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Emissions Scandal Expands: Mercedes-Benz, Honda, Mazda, and Mitsubishi (theguardian.com)
An anonymous reader writes: Volkswagen has taken some serious heat for deliberately circumventing emissions tests with "defeat devices" in some of their vehicles. While no other cars have been found to use specific devices to fool tests in the same way, we're now learning that many manufacturers still mysteriously perform worse in the real world. Last week, the Guardian revealed that diesel cars from Nissan, Hyundai, Citroen, Fiat, Volvo, and Renault emitted significantly more pollution in realistic driving conditions than the tests supposedly allow. Now, we learn that vehicles from Mercedes-Benz, Honda, Mazda, and Mitsubishi emit substantially more than they should as well. For example: "Mercedes-Benz's diesel cars produced an average of 0.406g/km of NOx on the road, at least 2.2 times more than the official Euro 5 level and five times higher than the Euro 6 level. Honda's diesel cars emitted 0.484g/km of NOx on average, between 2.6 and six times the official levels." This provides clear evidence that the automotive industry is designing its cars to follow the letter of the law (passing tests), but not the spirit (actually reducing pollution).
I know they are available, but they are of no relevance in the US as you can't buy a Diesel-powered Honda in the US for any amount of money. I see that the source here is from the UK - where they are available - but the headline or summary could better reflect that this does not include any Honda vehicles on the road in the US today.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
You need a controlled environment for consistent results.
In the US you mean? In Europe there is diesel hybrid, in Korea there is even a Hyundai Elantra LPG hybrid.
"Science will win because it works." - Stephen Hawking
There was an article in last week's Economist on this. From recollection... in Europe, the testing is not done by an EPA-equivalent government agency, but by third party test labs. There, to get the business, the testers allow the auto manufacturers to rig the test: remove mirrors, remove all weighty optional equipment, remove seats, tape the door and window cracks, etc., etc. In other words, they are not testing the same car that they are selling.
All manufacturers designed their engine/transmission management systems to pass the test, what happened outside the test conditions were in the "your actual mileage may vary" zone; It's just like "common core" where they teach the kids to specifically pass the test. If you want cars to perform under realistic driving conditions the same as they do under emissions test, you have to make the test conditions as close to realistic as possible. The big three used to test their suspensions by driving down a particular bumpy section of Woodward avenue in Detroit, when they announced that that section of road was going to be repaired and repaved, the manufacturer surveyed the road and duplicated it at their test tracks to maintain continuity, and keep the test as close to realistic as possible.
Volkswagon's mistake was they actually change the operating parameters based whether the vehicle was being tested for emissions or for mileage or under normal conditions, the next step is for the bureaucrats to realise that they can have vehicle emit differing levels of emissions based on location and weather; your car may suck donkey balls in San Francisco, but run like a champ in Montana.
Apocalypse Cancelled, Sorry, No Ticket Refunds
Diesels already almost always run in their optimum range. A car engine basically has three operating states that are important. Accelerating from a stop, cruising (usually at highway speeds), and accelerating at highway speeds (to pass).
Gasoline engines hit peak power and torque at the high-end of their RPM range. That's great for accelerating at highway speeds, not so good for cruising and accelerating from a stop. Because most of the engine's time is spent cruising, that's where you need to optimize fuel burn rate to improve overall fuel efficiency. Gas engines have a lot of problem with this because it's not coincident with their peak power and torque production. Consequently you're having to optimize the engine's performance at two hugely different RPMs. The hybrid helps a lot here because the electric motor provides a lot of torque at 0 RPM for accelerating from a stop (power = torque * RPM * a constant),and allows the gas engine to be shut off completely for a while during cruising. So now you can optimize the gas engine for high-RPM efficiency, and rely on the electric motor for what would normally be low-RPM operation.
Diesel engines have a higher compression ratio so hit peak power and torque at the low-end of their RPM range. That's great for cruising and accelerating from a stop, not so great for accelerating at highway speeds. This is why they're so common in tractor trailers - it's OK if the truck takes a long time to accelerate at highway speeds, but you want good power and fuel efficiency during cruise. Since the diesel engine's peak torque and power happen close to cruise, they're a lot easier to optimize for fuel efficiency.
A hybrid won't actually help much here because it doesn't add much - the diesel engine already has lots of torque close to 0 RPM, and is fuel efficient during cruise. About the only thing a hybrid would add would be regenerative braking. While that's a big deal in city driving, the vast majority of the driving tractor trailers do is on the highway, so again there's little benefit from the hybrid. The best thing to add to a diesel is actually a turbo. Their weakness is power output at higher RPMs, and a turbo provides extra power at the high-end of the RPM range, which improves accelerating to pass at highway speeds - precisely the driving stage diesels normally have problems with.