Report claims Daimler deployed previously unknown emissions defeat devices

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Deutsche Umwelthilfe (DUH), a German environmental group, claims that Daimler Group has been deploying defeat devices in its engines to game emissions regulations.

The group has published a report, within which automotive software expert Felix Domke documents eight previously unknown defeat devices in a Mercedes-Benz Euro 6 E-Class diesel car on behalf of a US law firm. Domke has already worked as an expert for the German Federal Motor Vehicle and Transport Authority (KBA) on the independent analysis of software implementation with regard to illegal defeat devices. He also served as an expert witness at the parliamentary inquiry committee into the VW emissions scandal in 2017.

In DUH’s view, the implementation of the devices is illegal and intended to reduce the effective purification of exhaust gases by the SCR catalytic converter. The result: the actual nitrogen oxide emissions on the road are claimed to be up to 500% above the legally prescribed limit value. Until now, Daimler AG has always denied using illegal defeat devices in diesel cars sold in Germany and Europe.

“The expert report by Felix Domke finally proves that Daimler is guilty. It shows us for the first time how the company succeeds in complying with the legal limits in the test laboratory while literally flooding our cities with harmful nitrogen oxides during real road use. The manipulation of the exhaust gas purification is not carried out because it is necessary for physical reasons or for the purpose of engine protection. The reason is as simple as it is cynical: it is about maximizing profits at the expense of the environment and the health of city residents,” said Jürgen Resch, DUH’s national director.

“We demand from the new federal government that all diesel vehicles with defeat devices in the exhaust gas purification system are either decommissioned or repaired via an official recall at the expense of the manufacturers, as is the case in the USA. The World Health Organization recently called for the nitrogen dioxide limit to be lowered from an annual average of 40 to 10µg/m3 . To do this, all illegal diesel exhaust sources must be targeted – action must finally be taken.”

Eight devices were allegedly found and documented, six associated with the SCR system. Three of them apparently depend on an ‘aging factor’ that significantly lowers the thresholds at which the shutdown devices activate. In two cases, this already begins to occur after aging of about 1% in relation to the vehicle’s service life – i.e. after only a few thousand kilometers. A further reduction occurs after the vehicle has aged by approximately 20%. Two allegedly illegal defeat devices are linked to the vehicle’s exhaust gas recirculation system.

“The defeat devices found activate in driving situations that are common in road use conditions. Even under normal driving conditions, at least one defeat device almost always actively prevents the improvement of emissions, even if it is not physically necessary or necessary for engine protection. This significantly reduces the amount of AdBlue injected, which is urgently needed to neutralize the nitrogen oxides in the SCR catalytic converter; similarly, the exhaust gas recirculation rate is reduced. As a result, the normally effective exhaust gas treatment hardware often only performs at a fraction of its potential capacity, and the vehicle emits unnecessarily large amounts of nitrogen oxides,” said Domke.

The report is claimed to be supported by current exhaust gas measurements obtained on the road by DUH’s Emissions Control Institute (EKI). These, it says, demonstrate that Daimler installed several illegal defeat devices in the vehicle under investigation. The vehicle complies with the legal nitrogen oxide limit values when examined on the test bench. However, based on a similar driving profile on the road, EKI’s exhaust measurements indicate an increase in nitrogen oxide emissions of up to 500% and more.

KBA has already demanded a software update for the model under investigation, the E350T Euronorm 6 engine. DUH notes that the defeat devices have been removed in the updated software.

“From a legal point of view, the factual situation is clear,” commented Glenn Phillips, managing partner of the international law firm Milberg, which commissioned the expert report. “The investigation concludes that the Daimler Group has installed a large number of unauthorized defeat devices that clearly violate applicable law. Affected consumers are now obviously entitled to damages. After all, they have been sold a defective vehicle for which they paid the full purchase price. Legally, this can be considered fraud – committed not only against the environment but also against consumers. Mercedes drivers should check to determine if their diesel vehicle is affected.”

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Lawrence has been covering engineering subjects – with a focus on motorsport technology – since 2007 and has edited and contributed to a variety of international titles. Currently he is responsible for content across UKI Media & Events' portfolio of websites while also writing for the company's print titles.

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