增压中冷柴油机燃用微乳化生物柴油放热规律研究

Study on Heat Release Rate of Turbocharged Intercooled Diesel Engine Fuelled with Micro-Emulsified Biodiesel

为了对比分析柴油机燃用微乳化生物柴油和生物柴油的燃烧特性,对微乳化生物柴油和生物柴油的放热规律展开研究。利用发动机试验台架和燃烧分析仪,测录了燃烧压力随曲轴转角的变化关系,计算了柴油机燃用微乳化生物柴油和生物柴油时的燃烧放热规律,并研究喷油提前角和含水率对微乳化生物柴油放热规律的影响。研究结果表明:与生物柴油相比,中低负荷时微乳化生物柴油的压力曲线、压力升高率曲线、放热率曲线均向后移,燃烧始点滞后,但是在高负荷时,上述参数差异明显缩小;由于水分强化燃烧,微乳化生物柴油燃烧持续期比生物柴油短,燃烧更加完全;供油时刻提前,气缸压力的峰值、最大压力升高率、放热率峰值均增大;微乳化生物柴油的含水率增加,滞燃期延长,燃烧持续期缩短,压力升高率增加。

To examine influence of biodiesel micro-emulsification on its eombustion characteristics, the curves of cylinder pressure vs. crank angle were measured on engine test bed by using a combustion analyzer, and the heat release rates were calculated and analyzed when the engine fuelled with miero-emulsified and original biodiesels. The effects of injection advance angle and water content were also investigated. Results indicate that compared to fuelled with original biodiesel, when the turbocharged intercooled diesel engine fuelled with micro-emulsified biodiesel at low load, the pressure, pressure rise rate and heat release rate curves obviously retard, and combustion timing delay. However, their differences reduce obviously in large load range. Since the water in miero-emulsified biodiesel can intensify its combustion, the combustion duration is shortened and the cylinder combustion is improved. The combustion pressure peak, pressure rise rate and instantaneous heat release rate increase with the injection advance angle increasing. With the water content in micro-emulsified fuel increasing, ignition delay period extends, combustion duration shortens and pressure rise rate increases.