基于实际道路测试的重型柴油车排放评估方法研究

Research on emission evaluation method of heavy-duty diesel vehicle based on actual road test

为分析重型柴油车实际道路测试情况下污染物的排放评估方法,选取了4辆国六重型柴油车进行实际道路排放试验。试验结果表明,现行《重型柴油车污染物排放限值及测量方法(中国第六阶段)》(GB 17691—2018)采用的功基窗口法在计算过程中剔除了大量发动机处于低功率段时氮氧化物(NO_(x))高比排放区域数据,大幅低估了重型柴油车在实际道路工况下的NO_(x)排放量,不能充分反映车辆实际道路排放水平,应进一步修改完善,建议后续标准修订时,去除法规中功率阈值最小10%的限制,采用全窗口的90%分位值来表征车辆的排放水平,或通过行程时间占比加权值法计算污染物比排放。

In order to analyze the emission evaluation method of pollutants under the actual road test of heavy-duty diesel vehicles,4 heavy-duty diesel vehicles of China Ⅵ were selected for actual road emission tests.The test results showed that the power-based window method adopted by the current “Limits and measurement methods for emissions from diesel fuelled heavy-duty vehicles(China Ⅵ)”(GB 17691-2018) could eliminate the data of a large number of areas with high NO_(x) emissions when the engine was in the low-power range,and greatly underestimate the NO_(x) emission of heavy-duty diesel vehicles under the actual road conditions,especially in urban conditions,which could not adequately reflect the actual road emissions of vehicles,so it should be further revised and improved.It was recommended that subsequent revisions to the standards should remove the minimum 10% power threshold limitation in the regulations and use the 90% quantile of the full window to characterize the vehicle's emission level,or calculate the pollutant specific emissions through the trip time share weighted value method.