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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



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.


The EDC17 analysis in this paper does not support this: “ Figure 4 shows how the fuel injection quantity (additive) correction (qCor) is modified by the acoustic condition.”

Not that it makes the cheating any less illegal, but I’m interested in the source of your analysis and why it differs from the model in the FR and the disassembly performed by that research group.


Then my source was too old, they just talked about Adblue dosage. What you say does make sense so, since after the software update cars in Germany had less power then before. My take is that Adblue dosage was the main issue so.


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-...


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.


"In June 2008, Bosch wrote a letter demanding that Volkswagen agree to pay any penalties if they were discovered using a defeat device."


The use of that software as a defeat device surely was a surprise to everyone when it came out years later...


Thanks! Nice paper, I didn't know they had access to the SW specifications


You can find these (leaked of course) easily by googling “Funktionsrahmen”. They are shared widely by tuners.




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