汽/柴油混合燃料对柴油机燃烧与排放特性影响的试验研究

Experimental Research on Effect of Gasoline/Diesel Blends on Combustion and Emissions Characteristics of Diesel Engine

系统地研究了不同比例汽/柴油混合燃料对柴油机燃烧与排放特性的影响。研究结果表明:随着汽油比例的增加,滞燃期增长,燃烧持续期缩短,有利于燃烧等容度的提高,同时最大压力升高率也升高;随着汽油比例的增加,碳烟排放大幅度降低,NO排放有所升高,同时指示热效率基本保持不变;随着汽油比例的增加,发动机喷油时刻可变范围变窄。综合考虑燃烧噪声、热效率和排放,在转速1 400r/min、喷射压力80MPa工况下,最佳汽油掺混比例应控制在50%左右;在废气再循环条件下,与纯柴油相比,燃用汽/柴油混合燃料能够同时降低NO排放和烟度,在实现低温燃烧上具有优势。

Effects of gasoline/diesel blends in different ratios were studied in a diesel engine. The results show that as gasoline ratio increases, ignition delay increases andcombustion duration shortens, beneficial to achieve constant volume combustion, but the max. pressure rise rate increases; soot emission reduces dramatically and NO emissions increase,while indicated thermal efficiency remains almost constant and the permissible injection timing range becomes small. Considered the trade-off among combustion noise, thermal efficiency and emissions, the best gasoline ratio should be about 50 % in this study. Compared to pure diesel combustion, gasoline/diesel blend can achieve low temperature combustion with low NO and soot emissions when combined with EGR.