正丁醚/柴油混合燃料在单缸柴油机中的燃烧与排放特性研究  

Combustion and Emissions of Di-N-Butyl Ether/Diesel Blend in a Single-Cylinder Diesel Engine

作　　者：任哲 卢康博 孙滔 杨凯 石磊[1] 韩东[1] REN Zhe;LU Kangbo;SUN Tao;YANG Kai;SHI Lei;HAN Dong(Key Laboratory for Power Machinery and Engineering of the Ministry of Education,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学动力机械与工程教育部重点实验室,上海200240

出　　处：《内燃机工程》2022年第4期1-11,共11页Chinese Internal Combustion Engine Engineering

基　　金：国家自然科学基金项目(51776124)。

摘　　要：基于一台单缸压燃式发动机,研究了正丁醚(di-n-butyl ether,DnBE)/柴油混合燃料的燃烧与排放特性,并与纯柴油的试验结果进行了对比。分别采用平均指示有效压力(indicated mean effective pressure,IMEP)即发动机负荷0.55 MPa、0.65 MPa、0.75 MPa,废气再循环(exhaust gas recirculation,EGR)率0%、15%、30%,喷油正时上止点后-15°、-10°、-5°、0°及正丁醚掺混体积比20%、40%,综合评估了正丁醚/柴油混合燃料在不同发动机运行工况下的特性。台架试验结果表明:相比于纯柴油,正丁醚的添加使得缸内压力上升相位及放热开始时刻提前,并且在30%EGR率工况下更加明显。在所有测试工况下,正丁醚/柴油混合燃料的预混燃烧比例均小于纯柴油,且第一阶段放热率峰值更低。由于十六烷值的差异,40%正丁醚/柴油混合燃料的着火延迟时间与燃烧持续期更短且燃烧重心更早,表明其具有更快的燃烧速率。试验发现大比例正丁醚/柴油混合燃料的燃烧等容度更高,指示热效率高于纯柴油。此外,添加正丁醚后尾气中的NO_(x)与碳烟排放都会降低,而提高EGR率或推迟喷油均能有效减少NO_(x)的生成。综合而言,添加正丁醚可以有效缓解柴油机中NO_(x)排放、碳烟排放与指示热效率之间的权衡关系。The combustion and emission characteristics of di-n-butyl ether(DnBE)/diesel blend were studied and compared to pure diesel fuel in a single-cylinder compression ignition engine.Engine operational parameters,including engine load,i.e.indicated mean effective pressure(IMEP)(0.55,0.65 and 0.75 MPa),the exhaust gas recirculation(EGR)rate(0%,15% and 30%),the fuel injection timing(-15°,-10°,-5°and 0° after top dead center),and the volume fraction of di-n-butyl ether in the fuel blend(20% and 40% in volume) were adjusted to evaluate the engine performances of di-n-butyl ether/diesel blend under changed operation conditions.In comparison to pure diesel fuel,the fuel blends show an earlier pressure rising phase and advanced heat release process,which is more obvious under 30% EGR rate condition.Under all testing conditions,the lower premixed combustion fraction of di-n-butyl ether/diesel blend leads to a lower first-stage heat release peak than diesel fuel.Owing to its higher cetane number,the 40% DnBE/diesel blend features a shorter ignition delay time,a shorter combustion duration,and an earlier combustion centen than diesel fuel,implying a higher combustion rate.The experimental results manifest that the 40% DnBE/diesel blend has a more isovolumetric combustion progress,resulting in a higher indicated thermal efficiency(ITE) than that of pure diesel.Compared with diesel fuel,the nitrogen oxides(NO_(x))emissions and soot emissions of DnBE/diesel blend are lower,and the NO_(x) emissions can be effectively reduced with the increased EGR rate and delayed injection timing.It is proved that the addition of DnBE can improve the trade-off relationship between NO_(x) emissions,soot emissions,and indicated thermal efficiency in the diesel engine.

关 键 词：正丁醚 柴油 混合燃料 发动机 燃烧 排放 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]