不同喷射策略低温预混合燃烧模式排放试验  

Effects of Injection Strategy on Emission Characteristics for Diesel Engine Run by Partially-Premixed Low Temperature Combustion Mode

作　　者：刘贝[1] 成晓北[1] 刘嘉璐 浦涵 卢宏广 龚志伟 Liu Bei;Cheng Xiaobei;Liu Jialu;Pu Han;Lu Hongguang;Gong Zhiwei(School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;DFM Commerical Vehicle Technology Center,Wuhan 430056,China)

机构地区：[1]华中科技大学能源与动力工程学院,湖北武汉430074 [2]东风商用车公司技术中心,湖北武汉430056

出　　处：《内燃机学报》2019年第1期1-8,共8页Transactions of Csice

基　　金：国家自然科学基金资助项目(51576083)

摘　　要：基于一台4缸增压柴油机,研究了不同喷射参数分别在单次喷射预混合燃烧(PPC)和预喷模式PPC下对发动机排放生成的影响,其中重点关注了颗粒物的排放特性.结果表明:单次喷射形成早期喷射PPC后可以显著降低颗粒物的数量、质量以及几何平均直径(GMD),但是当喷射正时过于提前,颗粒物数量又会上升到与常规模式相当.总体上,预喷可以显著地降低碳烟排放,但是当预喷正时提前到某一特定值时,如果继续提前预喷角,颗粒物质量、数量以及GMD将基本不变.提高预喷燃油比例,形成更高比例的预混合燃烧,颗粒物数量和质量可以同时下降,颗粒物GMD先增加后降低.单次喷射早喷PPC模式下NOx排放较高,相比之下采用预喷的方式却可以在降低碳烟排放的同时很好地控制NOx排放.早喷PPC模式下由于压缩阶段负功增加导致燃油消耗率急剧升高,而预喷模式下燃油消耗率随预喷正时的提前以及预喷燃油比的增加略有升高.A 4-cylinder turbocharged diesel engine was modified to run partially-premixed low temperature combustion mode.The influence of injection strategy on the emission characteristics,especially particles,was studied on the engine under the conditions of single-injection and pilot-injection respectively.The results show that the earlyinjection PPC formed by the single injection can reduce the quantity, quality and GMD of particles obviously.However,when the injection timing is too early,the quantity of particles will rise as those of normal mode.On the other hand,the pilot injection can reduce soot emission dramatically.However,if the timing of the pilot injection is advanced to a certain value,the quantity,quality and GMD of particles are almost unchanged. Furthermore,increasing the proportion of pilot injection fuel can form a higher proportion of premixed combustion.As a result,the quantity and quality of particles decrease,while GMD increases first and then decreases.The NOx emission is higher in the early-injection PPC mode under the single injection strategy.By contrast,the split strategy can control PM and NOx emissions simultaneously.In the early-injection PPC mode the fuel consumption rate increases sharply,and the fuel consumption rate increases slightly with the advance of pilot injection timing and the pilot injection fuel ratio.

关 键 词：柴油机 预混合燃烧 喷射策略 颗粒粒径分布 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]