基于10辆轻型汽油车的实际行驶与台架工况排放特征及影响因素研究

Characteristics and influencing factors of emissions from 10 light-duty gasoline vehicles under real-world driving and chassis dynamometer conditions

利用便携式排放测试系统(Portable emission measurement system,PEMS)分析了10辆轻型汽油车分别在实验室台架和实际行驶排放(Realdrivingemission,RDE)工况下典型空气污染物的排放特征和影响因素.测试结果表明,轻型汽油车在冷启动和热启动阶段产生的一氧化碳(CO)、碳氢化合物(HC)、氮氧化物(NO_(x))分别是热运行1阶段和热运行2阶段的28.0、32.9、28.4倍和4.0、11.2、5.4倍,表明车辆启动对机动车排放贡献显著.台架工况排放因子受车辆启动排放影响较大,在台架实验去除启动排放影响的情况下,台架CO_(2)、CO、HC和NOx排放因子将分别减小2.3%±1.3%、44.2%±30.6%、47.5%±29.6%和44.9%±30.8%.在相同速度下,RDE工况下的CO_(2)排放因子相比不考虑启动排放的台架工况排放因子要高出31.7%±5.0%.单车瞬态排放数据分析结果表明,RDE测试相比于台架工况测试覆盖了更多的机动车行驶工况特征,可以更准确地量化车辆在实际道路行驶过程中不同工况下的排放特征.因此,开展RDE排放测试对于准确量化机动车尾气排放特征,尤其是对建立微观尺度机动车排放清单支撑城市精细化管控具有重要意义.

This study explored the emission characteristics and the potential influencing factors of typical air pollutants emitted by 10 light-duty gasoline vehicles under a real driving emission test(RDE)and a laboratory chassis dynamometer test(i.e.,UDC)using the portable emission measurement system,respectively.Our results showed that the emission factors of carbon monoxide(CO),hydrocarbon(HC),and nitrogen oxides(NO_(x))in the cold start condition were 28.0,32.9,28.4 times and 4.0,11.2,5.4 times higher than the hot operation condition(#1)and(#2),respectively,emphasizing the importance of the start operation on the vehicular emission.The emission factor under the dynamometer condition was greatly affected by the start emission of the vehicle.The dynamometer condition derived emission factors of carbon dioxide(CO_(2)),CO,HC and NOx will be reduced by 2.3%±1.3%,44.2%±30.6%,47.5%±29.6%,and 44.9%±30.8%,respectively,if we don’t consider the start emissions.At the same speed,the CO_(2) emission factor under the RDE condition was 31.7%±5.0%higher than the dynamometer condition without start emissions.The instantaneous emission analysis showed that the RDE test covered more vehicle driving conditions than the chassis dynamometer test and can more accurately quantify the vehicle emission.Therefore,RDE emission tests are urgently needed to characterize and quantify the emissions of vehicles and will play an important role in establishing the micro-scale emission inventories that can be used to finely and effectively control air pollution in urban regions.