• Mar 19, 2011
2012 Mercedes-Benz SLK – Click above for high-res image gallery

The newest gasoline engines from Mercedes-Benz feature cutting-edge lean-burn technology that leads to fewer harmful emissions and a 10 percent improvement in fuel economy. Well, the new engine tech, which requires a much leaner fuel-to-air ratio, is making its way into many mills, but apparently not the ones destined for these United States.

Ward's Automotive quotes Daimler powertrain development vice president Bernhard Heil as saying that the gasoline in the U.S. contains sulfur at the rate of 95 parts-per-million; about twice as much as can be tolerated by the new engines. The problem? Excess sulfur apparently clogs the nitrogen oxide-capturing traps.

So, is the U.S. the only country lagging behind Europe in removing sulfur from its gasoline supply? Far from it. Heil points out that the gasoline in Africa and many areas of Asia also contain too much sulfur for the lean engines. The first engine to feature the technology is the direct-injected 3.5-liter V6 destined for the C350 sport sedan and the SLK roadster seen above. The 302-horsepower mill will not (obviously) utilize lean-burn tech here in the U.S.

[Source: Ward's Automotive]


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  • 22 Comments
      • 3 Years Ago
      Only Benzes I would buy anyway would be diesels or AMGs. Not that they'd be my first choice anyway...Just sayin'.
      • 3 Years Ago
      Our gasoline is too dirty. Our diesel is too clean.

      We can't win.
      • 3 Years Ago
      Didn't Benz pay fine after fine for emissions violations in the US? These guys have no moral to criticize us.
      • 3 Years Ago
      Mercedes Benz is resistant to producing cars that meet specifications in the markets in which it sells autos. Unlike others, MB hasn't produced cars that don't pay CAFE fines for at least a decade and probably more. If there was a steeper penalty they would have changed or been forced to abandon the market.

      Lean Burn was a technology tried and abandoned by American manufacturers in the mid late 1970s. At that time electronic engine controls were not advanced enough or so they said. But the real reason was that lean combustion mixtures burned at temperatures that burned N2 into NOx. Thirty years later MB can't get its autos to produce respectful enough fuel economy, so it complains that its version of 1970s technology is too good for the environment where it tries to sell cars. I suggest If MB feels that way, it simply withdraw from markets which do not meet it views on what is acceptable.

      Shut up and cleanse your Otto cycle engines like all others are doing. Shut up and cleanse your Diesel cycle engines like all others are doing. Work to convince the fuel committees that your idea of what constitutes a good fuel, is made the required fuel formulation.
        • 3 Years Ago
        Totally left you hanging
        • 3 Years Ago
        You totally hit the nail on the head.

        High five?
        • 3 Years Ago
        Now down low! Whiff! Oh, to slow... ; )
        • 3 Years Ago
        Now down low! Whiff! Oh, too slow!! ; )
      harlanx6
      • 3 Years Ago
      MB, then I guess we will just have to drive Lincolns! They out rate yours anyway.
      • 3 Years Ago
      seems like a good opportunity to go battery electric then
      • 3 Years Ago
      Time to introduce Urea injection and Particulate filters for gasoline engines.
        • 3 Years Ago
        Gee, as if gas engines needed more emissions equipment.

        Lipstick on a pig... they need to start using DI on their engines like everyone else.
      • 3 Years Ago
      Mercedes is a Republican's car in the US. You need only look at the locations of the top dealers to realize this. So what's their incentive to increase fuel economy when their buyers are paying them a premium not to? Their customer base is offended and embarrassed by ouverte attempts to add technology to their cars whose express purpose is fuel economy.
      • 3 Years Ago
      A Prius engine is also lean burning.
      And it seems to work quite well in the US.

      Mercedes is totally WRONG.
      The smaller enignes of the great looking SLK are not available in the US.
      Mericans don't want 4 cyls they say.
      Mericans give a crap they say.

      They even remove ON PURPOSE the start stop tech, which is now standard in germany.
      Because americans don't like start stop.

      what were they thinking.
      _Mercedes even can't tell the difference from the different octane ratings.
      they say us fuel is bad, but the rating is calculated differently.
        • 3 Years Ago
        It has nothing to do with the AKI of the fuel.
        The fuel has too much sulfur. The sulfur destroys the NOx trap/deNOx catalyst.
        Therefore lean burn combustion mode is not enabled.
        • 3 Years Ago
        Don't ascribe to malice what can easily be explained by decontenting.

        I wouldn't buy a post-W140 Benz anyway. Lease? Possibly. But only from a dealer with a good set of loaners, and only for the term of the bumper-to-bumper warranty.
        • 3 Years Ago
        You expect them to sell a 4-cylinder engine in a premium sports car in the USA? In a country, where you have problems to get mid-size customers on cheaper brands away from their V6? Come back with that once the Cadillac CTS is successfully sold with a 4-cylinder...

        About start-stop: US cars are way cheaper, so this is by far not the only feature dropped. Some others are useless because of the far lower topspeed. The new Volkswagen Passat is an extreme example for this: smaller, few features but those hightech, high quality and high price in Europe; bigger, a lot of features, lowtech and cheap in the USA.
      • 3 Years Ago
      Isn't this a repeat story?

      Lean burn is more about NOx emissions. North America has clamped down on those kinds of emissions and care about CO2 less. That's why a pushrod 6.2L motor is okay and a lean burn 1.6L Honda motor is not.

      What sucks is that Lean burn saves fuel in the end.

      Pick your poison, i guess!!
      • 3 Years Ago
      maybe they should redesign their engine then.
      If I was making something, I wouldn't design it with the mind set of creating something so good & new that it cant be used in several major markets. RIP Benz.
        • 3 Years Ago
        They have no choice if they are going to hit European emission targets.
      • 3 Years Ago
      Benz has a legitimate chemical complaint, but the company never meets CAFE standards so this might as well be another lame excuse.

      Paraphrase: We can't give you fuel efficiency b/c your gasoline sucks.

      Excuse #1,000,001. File it away with all of the other inexplicable excuses we get from luxury manufacturers. They want us to change our gas so they only have to build one inefficient V6 for global consumers. Why do they expect us to prepare a banquet for them? I understand the concept of business efficiency, but if we told them they should only make one car to reduce product costs, they'd scream bloody murder. One gasoline specification might not be right for our refining infrastructure and it might not be an efficient way to reduce pollution compared to hybrids.
        • 3 Years Ago
        Which is why 16% of Mercedes buyers in the Luxury catagory, switched to Lexus hybrids.
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