铁基燃油添加剂对共轨柴油机燃烧与排放特性的影响

Effects of Fe-Based Fuel Borne Catalyst on Combustion and Emission Characteristics of a Common-Rail Diesel Engine

按Fe元素质量分数分别为200、400和600 mg/kg的比例将Fe基燃油添加剂(Fe-FBC)添加到柴油中,制备得到分别命名为Fe200、Fe400和Fe600的3种Fe-FBC燃油样品。基于热重实验平台在氧化氛围下对Fe-FBC燃油及其燃油颗粒进行热重特性研究,分析燃油中Fe含量与燃油特征温度的关系,研究Fe-FBC燃油的蒸发特性;探究Fe含量对颗粒氧化特性的影响,并计算颗粒反应活化能。基于发动机台架试验分析Fe含量对燃油缸内燃烧与排放性能的影响规律。结果表明:随着Fe-FBC燃油中Fe含量的增加,燃油起始燃烧温度降低,质量损失率峰值温度向低温区域偏移;与纯柴油相比,柴油机在额定工况燃用Fe-FBC燃油时,滞燃期缩短,缸内最大燃烧压力略有上升,放热始点提前,燃烧持续期缩短,HC与CO排放均呈下降趋势,NOx排放变化不明显,3种Fe-FBC燃油的烟度排放分别降低了13.7%、20.4%和24.0%。颗粒热重实验中,随着Fe-FBC燃油中Fe含量的增加,氧化初始反应温度分别降低了75.1、107.3和128.4℃,质量损失峰值温度分别降低了80.3、112.0和122.7℃,颗粒的反应活化能分别降低了45.2%、63.3%和65.5%。

The Fe-based fuel borne catalyst(Fe-FBC)was mixed into diesel with the mass fraction of Fe element of 200,400 and 600 mg/kg,which were named as Fe200,Fe400 and Fe600.Thermogravimetric analysis of Fe-FBC fuel and particles were employed to study evaporation characteristics of fuel and oxidation characteristics of particles including the activation energy.The combustion and emission characteristics were further analyzed by the engine bench test of diesel engine fueled.The results show that the initial massless temperature decreases and the temperature of peak massless rate shifts to low temperature region with the increase of Fe element mass fraction.Compared with pure diesel,the ignition delay period becomes shorter,the maximum cylinder pressure increases,the phase of heat release advances and the combustion duration of Fe-FBC fuel is shortened.HC and CO emissions are significantly decreased and smoke emissions are decreased by 13.7%,20.4%and 24.0%,while the change of NOx emission is not obvious.With the increase of Fe element mass fraction,the initial oxidation temperature decreases by 75.1,107.3 and 128.4℃,peak oxidation temperature decreases by 80.3,112.0 and 122.7℃,the activation energies of particles decrease by 45.2%,63.3%and 65.5%.