研究了生物柴油及其与二甲醚混合燃料的喷油特性及喷油过程中嘴端压力特征，确定了喷油条件和生物柴油掺混比例对其影响规律。研究结果表明：喷油压力增加，喷油速率在喷油初期上升和喷油末期下降均变快，最大喷油速率增加，喷油持续期内喷油速率波动幅值变大，喷油引起的嘴端压力第一波谷下降幅度变大，喷油结束后嘴端压力各个波动幅值均变大，除第一波峰外，其余各个波峰的相位均提前且相位差别越来越大；喷油脉宽增加，喷油持续期延长，喷油终点延后，嘴端压力第一波谷和各波峰的大小变化不明显，各波峰的相位延后；随着燃料中生物柴油比例的减少，喷油始点不变，喷油终点延后，喷油持续期增加，喷油引起的嘴端压力第一波谷下降幅度变小，嘴端压力第一波峰降低。相同喷油条件下，高比例生物柴油的循环喷油能量最大，纯生物柴油的循环喷油能量居中，低比例生物柴油的循环喷油能量最小。

The fuel injection and fuel line pressure characteristics at the nozzle during the injection for biodiesel and its blended fuel with dimethyl ether were studied and the effects of injection conditions and mixing ratio were determined. The results show that the injection rate increase in the initial injection stage and decrease in the injection ending stage both accelerate, the peak injection rate increases, and the fluctuation amplitude of injection rate in the duration period increases with the increase of injection pressure. The first trough of nozzle pressure drops in an increasing extent during the injection and each fluctuation amplitude after the injection becomes larger. The phases of all the peaks except the first advance and the differences get large. The injection pulse width increases, the injection duration extends, the injection end delays, the amplitudes of first trough and each peak almost keep the same, but the phase of each peak delays. With the decrease of biodiesel mixing ratio, the injection timing keeps unchanged, the injection end delays and the injection duration prolongs, and the first trough drops and the first peak becomes smaller. Under the same fuel injection conditions, the order of fuel injection per cycle from high to low is high-proportion biodiesel, pure biodiesel and lowproportion biodiesel.