在一台火花点火式发动机上,对燃用不同比例的乙醇汽油混合燃料时的颗粒物排放特性的影响因素进行研究.结果表明,中小负荷时汽油掺醇能够有效地降低颗粒物排放的总数目浓度和质量浓度,如汽油机在平均有效压力为0.34MPa、乙醇掺混比为20%时,颗粒物的总数目浓度和总质量浓度分别比纯汽油下降了84.3%和50.7%.乙醇掺混比的增加使得数目浓度向小粒径方向移动,而点火提前角的减小、平均有效压力的增大和混合气过浓均会使颗粒物数目浓度的峰值向大粒径方向偏移.平均有效压力的减小、点火的推迟和过量空气系数的增加均能使颗粒物的总数目浓度和质量浓度降低.
Experimental studies on particle number and mass concentration distribution were conducted by us- ing electrical low pressure impactor in an SI engine fueled with ethanol/gasoline blends. The total number and mass concentration of particle can be effectively decreased fueled with ethanol/gasoline blends. The total number and mass concentration of particle fueled with E20 decreases by 84.3% and 50.7%, respectively at break mean effective pressure (BMEP) of 0.34 MPa. The diameter of peak number concentration moves to large size direction with increasing the brake mean effective pressure. Delay of ignition timing, decrease of excess air ratio and increase of BMEP move the peak number concentration to large size direction. The total number and mass con- centration of particle decrease with decreasing brake mean effective pressure, advancing ignition timing and increasing excess air ratio.