This week’s news was dominated by the big VW scandal. For those still scratching their heads about what exactly is going on, here is an overview.
In the USA, testing agency, the EPA, discovered that the VW Passat with a 2.0 TDI engine automatically switched to a different engine mapping during emission tests on the dynometers.These ‘dyno’ engine maps change the engines characteristics thus resulting in lower emissions. With the real ‘street’ mapping, the emissions would have been significantly higher, especially the NOx (Nitrousoxide). These NOx emissions would have been too high for the US’s strict law on NOx. The boundary value in the U.S. is currently at 31 miligram per kilomerer which is significantly lower than the boundary value for the European emission law for new EU6 cars (Diesel 80 mg/km; Gas 60 mg/km).
After the issue of VW cheating the system with the Passat escalated, Volkswagen admitted that Passats were not the only models detecting emission test conditions. Ultimately, Volkswagen has confirmed that about 11 million VW Group cars, including 2.1 million Audis were sold with this software. But why did this happen to VW and not to the American brands with their big gas-guzzling V8s?
NOx emissions weren’t a topic years ago but its importance is increasing with the goal of creating fuel-efficient engines and therefore lower CO2 emissions. NOx was always in the emissions of internal combustion engines. But with higher combustion temperatures through turbocharging, high pressure direct injection, high compression rates and lean fuel operation, more NOx is created in the internal combustion process of diesel and gasoline – less NOx is produced in the combustion process of gasoline than that of diesel.
As a result, NOx emissions are not an issue in big gasoline-powered naturally aspirated V8 engines. Another factor, which is problematic for the diesel engines regarding emissions is the fact that with a combustion process which decreases the carbon emissions, the NOx emissions will increase and vice-versa. To kill NOx emissions and fulfill current emission laws, Ad-Blue (which is basically artificial urea), is used in the exhaust gas treatment of diesel engines. Integrating this process is expensive for the manufacturers and also has its own risks, like the possibility of setting free ammonia gas. So manufacturers only implement this system when needed.
Coming back to the VW scandal, the problem is not only that VW cheated, but that the emission tests and boundary values are far from reality. Everyone of us uses our cars differently. Some people coast more than others while others use the accelerator peddle more excessively. Factors like wind, drag and tire pressure all have an impact on the fuel consumption and the resulting emissions.
I understand that the tests have to be reproducible, so driving in real traffic and monitoring the emissions is not a solution. Yet, law makers have the responsibility to set boundary values and test procedures that are realistic to modern driving habits and traffic situations. Clearly, the U.S. emissions law prefers their bigger capacity gasoline engines over European fuel efficient four-cylinder diesel engines. Another coincidence is that the scandal was made public the same week as the new VW Passat was introduced to the U.S. public.
Furthermore, the media is only making it worse and unfortunately it seems that it [media] has nowadays forgotten or doesn’t want to to do any research. This week they were literally bashing many other OEMs for cheating but so far only the VW cheat remains a proven fact.
The test procedure given by the European Union is called NEFZ. On Thursday, the mayhem reached its peak with German magazine Auto Bild writing without any prove that BMW cheated in some unnamed emission tests for the X3 2.0d as well. The same evening Auto Bild took back the accusations but not without harming BMW’s stock exchange price. And this is exactly the main problem in this scandal. The media exaggerating a topic which leads to more harm than good. A lot of jobs depend on the German automobile industry not only in Germany and Europe but also overseas. The media puts those jobs at risk just for clicks and audience ratings. Click-baiting is an uncouth behavior and that type of media reportage isn’t anywhere far off!