【摘要】 将汽油、柴油按一定比例进行混合制得不同着火性及挥发性的宽馏程燃料,试验研究了宽馏程燃料预混压燃燃烧及排放特性,分析了燃烧相位、废气再循环(EGR)及汽油掺入比例对预混压燃发动机燃烧及排放的影响规律,确定了核心燃烧边界条件对燃烧、排放的影响程度及范围.结果表明:汽油掺入比例对燃烧及排放均有显著影响,随汽油掺入比例增加,滞燃期延长,燃烧持续期相应缩短,有利于增大预混合燃烧量,降低排气烟度,并改善燃烧定容性.但在小负荷工况下,汽油掺入比例过大会导致CO、HC排放物增加,燃烧效率降低,进而引起热效率下降.通过采用汽油掺混体积比为40%的混合燃料,并合理控制燃烧相位,可在一定范围内保证较高的燃烧效率及燃油经济性.利用燃烧相位与EGR的协同控制策略,可在不降低热效率的情况下,进一步改善压燃式发动机排放特性,同时降低NOx及微粒排放.更多还原

【Abstract】 Premixed compression ignition combustion and emissions of diesel engine fuelled with gasoline-diesel blends were investigated. Combustion and emissions with varied combustion phase,EGR ratio and gasoline volumetric percentage were analyzed and compared. Addition of gasoline results in an increase in ignition delay and decrease in combustion duration. This will increase the premixed combustion proportion and decrease smoke emissions. However,large gasoline in blends significantly increases CO and HC emissions and results in a reduction in thermal efficiency under low loads. Blended fuel of 40% gasoline demonstrates high efficiency and clean combustion. When coupled with combustion phase and EGR flexible controlling,a reduction in NOx and smoke emissions is achieved without decreasing thermal efficiency.更多还原