Journal of Earth Sciences and Geotechnical Engineering

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

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• Abstract

   

  This paper reviews the emissions performance of 39 Euro 6 diesel passenger cars using a Portable Emissions Measurement System (PEMS). Comparisons are made with current 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 emission factors of COPERT. The mean NOx emission was 0.36 ± 0.36 g km^-1 , the mean nitrogen dioxide (NO₂) emission was 0.17 ± 0.19 g km-1. The average fraction NOx emitted as NO₂ (known as primary NO₂ or fNO₂) was 44%. Each vehicle was analysed over a test route composed of urban and motorway driving. On average NOx emissions were 5.3 times the Euro 6 limit for urban driving and 3.8 times the limit for motorway. A wide range of deviation ratios (ratio between real world measurements and type approval limit) were found, the highest being 27.3 for an urban section. The average PEMS measured NOx emission was 1.6 times COPERT’s average estimate. Similarly with primary NO2 (44% compared to 30% assumed by COPERT). Scenario analysis was then performed to assess the sensitivity of the mean annual roadside concentrations of NO2 to the discrepancies between type approval limits, COPERT estimates and on road emissions measured by PEMS.