喷孔形状对柴油机性能影响的试验研究

Experimental Study on Effect of Nozzle Hole Shapes on Diesel Performances

以一台2.5L柴油机为依托,在发动机性能试验台架上,对比研究了配备具有相同流量的渐缩形喷孔喷嘴和圆柱形喷孔喷嘴发动机经济性和排放性的差异。试验结果显示:在较高转速及较高负荷下,相比于圆柱形喷孔喷嘴,渐缩形喷孔喷嘴具有一定的油耗和Soot排放优势,但随着转速和负荷的降低,上述优势逐渐减弱;渐缩形喷孔喷嘴的Soot排放对EGR率变化的敏感度要弱于圆柱形喷孔喷嘴;不管是渐缩形喷孔喷嘴还是圆柱形喷孔喷嘴,随着EGR率的升高,NOx排放基本上均是呈线性降低的,但EGR率相同时,渐缩形喷孔喷嘴的NOx排放均是略高于圆柱形喷孔喷嘴的。该研究结果可为柴油机油嘴的匹配选型提供试验和理论指导。

With a 2.5L diesel engine, a lot of diesel performance experiments were carried out on test bench under dif- ferent operating conditions, and the economy performances and the emission performances of the engines equipped with convergent hole nozzle （ConN） and cylindrical hole nozzle （CylN） were analyzed. The results show that： the BSFC and the Soot of ConN are better than those of CylN under higher speed and higher load, but with the increase of engine speed and engine load, the above advantages of ConN are decreased gradually. For ConN, meanwhile, the EGR sensitivity of the Soot emission is weaker than that of CylN. With the increasement of the EGR rate, the NOx is reduced linearly for both of ConN and CylN, but for the same EGR rate, the NOx emission of ConN is higher than that of CylN. This study could provide experimental and theoretical guidance for nozzle selecting and matching of diesel engine.