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Compact "Green" Car Emission Comparison

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by usbseawolf2000, Mar 4, 2011.

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  1. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Lexus released CT200h on March 1st. The emission data was available since December 2010. To compare it with hybrids and other "green" alternative fuel vehicle in the compact size category, I made these charts. Enjoy!

    Note, Diesel fuel does not evaporate. AT-PZEV and Enhanced AT-PZEV emission rating is basically SULEV with longer warranty to the emission related components.

    Exhaust Emission:
    [​IMG]

    Fuel Evaporative Emission:
    [​IMG]

    CT200h
    A3 TDI
    Volt

    Attached Files:

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  2. wxman

    wxman Member

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    Thanks for the charts.

    For the Audi A3 TDI, the certified NOx emissions are 0.05 g/mi based on the CARB cert you reference (not 0.5 g/mi), and it's classified as ULEV. Don't see any obvious errors otherwise.
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  3. evpv

    evpv Active Member

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    I was looking for the specs on a 2011 Honda Accord EX-L I4 with PZEV rating for California, do you have the numbers?
  4. SageBrush

    SageBrush Senior Member

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    The CO amounts flatten everything else. I think a more descriptive graph would normalize each pollutant to the maximum allowable for SULEV cert, or use the number that is the middle of the range value for each pollutant in the SULEV tier.

    E.g, the allowable range of NMOG for SULEV cert out to 120k miles 0 - .01 g/mile. Normalize to 0.005 gram mile. In that case the CT200 would score 0.8.

    Another approach would be to use the lowest value among the cars being looked at set equal to 1.
  5. GrumpyCabbie

    GrumpyCabbie Senior Member

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    I'd have been interested to have seen the Prius figures on the chart too - or are they pretty much the same as the Lexus?
  6. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Will do correction and also add Prius to use as the benchmark.
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  7. usbseawolf2000

    usbseawolf2000 HSD PhD

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    evpv, I posted it in the midsize thread, here.

    Everyone, I corrected A3 and added Prius and PHV version to the original post. I simplified by putting all of them into two charts.
  8. Rybold

    Rybold globally warmed member

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    Thanks for creating the comparison graphs!

    I noticed the graph shows CO instead of CO2. I'm assuming this is because the PZEV and SULEV system has nothing to do with CO2, but rather all of the pollutants that come out of the tailpipe. Is my understanding correct?

    I typed PZEV into wiki, but the article did not answer my question: [ame]http://en.wikipedia.org/wiki/PZEV[/ame]
  9. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Yes, CO2 is directly tied to MPG also come out from the exhaust. EPA site has annual CO2 emission in tons. It is a great suggestion to include that as a third chart.
  10. Rybold

    Rybold globally warmed member

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    Well, actually since CO2 and MPG are 99.9% directly proportional, I think we can just compare MPG. (I have a degree in chemistry. CH4+2O2 => 2H20 + CO2 is the empirical equation of all hydrocarbon combustion) The reason I say 99.9% instead of 100% is because some of the combustion is incomplete combustion; resulting in CO and the other pollutants that you listed).

    I was just wondering if the "PZEV" qualification factors in CO2 or only the pollutants that you listed. (CO2 is not a pollutant. We breath it out of our lungs every time we exhale and the plants that we eat consume CO2 from the air) The sum of any and all carbon that exits your tailpipe is your "carbon footprint." Does "PZEV" factor in your carbon footprint, or only pollutants?
  11. SageBrush

    SageBrush Senior Member

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    Chem guy Rybold, hydrocarbon is ~ [CH(2)]n (ignoring the terminal methyl groups that decrease the carbon w/w by ~ 1%)

    The *EV CARB categories do not consider CO2.
    CARB dates from the 1970s I think. The state desire to regulate CO2 is much more recent.
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  12. Rybold

    Rybold globally warmed member

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    Of course that's the more accurate way to write it, but I was hoping my equation would be understood by others and not look overly complex.



    Thanks for answering my question. :)
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