电控高压共轨柴油机燃用生物柴油-柴油混合燃料的燃烧特性

针对1台6缸增压中冷电控高压共轨柴油机,在不改变原柴油机结构和喷油参数的条件下,研究了生物柴油的掺混比例对发动机燃烧特性的影响。结果表明:小负荷时发动机有预喷射,随着生物柴油掺混比的增大,生物柴油-柴油混合燃料的滞燃期缩短、缸内最高燃烧压力下降,预喷阶段压力升高率峰值和瞬时燃烧放热率峰值减小,且对应的相位提前;主喷阶段压力升高率峰值和瞬时燃烧放热率峰值增大,且对应的相位后移。随着负荷的增大,发动机喷油策略改为单次喷射,随着生物柴油掺混比的增大,缸内最高燃烧压力下降,燃烧持续期缩短,压力升高率峰值略有增大,瞬时燃烧放热率峰值逐渐减小且对应的相位前移。两种不同负荷条件下,随着生物柴油掺混比的增大,混合燃料的指示热效率逐渐下降。

Combustion Characteristics of Electronically Controlled High Pressure Common Rail Diesel Engine Fueled with Biodiesel-Diesel Blended Fuel

The influence of biodiesel mixing ratio on combustion characteristics was investigated on a 6-cylinder supercharged intercooled common rail diesel engine based on the original structure and injection parameters .The results show that the pre-in-jection of engine happens at low load .With the increase of biodiesel mixing ratio ,the ignition delay period shortens and the maximum cylinder pressure decreases .In addition ,the peak of pressure rise rate and instantaneous heat release rate decrease and their corresponding phase angles advance in the stage of pilot injection .While in the stage of main injection ,the engine spray strategy changes to single injection when the load increases .With the increase of biodiesel mixing ratio ,the maximum cylinder pressure decreases ,the combustion duration shortens and the peak of pressure rise rate slightly increases .Besides ,the peak of instantaneous heat release rate decreases and its corresponding phase angle advances .Moreover ,the indicated thermal efficiency of biodiesel/diesel blended fuel decreased gradually .