采用双段喷射改善二冲程柴油机的排放性能

在配有电控共轨系统和扫气系统的二冲程柴油机试验台上进行了3种不同喷油模式对柴油机燃烧及排放性能影响的试验研究。试验结果表明,单段早喷有助于实现低NOx和碳烟排放,但柴油机无法在高负荷下运行;标准喷射的排放很高;双段喷射表现出良好的性能,它实现了柴油机的柔和运行,并且在全负荷范围内使NOx和碳烟排放降低40%以上。在双段喷射基础上,利用高压喷射及内部EGR进一步改善了柴油机的排放。

Improvement of Emission Performance of Two-stroke Diesel Engines with Two-stage Injection

On a test bench for two-stroke diesel engine equipped with electronically controlled common rail system and scavenging system,the effect of three different injection modes on the combustion and emission performances of the diesel engine is studied.The results indicate that single stage early injection contributes to low emissions of NOx and smoke,but the engine can't operate properly at high load while the standard injection mode produces much higher emissions.Compared with these two modes,the two-stage injection presents good performance,which realizes smooth running and reduces both NOx and smoke emissions by more than 40% in wide operation range.Based on two-stage injection,the adoption of high-pressure injection and internal EGR further improves the engine emissions.