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Saturday Morning Physics: How Volkswagen Got Caught


Joe Frickin' Friday

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Joe Frickin' Friday

University of Michigan hosts a lecture series called Saturday Morning Physics. Early last month, the lecture was given by a gentleman from the International Council on Clean Transportation. He provided detailed background on what exactly the problem was with Volkwagen's diesel passenger cars, and what led up to their cheat being discovered. If you've got an hour to kill, you might find this interesting:

 

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It ain't over yet! I own a 2014 Passat SEL TDI and I hope they get screwed to the wall! I want the lying bums to buy my car back. They will never get there reputation back after this screw job. GT

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Joe Frickin' Friday

Hacker types may also appreciate this one:

 

https://www.youtube.com/watch?v=xZSU1FPDiao&t=40m

 

This video contains two presentations. The first one is probably not worth your time, but the second one (starts at t=40 minutes, 25 minutes long) is much more interesting. A (I think German) hacker reverse-engineered his car's (Volkswagen) ECU and took a close look at what was going on in the code. He found a lot of weirdness, but perhaps the most interesting material starts around 56:00. Here, he points out the criteria that make the ECU switch between the low/no DEF-dosing scheme (lots of NOx out the tailpipe) and the high DEF-dosing scheme (low NOx emissions). Several of the criteria are related to diagnostic conditions that would only be encountered during shop work, but one group of parameters clearly related to when the vehicle is (or is not) undergoing emissions testing, including a set of distance-versus-time curves that tightly bracket the NEDC driving cycle. He even showed that when he was driving the cycle on a dyno, and deviated outside the prescribed distance-versus-time limits of the test, the ECU immediately switched from clean to dirty and stopped dosing DEF.

 

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