正丁醇/柴油复合燃烧对轻型柴油机排放的影响

通过在一台轻型柴油机上加装低压共轨实现在进气歧管上的正丁醇喷射,喷射压力恒定为0.35 MPa;柴油采用缸内直喷,喷射压力恒定为120 MPa;采用自主开发的电控单元(ECU)分别控制柴油与正丁醇的喷射,实现正丁醇/柴油复合燃烧.试验研究了在2800 r·min~(-1)不同负荷下正丁醇喷射量对排放量及颗粒物粒径分布的影响.结果表明:随正丁醇喷射量增加,NO_x和碳烟排放减少,高负荷时降低幅度较大;HC和CO排放增加,低负荷时增加幅度较大;颗粒物生成总量降低且粒径分布重心左移;低负荷时相比于大粒径颗粒物,正丁醇对小粒径颗粒物数浓度的减少更明显;大粒径颗粒物减少比例与小粒径颗粒物减少比例的差距随正丁醇喷射量的增加而减小.

The effect of n-butanol/diesel compound combustion on emissions of light duty diesel engine

The aim of this research is on effect of n-butanol/diesel compound combustion on emission by a light duty diesel engine. A low pressure common rail was added to the intake manifold of the experimental engine for n-butanol injection. The diesel fuel injection was accomplished by the original injection system and no modification was performed. A self-developed electronic control unit was used to control the n-butanol injection and diesel fuel injection. The injection pressure of n-butanol and diesel fuel was keeping constant at 0.35 MPa and 120 MPa throughout the experiment. Also, the injection timing was keeping constant through all the experiments respectively. Effects of n-butanol injection quantity on emission and particle size distribution were obtained at a constant engine speed of 2800 r·min^-1 and at four engine loads. Experimental results showed that NO_x and soot emissions were decreased with n-butanol injection quantity increased, especially under heavy load. But HC and CO Emissions were increased with increase of n-butanol injection quantity, especially in light load. Total particle number concentration was decreased when the n-butanol injection quantity increased, and also the peak of particle size distribution curves shifted to small particle side. N-butanol could reduce the number concentration of small particles more obviously than that of large particles at light engine load. The difference of reduction proportion between large particle and small particle was decreased with increase of n-butanol injection quantity.