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Its not clear this is any kind of problem. Reducing emissions in lab tests may very well result in car designs that have reduced road emissions. This is the lo
by Reason077 11y ago
Its not clear this is any kind of problem. Reducing emissions in lab tests may very well result in car designs that have reduced road emissions.
This is the logic that European politicians have used in the past.
If there were a direct relationship between lab test emissions and real-world emissions, that approach may be acceptable. Unfortunately, that is not the case.
In the case of NOx, implementing the Euro standards should have resulted in an 80% reduction in emissions over the past 15 years. As the vehicle fleet is renewed, that should have translated into significant reductions in kerbside NOx levels. But this has not happened, and London continues to suffer some of the worst NOx levels in the world.
It turns out that an 80% reduction in lab test emissions has not translated into anything like an 80% reduction in real-world emissions - not even close!
The current system is inadequate because manufacturers simply "design for the test". There is huge real-world variability between vehicles that may record very similar lab test scores. A vehicle may claim similar test score results as another, but in fact have hugely differing levels of emissions in the real world.
Test environments need to reflect real-world conditions!
- dongping 11y agoThere is a new testing procedure (WLTP, Worldwide harmonized Light vehicles Test Procedures). Major carmakers just want to delay it: http://www.transportenvironment.org/news/carmakers-pushing-3-year-delay-tougher-co2-tests http://www.transportenvironment.org/news/carmakers-pushing-3... The emission cycle used now (New European Driving Cycle, or NEDC) is actually a joke, nobody drives like that: https://en.wikipedia.org/wiki/New_European_Driving_Cycle#/media/File:New_European_Driving_Cycle.svg https://en.wikipedia.org/wiki/New_European_Driving_Cycle#/me... comparing to the new one (WLTP): https://en.wikipedia.org/wiki/Worldwide_harmonized_Light_vehicles_Test_Procedures#/media/File:WLTC_class_3.svg https://en.wikipedia.org/wiki/Worldwide_harmonized_Light_veh... With the new testing procedure in place, you can still cheat like Volkswagen. But it will benefit the customers more, when the OEMs try to game the system by optimizing solely for the cycle.
- sitkack 11y agoWhat they need to do is more like a clinical trial for a drug. Step 0) measure on a dyno Step 1) measure on small closed course with a handful of drivers who are unknown to the car companies Step 2) measure on a larger group of cars in the real world If these "costs" are unacceptable, then auto manufacturers shouldn't be putting cars on the road. I always thought trusting the ECU to tell the truth was ridiculous, mostly because over end user tampering not the original code. But the effect is the same. It really is bullshit that so much time has been spent overfitting to the test when real universe exists right here. No model required.
- dongping 11y agoIt makes technically no sense if you can harmonize the regular driving condition into one single realistic cycle. Then the results are reproducible and comparable. OEMs all have their in-house driving cycle to better reflect the reality[1] than the boring standard cycles. The emission/consumption performance for some given customers is easily predictable. To prevent cheating, you'll just have to open source the software inside. [1] Lino Guzzella, Antonio Sciarretta: Vehicle Propulsion Systems: Introduction to Modeling and Optimization (page 22) https://books.google.de/books?id=aVNEAAAAQBAJ&pg=PA22&lpg=PA22&dq=%22driving+cycles%22+%22in+house%22&source=bl&ots=ZzyX2KaxGv&sig=8KAXxVNv6VJCsn3NjUV6px8p558&hl=en&sa=X&ved=0CDAQ6AEwA2oVChMIy5ifgbm4yAIVTJUsCh1P0AqU https://books.google.de/books?id=aVNEAAAAQBAJ&pg=PA22&lpg=PA...
- sitkack 11y agoMy assertion is that you can't do that with a single realistic cycle precisely because there is a single one. Overfitting will occur, an ensemble of actors can't be gamed.