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众所周知,柴油机应用生物柴油燃料时会使 NO_x 排放量增加。这被认为是由于生物柴油的可压缩性低而引起喷射定时不同的缘故。对柴油和一系列生物柴油混合物(B20～B100)的喷射定时和喷射持续期进行了比较。把一台四冲程单缸4hp 风冷直喷式柴油机的喷油器装到一个喷雾室中,发动机被拖动时,燃油通过发动机上的燃油泵供给喷油器。使用发动机视频示波器,观察氦氖激光的光衰减以及测量燃油的管路压力,在喷雾室中进行喷雾的可视化和喷射定时的定量化,并与曲轴位置同步。观察到不同燃料混合物之间的喷射定时有变动,在柴油和纯生物柴油(B100)之间喷射定时约有1°CA 的差异。还进行了燃烧研究,以便观察喷射定时的变动对燃烧过程定时的影响。使用B100时,着火提前达4°CA,这至少可以部分归咎于喷射定时的提前。
As we all know, diesel engine application of biodiesel fuel will make NO_x emissions increase. This is believed to be caused by the difference in injection timing due to the low compressibility of biodiesel. Diesel and a series of biodiesel blends (B20 ~ B100) injection timing and injection duration were compared. A four-stroke single-cylinder 4hp air-cooled direct injection diesel engine injector mounted to a spray chamber, the engine is dragged, the fuel through the engine fuel pump to the injector. Using an engine video oscilloscope, observe the light attenuation of the He-Ne laser and measure the line pressure of the fuel, visualize the spray in the spray chamber, and quantify the injection timing and synchronize with the crankshaft position. It was observed that there was a change in injection timing between the different fuel mixtures, with an injection timing difference of about 1 ° CA between diesel and pure biodiesel (B100). A combustion study was also conducted to see the effect of changes in injection timing on timing of the combustion process. With the B100, the ignition was advanced by 4 ° CA, which could be at least partly attributed to the advance timing of the injection.