Post-Dieselgate: Evidence of NOx Emission Reductions Using On-Road Remote Sensing
journal contributionposted on 30.04.2020, 19:14 by Stuart K. Grange, Naomi J. Farren, Adam R. Vaughan, Jack Davison, David C. Carslaw
The Dieselgate scandal which broke in September 2015 demonstrated that vehicle manufacturers, such as the Volkswagen Group (VWG), engaged in software-based manipulation which led to vehicles passing laboratory-based emission testing limits but were far more polluting while being driven on roads. Using 23 000 on-road remote sensing measurements of light-duty Euro 5 diesel vehicles in the United Kingdom between 2012 and 2018, VWG vehicles with the “Dieselgate-affected” EA189 engine demonstrated anomalous NOx emission behavior between the pre- and post-Dieselgate periods which was not observed in other vehicle makes or models. These anomalous changes can be explained by voluntary VWG hardware and software fixes which have led to improved NOx emission control. The VGW 1.6 L vehicles, with a simple hardware fix and a software upgrade, resulted in a 36% reduction in NOx, whereas the 2.0 L vehicles that required a software-only fix showed a 30% reduction in NOx once controlled for ambient temperature effects. These results show that even minor changes or upgrades can considerably reduce NOx emissions, which has implications for future emission control activities and local air quality.
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2.0 L vehiclesx emissionsx emission controlresults showSeptember 2015ambient temperature effectspost-Dieselgate periodsVGW 1.6 L vehiclesvehicle manufacturerssoftware fixesOn-Road RemoteEAfuture emission control activities23 000 on-roadEuro 5 diesel vehiclesDieselgate scandalsoftware-based manipulationlaboratory-based emission testing limitsx Emission ReductionsVolkswagen Groupair qualityx emission behaviorVWG hardware