丘陵道路下实际行驶污染物排放研究

Study on real driving emission on hilly road

为研究丘陵道路特征对实际行驶排放(RDE)试验中污染物排放和动力学特性校验的影响,本文利用一辆轻型汽油车,在重庆地区满足国六排放法规要求的4条不同道路特征的路线上各进行了两次RDE试验.结果表明:CO_(2)与道路坡度呈显著线性相关,坡度每增加1%,CO_(2)排放因子平均增加22.4%,CO和PN则与道路坡度呈二次多项式关系,NO_(x)与坡度无明显相关性.从移动平均窗口层面对比考虑坡度的VSP_(pos)[95](路段中正比功率升序排列的第95个百分位值)和不考虑坡度的v·a_(pos)[95](速度与正加速乘积升序排列的第95个百分位值)与PN的关系,发现窗口VSP_(pos)[95]和v·a_(pos)[95]与PN的二次拟合R2平均值分别为0.93和0.72,当窗口累计正海拔增量大于600 m/100 km时,VSP_(pos)[95]与PN的相关性明显优于v·a_(pos)[95],建议在累计正海拔增量大于600 m/100 km的丘陵地区使用VSP_(pos)[95]进行RDE动力学特性校验.该研究可对丘陵地区生态驾驶普及和国六法规中RDE试验行程动力学边界条件在丘陵地区的适应性提供参考.

Vehicle emission and dynamic characteristics are significantly influenced by road conditions.This work investigates the real driving emission(RDE)of a light gasoline vehicle on four different road characteristics in Chongqing according to China VI vehicle emission standards.The results show that there is a strong linear correlation between CO_(2) and road slope.When the slope increases by 1%,the CO_(2) emission factor increases by 22.4%on average.CO and PN show a quadratic polynomial relationship with road slope,while no clear correlation was observed between NO_(x) and the slope.The relationship between PN and VSP_(pos)[95](the 95th percentile value of the ascending order of positive vehicle specific power in the road section)considering slope and v·a_(pos)[95](the 95th percentile value of the ascending order of the product of speed and positive acceleration)without considering slope was compared from the moving average window level.To be more specific,VSP_(pos)[95]and PN shows an average coefficient of 0.93 while v·a_(pos)[95]and PN displays an average coefficient of 0.72.Nevertheless,the coefficient differences of aforementioned parameters become remarkable when the cumulative positive elevation incremental window goes beyond 600 m/100 km.Therefore,VSP_(pos)[95]is suggested to verify the dynamic characteristics of RDE in hilly areas where the cumulative positive elevation increment is greater than 600 m/100 km.The presented study in this paper light on the popularization of ecological driving in hilly areas and the adaptability of RDE dynamic boundary conditions in hilly areas.