摘要
非城市柴油车在柴油车市场中占据了较大的份额,开展国六非城市在用柴油车实际运行工况与氮氧化物(NO_(x))排放特征分析,对于下一阶段实际道路排放测试方法的升级以及降低NO_(x)排放具有重要意义。利用在用柴油车远程监控数据,系统研究了国六N_(2)和N_(3)类非城市在用柴油车实际运行工况与NO_(x)排放特征,并与便携式排放测试系统(PEMS)测试结果进行对比。结果表明,在市区和市郊工况下,国六非城市在用柴油车实际运行时间占比和NO_(x)排放贡献率均低于PEMS测试,而在高速工况下的实际运行时间占比和NO_(x)排放贡献率均高于PEMS测试。建议在后续标准的修订中,应进一步优化PEMS测试中非城市车辆的行驶工况构成比例,以便更真实地反映其实际NO_(x)排放水平。此外,国六非城市柴油车NO_(x)比排放随车速和发动机负荷的提高呈下降趋势。高速工况下,N_(2)和N_(3)类非城市在用柴油车的NO_(x)比排放较于市区工况分别降低了72.1%和64.7%。值得注意的是,约13%的N_(2)类非城市在用柴油车在市区工况下表现出选择性催化还原(SCR)入口排气温度较低,导致SCR装置处于低转化效率状态。因此,应提高SCR装置低温转化效率,以降低市区行驶工况下的NO_(x)实际排放量。
Non-urban diesel vehicles occupy a large market share among heavy-duty diesel vehicles,and it is of great significance to characterize the operating conditions and emissions characteristics of China Ⅵ non-urban in-use diesel vehicles for the improvement of on-road emission test methods and the reduction of nitrogen oxide(NO_x) emissions in the next stage.The operating conditions and NO_(x) emissions characteristics of China Ⅵ N_(2) and N_(3) non-urban diesel vehicles were systematically investigated by using the portable emission measurement system(PEMS) and remote monitoring data of in-use diesel vehicles,and the differences were analyzed with the results of the PEMS tests.The results showed that the percentage of time and NO_(x) emission contribution of China Ⅵ non-urban diesel vehicles operating under urban and suburban operating conditions was lower than that of the PEMS test,while the percentage of time and NO_(x) emission contribution of China Ⅵ non-urban diesel vehicles operating under high-speed operating conditions was significantly higher than that of the PEMS test.It was recommended that the proportion of non-urban vehicle operating conditions in the PEMS test should be further optimized in the next revision of the standard to more realistically reflect their actual NO_(x) emission levels.In addition,the NO_(x) specific emissions of China Ⅵ non-urban diesel vehicles showed a decreasing trend with increasing vehicle speed and engine load,and the NO_(x) specific emissions of N_(2) and N_(3) category vehicles were reduced by 72.1% and 64.7%,respectively,under high-speed operating conditions compared to urban operating conditions.Almost 13% of the N_(2) category diesel vehicles in service had low exhaust temperatures under urban operating conditions,resulting in a low conversion efficiency of the selective catalytic reduction(SCR) aftertreatment system.Therefore,the low-temperature conversion efficiency of SCR aftertreatment system should be improved in order to reduce the actual NO_(x) emissions
作者
白晓鑫
吴春玲
景晓军
刘卫林
李旭
杨永真
BAI Xiaoxin;WU Chunling;JING Xiaojun;LIU Weilin;LI Xu;YANG Yongzhen(CATARC Automotive Test Center(Tianjin)Co.,Ltd.,Tianjin 300300;School of Mechanical Engineering,Tianjin University,Tianjin 300072)
出处
《环境污染与防治》
CAS
CSCD
北大核心
2024年第6期789-795,809,共8页
Environmental Pollution & Control
基金
国家重点研发计划项目(No.2022YFC3703600)。
