Internet of criminal things

Posted Sep 24, 2015 21:49 UTC (Thu) by dlang (guest, #313)
In reply to: Internet of criminal things by jzbiciak
Parent article: The Internet of criminal things

the thing is that dyno results are also how they measure the power of the engine, so if the only difference between a 'power test' and an 'emissions test' is the throttle setting and how long it's at that setting, this seems very fragile and easy to 'defeat'. Just change the testing process to include some time at full throttle, and/or more variations on the throttle/load during the test.

Which would actually make the test far more representative of the real world.

If it really is as trivial a set of tests as this shows (again, unknown source, unknown reliability), just wiggling the steering wheel during a test would result in drastic power and emissions changes, with no throttle changes at all.

I know that the initial findings of this were based on doing emissions testing on the road, not on a dyno, resulting in drastically different emissions. But from that it's not necessarily even anything wrong with the car, but rather something wrong with the test (the purpose of the test is to try and simulate real-world driving)

It also wouldn't be the first time that the EPA test was found to be so horrifically different from real driving that it needed to be changed. As I've said before (Elsewhere at least), the early Hybrid cars resulted in insanely good test results because the profile let them run on battery most of the time.

It may just be time for the EPA to make a drastic (not just incrimental) change to their test process.

Very little real-world driving involves constant throttle settings over any significant distance, with modern computer controlled Dynos, they should be able to do tests where they vary the throttle, vary the load, vary the speed, etc.

Even the systems in Smog Test stations around the country allow for many different test profiles.

Internet of criminal things

Posted Sep 24, 2015 22:25 UTC (Thu) by dlang (guest, #313) [Link] (5 responses)

By the way, in another forum it was pointed out that there is a _really_ good reason for the car to detect that it's on a Dyno

if you have one set of wheels stationary and the other set moving, that's going to trigger your traction problem detection and attempt to slow the spinning wheels.

Apparently this is even more interesting on the very high-end cars, and so to test those cars you have to do some specific things to disable the traction control. For VW to detect a dyno mode to disable things like this is a user-friendly and mechanic-friendly thing to do.

Since you don't have the same airflow and cooling on the dyno (for things like your tranmission, differentials, etc) there's also legitimate reasons to be more cautions about thinks that can generate heat in those areas.

Again, we really need to see the results of the investigation.

Internet of criminal things

Posted Sep 24, 2015 22:54 UTC (Thu) by jzbiciak (guest, #5246) [Link] (4 responses)

I don't think it's specifically dyno vs. not-dyno that's at play here. Given the number of people who like to tune their cars, soup them up, etc., you'd think someone would notice messed up power curves in a dyno test.

My guess (and yes, it's just pure speculation) is that the code actually looked very narrowly for the test profile, and that the EPA test profile used for certification is fairly fixed. You're right, though: We really do need to see the results of the investigation. I'm quite curious what exactly they did. Knowing how these things go, we may not know the specifics for years, though.

Internet of criminal things

Posted Sep 24, 2015 23:23 UTC (Thu) by dlang (guest, #313) [Link] (3 responses)

> My guess (and yes, it's just pure speculation) is that the code actually looked very narrowly for the test profile, and that the EPA test profile used for certification is fairly fixed.

The EPA test profile is very fixed, but the profile used at Smog Check stations in California (where the strictest emissions requirements are), both varies over time and is subject to a lot more variation than the "official EPA" test, both from the impossibility of keeping so many thousands of stations _exactly_ in tune, and the fact that they all run their tests on ambient air, rather than 'Standard Temp and Pressure' the way the official EPA test does. The fact that the cars going through the periodic testing are going to have wildly different internal drag (tire pressure, how fresh the lubricants throughout the vehicle are), is going to make it so that the throttle setting needed to run the car at a specific speed for the test is going to vary a fair bit.

This is why I'm a bit sceptical that this is deliberate cheating. The fact that California can and does change it's test profile FAR more frequently than the EPA does makes detecting specific driving profiles much harder.

If (as reported) not triggering the 'EPA test mode" made the NOX levels exceed the testing limits by 40x, just can't see how these cars have been triggering 'test mode' reliably enough to not be an epidemic of failures in the California Smog Test stations.

I'm not saying it's impossible, but some things are far more likely than others, and I know enough of the field (having been Smog Certified in California as well as a car performance guy, and then Information Security as my day job) that some things are far more likely than others, and these claims are odd enough for me to question them. Or at least question that we have valid info yet.

Internet of criminal things

Posted Sep 24, 2015 23:34 UTC (Thu) by jzbiciak (guest, #5246) [Link]

Gotcha. I guess I'm just going to have to stay tuned.

Internet of criminal things

Posted Sep 25, 2015 13:40 UTC (Fri) by mstone_ (subscriber, #66309) [Link] (1 responses)

You may have CA smog test experience, but apparantly not CA diesel smog test experience: CA does not test diesels on a dyno. The diesel smog test consists of looking for smoke, looking to see if the emissions components are connected, and seeing if the ODB II says the car is compliant. The entire structure is based on the premise that the initial EPA testing has certified that the car is compliant and that the report from the ODB is valid. (This is true in my experience on the east coast as well--with a diesel you basically pay for an emissions tech to make sure the check engine light isn't on.)

The allegation is that VW cheated on the initial EPA test, so that all of the subsequent reporting (including everything done by CA) is invalid.

http://www.smogcheck.ca.gov/pdf/DieselFlyer_final.3.pdf

Internet of criminal things

Posted Sep 25, 2015 17:05 UTC (Fri) by dlang (guest, #313) [Link]

When I was licensed for Smog, Diesels didn't need any Smog testing. That changed in the late '90s (this flyer talks about 2010, but there were requirements before that)

When I was first certified, the Dyno was not used for any vehicles, it got added much more recently.

If there has not been an update to the check requirements for Diesels to have them use the same Dyno profiles and emissions sniffing process as Gas vehicles do, it's only a matter of time until there is (and after this mess, I would expect that it will be a fairly short time)