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UBA study: Euro 6 passenger car diesel with higher NOx emissions

Hans-Dieter Seufert
Study by the Federal Environment Agency
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D he list of vehicles according to Euro 5 and Euro 6 was made available to auto motor und sport after the reference to the Environmental Information Act. The three Euro 5 models with the highest NOx emissions when the engine is warm are the Fiat Doblo 1.6 Multijet with 1,791 mg /km, the Kia Optima 1.7 CRDi ISG 1,362 mg /km and the Mercedes C 220 CDI T with 990 mg /km. The limit is 180 mg /km.

The three Euro 6 models are the Renault Grand Scénic 1.6 dCi130 (937 mg /km), the Mazda CX-5D LP 4WD 498 mg /km) as well the Porsche Macan S Diesel (482 mg /km) The limit is 80 mg /km.

Federal Environment Agency drives the Federal Motor Transport Authority

However, the values ​​for the individual models are difficult to determine Compare with other values ​​because they were partially determined in the laboratory after the less common CADC cycle and temperature-dependent changes were then included with the aid of field data. The Federal Environment Agency also expressly points out that the results do not allow any model-specific conclusions. The Federal Motor Transport Authority (KBA) carried out such measurements and this would have to demand consequences from the relevant manufacturers.

Rather, the aim of the UBA study was to determine the effects of NOx emissions, which in reality are well above the limit values to determine the city air at temperatures that are outside the so-called thermal windows. Outside of these narrow temperature ranges, many manufacturers greatly reduce exhaust gas cleaning or switch it off completely. The Federal Environment Agency wants to get Federal Transport Minister Dobrindt and KBA to take action to encourage car manufacturers to improve exhaust gas cleaning over a wide temperature range, including for existing vehicles. This is the only way to improve air quality.

According to the study, the average NOx pollution of the entire diesel car fleet in Germany in 2016 was 767 mg NOx /km instead of 575 mg NOx /km. 'For the reassessment, measurements for the warm engine were also taken into account for the first time at all outside temperatures typical in Germany,' said the UBA. The authority not only used measurements with the engine at operating temperature and outside temperatures of 20 degrees Celsius, but also used the emissions behavior of diesel vehicles over all seasons and for all temperatures common in Germany. Half of car mileage inGermany is completed at temperatures below 10 degrees Celsius.


Euro 5 diesel cars are considered to be particularly “dirty”; they average 906 mg NOx /km and exceed the limit of 180 mg NOx /km by 403 percent. Diesel cars according to Euro 4 have 674 mg NOx /km (limit value: 250). The Euro 6 diesels have to adhere to a limit of 80, but in the UBA study they have an average of 507 mg NOx /km. Exceeding 534 percent.


VDA criticizes the UBA

The Association of the German Automotive Industry (VDA) reacted promptly to the UBA study. “It is well known that emissions on the road are higher than in the laboratory. The VDA's statement that Euro 6 vehicles have significantly better NOx values ​​than Euro 5 diesels is confirmed. However, emissions on the road vary depending on the model, driving style, and traffic and weather conditions. It is also known that real values ​​also depend on the exhaust technology used. An average view is therefore not very meaningful. '' We welcome the introduction of RDE and WLTP, and we are also open to reforms of type approval. But you shouldn't throw the child out with the bathwater. The federal government has a duty, as it were, to prevent excessive bureaucracy and European centralism. Many other governments of EU member states are also turning against European centralism at this point.

The problem of increased real emissions is actually well known. auto motor und sport has been testing Real Drive Emissions (RDE) for over a year in its own complex test procedure. The sometimes dismaying results can be found in the photo show. That an average view is not very meaningfulis for individual models, says the UBA. For the air outside of laboratories, however, the average view is decisive.


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