为保护环境和人体健康,对现代柴油机的重新认识和研究势在必行.利用全气缸取样系统对不同工况下的柴油机燃烧过程中的微粒生成历程、微粒形貌及基本粒子化学成分进行了研究.结果表明,微粒质量浓度曲线呈单峰状,峰值出现在上止点后约20°CA ATDC.在燃烧后期,约70%-80%碳微粒被再次氧化;此后微粒质量浓度接近于排放水平.微粒形貌呈现出链状结构.链状粒子由直径为10~30nm准球状的基本粒子连结而成,主要由碳元素构成,并包含少量如氧、氮和硫等其他元素.
Based on a new-designed total cylinder sampling system done by authors, particulate evolutionary process, shape character and physiochemical property in diesel combustion under different engine operating conditions are investigated. The experimental results indicate that mass concentration of particulate shows unimodal distribution and the peak point lies at 20°CA ATDC. The soot particles formed in the cylinder during the early combustion phase are oxidized by about 70%-80% in the late combustion phase, whereas the soot particle sizes distribution in the cylinder at the end of the expansion phase are equal to that in the tail pipe. Particulate is in chain structure and agglomerated by elementary spherules. The spherule varies in diameter from 10 nm to 30 nm and consists of dominating carbon with residual contents of oxygen, nitrogen and sulfur.