添加剂对柴油机燃用乙醇柴油时排放颗粒特性的影响

为研究十六烷值改进剂和消烟剂对柴油机燃用乙醇柴油时颗粒排放特性的影响,在乙醇柴油中加入0.1%(以w计)、0.3%和0.5%的十六烷值改进剂或消烟剂,并在YZ4DB3柴油机上分别对这些燃料的排气烟度、颗粒比排放和粒径分布等进行研究. 结果表明:含添加剂的乙醇柴油颗粒物排放远低于0#柴油,降幅在50%以上；与0#柴油相比,添加0.3%十六烷值改进剂的乙醇柴油降低颗粒排放效果较显著,降幅高达64.2%,而添加0.1%消烟剂的乙醇柴油颗粒物排放降幅更高达84.0%,表明消烟剂的降颗粒效果更加显著. 柴油机燃用柴油时,排放颗粒的粒径呈双峰分布,峰值分别在0.56和0.18μm左右；但燃用含添加剂的乙醇柴油时,排放颗粒的粒径则呈单峰分布,其峰值均在>0.56~1.00μm粒径范围内. 柴油机燃用含添加剂的乙醇柴油后,0.18~0.32μm粒径范围内的排放颗粒显著减少,但在>0.32~1.00μm粒径范围内增加；同时,排放颗粒物中的积聚模态颗粒占排放颗粒总质量的比例降低,而粗粒子模态颗粒的所占比例相应增加. 排气烟度与积聚模态颗粒质量分布密切相关. 研究结果表明,柴油添加剂能够显著改善柴油机颗粒物排放特性,有利于改善大气质量. 

Effect of the Fuel Additives on Particle Emission Characteristics of Diesel Engine Fueled with Ethanol-Diesel Blends

The effects of the cetane number (CN) improver and smoke suppressant on the characteristics of particle emission and its size distribution measured with a turbo-charged intercooled diesel engine (YZ4DB3) were investigated. During this process, the ethanol-diesel were blended with the fuel by adding different percentages of fuel additives at 0.1%, 0.3%, and 0.5%(by weight). The results showed that the effects of ethanol-diesel blends added with the fuel additives, CN improver and smoke suppressant, significantly reduced particle emission by 64.2%, compared with 0# diesel combustion. Accordingly, the size distribution of emitted particles was also significantly altered with fuel additive application that demonstrated a mono-modal distribution pattern characterized with a peak values ranged at 0.56and 0.18μm, while a bi-modal distribution pattern with two peaks ranged at >0.56-1.0μm was observed with the combustion of 0# diesel. Meanwhile, the emitted total particle mass distribution presented a different pattern, when fuel additives were applied, where a significant drop in the particle size at 0.18-0.32μm and a raise at >0.32-1.0μm were observed. Adding fuel additives can lead to more coarse mode particles and less accumulation mode particles. The relationship between smoke and weight percent of accumulation mode particulate were affected by the particle size distribution. The results suggested that the fuel additives, CN improver and the smoke suppressant, can significantly improve the engine particle emission and its characteristics that will improve the air quality.