甲醇和EGR降低柴油机NO_x和碳烟排放的试验研究

Experimental Study on Reducing NO_x and Soot Emissions from Diesel Engine Fueled with Methanol-Diesel Using EGR

在4100QBZL增压中冷柴油机上进行了M15甲醇柴油的试验研究。在维持原机动力性的基础上,研究了不同EGR率对柴油机燃用M15甲醇柴油时的动力性、经济性、燃烧特性、NOx和碳烟排放的影响。结果表明:甲醇可以同时降低柴油机的NOx和碳烟排放,但造成柴油机动力性下降,经济性变差。增加9.5%的供油量后,柴油机可以维持原机的动力性,碳烟排放较低,但NOx排放量大幅度上升。采用EGR系统后,随着EGR率的增加,最高缸压、最大放热率和缸内温度逐渐降低,所对应的曲轴转角后移,NOx排放大幅度降低,烟度有不同程度的恶化。在维持动力性和经济性的基础上选择合适的EGR率可以使柴油机的NOx排放和烟度排放均低于燃用0#柴油。

Experimental study on application of methanol-diesel blended fuel M15 in model 4100QBZL turbocharged diesel engine was carried out. Under the condition of the same engine power, influences of different EGR rates on engine power characteristics, fuel economy, combustion process, NOx and soot emissions were studied while it fueled with M15. Results show that methanol-diesel blended fuel can reduce both engine NO~ and soot emissions, but cause power and fuel economy deterioration. By increasing 9.5 fuel delivery to recover engine power decrease, the NO~ emissions ascend obviously and the soot emissions get lower. After introduction of EGR system, max. cylinder pressure, heat release rate and temperature are all gradually reduced and their corresponding crank angles shift rearward, NOx emissions are decreased by a large margin, soot emissions are aggravated in varying degrees with EGR rate increasing. By selecting properly EGR rate, the NOx and soot emissions can be reduced to the levels lower than that while the engine fueled with 0^# diesel fuel in condition of maintaining original power output and fuel economy.