EPA caught VW cheating - how does the car know it's being tested?

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On Mon, 21 Sep 2015 07:13:08 -0700 (PDT), snipped-for-privacy@yahoo.com wrote:

Why is it called a dyno if it's spelled dynamometer? Why not call it a dyna?
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On 9/21/2015 8:27 PM, Alina Popescu wrote:

Mechanics are unable to spell and can seldom pronounce words with more than one syllable?
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On Sun, 20 Sep 2015 16:29:30 -0400, Mitch Kaufmann wrote:

That answers what. But it doesn't answer HOW.
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On Mon, 21 Sep 2015 12:46:48 +0000 (UTC), Ewald Böhm wrote:

http://www.greencarreports.com/news/1100125_vw-diesel-emissions-recall-what-you-need-to-know-in-10-questions/page-2
Based on discussions with knowledgeable sources, we surmise that once an emissions test was detected, VW got the affected TDI engines to meet the Tier 2, Bin 5 NOx limits by reducing the fuel flow rate.
This would reduce performance, but most likely not to the point where the car couldn't complete the emission cycles.
Lowering fuel flow would also reduce combustion temperatures and/or the duration of high-temperature operation enough to keep NOx emissions barely within EPA limits.
If the car detected that it was no longer in "testing mode" but had returned to "driving mode," it would restore fuel flow to the regular level--which would send NOx emissions soaring.
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On Sat, 19 Sep 2015 00:19:10 +0000, Ewald Böhm wrote:

The best answer to the question seems to be here, as noted by Sofa Slug:
http://www.rocketnews.com/2015/09/did-volkswagen-cheat/ http://www.latimes.com/opinion/editorials/la-ed-vw-20150919-story.html
"How can the program tell the difference? By noting the position of the steering wheel, variations in speed and other data that suggest no one is driving the car, and thus it is likely being tested."
Apparently VW lied at first, & apparently they can no longer sell the cars:
"The cheating came to light when the California Air Resources Board and the EPA pressed Volkswagen for an explanation for disparities found between lab tests and road tests of its vehicle emissions. The agencies didn't find the technical reasons offered by VW to be convincing and said they would not issue certificates allowing 2016 models to be sold until the automaker offered an adequate explanation. "Only then did VW admit it had designed and installed a defeat device in these vehicles," the EPA said. VW said it was cooperating with the investigation but otherwise had no comment."
It's interesting that VW didn't fess up until they were forced to.
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wrote:

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That's pretty much human nature going back to the Garden of Eden. The next trick is to blame someone else. A TV show from long ago had comedian Flip Wilson on. His line was "The devil made me do it".
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On Mon, 21 Sep 2015 12:57:34 +0000 (UTC), Ewald Böhm wrote:

Staying on topic, this article says the cheat only worked when there was a DYNO involved! http://www.chron.com/business/energy/article/For-7-years-VW-software-thwarted-pollution-6520088.php
Here are the contiguous quotes: (begin quote) VW used secret software — an algorithm that detects when cars are being tested on treadmill-like devices called dynamometers, and stealthily switches the engines to a cleaner mode.
Because *smog tests are almost always done on dynamometers*, VW got away with the scheme for seven years, until the "clean transportation" advocates went to West Virginia University, which tests emissions using equipment that fits in car trunks. (end quote)
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I have seen a suggestion that the onboard computer takes note of the fact that the rear wheels are rotating and the front wheels are stationary. That seems plausible to me.
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On Mon, 21 Sep 2015 21:07:31 -0700, Jack Myers wrote:

They didn't explicity mention that, but this article has a section named How did this alleged cheat work exactly? http://jalopnik.com/your-guide-to-dieselgate-volkswagens-diesel-cheating-c-1731857018
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On Mon, 21 Sep 2015 21:44:12 -0700, Sam Wilhelm wrote:

http://www.greencarreports.com/news/1100125_vw-diesel-emissions-recall-what-you-need-to-know-in-10-questions/page-2 (4) What exactly did VW do?
Volkswagen has admitted that it equipped the control software for its 2.0-liter TDI diesel vehicles with a "defeat device" that detected when the car was undergoing emissions testing and significantly changed the operations of its powertrain to reduce emissions during the tests.
That detection was likely based on a combination of sensor data from the car, which might include steering angle (since cars on dynamometer tests don't make turns), front-wheel versus rear-wheel rotation speed, and a variety of other factors.
It appears that a combination of the factors above plus extremely gentle acceleration and braking might alert the car that it wasn't on the road but being tested in a lab.
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That's the most feasible, i.e. simple, approach to designing the bypass firmware algorithm that I've seen.
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On Tuesday, September 22, 2015 at 8:42:32 AM UTC-4, CRNG wrote:

