中文关键词远程通讯技术混合动力公交车SCR系统NO_x排放环境温度 英文关键词remote communication technologyhybridbusselective catalytic reduction system (SCR system)NO_x emissionambient temperature

作者	单位	E-mail
杨强	杭州市环境保护科学研究院, 杭州 310014	yqeia@qq.com
胡磬遥	上海市环境科学研究院, 上海 200233 国家环境保护城市大气复合污染成因与防治重点实验室, 上海 200233	huqy@saes.sh.cn
黄成	上海市环境科学研究院, 上海 200233 国家环境保护城市大气复合污染成因与防治重点实验室, 上海 200233
陈昀	杭州市机动车排气污染管理处, 杭州 310014
刘佳栋	杭州鑫翔七讯科技有限公司, 杭州 310012
李莉	上海市环境科学研究院, 上海 200233 国家环境保护城市大气复合污染成因与防治重点实验室, 上海 200233
熊忠亮	上海海事大学商船学院, 上海 201306
唐伟	杭州市环境保护科学研究院, 杭州 310014

中文摘要 SCR技术是降低包括常规、混合动力公交车在内的重型柴油车NO_x排放的重要手段.基于无线远程通讯技术，对杭州市秋冬季11辆实际运行的混合动力公交车SCR系统的运行和NO_x排放特性进行了研究.分别研究了混合动力公交车内燃机模式下车速及发动机运行工况和环境温度对SCR催化器后温度、尿素喷射量和SCR催化器后NO_x排放浓度的影响.结果表明，安装有SCR系统的混合动力公交车有（32.4±4）%的运行时间处于内燃机模式下，模式下平均有（26.9±11）%的运行时间SCR没有工作；SCR系统正常工作的混合动力公交车的NO_x平均减排率约为59%；SCR系统未达到运行要求而不工作和SCR催化器低温转化效率低是造成公交车NO_x排放较高的主要原因；当车速高于40 km·h^-1时，SCR催化器后温度上升至230℃以上，SCR系统的工作比例和尿素喷射量上升的同时NO_x排放大幅下降；进入冬季，随着环境温度的降低，混合动力公交车SCR催化器出口温度降低的同时，平均尿素喷射量降低导致NO_x排放恶化. 英文摘要 The selective catalytic reduction system (SCR) is an essential method to reduce NO_x emissions from heavy-duty diesel engine-powered vehicles, which include conventional diesel buses and diesel-electric hybrid buses. Using wireless remote communication technology, the SCR system status and NOx emissions were reviewed for ten fully-operational hybrid buses from Hangzhou China in this research. Under the internal combustion engine mode, the main factors studied were vehicle speed, engine operation conditions and environment temperature, impact on the SCR catalyst outlet temperature and NO_x concentration and dosing rate of the urea injector of the SCR system. The research result shows that (32.4±4)% of the operational time of the hybrid buses with SCR system was spent in internal combustion engine mode, and under (26.9±11)% of the operation time of this mode, the SCR system did not dose urea. The average NOx emission reduction rate of the SCR system, when operating normally with hybrid buses, is about 59%. The main reasons for the high NO_x emission of the diesel-electric hybrid buses in operation condition are poor satisfaction of the requirements of the SCR system control strategy and the SCR catalyst's low temperature conversion efficiency. Whenever the speed of the hybrid buses was above 40 km·h^-1, the SCR catalyst outlet temperatures were higher than the 230℃, and the NO_x emission concentrations were significantly reduced, as the urea injector working proportion and urea quantity increased. In the winter, the SCR catalyst outlet temperature and urea injection quantity dropped with the reduced environment temperature, which led to increased NO_x emissions.

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