Mercedes-Benz could in turn be again splattered by the scandal of the diesel car emissions. According a report Quoted by the German environmental association Deutsche Umwelthilfe (DUH), some diesel models of the brand would have up to eight “cheat software” to avoid decontamination of the exhaust gases of those cars.
When the Dieselgate exploded in Volkswagen’s face, the German group was not the only one under suspicion. Mercedes-Benz was another of the German manufacturers suspected of having cheated with the emissions of some of its diesel models.
Although Mercedes-Benz had to recall nothing less than 774,000 diesel cars In 2018 across Europe, by order of the German Ministry of Transport (the KBA), the brand never admitted to having made any kind of cheating.
For now, that the star brand has deliberately made some kind of cheating remains a suspicion. However, a report from the automotive informatics expert Felix Domke, commissioned by the international law firm Milberg, could change this situation.
The 32-page document, published by the German environmental association German Environmental Aid (DUH), reveals the presence of eight “cheat programs” in the E-Class 350 BlueTec 4Matic Estate from previous generation (type W212). The specific model was registered for the first time in January 2016, it equips the V6 diesel type OM642 and complies with the Euro 6 standard.
According to this expert, six of the cheat software would reduce the effectiveness of the SCR catalyst, responsible for combating dangerous nitrogen oxides (NOx) by converting them into harmless nitrogen and water with the help of Adblue. (That we explain how they work here).
The other two programs act on an older design contamination control system, the EGR valve. All of them are activated based on different parameters: volume of exhaust gases or NOx at a given moment, temperature of the intake air or inside the SCR, consumption of AdBlue, etc.
In addition, says Felix Domke, the programs have incorporated a function that limits the use of decontamination systems when the elements that compose it wear out over time.
On certain occasions, decontamination systems may be disconnected or legally cease to function. In general, it is usually to protect the engine, usually when the engine is cold or too hot or when there is a component that fails due to temperature reasons.
However, the Felix Domke report states that these malfunctions of emission control systems occur far too often.
“Even under normal driving conditions, there is almost always at least one deactivation device that prevents the reduction of pollutant emissions, even if it is not necessary for physical reasons or for engine protection”, explains the expert. significantly reduces the amount of AdBlue that is injected, while it would take much more to neutralize the Nox in the SCR catalyst ”.
To reach these conclusions, Felix Domke relied mainly on an analysis of the ECU that controls the operation of the engine. It is not an easy task, as this ECU is capable of emitting more than 10,000 different signals. In addition, the manufacturers do not disclose its operation. On the other hand, to make things easier for itself, the study was based on a single car, which is sure to attract some criticism. Even so, For the director of the DUH, Jürgen Resch, “Daimler is guilty”.
Mercedes-Benz is silent for the moment
It is very likely that Mercedes-Benz is already preparing its response. In fact, it has been running emissions tests on the road with some of its old models this summer, such as a similar E-Class and a G-Class equipped with the same OM642 diesel V6.
What could have supposedly led Mercedes-Benz to cheat? Why such drastic differences between homologation and actual use? In the case of Volkswagen, it was to be able to comply with the American homologation standard, when in reality the cars could not have been homologated. And although in Europe they did pass the homologation, the European models still equipped the cheating software, which is illegal.
In the case of Mercedes-Benz it is not clear if it is about being able to pass the European homologation and outside of laboratory conditions the car does not use these systems or if the little use that the car makes in normal conditions of these systems decontamination are due to a desire to space out their maintenance.
I mean, why limit the use of AdBlue? Was AdBlue consumption so exorbitant that it would have pissed off users or given a bad image? Were they fragile systems that would have had to be changed often, undermining the Mercedes-Benz brand image?
For now, the DUH has asked the German federal government to call all cars that are still equipped with this software for a mandatory check to deactivate it. According to the report, this measure would have the effect of doubling the consumption of AdBlue. Precisely, now that the price of this additive is increasing.