NOx emissions of heavy-duty vehicles with Euro VI certified engines
van Gijlswijk, R.N.
van Goethem, S.
In the Dutch in-service emissions testing programme, the nitrogen oxide (NOx) emissions of 46 vehicles with Euro VI certified engines were measured during normal daily operation using the Smart Emission Measurement System (SEMS). To screen the in-service conformity, a number of vehicles were tested over the prescribed in-service conformity test routes using SEMS and in some cases the Portable Emission Measurement System (PEMS). All the screened vehicles showed indicative good results over the in-service conformity routes using the pass-fail evaluation method. In daily operation however, the NOx emissions vary a lot from case to case and are often not as low as one might expect based on the EU standard. The variation in NOx emissions is largely caused by the spread in operation profiles between the vehicles. Average speeds vary and especially at low speed, low load the probability that NOx emissions increase is higher. The cause is the fact that in these conditions the NOx abatement technology that is present on Euro VI step A to C certified engines is not always fully effective.
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Mobility & Logistics
Transport and Air Pollution Conferene in Thessaloniki, Greece, 15-17 May 2019, 1-11