摘要
采用1台满足国Ⅳ标准的高压共轨、涡轮增压中冷柴油机,研究了在加装尿素选择催化还原器(ureaSCR)前后的NO2排放特性。通过测量urea-SCR前后排气温度、压力、氮氧化物(NOx)和二氧化氮(NO2)排放量等参数,研究了NO2对柴油机urea-SCR性能的影响。分析结果表明:随着urea-SCR前排气温度上升,NOx中NO2百分比降低;当发动机转速一定时,NO2比例随扭矩的增大而降低;当发动机扭矩一定时,NO2比例随转速的上升呈现"V"形变化趋势;当urea-SCR前排气温度为255℃时,urea-SCR转化效率受NO2比例的影响波动性较大;在335℃时转化效率和NO2比例的变化趋势一致性最大。
For a turbocharged and intercooled State IV diesel engine with high-pressure common rail, the NO2 emission before and after the urea-SCR was researched. Based on the measured exhaust temperature, exhaust pressure, NO~ and NO2, the in- fluence of NO2 on urea-SCR performance was studied. The results show that the NO2/NOx ratio decreases with the increase of temperature before the urea-SCR. For the constant speed, the NO2/NOx ratio decreases with the increase of engine torque. For the constant torque, the NO2/NOx ratio shows the V-typed trend with the increase of engine speed. When the temperature be- fore the urea-SCR is 255 ℃ , the influence of NO2 on SCR efficiency fluctuates. At 335℃ , the trends of SCR efficiency and NO2 fraction have the best consistency.
出处
《车用发动机》
北大核心
2013年第5期53-56,共4页
Vehicle Engine
基金
国家自然科学基金资助项目(51006085)
云南省应用基础面上项目(2010ZC091)
云南省教育厅科学研究基金项目(2011Y288)
关键词
柴油机
二氧化氮
选择性催化还原
diesel engine
nitrogen dioxide
selective catalytic reduction （SCR）
