掺混比对异丁醇-柴油混合燃料性能的影响

在1台增压中冷高压共轨柴油机上,试验探讨了异丁醇-柴油不同掺混比的混合燃料对发动机燃烧过程及性能的影响。结果表明:相同负荷率下,掺混异丁醇降低了燃料热值,发动机燃油消耗率增加;柴油掺混异丁醇后,含氧量增加,可有效抑制碳烟排放,但十六烷值降低。重型柴油机稳态测试循环(ESC-13工况)加权比排放测试发现,掺混10%异丁醇的柴油燃烧产生的微粒比排放最低;同转速小负荷工况下,加大异丁醇掺混比后,混合燃料增高的汽化潜热和低十六烷值共同引起滞燃期延长,使缸内温度降低,CO、HC及微粒排放增加;而大负荷工况下缸内燃烧高循环热量可有效抑制这一趋势,除NOx排放外,其余有害物比排放降低。

INFLUENCE OF MIXING RATIO ON PERFORMANCE OF ISOBUTANOL-DIESEL FUEL

The influence of the isobutanol-diesel mixing ratios on the engine combustion process and performance was investigated by turbocharged and intercooled common rail diesel engine.The results showed that under the same load，the fuel heating value is reduced as the increase of mixing ratio，while the fuel consumption is increased； after blending isobutanol，the oxygen content is increased，which can inhibit soot emission effectively，but the cetane number is decreased.At the working conditions of ESC-13，the fuel with 10% isobutanol generates the lowest soot weighting specific emissions.Under the same speed and small load conditions，increasing the mixing ratio has a trend of increasing the latent heat of vaporization of the fuel，and with a lower octane number，causing the prolonged ignition delay of the fuels and lower cylinder temperature and more the CO，HC and particulate emissions.While the higher cycle heat in cylinder under large load working conditions can effectively restrain the trend，except for the NOx emission，the rest of the harmful specific emissions are lowered.