Comparison of CVS and PEMS measuring devices used for stating CO2 exhaust emissions of light-duty vehicles during WLTP testing procedure

Abstract

In 2014, the United Nations Economic Commission for Europe (UNECE) released the Worldwide Harmonized Light-Duty Vehicles Test Procedure (WLTP). The European Commission focused on introducing a new trial test procedure into the European legislation with the aim to replace the existing test for stating exhaust emissions, the so-called New European Driving Cycle (NEDC). The official data measured in laboratories show lower average fuel consumption and emission production of carbon dioxide (CO2) of European car fleet than it is in real driving conditions. Experts and the public declare that the officially stated CO2 values do not reflect the reality. This article presents results from two measuring devices from constant volume sampler (CVS) and from portable emissions measurement system (PEMS) used for stating the concentration of CO2 emissions. The experiment was conducted according to the Worldwide Harmonized Light-Duty Vehicles Test Procedure. The results show that there are not statistically significant differences between the CVS and PEMS devices, which are usually used for emission measuring in real driving emissions (RDE). Results of this paper provide information from the measurement, which was carried out according to WLTC with PEMS and CVS equipment. The experiment reflects the actual legislation requirements for emissions measurements. The results are useful tools for comparation technologies used for emissions measurements in laboratories (CVS) and on road emissions (PEMS).