Portable Emissions Measurement System (PEMS) data for Euro 6 diesel cars and comparison with emissions modelling

摘要

Thispaper reviews the emissions performance of 39 Euro 6 diesel passenger cars usinga Portable Emissions Measurement System (PEMS). Comparisons are made withcurrent emissions regulations (in particular the Euro 6 standard for nitrogen oxides(NOx = NO+ NO2) of 0.80 g km-1) and predictions by the speed dependent emissionfactors of COPERT. The mean NOx emission was 0.36 ± 0.36 g km-1 , the meannitrogen dioxide (NO2) emission was 0.17 ± 0.19 g km-1. The average fractionNOx emitted as NO2 (known as primary NO2 or fNO2) was 44%. Each vehicle wasanalysed over a test route composed of urban and motorway driving. On averageNOx emissions were 5.3 times the Euro 6 limit for urban driving and 3.8 timesthe limit for motorway. A wide range of deviation ratios (ratio between realworld measurements and type approval limit) were found, the highest being 27.3for an urban section. The average PEMS measured NOx emission was 1.6 timesCOPERT’s average estimate. Similarly with primary NO2 (44% compared to 30%assumed by COPERT). Scenario analysis was then performed to assess the sensitivityof the mean annual roadside concentrations of NO2 to the discrepancies betweentype approval limits, COPERT estimates and on road emissions measured by PEMS.