In a comprehensive analysis of tests and studies from several years, the international environmental research association ICCT has found that many diesel cars in Europe have significantly too high exhaust emissions. The reason for the summary "re-evaluation" were rulings by the European Court of Justice (ECJ) on so-called shutdown devices - cleaning may only be shut down if there is a risk of concrete technical damage and safety risks.
Nevertheless, according to the ICCT, a good 85 percent of the Euro 5 and 77 percent of the Euro 6 diesel showed "suspiciously high emissions" under the provisions of the restrictions now in force, as the researchers reported on Thursday. In 40 percent of the cases, there were even "extreme" values for harmful nitrogen oxides (NOx).
The figures are not based on our own surveys, but on a large test database and secondary evaluations of emissions tests by authorities and organizations that have been running since 2016. A year earlier, the diesel manipulations at Volkswagen had become known.
According to the ICCT, the figures cover around 700,000 cars from different European countries. In doing so, the scientists took into account different measuring methods - mostly "remote sensing", i.e. exhaust gas values of passing cars from the roadside, but also tests with mobile measuring devices on the exhaust. They then related the values determined in this way to a threshold value for the respective engine and vehicle type, "which we derived from the emission control behavior that would normally be expected".
The interpretation of deviations revealed, among other things, that for diesels with NOx emissions classified as "extreme", "the use of a defeat device can be considered almost certain". Slightly less elevated values also indicated the "probable use of an engine calibration strategy that can be classified as a prohibited defeat device according to the ECJ's recent rulings".
With regard to the method used to refer to roadside measurements for individual cars, which are sometimes considered to be imprecise, the ICCT explained that they had worked intensively to show how these “can deliver robust estimates of the real emissions of individual vehicle groups despite some limitations”. Together with the data from measurements directly at the exhaust, they provide a basis for additional evidence of excessive NOx emissions in various test procedures.
The German Environmental Aid asked the Federal Motor Transport Authority (KBA) to bring all diesel cars with emissions standards 5 and 6 in Germany into line with the applicable regulations and to have all impermissible defeat devices removed. It is about more than eight million cars. An appeal has already been filed against the KBA.