一种新型含氧燃料对柴油机燃烧特性的影响

为解决柴油机的碳烟颗粒和氮氧化物排放难以同步降低的矛盾,在一台TY1100直喷柴油机上对新设计的一种含氧添加剂乙酸-2-甲氧基乙酯(MEA)和柴油的混合燃料进行了燃烧和排放的试验研究.结果表明:MEA可与柴油实现良好的互溶;在相同的工况下,随着混合燃料中MEA比例的增加,柴油机缸内的最高压力变化较小,但滞燃期略有延长,瞬时放热率增加,燃烧持续时间变短;MEA可以显著降低柴油机的碳烟排放,可使HC和CO的排放有一定程度的降低,但对发动机NOx的排放没有明显的影响;在不改变发动机结构参数的条件下,当燃用体积分数为15%的MEA混合燃料时,发动机的碳烟排放平均降低约50%,发动机的标定功率下降约5%,而热效率提高约2%.

Effects of 2-Methoxyethy1 Acetate on Combustion Characteristics of Diesel Engine

In order to reduce diesel particulate matter (PM) and NO_x emissions simultaneously, a new type of oxygenate additive was designed. It is 2-methoxyethyl acetate (MEA). It is mixed with different fraction of diesel to form different oxygenated fuel blends and the experiments were conducted on a TY1100 single cylinder DI diesel engine. The effects of the oxygenated fuel blends on engine combustion, performance and emissions were studied. MEA has good solubility in diesel. Under the same operating conditions, the variations in maximum cylinder pressure are little, however, the ignition delay increases, the heat release rate increases, and the combustion duration decreases, with the increased proportion of MEA. The experimental results show that MEA can significantly reduce the engine smoke and also reduce HC and CO emissions to some extent, but it has a little effect on NO_x emission. When the engine without any modification fueled with 15% MEA in volume, the exhaust smoke decreases about 50% with expense of 5% power output, and the engine thermal efficiency is 2% higher than that with diesel.