中文摘要：

对一台高压共轨增压中冷压燃式发动机燃用汽油/柴油混合燃料的燃烧和排放特性进行试验研究,分析不同汽油掺入比例对发动机的燃烧过程和微粒排放粒度分布的影响规律。结果表明,燃用汽油/柴油混合燃料改善了燃料的挥发性,有助于加快油气混合,增大预混合燃烧量,显著降低排气烟度,但会导致NO_x排放增加,在较大负荷工况下更为明显。引入适当的废气再循环,可同时降低NO、和微粒排放。随汽油掺入比例的增加,燃烧持续期缩短,有利于改善燃烧定容性,配合EGR、喷油参数等燃烧边界条件的控制,合理匹配燃烧相位,有利于提高发动机热效率。但过大的汽油掺入比例易导致燃料着火性变差,滞燃期延长,燃烧相位过于推迟,热效率有所降低。燃用汽油/柴油混合燃料时,微粒数量浓度分布曲线中核态微粒与积聚态微粒数量浓度峰值均向小粒径方向移动。随着负荷的增加,预混合燃烧量减少,汽油掺入比例对微粒排放浓度的影响加大。在中等负荷工况下,汽油掺入比例在40%以上的混合燃料能够有效降低积聚态微粒数量浓度。

英文摘要：

An experimental study on the combustion and emission characteristics of a high-pressure common-rail lurbocharged intercooled compression ignition engine fueled with gasoline/diesel blend fuel is conducted to analyze the law of influence of different gasoline proportions on the combustion process and emitted particulate size distribution of engine.The results indicate that the blending of gasoline and diesel fuel improves the volatility of fuel,being conducive to quick mixing of fuel and air,increases the proportion of premixed combustion and hence greatly reduces the opacity of exhaust gas,but may increase the emission of No_X,especially in larger load conditions,and the introduction of reasonable exhaust gas recirculation（EGR） can reduce both No_X and particulate emissions.With the increase of gasoline proportion,the combustion duration shortens,conducive to enhancing the extent of constant-volume combustion.Combined with the control of combustion boundary conditions including EGR and fuel injection parameters and proper combustion phase,the thermal efficiency of engine can be improved.However,too large a gasoline proportion may result in the deterioration of fuel flammability,and hence the extension of delayed burning period,the delay of combustion phase and the drop of thermal efficiency.When gasoline/diesel blend fuel is used,the peaks of number concentration distribution curves for both nucleation and accumulation mode particulates move towards small size direction.With the increase of load,the proportion of premixed combustion reduces and the effects of gasoline proportion on the concentration of particulate emission become apparent.In medium loading condition,the blend fuel with a gasoline proportion larger than 40% can effectively reduce the number concentration of accumulation mode particulates.