EGR率和进气温度耦合作用下的低温燃烧试验研究

摘要

基于冷热废气再循环(exhaust gas recirculation,EGR)双回路系统,通过进气温度与EGR率解耦控制,研究了EGR率和进气温度对柴油低温燃烧和排放的影响,并在低温燃烧负荷上限探索EGR率和进气温度耦合作用规律.研究结果表明,负荷上限时,进气温度升高对进气充量的稀释作用占主导地位,进气温度升高对燃烧起抑制作用.EGR率和进气温度的耦合作用在负荷上限时体现在:低EGR率、高进气温度时,燃烧始点提前、燃烧持续期增大;高EGR率、低进气温度时,指示功增加,平均有效压力增大.EGR率升高,NOx排放量降低,进气温度升高,HC,CO排放量升高.%Based on the hot and cold dual circuit EGR,the impacts of EGR rate and intake temperature on combustion performance and emissions and the coupled laws on EGR rate and intake temperature at the upper limit of low temperature combustion load were studied through decoupling of intake temperature and EGR rate.The results showed that the rise of intake temperature dominated in the dilution effect of intake charge at the upper load limit,but suppressed the combustion.The combustion timing advanced and the combustion duration increased at low EGR rate and high intake temperature and the indicated work and the mean effective pressure increased at high EGR rate and low intake temperature.In addition,the NOx emission decreased with the increase of EGR rate and the HC and CO emissions increased with the increase of intake temperature.