采用内窥镜直接高速摄影的方法,对燃烧柴油和生物柴油发动机的燃烧过程进行了试验研究,分析了柴油、生物柴油、不同比例的生物柴油/柴油混合燃料的着火延迟期、着火点位置、燃烧温度和燃烧速度的变化规律。研究结果表明:燃油喷射过程中,柴油的喷雾锥角大于生物柴油的喷雾锥角;生物柴油在预混燃烧阶段的燃烧速度大于柴油,其最高燃烧温度小于柴油。在相同工况下,生物柴油的燃烧终点早于柴油,燃烧持续期也小于柴油。燃烧生物柴油时,高转速工况下的燃烧终点对应的曲轴转角较低转速时有所增加,燃烧持续期对应的角度有所延长。
Combustion process of engine operating on diesel fuel and bio-diesel was studied by end scope high-speed photography. Ignition delay, position of ignition, gas temperature and combustion speed were analyzed. The study shows that the spray angle of diesel fuel is larger than that of bio-diesel fuel. Combustion temperature and speed of bio-diesel fuel in the pre-mixed combustion period is higher than that of diesel fuel. Combustion completes early in the case of bio-diesel fuel along with shorter combustion duration. When bio-diesel fuel operates on high-speed condition, combustion duration will be extended.