轻型汽油车实际行驶污染物排放的影响因素

为了研究车辆冷起动、行程动力学参数和不同数据处理方法对实际行驶排放(RDE)试验的影响,本文利用4辆轻型汽油车进行试验研究,通过CO2移动平均窗口法和欧6新方法进行排放计算。结果表明:冷起动对CO和NOx排放影响偏差均在10%以内,对于未装配汽油机颗粒捕集器(GPF)车辆的市区PN排放影响偏差最大可达32.25%,在国6车型标定时应重点关注。相对正向加速度(RPA)与PN排放成正相关,与CO、NOx排放相关性不明显;v*apos,95(速度与正向加速度乘积按升序排序的第95个百分位取值)与CO、PN排放成正相关,与NOx排放成负相关,与CO和PN的相关系数大于与NOx的相关系数。对于同一个有效行程的污染物排放计算结果,欧6新方法大于CO2移动平均窗口法,欧6新方法能更加真实地反映车辆在RDE试验中的污染物排放水平。

Influential factors of the real driving emission for light-duty gasoline vehicles

The real driving emission tes(t RDE)was carried out with four gasoline vehicles to investigated the influence of cold start,the dynamic parameters and two different calculation methods to real driving emission,and the pollutant emission was calculated with the CO2 moving average window method and the new Euro 6 method.The results show that the deviation of the influence of cold start on CO and NOx emission is within 10%,and cold start has a greater influence on urban PN emission for vehicles without gasoline particulate filter(GPF),with a maximum difference is up to 32.25%,so it is necessary to pay more attention on the calibration of new vehicles.Relative position acceleration(RPA)is positively correlated with particle number(PN)emission,but has no obviously correlation with CO and NOx.The v*apos,95(the 95th percentile of the value of velocity times positive acceleration)is positively correlated with CO and PN emissions,as opposed to NOx emission,and the positive correlation coefficient is greater than negative correlation coefficient.For the same valid test,the calculation result with newly Euro 6 is larger than that with the CO2 moving average window method,the newly method can more truly reflect the vehicle pollutant emission in the RDE test.