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for me it was also hard to grasp what went wrong here. i always thought if this test can be gamed something is flawed with this test. they were given the task t

for me it was also hard to grasp what went wrong here. i always thought if this test can be gamed something is flawed with this test. they were given the task to pass the test and they did although that did not translate to the outcome the engineers developing this test envisioned for it i guess. It feels like they changed the requirements and then went after anyone not passing anymore. i do understand that they purposefully tried to detect the test to game the result "somehow" but i cant help it but to think if its possible to reduce emissions for the test then its a viable strategy on the road given the same usage pattern... although i don't really know how they actually did it...

adgjlsfhk1 5y ago
so the problem is that vw purposefully lowered engine performance during the test. they could have done that on the road, and been within spec, but then their cars would have felt sluggish, so instead they just made their cars lie during the epa test
- hef19898 5y ago
  VW detected a test cycle and turned emissions treatment, Adblue and some other things, on. When on the road, these systems were tuned down or fully turned off.
- contravariant 5y ago
  From my limited understanding it wasn't just lowering engine performance they couldn't be simultaneously be efficient with fuel and low in emissions (IIRC burning at a higher temperature is good for fuel economy but bad for other pollutants). It's very well possible that no single configuration could have made them meet the requirements.
hef19898 5y ago
If memory serves well, they used steering, rev and so on as input to decide if the car was on a test bench. Then they turned on emissions treatment, or rather turned it up. Obviously that works on the road as well. As a tangent, VW was part of group of German manufacturers colluding in limiting Adblue tank capacity (I'd have too look up details). in order to maximize revenue, they also extended the refill periods to match inspection intervals. Basically so the OEMs could sell dirt chepa Adblue to customers. Now the smaller tanks were insufficient to treat emissions on the road without being refilled between inspections. Instead of mounting bigger tanks, VW decided, apparently, to just turn the system of while on the road. Clearly illegal because test cycle recognition is illegal. As opposed to using technical loop holes when road operations are concerned.
- bri3d 5y ago
  It was sort of the opposite - there was a control module called "kundenspezifische Akustikbedingung" or "customer acoustics condition" in Bosch diesel control units which was _deactivated_ by conditions like steering input that indicated real driving. So the car started in "low emissions" mode by default (essentially, running richer, which increased consumption and CO2 emissions but reduced NOx), and then leaned out (decreasing consumption but increasing NOx) once the "acoustic model" was deactivated. https://cseweb.ucsd.edu/~klevchen/diesel-sp17.pdf https://cseweb.ucsd.edu/~klevchen/diesel-sp17.pdf
  - hef19898 5y ago
    The acoustic mode was used to recognize the test cycle and to properly dose Adblue. It didn't impact fuel mixture, that was something VW later did to make the engine generally compliant. The new, leaner mixture resulted in some power losses. Under all other operating modes, the Adblue dosage was reduced to almost zero. That is clearly illegal. In addition to that, VW did some other stuff especially for the US market to meet California's emission requirements. What everyone else did was playing with temperature windows, under all operating conditions to reduce Adblue and optimizing for other things. Not ullegla per-se, as these windows kinda used to be legal, but definitely violating the spirit of regulations. Some manufacturers exaggerated more than others. But only VW cheated as clearly, as bluntly, as long and at as large a scale. No amount of VW PR can change that.
    - belter 5y ago
      With the help from Bosch: "Supplier’s Role Shows Breadth of VW’s Deceit" https://www.nytimes.com/2017/02/01/business/bosch-vw-diesel-settlement.html https://www.nytimes.com/2017/02/01/business/bosch-vw-diesel-...
      - hef19898 5y ago
        Yep. Bosch tried to protect their asses by sending VW a letter that this software was test purposes only, any road or production use would be illegal. They still got fined.

adgjlsfhk1 5y ago

so the problem is that vw purposefully lowered engine performance during the test. they could have done that on the road, and been within spec, but then their cars would have felt sluggish, so instead they just made their cars lie during the epa test

hef19898 5y ago
VW detected a test cycle and turned emissions treatment, Adblue and some other things, on. When on the road, these systems were tuned down or fully turned off.
contravariant 5y ago
From my limited understanding it wasn't just lowering engine performance they couldn't be simultaneously be efficient with fuel and low in emissions (IIRC burning at a higher temperature is good for fuel economy but bad for other pollutants). It's very well possible that no single configuration could have made them meet the requirements.

hef19898 5y ago

If memory serves well, they used steering, rev and so on as input to decide if the car was on a test bench. Then they turned on emissions treatment, or rather turned it up. Obviously that works on the road as well. As a tangent, VW was part of group of German manufacturers colluding in limiting Adblue tank capacity (I'd have too look up details). in order to maximize revenue, they also extended the refill periods to match inspection intervals. Basically so the OEMs could sell dirt chepa Adblue to customers. Now the smaller tanks were insufficient to treat emissions on the road without being refilled between inspections. Instead of mounting bigger tanks, VW decided, apparently, to just turn the system of while on the road. Clearly illegal because test cycle recognition is illegal. As opposed to using technical loop holes when road operations are concerned.

bri3d 5y ago
It was sort of the opposite - there was a control module called "kundenspezifische Akustikbedingung" or "customer acoustics condition" in Bosch diesel control units which was _deactivated_ by conditions like steering input that indicated real driving. So the car started in "low emissions" mode by default (essentially, running richer, which increased consumption and CO2 emissions but reduced NOx), and then leaned out (decreasing consumption but increasing NOx) once the "acoustic model" was deactivated. https://cseweb.ucsd.edu/~klevchen/diesel-sp17.pdf https://cseweb.ucsd.edu/~klevchen/diesel-sp17.pdf
- hef19898 5y ago
  The acoustic mode was used to recognize the test cycle and to properly dose Adblue. It didn't impact fuel mixture, that was something VW later did to make the engine generally compliant. The new, leaner mixture resulted in some power losses. Under all other operating modes, the Adblue dosage was reduced to almost zero. That is clearly illegal. In addition to that, VW did some other stuff especially for the US market to meet California's emission requirements. What everyone else did was playing with temperature windows, under all operating conditions to reduce Adblue and optimizing for other things. Not ullegla per-se, as these windows kinda used to be legal, but definitely violating the spirit of regulations. Some manufacturers exaggerated more than others. But only VW cheated as clearly, as bluntly, as long and at as large a scale. No amount of VW PR can change that.
  - belter 5y ago
    With the help from Bosch: "Supplier’s Role Shows Breadth of VW’s Deceit" https://www.nytimes.com/2017/02/01/business/bosch-vw-diesel-settlement.html https://www.nytimes.com/2017/02/01/business/bosch-vw-diesel-...
    - hef19898 5y ago
      Yep. Bosch tried to protect their asses by sending VW a letter that this software was test purposes only, any road or production use would be illegal. They still got fined.