DMF/柴油和汽油/柴油混合燃料对柴油机燃烧和排放特性的影响  

Effects of DMF/Diesel and Gasoline/Diesel Blends on Diesel Engine Combustion and Emission Characteristics

作　　者：陈贵升[1] 李伟东[1] 沈颖刚[1] 郑尊清[2] 尧命发[2] 张韦[1] 

机构地区：[1]昆明理工大学云南省内燃机重点实验室,昆明650500 [2]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《内燃机工程》2014年第3期6-13,共8页Chinese Internal Combustion Engine Engineering

基　　金：云南省科技厅面上项目(2013FB019);云南省级人培项目(KKSY201302127)

摘　　要：在一台共轨柴油机上,通过向柴油分别掺混30%体积比的2,5-二甲基呋喃(DMF)和汽油,研究了含氧燃料和低十六烷值燃料对柴油机燃烧过程和排放特性的影响机理。研究结果表明:D30的滞燃期最长,G30次之,纯柴油最短,表明十六烷值是影响着火滞燃期的关键因素。混合燃料的挥发性、硫和芳香烃含量对碳烟排放影响较小,扩展的着火延迟期和增加的燃料氧(原子氧)是降低低温燃烧过程中碳烟生成的两个关键因素。柴油掺混DMF,通过采用中等强度EGR率(低于40%),能显著扩展低排放区域(NOx排放<0.4g/(kW·h),碳烟排放<0.01g/(kW·h))并保持较好的燃油经济性。相比汽油/柴油混合燃料,DMF/柴油混合燃料对碳烟的降低效果更显著,表明DMF作为一种低十六烷值的新型生物质含氧燃料,其与柴油混合后的理化特性更适合于柴油机低温燃烧的排放控制。多次喷射试验表明:在柴油中掺混DMF或汽油,喷油控制策略对碳烟生成影响减小。综合来看,石化柴油与低十六烷值含氧燃料混合,通过燃料改性与中等强度EGR率(低于40%)耦合并合理控制CA50,是在简化喷油控制策略下实现现代柴油机高效、清洁低温燃烧的一项有效技术途径。In a common-rail diesel engine, effects of DMF/diesel and gasoline/diesel blends on combustion and emission characteristics were investigated. Results show that ignition delay of DMF is the longest, followed by G30, and pure diesel is the shortest, that demonstrates that cetane number （CN） is the key factor affecting ignition delay period. Volatility, aromatics and sulphur contents of blend slightly effect soot formation slightly. Ignition delay period extension and fuel oxygen （atomic state） increase are two key factors reducing soot of engine low-temperature combustion （LTC）. Low-emission region （NOx〈0.4 g/（kW.h）, soot%0.01 g/（kW·h）） can be remarkably extended while maintaining good fuel economy by adding DMF into pure diesel and utilizing medium EGR rate （%40%）. Compared to gasoline/diesel blend, DMF/diesel blend has obvious effects in soot reduction. That is, as a novel oxygenated biologic fuel, DMF physical and chemical properties is superior to gasoline for low emission diesel engine LTC. A series of injection tests show that, the impact of fuel injection control strategy on soot formation is reduced when fueled with DMF/ diesel and gasoline/diesel blends compared to pure diesel. Therefore, the combination of adding low CN oxygenated fuels with medium EGR rate and reasonable control of CA50 is an effective way to achieve high-efficient, low emission LTC for modern diesel engine.

关 键 词：内燃机 柴油机 燃料特性 2 5-二甲基呋喃 十六烷值 着火延迟 排放 

分 类 号：TK427[动力工程及工程热物理—动力机械及工程]