The characteristics of combustion and spray,power performance,fuel economy and emission characteristics for e-mulsified diesel were reviewed,the differences of engine fueled with conventional and emulsified diesel and their causing factors were analyzed,and the application and optimization methods of emulsified diesel in diesel engine were finally summarized.The results showed that the ignition delay and combustion duration period of emulsified diesel delayed and shortened respectively.In addition,spray penetration of emulsified diesel was almost the same as or longer than that of pure diesel and its flame height al-so increased.The power of diesel engine decreased,but the brake thermal efficiency improved after being fueled with emulsified diesel.The NO xand soot emissions reduced and the HC and CO emissions increased at most operating points,especially at low speed and medium and low load.The total particle number concentration increased,the particle volume fraction decreased and the aldehyde and noise emissions were little influenced.The addition of appropriate additives or the introduction of engine col-laborative technology could improve the combustion process of emulsified diesel and hence the low fuel consumption and emis-sion were realized.The fuel design based on fuel stability and physiochemical features and the optimization of combustion pa-rameter for high pressure common rail diesel engine fueled with emulsified diesel would be concerned in the future.%综述了柴油机燃用水乳化柴油的燃烧与喷雾特性、动力性与经济性及排放特性,对比分析了发动机燃用水乳化柴油与普通柴油在性能上的差异及其原因,总结了水乳化柴油在柴油机上的应用优化方法.结果表明:与柴油相比,乳化柴油着火滞燃期延迟,燃烧持续期缩短,喷雾贯穿距变长或相差不大,火焰升起高度增加;燃用乳化柴油时动力性下降,但有效热效率较柴油升高;乳化柴油可以明显降低NO x和炭烟排放,但多数工况下 HC和CO排放有所升高,低转速和中低负荷工况下尤为明显;燃用乳化柴油时颗粒物数量浓度增加,体积浓度减小,且对于醛类和噪声排放并没有改善作用;添加合适添加剂或结合发动机技术协同作用,可以针对性地改善乳化柴油的燃烧过程,进一步起到节能减排的效果.基于燃料稳定性与燃料理化特性综合优化目标的燃料设计,以及适用于乳化柴油的高压共轨柴油机燃烧组织参数优化是未来的研究方向.
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