燃料特性对小型压燃式发动机增负荷工况燃烧及HC排放的影响

应用自行开发的瞬态工况控制系统及排气采集装置,研究了具有不同理化特性的燃料对小型压燃式发动机冷态突增负荷工况下燃烧及 HC排放特性的影响;利用气相色谱仪分析了HC的排放成分。研究结果表明:对于普通柴油燃料,在突增负荷工况下,燃油开始增加后,总碳氢HCt 排放浓度急剧增加,最大值达到稳态工况的 100 倍左右。随循环数的增加,滞燃期缩短,HC排放逐渐降低。采用具有相同十六烷值、挥发性好的燃料,可有效改善冷态增负荷工况下的燃烧,降低HC排放。与燃烧柴油相比,采用挥发性好的正庚烷和 GTL燃料,HCt排放降低约80%。

Effects of Fuel Parameter on Combustion and HC Emissions at Sudden Loading Operation of Small Compression Ignition Engine

The combustion and HC emission at cold modes sudden loading operation were investigated on a small compression ignition engine under different fuels with a self-made special transient operation and exhaust measuring and control system. HC emission components were analyzed by gas chromatography. Experiment results indicate that by using diesel fuel that HC_t emission rapidly increased at sudden loading operation, which the peak approximately 100 times of steady operations. With the increase of sampling cycle number the ignition delay was decreased and HC emission was reduced. Combustion was improved and HC emission was reduced at cold modes sudden loading operation conditions by using better volatile fuel with the same cetane number. HC_t emission was reduced by 80% for using heptane fuel and GTL fuel compared with diesel fuel.