
Inside the Volkswagen emissions cheating - dmmalam
http://lwn.net/Articles/670488/
======
bxh
The line about how the engineers view the tests as an optimization problem
really resonates with me. When the results of tests administered in an
artificial setting becomes the primary method of assessment, such a trend will
inevitably emerge.

Take school examinations for example, in highly competitive environments where
test scores alone are the major determining factor, students begin to consider
the benefits of forgoing comprehension of the material for rote learning.

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bijection
These are both good examples of Goodheart's law — "When a measure becomes a
target, it ceases to be a good measure."[1]

[https://en.wikipedia.org/wiki/Goodhart%27s_law](https://en.wikipedia.org/wiki/Goodhart%27s_law)

~~~
csours
Thanks for that, I remembered that this was a "law", but I never remember the
name, and whenever I try to tell anyone I get it wrong or express it in a
confused manner.

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bri3d
> He then disassembled the firmware, which looked quite a bit different than
> disassemblies of normal code. It looked somewhat like electronic schematics
> had been turned into code, rather than spaghetti-like output from other
> kinds of programs, he said.

The actual logic diagrams and definitions of this data for Bosch ECUs (sans
the emissions cheat, obviously) can be found in the "Funktionsrahmen," leaked
but easily available from many VW tuning forums online. It's quite fascinating
and worth a look for anyone interested in how modern ECUs work (it's a far cry
from the oldschool "fuel table" style of engine management).

~~~
semi-extrinsic
Wow, that's an acronym soup if I ever saw one:

[http://s4wiki.com/wiki/Tuning](http://s4wiki.com/wiki/Tuning)

~~~
bri3d
Wait until you see some of the logic diagrams (this is the one for intake air
temperature sensing):

[http://imgur.com/KWob8Xf](http://imgur.com/KWob8Xf)

~~~
wnesensohn
These look like diagrams from Bosch Otto ECUs (ME series).

FWIW, the ECUs in question (EDC17) use much more descriptive names:

Epm_nEng - engine speed; InjCt1_qSetUnBal - set quantity for first injection
(roughly); VehV_v - vehicle speed

I much prefer the EDC17 style, but your mileage may vary.

~~~
bri3d
Oh, you're right! I've never owned a diesel so I've only looked at EDC17 in
passing. :)

The variables certainly aren't as cryptic... I think even a native German
speaker would have trouble with the ME7 ones.

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rconti
The statement that the cheating was to reduce AdBlue usage is not the complete
answer to "why", as many of the affected cars in the US didn't use after-
treatment at all.

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eric_h
Interesting quote:

"he noted that there is a 12KB block of code that is used to ensure the
tachometer always shows 780 RPM when the car is idling. Even though the engine
is not that steady, car owners want to see that value hold steady at idle, so
car makers effectively lie to satisfy them. Domke said that it is clear that
lots of different kinds of cheating is going on in the ECU and noted that the
speedometer doesn't really show the speed of the vehicle, just something
related to it."

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snyderize
previous discussion
[https://news.ycombinator.com/item?id=10870518](https://news.ycombinator.com/item?id=10870518)

