Lawsuit: Mercedes Diesel Emissions 65x Over EPA Limit


Mercedes Diesel Emissions Next EPA Target

A new lawsuit brought against Mercedes-Benz states that the company’s existing diesel engines pollute up to 65x (sixty-five times) more than the legal amount when it’s cold out. The claim is that when the temperature drops below 50 degrees fahrenheit the nitrogen oxide reduction system simply turns off. If that’s true, it could be bad news for Mercedes-Benz.

Mercedes, for its parts, uses a number of technologies to control diesel emissions and markets them under the “BlueTEC” banner. One of those technologies is called “AdBlue”, and that’s what MB uses to keep nitrous oxide emissions- the ones that have gotten Volkswagen in so much recent trouble– to a minimum.

Mercedes describes the AdBlue process, in its own words, below:

    BlueTEC brings together an array of advanced technologies to create the world’s cleanest diesel automobiles. Advanced and highly precise components, from high-pressure fuel injection to a variable-vane turbo, create more complete and powerful combustion. But the breakthrough is an innovative liquid solution called AdBlue. When injected into the exhaust, AdBlue converts the nitrogen oxide emissions into harmless nitrogen and oxygen. And BlueTEC vehicles can use both ultralow-sulfur fuels (now the standard nationwide) or even B5 Biodiesel.

    Mercedes-Benz Genuine AdBlue is composed of urea and de-ionised water. It is injected into the exhaust gasses of selected diesel engines as a post combustion process. Mercedes-Benz vehicles using AdBlue® technology are identified with the ‘BlueTEC’ symbol. AdBlue’s® purpose is to reduce the percentage of harmful NOx (Nitrogen Oxide) found in the vehicle’s emissions. With BlueTEC technology, Mercedes-Benz has been able to heavily reduce exhaust gas emissions while at the same time maintaining the performance of diesel engines in terms of power and torque output.

How bad would it emissions get if the system does cut off? According to the lawsuit- filed by the same firm that’s currently suing GM for ignition switch failures- it’s catastrophically bad, with emissions spiking to more than 65x the EPA allows. “Real world testing,” says the suit, “has recently revealed that these vehicles emit dangerous oxides of nitrogen (NOx) at a level more than 65 times higher than the United States Environmental Protection Agency permits. The Mercedes’ ‘Clean Diesel’ turns out to be far from ‘clean’.”

As I write this, there has been no official response from Mercedes-Benz. That said, the company recently announced an all-new lineup of cleaner, more efficient diesel engines that will- no doubt- be highly scrutinized by government and independent testing agencies.

You can read the lawsuit for yourself at the source link, below, and let us know what you think of this lawsuit against Mercedes-Benz in the comments section at the bottom of the page.


Sources: Boostaddict, HBSS Law.

About the Author

I’ve been in the auto industry 1997, and write for a number of blogs in the IM network. You can also find me on Twitter, at my Volvo fansite, or chasing my kids around Oak Park, IL.

  • James

    Not only that. Anyone can buy a diesel defeat device that bypasses the Adblue system 100 % of the time and although illegal Amazon and eBay sell them anyway.
    Seach for adblue emulator on Amazon or eBay

    • bioburner

      Yes the EPA should go after the companies that are making and selling those defeat devices

      • James

        And go after Amazon and eBay for selling them as selling is illegal. But Amazon and eBay are “untouchable”

  • Joe Viocoe

    This looks like lawyers out for a payday. Although I do think automakers should be held responsible…. there is no reason to suspect Mercedes of cheating. The testers found a specific circumstance where emissions are much worse than a regular test cycle.

    NOx can be very misleading.

    NOx is one of those emissions that has more to do with engine conditions, than fuel.

    CO2 and other emissions are directly related to how much fuel is burnt. So those emissions don’t vary a whole lot unless the efficiency of the engine is drastically different.

    So if the “real world test” is within 10% of the MPG of the EPA or Euro standard cycle.. all other emissions should be within 10%.

    But NOx is a tricky beast that can go completely off the chart if you run the engine at different loads, temperature, altitude, with fuel impurities, or even a faulty sensor.

    Even if MPG is fairly close to government tests… under varying conditions, NOx can change substantially.

    It is a good thing to have independent tests… but there unless there is a “standard”, the results have little meaning.

  • Joe Viocoe

    It is telling that they are trying to sue the automaker, instead of suing the EPA for not testing vehicles under the conditions that would result in this level of NOx.

  • Eco Logical

    It’s not just when they are cold, diesels emit visible clouds of toxic soot when under heavy load (accelerating or going uphill). According to the WHO the soot fibres get into our lungs (especially children) and scar over the lung tissue making it incapable of exchanging oxygen. The nitrous oxides combine with water in our lungs forming NITRIC ACID causing asthma, emphysema, and ultimately death. Isn’t it time we BAN DIESELS FROM URBAN AREAS?