More evidence Dieselgate affects other automakers besides Volkswagen

There’s more evidence that Volkswagen’s diesel vehicles are just the beginning of faked emissions.   A couple weeks ago I’d reported on research from Transport & Environment showing the vast majority of cars sold in Europe give much worse emissions on the road than in the lab.  Now, the Guardian has a story about research from Emissions Analytics showing the same behavior in Diesel cars from Mercedes-Benz, Honda, Mazda and Mitsubishi.

To recap, the Volkswagen Dieselgate emissions fraud scandal arose with revelations that Volkswagen had, over the last six years, committed fraud by lying to government regulators like the EPA and CARB.  It had been learned that VW and Audi branded 2.0 liter TDI Diesel cars emit far more NOx air pollution on the road than is allowed (10-40x the allowable limit), while the same cars pass the emissions test in the lab.  The EPA and CARB finally got Volkswagen to admit to cheating on emissions control tests, and since then we’ve had a bit of an uproar in the automotive industry.

According to the Guardian, Emissions Analytics tested both Euro6 and Euro5 Diesel cars in an on-road test program close to the real-world testing the European Commission wants to introduce.  The Euro5 and Euro6 monikers refer to different stages of European Commission emissions standards.  The Euro6 standard was supposed to go into effect next year, but I’ve seen reporting saying the EC is planning to delay introduction of tighter standards until 2019.  The Dieselgate scandal has everyone scratching their heads and rethinking emissions control standards plans.

The EC was also due to start a new test program meant to be more closely aligned with real world on-road conditions.  The Transport & Environment report says that existing test methodologies exercise only a small portion of the performance envelope, making it easy for a manufacturer to optimize for the test and not worry about performance outside the tested parameters.

The figures reported via The Guardian are:

  • Mercedes-Benz’s diesel cars produced an average of 0.406g/km of NOx on the road, at least 2.2 times more than the official Euro 5 level and five times higher than the Euro 6 level.
  • Honda’s diesel cars emitted 0.484g/km of NOx on average, between 2.6 and six times the official levels.
  • Mazda’s diesel cars had average NOx emissions of 0.293g/km in the real world, between 1.6 and 3.6 times the NEDC test levels. One Euro 6 model, the Mazda 6 2.2L 5DR, produced three times the official NOx emissions.
  • Mitsubishi diesel cars produced an average of 0.274g/km of NOx, between 1.5 and 3.4 higher than in the lab.

In the aggregate, Emissions Analytics tested 50 Euro 6 diesels and 150 Euro 5 diesels and found that only 5 of those vehicles had real-world NOx emissions matching the emissions requirements.  The other 195 vehicles violated the standard in some way.  The worst were 4×4 vehicles with several emitting 15x the allowable NOx levels, and one emitting 20x the limit.

Emissions Analytics hasn’t published anything on their website.  Instead they seem to be in the business of selling pricey reports and other services.  In any case, Emissions Analytics has published some analysis and recommendations.

According to their figures NOx emissions are, on average, 4x official laboratory levels, and that CO2 emissions are on average 31% higher.  The latter fact indicates that on average fuel economy is 24% worse than official figures.  Emissions Analytics suggests that even if no illegality is found by any company, we still must be worried about this discrepancy because of the environmental impact of higher-than-expected NOx and CO2 emissions.

About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.

About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.

2 Comments

  1. It is indeed unfortunate that in Europe it is not illegal to emit more toxic gas once the regulatory test is passed.

    The regulatory test uses only a little area of the engine operating surface where emissions can be “optimized”. If the optimized area is connected to the rest of the surface without blatant discontinuities, then there is no cheating… and it is legal.

    Hopefully this will change.

  2. Actually there is a real cheat:

    In the regulatory tests, there is a particulate matter evaluation (smoke) which should be run at 4000 rpm in neutral.

    Most european diesel cars do not go above 2500 rpm in neutral. This is a “feature” to protect the engine. The test lab then just annotates the test sheet with “will not go above 2500, test done at 2500”, this is considered as “PASSED”.

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