【摘要】 为了控制压燃式发动机的气体排放,在一台增压中冷共轨发动机上对聚甲氧基二甲醚（PODE）引燃乙醇均质充量的复合燃烧性能及其气体排放特性进行了研究.结果表明:随着进气道预混乙醇比例增加,复合燃烧滞燃期被延长,其预混燃烧量与放热率峰值增大,扩散燃烧量降低;复合燃烧的NO_x排放随着预混乙醇比例增加而降低,但m（NO₂）/m（NO_x）值显著增大,经过氧化催化转换器（DOC）后,纯PODE燃烧的m（NO₂）/m（NO_x）值增大而复合燃烧的m（NO₂）/m（NO_x）值减小;复合燃烧的HC、CO、甲醛和乙醛排放量均明显高于纯PODE燃烧,且随着预混乙醇比例增加而增大,但可以被DOC高效氧化.复合燃烧的HC、CO和NO_x排放量经过DOC后均明显低于纯PODE燃烧的排放,而甲醛、乙醛和NO₂排放量与纯PODE燃烧时处于同一水平.更多还原

【Abstract】 In order to control gas emissions from the compression ignition engine,a compound combustion process,which has a homogeneous ethanol charge ignited by polyoxymethylene dimethyl ethers（PODE）,and its gas emission characteristics were studied on a turbocharged inter-cooled common-rail engine.Results show that,with the increment of the inlet premixed ethanol ratio,the ignition delay period of the compound combustion is prolonged,the amount of premixed combustion and the peak heat release rate increase,and the amount of diffusion combustion decreases.NO_x emissions in the compound combustion decrease,but the value of m（NO₂）/m（NO_x）increases significantly with the increment of premixed ethanol ratio.After the diesel oxidation catalyst（DOC）,the m（NO₂）/m（NO_x）of pure PODE combustion is increased while the m（NO₂）/m（NO_x） of the compound combustion is reduced.In addition,HC,CO,formaldehyde and acetaldehyde emissions of the compound combustion are significantly higher than those of the pure PODE combustion.They increase with the increase of ethanol ratio,but could be effectively removed by the DOC.The results also indicate that the HC,CO and NO_xemissions are lower than those of the pure PODE combustion after the DOC,while the formaldehyde,acetaldehyde and NO₂ emissions are at the same level as those of the pure PODE combustion.更多还原