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为了降低柴油机的排放,氢作为柴油机燃料的研究正在引起研究者的关注。该文进行了在2004 Mack MD11柴油机中添加不同比例氢气(最高氢气比例达7%)与柴油形成混合燃料的NOx、微粒(PM,particulate matter)排放特性研究。研究表明:负荷工况不同,添加氢气对NOx排放特性的影响不同;随着添加氢的增加,有NO转化为NO2现象;NOx排放很大程度还与发动机可变截面涡轮增压系统(VGT,variable-geometry gas turbine)和废气再循环系统(EGR,exhaust gas recirculation)工作状况有关;添加氢气后即使在大、全负荷下,NOx排放量也没有明显增加。这主要归因于2004 Mack MD11采取了EGR,并且随着负荷增加,EGR率也在增加。在各种负荷工况下,添加氢气对降低PM排放量的作用明显,PM排放量减小率一般达50%以上,最高达75%。
In order to reduce the emissions of diesel engines, hydrogen as a diesel fuel research is arousing researchers’ attention. In this paper, we studied the emission characteristics of NOx and particulate matter (PM particulate matter) by adding different proportions of hydrogen (up to 7% of hydrogen) to diesel fuel in a 2004 Mack MD11 diesel engine. The results show that: with different load conditions, the effect of adding hydrogen on the NOx emission characteristics is different; with the addition of hydrogen, NO is converted to NO2; and NOx emission is largely related to the variable turbocharger system (VGT, variable-geometry gas turbine, and exhaust gas recirculation. No significant increase in NOx emissions even under large or full load after adding hydrogen. This is mainly due to the fact that the 2004 Mack MD11 adopted EGR, and as the load increased, the EGR rate also increased. Under various load conditions, the effect of adding hydrogen on reducing PM emission is obvious. The reduction rate of PM emission is generally over 50% and up to 75%.