴油，颗粒物排放主要集中在积聚态颗粒物; 乙醇的掺混能有效降低颗粒物几何平均直径，随掺醇比的增加，颗粒物的几何平均直径呈下降趋势．

An experiment in a diesel engine fueled with diesel /ethanol blends was conducted,and the particle concentration and particle size distribution of the particulate matter from the diesel engine were investigated by DMS500 analyzer with fast response particulate.Then,the size distribution,mass concentration and geometric mean diameter of the particulate matter obtained under different running conditions of engine with different ethanol ratios were analyzed.The results show that ( 1) the particulate matter from diesel /ethanol blends follows a logarithmic distribution,which has two modes,namely,nucleation mode and accumulation mode; ( 2) with the increase of ethanol ratios,the nucleation mode particle number ( PN) density significantly decreases under a low load,while under medium and high loads,the accumulation mode PN density significantly decreases with an increase of the nucleation mode particle ratio and a decrease of the particle size; ( 3) for the particulate matter from diesel /ethanol blends,the mass concentration is lower than that from diesel,and the particle mass concentrates mostly in the accumulation mode; and ( 4) after the addition of ethanol to diesel,the geometric mean diameter of particulate matter significantly decreases,and it decreases gradually with the increase of ethanol ratios.