Effect of equalising ignition delay on combustion and soot emission characteristics of model fuel blends  

均衡点火延迟对模型燃料混合物的燃烧和烟尘排放特性的影响

作　　者：Hamisu Adamu Dandajeh Nicos Ladommatos Paul Hellier 

机构地区：[1]Department of Mechanical Engineering,Ahmadu Bello University,Zaria PMB 1045,Nigeria [2]Department of Mechanical Engineering,University College London,Torrington Place,London WC 1 E 7 JE,UK

出　　处：《Journal of Central South University》2022年第1期89-101,共13页中南大学学报（英文版）

摘　　要：This paper examines the effect of equalizing ignition delay in a compression ignition engine.Two sets of tests were conducted,i.e.a set of constant injection timing tests with start of fuel injection at 10°crank angle degree(CAD)before top dead center(BTDC)and a set of constant ignition timing tests while also keeping the 10℃AD BTDC injection and adding ignition improver(2-ethylhexylnitrate-,2-EHN)to the fuel mixtures.Soot particles were characterized using DMS-500 instrument in terms of mass,size,and number.The experimental results showed that adding 2-EHN to the model fuel blends reduced the soot surface area,soot mass concentration and soot mean size.Replacing 20 vol%of a C 7-heptane with 20 vol%methyl-decanoate(an oxygenated C 11 molecule)did not affect the ignition delay or rate of fuel air premixing,the peak in-cylinder pressure or heat release rates.Toluene addition(0−22.5 vol%)to heptane increased the mean size of the soot particles generated by only 3%while also resulted in a slight increase in the peak cylinder pressure and peak heat release rates.Blending toluene and methyl-decanoate into heptane without adding 2-EHN increased the premix phase fraction by at least 13%.However,by adding 2-EHN(4×10^(−4)−1.5×10^(−3)),the premixed phase fraction decreased by at least 11%.本文研究了均衡点火延迟在压缩点火发动机中的作用。进行了两组实验,一组在10°曲柄角度(CAD)上止点前(BTDC)开始对燃油喷射进行恒定喷射定时测试,另一组则为持续点火定时测试,同时保持10℃ADBTDC喷射,并在燃油混合物中添加点火改良剂(2-乙基己基硝酸盐,2-EHN)。使用DMS-500仪器表征烟尘颗粒的质量、大小和数量。实验结果表明,在模型燃料混合物中加入2-EHN可降低烟尘表面积、质量浓度和平均尺寸。用20 vol%的十烷酸甲酯取代20 vol%的C7-庚烷不影响点火延迟或燃料空气预混速率、缸内峰值压力或热释放速率。在庚烷中加入甲苯(0~22.5 vol%)使烟尘颗粒的平均尺寸仅增加3%,同时气缸峰值压力和热释放峰值也略有增加。将甲苯和癸酸甲酯混合加入庚烷中,且不添加2-EHN,使预混相含量提高了至少13%。然而,添加2-EHN(4×10^(−4)~1.5×10^(−3))后,预混相含量至少降低了11%。

关 键 词：combustion characteristics soot emission compression ignition engine ignition improver premixed phase 

分 类 号：TK401[动力工程及工程热物理—动力机械及工程]