By on April 13, 2015

Diesel Sticker

Is clean diesel the cleanest diesel in the tub? Not as previously hoped, according to a new report.

According to Green Car Reports, the International Council on Clean Transportation says most clean-diesel vehicles actually emit higher levels of nitrous oxide than what both the Euro 6 and U.S. Tier 2, Bin 5 standards allow. In particular, the amount of NOx produced by said vehicles exceeds the limits set by the Euro 6 standard seven times over.

The cause? “Transient increases in engine load typical of everyday driving (e.g., going up a slight incline),” as well as “normal regeneration events in the normal diesel exhaust aftertreatment systems.”

The ICCT report — published last October — follows calls from environmental groups like Transport & Environment to bring test-cycle results in line with real-world driving conditions, such as the European Union’s plan to cast aside the New European Drive Cycle for the Worldwide Harmonized Light-Vehicle Test Procedures.

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17 Comments on “Report: Clean Diesel NOx Levels Exceed European, US Standards...”

  • avatar

    Ok, so to summarize, some diesels pollute more than allowed under certain circumstances. Some other diesels don’t but I bet this group ICCT, just wants them all banned and replaced by lithium battery vehicles because those are very clean and not polluting at all. Actually, they don’t quite say they want them banned. They just want to make the standards impossible to pass. That’s reading between the lines. I wonder who paid for ICCT’s study?

    • 0 avatar

      It appears the claim is that the emission testing standard is like the efficiency test–not representative of real-world conditions. I don’t necessarily see that as a problem, though. You need a benchmark test regardless of how it’s used. The real question is do do the requirements of the benchmark produce vehicles that perform well enough in the real world that the results are acceptable. Again, to compare to efficiency, one goal of improving efficiency is to use less oil. Regardless of whether Monroney sticker numbers match what people actually get, if total oil consumption (due to vehicle fuel) goes down, then the CAFE requirements accomplish that goal.

  • avatar

    Warning: Slighty off topic

    What’s with this plastic Fuel door mess I’m seeing all of a sudden? That’s something that’s touched more often than any of the “soft materials” on the dash yet you want the owner to feel some utterly cheap door for the rest of the time they own the vehicle, go metal or go doorless.

  • avatar

    So more fuel = more emissions? Duh. In other words their complaint is that diesel cars use more when going uphill than on a flat? What, and gassers don’t?

    • 0 avatar

      You’re not getting it.

    • 0 avatar

      No, gasoline cars don’t do this—that’s the point. Gasoline cars’ emissions don’t spike out of acceptable range under loads; diesel does.

      Older diesel were really bad: the short burst of overboost spat out more soot and oxides of nitrogen and sulphur than a gasoline car would over quite a long period. Newer ones are better, but they aren’t close.

  • avatar

    “diesel vehicles actually emit higher levels of nitrous oxide”

    Great info…..I suppose dentists and drag racers will be collecting diesel fumes now.

  • avatar

    I would be interested in learning which vehicles do this, or if it’s mostly all of them.

  • avatar

    to my eye the title is also misleading. ‘exceed ….. standards’. to me that means they are better than the standard. consider, oils that meet or exceed oem standard.

    if you want to indicate that the engines do not meet standards you have a few choices e.g. fail, fail to meet, do not meet, in excess of, etc. granted it requires more words but the titles to these info-articles do not seem to be word limited.

    carry on.

  • avatar

    The one thing I have noticed running a “Bluetec” Mercedes in the shop is that it starts bothering people very quickly. If someone runs a gasoline engine in the shop, nobody even notices. If an old “dirty” diesel is run the the shop, it’s just like running a kerosene space heater. I am expecting that at some point soon they will realize that although this new emissions technology helps with the emissions that are measured, there are other pollutants in the exhaust stream that cause issues.

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