柴油、生物柴油后喷燃烧过程中颗粒物粒数粒径及质量的变化规律

摘要

Experiments were conducted on a direct-injection diesel engine,which was equipped with a common rail system.The number and size distribution,the total particulate number density and mass concentration of particulates produced from biodiesel and fossil diesel during the post-injection combustion were investigated using a total cylinder sampling system.Experimental results indicate a similar tendency for biodiesel and diesel in the variation of number and size distribution,total particulate number density and mass concentration of particulates at the same stage of post-injection combustion.The number and size distributions of particulates for both fuels ap-proximate to the lognormal distribution,with the peak values in the range of 39.2—69.8,nm for biodiesel and of 60.4—93.1,nm for diesel.At the same stage of post-injection combustion,the total particulate number density for biodiesel is higher than that for diesel,while an opposite result is found in the mass concentration of particulates.%基于全气缸取样平台,在一台高压共轨柴油机上,对近后喷和远后喷策略下生物柴油和柴油后喷燃烧过程中颗粒物的粒数粒径分布、总粒子数密度及质量的变化规律进行了研究.实验结果表明,在后喷燃烧过程中各阶段,生物柴油和柴油所产生的颗粒物的粒数粒径分布、总粒子数密度及质量变化规律相似.颗粒物粒数粒径均呈类似对数正态分布,生物柴油的峰值粒径范围为39.2~69.8,nm,柴油的峰值粒径范围为60.4~93.1,nm.与柴油相比,在相同后喷燃烧阶段生物柴油的颗粒物的总粒子数密度较高,但质量浓度较低.