喷射量对预混合丁醇/柴油复合燃烧排放的影响

Effect of injection quantity on emission of butanol homogeneous charge and diesel fuel compound combustion

基于一台轻型高压共轨柴油机增加一套低压共轨系统实现气道定差压丁醇喷射,并控制进气温度不低于110℃以形成均质预混合气。研究了3 350 r·min^(-1)不同负荷条件下小比例丁醇喷射量对柴油机的气体排放物和颗粒物排放数量浓度、质量浓度及颗粒数量浓度粒径分布特性的影响。结果表明,在中小负荷范围内的HC和CO排放随丁醇喷射量几乎呈线性增加;在大负荷HC排放增加,但是CO排放略微减小。在小负荷工况soot质量比排放和NO_x排放随丁醇喷射量增大而降低,不存在折衷关系;在中大负荷工况soot质量比排放随丁醇喷射量增大而降低但NO_x排放随丁醇喷射量增大而升高。丁醇可明显降低各个负荷的大粒径颗粒物的数量浓度,但是会增加小粒径颗粒的数量浓度。丁醇可降低各个负荷下颗粒物的总数浓度。

In order to inject butanol at intake manifold a suit of low pressure common rail was added on to a light duty high pressure common rail diesel engine. To ensure the butanol injection mix well with air flow the intake air temperature not lower than 110℃ and the injection pressure is 3.5 bar. Based on improved diesel engine the effect of butanol injection quantity on gas exhaust emission and particle mass concentration, particle size distribution and particle total number concentration was investigated at 3 350 r·min-1. The results of butanol homogeneous charge and diesel fuel compound combustion show：that from light duty to medium duty the HC （hydra carbon） and CO （carbon monoxide） increase linearly with the increase of butanol injection quantity, and on heavy duty the HC emission increase with the increase of butanol injection quantity but the CO decreased lightly. On light duty the specific soot mass and NOx （nitrogen oxide） emission decrease with the increase of butanol injection quantity. From medium to heavy duty the specific soot mass decrease with the increase of butanol injection quantity also but the NOx emission increase with the increase of butanol injection quantity. The butanol injection partly replace diesel fuel can reduce big particles number concentration on every load but increase small particles number concentration. The butanol injection partly replaces diesel fuel also can reduce total particle number concentration on every duty.