【作者】 栗工； 李理光； 邱冬平； 刘志敏；

【Author】 Gong Li, Liguang Li, Dongping Qiu , Zhiming Liu (Institute of Internal Combustion Engine, Shanghai Jiaotong University, Shanghai 200030, P. R. China;School of Automotive Studies, Tongji University, 4800 Cao An Road, Shanghai 201804, P.R. China)

【机构】 上海交通大学内燃机研究所； 同济大学汽车学院；

【摘要】 基于循环控制的概念,详细研究了LPG点燃式发动机冷起动首循环瞬态HC排放和进气道燃料输运特性之间的关系。试验在一台电控LPG进气道喷射单缸风冷四行程125cm3发动机上进行。通过高速采集系统记录发动机首循环瞬态HC排放、瞬时缸压和转速,分析了首循环瞬态HC排放的变化规律与首循环进气道燃料输运特性的关系。结果表明:虽然LPG燃料是气态喷入进气道中,但仍有一定比例的燃料不能进入缸内,残留在进气道内．首循环进气冲程结束时,进气道残留的HC浓度随首循环混合气浓度的增加而增大,而残留比例(进气道残留HC 与喷入燃料之比)随首循环混合气浓度的增加而减少;进气道残留HC浓度和残留比例都随节气门开度的增加而降低;喷射相同燃料时,推迟喷射时刻对于残留HC浓度和残留比例没有明显影响,若喷射燃料发生在进气门开启之后时,由于燃料与空气混合不良,将导致缸内燃烧的恶化。更多还原

【Abstract】 Based on the cycle-by-cycle control strategy, this paper presents transient HC emission characteristics at cold-start in a small electronic fuel injected (EFI) SI engine fuelled with LPG.The results show that some fuel was still residual in the intake port intake even if the gaseous LPG was used in the tests. The residual hydrocarbon concentration of the intake port after the intake valve closing increase with more fuel injection of the first firing cycle (FFC), while the ratio of the residual fuel and the total injection fuel is decreases. The residual hydrocarbon concentration and the residual ratio are both reduced with more degrees throttle valve opening. For same fuel injection, the residual HC concentration and the residual ratio have no remarkable variety with retarded injection timing, and the combustion in the cylinder became worse when the injection happened after intake valve opening.更多还原