Seems to me that's a failed algorithm. Aren't these cars front wheel drive, ie he has it backwards? Heard on the news last night mention of the steering wheel remaining stationary was an input used too.
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On 9/21/2015 9:07 PM, Jack Myers wrote:
<snip> > I have seen a suggestion that the onboard computer takes note of the

Well the opposite for most or all VWs, but that makes sense.
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Oops! Right-o. What do you want to bet that the source code has this feature documented as a special low-torque mode to facititate getting out of snow banks?
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Jack Myers wrote:

Not all dynos work that way. I would expect such a dyno to drive the stability/ABS systems crazy, possibly SLAMMING on the brakes or other actions. (Most cars today are FRONT wheel drive, so the case would be the front wheels turning and the back stationary. For rear wheel drive trucks, of course, it is the opposite case. on these, it would be VERY hard to keep the truck on the rear wheel only dyno. If it started to drift to either side, the steering wheel could not get the tires centered back on the treadmill.) On such vehicles, it might be necessary to shut down the stability/ABS systems to even do these tests, which would clue in any test detection software.
As for how the software could tell, this gives me an idea! The dynos have some considerable inertia, but it is likely much less that the inertia involved in accelerating the car to 60 MPH. So, the software might detect VERY easy acceleration to highway speed as a sign of a dyno test. This might also look like accelerating down a long hill, but if it goes on too long, it indicates minimal wind resistance. If you are cruising at 60 MPH with 4 HP effort, that would be a DEAD GIVEAWAY you are on a dyno! The emissions test dynos probably cannot absorb the output of a big car's engine to give it the normal highway load. That can be a LOT of power that you have to absorb for several minutes.
Jon
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| > My question is HOW did the car *know* it was being *tested* for emissions? |
I'm more curious about how the EPA didn't figure it out earlier. Reports say the EPA saw a discrepancy between testing and on-road results. But they've been haggling with VW all this time and somehow never thought to look at the software. Is the software accessible to EPA? Do they have developers who could understand it?
How the test is faked is just a technical issue. How the EPA didn't figure it out seems to be the important issue. They only found out because they threatened to hold up sales and at that point the VW execs admitted what they were doing. (Have they disclosed everything? Surely if there's more dirty dealing they're not going to tell if they don't have to.)
... Then of course there's the question that begs to be asked: How could all of those executives, in a company whose clientelle tend to be liberal environmentalists, have possibly decided it was a good idea to be so dishonest and shortsighted?
There should be arrests. Either way, it's likely to be a serious, perhaps fatal, blow to the company. If it were Chevy I'm sure rednecks would come out of the woodwork to support "the company that denies global warming". But VW customers are almost a cult following, and mostly liberal.
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Should there have been arrests of EPA miscreants (or the environmentalists that petitioned them to do so) for the hatchet job they did on DDT? This resulted in millions of third-world deaths from malaria due to other countries following our lead:
http://www.discoverthenetworks.org/viewSubCategory.asp?id 59
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This article is not exactly accurate.
In the fifties, DDT was amazing, it worked great. We put it between our sheets. You could spray it in the air and see insects dropping out right and left.
But... by the seventies, mosquitoes (at least in Hawaii where I lived) had pretty much become immune to the stuff. Enormous, absolutely enormous amounts were necessary to kill insects. This is why there were environmental effects. My father had a gadget that would drop a mix of diesel and DDT into the muffler of the lawnmower and the smoke would kill mosquitoes, but by the seventies it wasn't killing them any more, even with a couple pounds of the stuff being burned.
Give it another forty years or so and we might be able to start using DDT in a small way again. But it was the massive overuse and abuse of DDT that got us to the point where it was banned, not some crazy left-wind conspiracy.
And yes, it WAS one of the big weapons in the fight against malaria, and it was a crime to lose that weapon. But it wasn't politicians that lost it. --scott
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The point is that government malfeasance, which can and does result in massive death, rarely if ever goes punished. I don't know how much additional pollution is being caused by VW diesels or if the effect is even measurable given their relatively low numbers. I do know that governments routinely lie, cheat, steal, and kill (sometimes en masse) all in a day's work. There's no doubt that what VW did was bad, but the outcry seems out of proportion given the routine misdeeds of the State.
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On 9/22/2015 10:08 AM, Roger Blake wrote:

What a goof!
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