不同测试循环轻型汽油车氨排放特性研究

Study on Ammonia Emission Characteristics of Light-duty Gasoline Vehicles under Different Test Cycles

随着人们环保意识的提高,道路车辆产生的氨(NH3)排放问题越来越受到重视。为了掌握某些特定场景下轻型汽油车NH3排放的实际状况,以2辆国六标准和1辆国五标准轻型汽油车为研究对象,分别对车辆在不同负荷、不同测试循环(包括WLTC循环和RDE循环)、不同排放标准、采用特殊技术路线(清氧功能)下进行了NH3排放测试。结果表明:车辆在WLTC循环低速段的NH3最高瞬时排放速率为RDE循环市区路段的2.7倍。在前1500 s内,空调开启状态,NH3排放因子较空调关闭状态升高了1.47倍,NH3最高瞬时排放速率较空调关闭状态增加了26.7倍;且当空调开启后,NH3的高排放区域分布更加集中。在RDE循环的总行程,国六标准车辆,NOx排放因子较国五标准车辆降低了56.1%,但NH3排放因子较国五标准车辆升高了12.8倍。车辆执行清氧操作后,NOx和NH3的生成规律都发生了明显改变,NOx排放得到了较好的控制,但增加了NH3产生的概率。

With the increasing awareness of environmental protection,the problem of ammonia(NH3)emissions from road vehicles is getting more and more attention.In order to grasp the actual situation of NH3 emission from light-duty gasoline vehicles under certain specific scenarios,two China VI and one China V light-duty gasoline vehicles were used as research objects,and the NH3 emission tests were conducted under different loads,different test cycles(including the WLTC cycle and the RDE cycle),different emission standards,and the use of a special technological route(oxygen scavenging function),respectively.The results show that the maximum instantaneous NH3 emission rate of the vehicle in the low-speed section of the WLTC cycle is 2.7 times higher than that of the urban section of the RDE cycle.In the first 1500 s,the NH3 emission factor in the air-conditioning-on state was 1.47 times higher than that in the air-conditioning-off state,and the maximum instantaneous emission rate of NH3 was 26.7 times higher than that in the air-conditioning-off state;and when the air-conditioning was turned on,the distribution of the high-emission areas of NH3 was more concentrated.In the total trip of RDE cycle,the NOx emission factor of the National VI standard vehicle was 56.1%lower than that of the National V standard vehicle,but the NH3 emission factor was 12.8 times higher than that of the National V standard vehicle.After the vehicle performed the oxygen scavenging operation,both NOx and NH3 generation patterns were significantly changed,with better control of NOx emissions but increased probability of NH3 generation.