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Published on June 9th, 2019 | by Steve Hanley


Uh-Oh. Emissions Analytics Claims New Emissions Discrepancies Using WLTP Standard

June 9th, 2019 by  

When the EU adopted the new Worldwide Harmonized Light Vehicle Test Procedure, known as WLTP, it was supposed to cure some of the defects in the prior New European Driving Cycle test. In general, the NEDC was next to useless when it came to predicting real world fuel economy.

WLTP emissions standard

Credit: Emissions Analytics

As the EU prepares for new, tougher emissions rules, the WLTP will be utilized to determine whether automakers are in compliance with those rules. But things are not as straightforward as that. According to Emissions Analytics, the actual compliance assessment involves applying a complex formula to WLTP results to translate them into NEDC equivalents. According to Emissions Analytics, they are finding a big difference between WLTP results and real world emissions.

Which raises the question of whether some manufacturers are using the complexity of the new rules to simulate compliance when in fact their cars do not meet the new standards. There are billions in fines at stake here, so the car companies have an incentive to show the best possible results in the tests.

Emissions Analytics says in a press release, “Latest WLTP-certified vehicles show that, despite the test getting tougher and more representative of actual use, CO2 emissions for petrol cars have fallen – when they would have been expected to have risen – to a fleet average of 133g/km on an NEDC-equivalent basis. Yet the real world average CO2 figure, as measured by Emissions Analytics, is in fact much higher: 185g/km. This anomaly raises concerns that while car makers have got their houses in order over diesel they may still be ‘optimizing’ vehicles for official lab tests.”

“A potential explanation for these movements,” it says, “is that focus and expertise have been put into optimizing gasoline vehicles on the new WLTP cycle, driving the official CO2 down despite this not translating into better real world performance. If this turns out to be true, it would give further credence to the argument for including on-road testing in the official CO2 certification process, to limit the ability to optimize to the test. In the meantime, the use of WLTP results for fuel economy labeling will be hardly more useful to consumers that the old, discredited NEDC system it replaced.”

The solution, EA suggests, is to simply use real world testing instead of all this in-the-lab hypothetical mumbo jumbo that practically invites companies to cheat. Perhaps “build to the test” might be a more polite way of putting it. The EU fleet average standard for passenger cars will soon be 95 grams per kilometer. The cars EA has tested that theoretically meet the latest standards are nowhere near that standard in real world driving. In fact, on the road their CO2 emissions are nearly double that figure.

Figures Lie & Liars Figure

This sort of bureaucratic nonsense is not limited to the EU. In the US, the exhaust emissions fight is about EPA rules put in place by the prior administration that require new vehicles to get as much as 54 mpg. Critics scream that 54 mpg is absurd, impossible, ridiculous, and stupid. It’s true. 54 mpg sounds like something out of science fiction.

But here’s the thing. That 54 mpg is measured by the old fuel economy standard, the one that greatly overstated mileage claims. That standard was updated with a new formula designed to more accurately project real world performance but the emissions rules are still based on the old formula. If the fuel economy rules were based on the current standard rather than an outdated formula, that top number would be closer to 38 mpg — quite a bit less scary than 54 mpg, right?

There’s another twist here. The US uses fuel economy as a way of estimating exhaust emissions, which introduces yet another distortion into the process. Fuel economy and emissions are related but not the same thing.

My wife’s 2013 Honda Civic Si has enough power to make your eyes water under acceleration but it still gets 36 mpg on the highway. My 1994 Saturn SL2 consistently got 38 mpg on the highway and 32 mpg in town. Is it too much to expect the auto industry to have made significant gains in the past 20 years?

Apparently so. The other kicker is the “footprint” rule which the car companies got the EPA to accept. Essentially, it says larger vehicles should be allowed to get lower fuel economy. Is the boom in large SUVs and pickup trucks sales caused by customer demand or by car companies constantly advertising larger, thirstier vehicles that also happen to have fat profit margins? You decide.

Arguing over formulas seems ludicrous. Measure the cars in the real world, not in the lab. Then we will all know who is cheating and how isn’t. Is that so hard? 

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About the Author

Steve writes about the interface between technology and sustainability from his home in Rhode Island and anywhere else the Singularity may lead him. His motto is, "Life is not measured by how many breaths we take but by the number of moments that take our breath away!" You can follow him on Google + and on Twitter.

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