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Automotive News & Views MPG Ratings Will Drop Under EPA Proposal
375 messages, Last post on Oct 02, 2008 at 9:08 PM
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See this Edmunds.com article! EPA Overhauls Fuel Economy Estimates for 2008 - As the 2008 model-year cars hit the lot, shoppers will notice a big difference — the EPA has changed its fuel economy testing methods to produce mileage estimates that reflect "real world" driving habits. - (more)
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The EPA played a role in why hybrids were 25 years late to market: This is very good. This tells who "Mr. X" was: Mr. X = Erik Stork (heretofore known as Stork The Dork)
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Replying to: larsb (Sep 26, 2008 12:20 pm)  Of course the EPA would never do anything to hold up diesel technology. When will you admit they are just another corrupt agency in a corrupt government.
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Replying to: gagrice (Sep 26, 2008 1:51 pm) I will admit to figments of MY OWN imagination, but not some else's. And in the same manner in which you have zero proof that the EPA is corrupt in regard to the EPA mileage tests, you have zero proof that the EPA is holding up diesel engine cars. EVEN WHEN I take a spreadsheet in which YOU commented upon and use data in that sheet to PROVE beyond a shadow of ANY DOUBT that the Jetta TDI was not jobbed, you STILL will not admit you were wrong. Sad. |
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Replying to: larsb (Sep 26, 2008 7:11 am) i had a focus that was pzev rated just like a prius. the gas mileage ratings were 25/33. how can this be? gm and ford had electric only vehicles in the 90's. why can't i find them on the epa site?
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Replying to: explorerx4 (Sep 26, 2008 2:34 pm) And the Prius is technically rated as AT-PZEV, which is a slightly different classification than regular PZEV. This is a certification given to just a handful of vehicles and stands for Advanced Technology Partial Zero Emissions Vehicle. What all that means is that the car gives off 70 percent less smog-forming emissions than the average car. This also means that there are almost no fuel leaks or fuel vapors escaping from the fuel system. The AT-PZEV certification requires the SULEV exhaust standard linked with the ability to meet a zero-fuel-evaporative standard, a 150,000-mile durability demonstration, extended emissions system warranty, and technology deemed by the California Air Resources Board (CARB) to advance future fuel cell vehicles. There are no gasoline engine cars which have achieved an AT-PZEV rating. The EPA test system is not setup for electric cars. They do not use diesel or gasoline by the gallon, so cannot be assigned a "miles per gallon" figure. The could be assigned a "cost per mile" which could then be correlated to gasoline equivalents. |
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Replying to: larsb (Sep 26, 2008 2:45 pm) i think you are making conclusions based on the way you think things work.
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Replying to: larsb (Sep 26, 2008 2:45 pm) That is because the mnemonic was derived for the hybrids. Just so we are clear here. A PZEV rated car getting 40 MPG actual will be just as clean in every way as an AT-PZEV rated hybrid getting 40 MPG actual. Don't be confused by the erroneous EPA ratings game.  CO2 emission is directly related to the amount of fuel used. Not some number on a window sticker.
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Replying to: gagrice (Sep 26, 2008 3:18 pm) This is true. However, the CAFE standards were not created in order to limit CO2 emissions. CO2 is not regulated by the EPA as a pollutant at all. The emission standards of cars are for pollutants such as NOx, hydrocarbons and CO. http://www.fueleconomy.gov/feg/airpoll.shtml While greater fuel efficiency would likely be related to lower emissions of HC and CO as those are products of incomplete combustion, this is not the case for NOx. In fact for NOx, it tends to be the opposite, optimising for low NOx would tend to make a less efficient engine. The EPA standards currently are met by equipping cars, no matter how fuel efficient they are, with catalytic converters not by designing an engine capable of meeting the standards without add on controls. While there may be some connections, CAFE standards were not created for purposes of controlling NOx, HC, or CO. There are explicit standards, expressed in grams per mile, that must be met for these pollutants.
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Replying to: explorerx4 (Sep 26, 2008 2:55 pm) Actually, no. Having a battery has nothing to do with it. AT PZEV: Advanced Technology PZEVs AT PZEVs meet the PZEV requirements and have additional "ZEV-like" characteristics. A dedicated compressed natural gas vehicle, or a hybrid vehicle with engine emissions that meet the PZEV standards would be an AT PZEV. And: AT PZEV—Advanced Technology PZEV Compressed natural-gas or hybrid vehicles that meet SULEV standards for tailpipe emissions, have a 15-year/150,000-mile warranty, zero evaporative emissions, as well as include advanced technology components. There are no gasoline-only cars which are AT-PZEV. This is as clean as you can get without being ZEV.
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Replying to: jeffyscott (Sep 27, 2008 4:45 am) Light-duty vehicles and light-duty trucks must calculate and report the weighted mass of each relevant pollutant, i.e., THC, CO, THCE, NMHC, NMHCE, CH4, NOX, and CO2in grams per vehicle mile. Title 40: Code of Federal Regulations (the regulations governing the EPA measurements of automotive exhaust emissions) Part of what makes all this so confusing and maddening is that the EPA really does not measure miles per gallon, at least not in the way that we might commonly think about measuring MPG. They measure emissions. They measure the byproducts of combustion. This is in keeping with the EPA's charge to protect the environment. The data reflects how efficiently a fuel has been burned, and does not reflect how far a car traveled while burning that fuel. They take that data and calculate estimated MPG. It is a convoluted and complex process that ultimately estimates MPG rather than measuring MPG. We have known since the beginning that the calculation produced a high result, and even under the new test it still does. So, those results of that calculation is further massaged to get to the numbers you and I see on those window stickers. Some may claim that this process is erroneous, but it is a highly controlled process intended to get at least somewhat consistent results. Despite the controls, the assumptions, stipulations, simulations, predictions, and other factors are susceptible to outside political influence. We have been arguing about all that since the beginning. You and me and most of the automotive press usually employ a much simpler method. Fill up the car, drive for a while, fill up again. Divide the number of miles driven by the amount of fuel consumed. Voila. Not nearly as controlled, ends up with a wide variety of results, but a whole lot simpler.
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