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燃烧时掺水或掺甲醇可减少柴油机的排气烟度和NO排放物,这是大家都知道的。为了有效和有目的地使用这些掺入物,对由此产生的物理的和化学的机理,发生了浓厚的兴趣。化学平衡计算表明,向柴油中掺水或掺甲醇可降低过量空气系数下限,直到不产生炭烟。尤其在喷射柴油-水乳化液的情况下,蒸发时局部的强烈吸热延长了滞燃期,有助于混合气形成和降低最高燃烧温度。喷射乳化液的高速摄影表明,射束锥角和射束扩散都没有变化。掺甲醇可以提高热效率,而掺水则降低热效率。用不同方式掺水或掺甲醇的发动机试验表明,喷射乳化液或用两个喷嘴同时喷射柴油和甲醇可以获得较好的结果。
It is known to all that watering or blending with methanol reduces the exhaust smoke and NO emissions of diesel engines. In order to use these sprites efficiently and purposefully, there has been a great deal of interest in the resulting physical and chemical mechanisms. Chemical equilibrium calculations show that adding diesel to water or methanol can reduce the lower limit of excess air coefficient until no soot is produced. Especially in the case of diesel-water emulsions, localized strong endotherms during the evaporation extend the retardation period, contributing to the formation of the mixed gas and the reduction of the maximum combustion temperature. High-speed photography of the jet emulsion showed no change in beam cone angle and beam spread. Addition of methanol can increase the thermal efficiency, while water reduces the thermal efficiency. Engine tests that have been mixed or mixed with methanol in different ways show that better results can be obtained by spraying the emulsion or injecting diesel and methanol simultaneously with two nozzles.