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EPA To Overhaul Emissions Testing In the Wake of VW Cheating

Posted by timothy on from the hand-it-to-nbc-news-for-filmed-evidence dept.

New submitter kheldan writes with this snippet from The Consumerist: A week after ordering Volkswagen to recall 500,000 vehicles that contain "defeat devices" designed to cheat emissions tests, the Environmental Protection Agency announced it would overhaul its compliance processes to ensure vehicles meet standards not only in controlled environments but in real-world driving conditions, and adds What may be the story-behind-the-story here, are the two Elephants in the Room: One, how many other automakers in the world have been 'gaming' the system like German automakers apparently have been all along, and Two, are these changes to the certification process at the USEPA going to 'trickle down' to the state and local levels, affecting routine emissions testing of individual vehicles? Questions peripheral to these may include: How much is this going to affect new vehicle prices in the future, and how much is this going to affect the fair market value of used vehicles?

8 of 203 comments (clear)

  1. VW Diesel's do have low polluting exhaust ... by drnb · · Score: 4, Informative

    It's especially difficult to clean NOx from diesel engine exhaust because unlike gasoline engines, the exhaust contains lots of extra oxygen. Diesels need special NOx-cleaning devices which add cost and weight, and can seriously limit performance in some situations.

    No. It is no longer especially difficult because VW and other diesel makers have already solved this problem. Every cheating VW diesel on the road can have low polluting exhaust. The hardware and software is there, already installed and operating. That is how they pass emissions tests, the software enables all the emissions controls. How the software cheats is to turn off the emission controls if it looks like someone is actually driving.

    The fix is a simple software patch to stop turning off the emissions controls.

    The downside is that performance and mileage will be reduced.

    1. Re:VW Diesel's do have low polluting exhaust ... by goodmanj · · Score: 5, Informative

      You're right that the technology is installed and works, but the performance and maintenance downsides are severe. I didn't want to make my original post too long to read, but here's more detail to explain.

      Most small VWs (Jetta, etc) use a "lean NOx trap" to capture NOx in a zeolite sponge. The zeolite fills up with NOx and needs to be cleaned out periodically (every minute or two, takes a few seconds). During the cleaning cycle, engine power is limited to *20%* of maximum. VW's patent says they wait until the driver eases off on the throttle to do it, but still, that's a huge performance hit and a big incentive to cheat (by not doing the cleaning.)

      See patent link in my original post for details (warning: machine-translated from German.)

      In VW's larger vehicles (Passat, mostly), the car carries an extra tank full of gallons of urea, which is sprayed into the exhaust to react with the NOx. This reaction needs precise temperature controls (which probably limits engine performance), and the tank is big and heavy. By using less urea than needed, VW can use a smaller lighter tank, which needs to be refilled less often. (VW pays for urea replacement for the first 30,000 miles.)

    2. Re:VW Diesel's do have low polluting exhaust ... by goodmanj · · Score: 4, Informative

      It's very clever (but evil): EPA says the software looks at a variety of factors, including wheel speed, steering wheel position, engine run time, and barometric pressure (!), and compares those data against EPA's published testing guidelines.

    3. Re:VW Diesel's do have low polluting exhaust ... by Sorny · · Score: 5, Informative

      VW's patented setup sounds far less ideal than the well understood SCR/DEF setup everyone else uses. 20% of max power to burn out the NOx trap? No way in hell would I want that!

      The precise temperature controls you allude to for SCR/DEF is hogwash. You've got quite a bit of leeway to get up to temp before the system starts dosing before throwing codes and going into limp mode (think like over an hour of operation). If you didn't, then all of us in places with 4 real seasons would have diesels that wouldn't go anywhere because DEF freezes at about 18 degrees F. Where I live, we can go months with temps lower than that, and it takes time to thaw the DEF so it'll flow.

      DEF consumption is 1-3% of fuel consumption. So figure 1-3 gallons of DEF used for every 100 gallons of diesel; that's for the puny little 2 liters in a VW all the way up to the 13L monsters in a Peterbilt... 1-3% of fuel, like clockwork. How many gallons of DEF would be needed to go the oil change interval on a VW TDi? Not many.

      Lastly, on DEF, any fool paying stealership prices deserves to get ripped off. Drive to a truck stop and enjoy ISO rated DEF/AdBlue at $2.70 or so a gallon. My last DEF fill cost me a whopping $16 for my truck at just over 6 gallons in ~8k miles.. A 3.0L diesel truck that gets 24-27 MPG in mixed driving. A 2.0L TDi should be able to go 12k+ miles on 5 gallons considering how much less fuel they burn than my truck does.

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      OSX pwns.
    4. Re: VW Diesel's do have low polluting exhaust ... by goodmanj · · Score: 4, Informative

      I see this a lot: "hey, they passed the EPA's test, so they're technically not in violation."

      Unfortunately, the EPA regs also state that you may not include devices designed to defeat EPA testing. See the EPA complaint for details.

    5. Re:VW Diesel's do have low polluting exhaust ... by caseih · · Score: 3, Informative

      Actually, no. Urea does require hotter temperatures, true, but it surely doesn't impact performance. The way diesel pollution works is that you can either lower compression and combustion through EGR to reduce NOx, but this tends to produce particulates and reduces fuel efficiency. Or you can increase efficiency and run the engine hotter, possibly with more compression, which virtually eliminates particulates, but hotter combustion temperatures increase NOx production.

      If anything Urea lets the engine run a lot closer to its more efficient state with more compression and higher temperatures. As you say the urea plus the catalyzing exhaust chamber does add weight. But the biggest problem is the availability of urea (in north America) and the handling of it. Especially in the winter.

      We run a machine on the farm with Tier 4I emissions on it, and every year we buy about 800 L of urea. It's about $1 CAD/L. So it does add overall cost, though to put it in perspective, it costs nearly $400 a day in diesel fuel during harvest for the same machine, totaling $800 a day for the two machines. But this engine is also more efficient than previous models, so fuel consumption is lower. We don't run the machine in the winter so we've never had any problems with it gelling, and we've never had the machine derate due to urea problems. In my mind, urea injection is really the only practical way to produce cleaner diesels. This is important with biologically-derived fuels as well, such as biodiesel. The carbon cost of urea production and handling probably makes it a wash in terms of CO2 emissions, despite higher efficiency engines. Urea is made from natural gas reformation.

  2. Re:On the fly/road measurements by Grishnakh · · Score: 2, Informative

    Yeah, the problem is they don't want to do that, because it's "unfair" to people who have old, poorly-maintained cars, because supposedly these cars are either "classics" or they're too poor to afford newer cars. Basically, cars past a certain age are "grandfathered".

  3. Re:Poor VW by Mashiki · · Score: 3, Informative

    Just buy a Tesla already

    Battery based cars tend to do very poorly in very cold countries.

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    Om, nomnomnom...