IVE模型中区间划分方法对排放因子估算的影响

Influence of different bin-grouping methods on the estimation of emission factors in model IVE

利用便携式排放测试系统(Portable Emission Measurement System,简称PEMS)和GPS系统(Global Position System,简称GPS)选取多辆天津市机动车进行了道路测试,并对其排放及行驶数据进行了研究,分析了在IVE(International Vehicle Emissions,简称IVE)模型中不同区间的划分方法下,机动车比功率(Vehicle Specific Power,简称VSP)与排放相关系数的差异.CO、CO_2、NO_x排放与VSP相关系数在Paps(Preaverage Power Stress,前平均比功率负载,简称Paps)方案下进行划分时的平均值从原有的引擎负载(Engine Stress,简称ES)方案下的0.1以下上升到0.4以上;但是HC排放与VSP相关系数在ES方案下的均值为0.0370,在Paps方案下却为-0.0766.分别计算污染物实测排放因子与IVE模型改进前和改进后的污染物排放因子的比值,发现采用Paps区间划分方法计算得出的排放因子数据比ES区间划分方法得出的数据显著接近于实测排放因子,显示Paps区间划分方法有助于改善机动车排放估算的准确度.

Many vehicles were tested on road by Portable Emission Measurement System and Global Position System in Tianjin,China.Emission data and GPS data were collected to analyze the differences of the correlation coefficient of VSP and emission when being classified by different bins in IVE model.The correlation coefficients of CO,CO2,NOx and VSP increased from below 0.1 at the scheme of Engine Stress(ES)to above 0.4 at the scheme of Preaverage Power Stress(Paps),but the correlation coefficients of HC emission and VSP were from 0.0370 at ES to-0.0766 at Paps.The ratios of the measured emission factors of pollutants to the pollutant emission factors before and after the improvement of the IVE model were calculated separately.It was found that the data obtained by the Paps bin-grouping method were closer to the measured emission factors than the data obtained by the ES bin-grouping methods.The results showed that the Paps bin-grouping method could be helpful to improve the accuracy of the vehicle emissions estimation.