喷油器喷孔积碳对柴油机喷油压力影响研究

使用光学电子显微镜,拍摄了新喷油器和积碳喷油器的喷孔图像。图像表明:喷油器喷孔积碳后,喷孔出口有明显的不规则积碳,对喷孔造成了一定程度的堵塞,改变了原有的喷孔结构;喷孔内部粗糙度有所增大,有少量不规则积碳存在于喷孔内部出口一侧。利用喷油泵试验台架,分别使用新喷油器和积碳喷油器进行了燃油喷射试验,测试了不同工况下的泵端压力和嘴端压力波形。试验结果表明:与新喷油器相比,喷孔积碳后喷油压力增大,压力峰值时间延后,针阀落座时间延后,喷油持续期增长,残余压力增大;嘴端压力波形由双峰曲线变成3峰曲线;喷油器开启压力增大,积碳对嘴端压力影响作用增大。

Effect of Injector Nozzle Carbon Deposition on Injection Pressure of Diesel Engine

The nozzle morphology of new injector and carbon deposition injector were attained by using the optical electron microscope. The image revealed that there are obviously irregular deposit in nozzle external. The nozzle hole were clogged and the structure was changed by carbon deposition. The nozzle hole roughness were increased with few irregular deposit in it. The injection experiments with new injector and carbon deposition injector were carried out with fuel injection test bench and injection pressure was tested in different operating status. The results showed that the injection pressure increases, the pressure peak comes later and needle value closes later, the injection duration prolongs and the remaining pressure increases. The pressure of injection waveform changed into three peak curve by bimodal curve. The effect of carbon deposition on injection pressure increased with the increase of injection opening pressure.