在一台整车排放达到国Ⅲ标准的YC4D140电控单体泵增压中冷柴油机上加装甲醇喷射系统,改成柴油甲醇组合燃烧(DMCC)发动机.使用AVL 415S烟度计和DMS 500快速颗粒物光谱仪研究不同后处理器对DMCC发动机颗粒物(PM)排放的影响.试验结果表明,各工况下单独CDPF、DOC+CDPF基本可以消除发动机产生的干炭烟.DOC+CDPF后处理方式与单独CDPF相比,颗粒物捕集效率明显提高,且前者对颗粒物中核态部分的捕集效果更加突出.甲醇掺烧后,炭烟和颗粒物几何平均直径降低.经CDPF和DOC+CDPF处理,415S烟度计测得的炭烟进一步降低;DMS颗粒物光谱仪显示的颗粒物粒径,因其中核态部分大部被氧化捕集而仅余较大几何平均直径的部分.小负荷时经CDPF和DOC+CDPF处理,颗粒物的几何平均直径会增大,大负荷时则相反.各工况下相比于CDPF,DOC+CDPF对核态颗粒物捕集更有效.
Experiments were conducted on YC4D140 electronic unit pump turbo-charged,inter-cooling diesel engine which was modified to run in the mode of diesel / methanol compound combustion( DMCC). By using AVL 415 S smoke meter and DMS 500,the effect of different post-processors on the PM emission of DMCC engine was investigated. The results showed that either individual CDPF or DOC + CDPF could remove most of the dry soot.Compared with individual CDPF,DOC+CDPF had higher efficiency on trapping particulates,especially those in the nuclear mode. Soot and particulate matter could be reduced further with addition of methanol in combustion. After treated by CDPF and DOC+CDPF,dry soot could be further reduced but geometric mean diameter( GMD) slightly increased. The experimental results illustrated that CDPF and DOC +CDPF would increase the GMD at small load,but would reduce GMD at heavy load. Compared with CDPF,DOC+CDPF was more effective in eliminating the nuclear mode.