为探究聚甲氧基二甲醚(PODE)用作燃料添加剂时柴油机的燃烧、压力振荡和排放特性,以0号柴油为基础,按照体积分数配制PODE占比分别为0%(DP0)、5%(DP5)和15%(DP15)3种混合燃料,在一台共轨柴油机上进行2 000 r/min,50%负荷固定工况试验,分析不同PODE掺混比例对于柴油机性能的影响。研究结果表明:随着PODE比例增加,燃料燃烧时缸内压力、压力升高率和放热率峰值减小,峰值所对应的相位提前,滞燃期缩短,产生的燃烧振荡能量减小,振荡幅值减小,PIC能量所占比例及其能量循环变动率降低,燃烧更为柔和;DP15的振荡能量最小,相比0号柴油降低1.01×1012 Pa2,循环压力能量振荡变动率降低1.55%,燃烧更为稳定;随着PODE比例增加,柴油机排放性得到改善,NOx和Soot排放均降低。
In order to investigate the combustion, pressure oscillation and emission characteristics of diesel engine fueled with diesel with polyoxymethylene dimethyl ethers (PODE) additive, 0# diesel was mixed with PODE according to the volume fraction of 0%, 5% and 15%, then DP0, DP5 and DP15 fuel blends were prepared. The influences of different PODE blending ratios on engine performance were analyzed based on the test of 50% load at 2 000 r/min. The results show that the incylinder peak pressure, pressure rise rate and heat release rate decrease, the corresponding phase to peak value advances, the ignition delay shortens, the combustion oscillation energy reduces and its oscillation amplitude decreases, the proportion of PIC energy and its energy cycle variation rate reduce, and the combustion becomes gentle with the increase of PODE mixing ratio. The oscillation energy of DP15 is the smallest and reduces by 1.01×1012 Pa2 compared with 0# diesel fuel. The fluctuation rate of cyclic pressure energy oscillation decreases by 1.55% and the combustion becomes more stable. Besides, diesel exhaust emissions improve and both NOx and SOOT emissions reduce with the increase of PODE mixing ratio.