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How will the Chevrolet Volt be better than a Toyota Prius plug-in hybrid?

Discussion in 'Chevrolet Volt' started by Adaam, Jan 31, 2011.

  1. usbseawolf2000

    usbseawolf2000 HSD PhD

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    The notion of "outdated" is unfounded. Prius just went mainstream and a slew of Prii (Prius v, Prius c and Prius PHV) are going to join the family. Prii are class leading in low emission and fuel efficiency at an affordable price.

    50-100 EV miles actually increases emission. Less than 20 EV miles does not compromise emission. It is supported by the DOE report which agrees with the earlier CMU study that smaller battery is better. It is not "sexy" but it is the reality.

    Higher EV range is great as a trophy vehicle whereas a realistic EV mile is great for cutting emission and gasoline consumption at a price the many can afford.
     
  2. tpfun

    tpfun New Member

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    The DOE report is limited in its scope to comparing PHEV10-20-parallel and PHEV30-40-series configruations. While the parallel config is based on the real world design (Prius), the series configuration is purely hypothetical meaning there's no real vehicle with that series setup (not surprisingly, running an ICE to charge a battery to run a motor is inefficient.). Notice the AER of the series design being reduced by 30% (PHEV40 down to 30miles) for comparison purpose while the PHEV10/20 design was not since the ICE is assumed to assist CD mode operation while operating at the CS efficiency level (probably not realistic). That obviously skews the results of the study.
    The conclusions of the report are therefore unremarkable.

    Two PHEV design configurations were considered for this analysis: a power-split design for PHEV10 and 20 (i.e., with 10 and 20 miles of all-electric range [AER]) and a series design for PHEV30 and 40 (i.e., with 30 and 40 miles of AER).
    The power-split configurations are based on a single planetary gearset with ratios similar
    to those of the Toyota Prius. The series configurations are based on a two-speed automated manual transmission (ratios 1.8/1) in order to allow the vehicle to reach the maximum speed (100 mph) without oversizing the components.


    The CMU study says the best capacity depends on the driving distance between charges. The chart (Fig 6) clearly shows for distances of 21-45 miles between charges (daily commute), the PHEV40 is the best (min GHG's). The study does not support your claims that "smaller battery is better" or "50-100 EV miles actually inceases emission". The study shows CD mode is 2-3x more efficient than CS and that the additional weight to support longer AER's reduces those efficiencies (as expected); therefore the final analysis takes into account the CS/CD driving ratios which leads to the conclusion of the study.

    quote: The best choice of PHEV battery capacity depends critically on
    the distance that the vehicle will be driven between charges. Our
    results suggest that for urban driving conditions and frequent
    charges every 10 miles or less, a low-capacity PHEV sized with an
    AER of about 7 miles would be a robust choice for minimizing
    gasoline consumption, cost, and greenhouse gas emissions. For
    less frequent charging, every 20–100 miles, PHEVs release fewer
    GHGs, but HEVs are less costly
     
  3. UsedToLoveCars

    UsedToLoveCars Active Member

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    Did you read your own CMU link?

     
  4. SageBrush

    SageBrush Senior Member

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    ^^ Did you ?
    No one disputes that an EV run off PV or hydro is GHG clean. The discussion has to do with drivers who charge off the grid with prominent coal based fuel supplying the marginal demand.
     
  5. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Yes, I saw that. The key word are "could", "some drivers" and "potential".

    It wildly depends on how electricity was generated. If Volt is powered by coal electrons, it will be dirtier than a cordless Prius. Even the US average mix still put Volt with higher GHG emission than a cordless Prius.

    This quote was highlighted:

    “Larger battery packs allow drivers to go longer distances on electric power. But batteries are heavy and expensive. Over a range of scenarios—including fluctuating gas prices, new battery technologies or high taxes on carbon dioxide emissions—plug-ins with small battery packs are economically competitive with ordinary hybrid and conventional vehicles for drivers who charge frequently.â€
    —Prof. Jeremy Michalek
     
  6. john1701a

    john1701a Prius Guru

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    Yet another opportunity for cherry-picking!

    Of course, the lack of real-world detail is a dead giveway of trouble. Vague claims don't attract mainstream purchases. Those from middle-market (little disposal income available) study before purchasing, often depending upon endorsements from people they know.

    Just think what those On-Star reports will stir, completely disregarding some info people what to know and pushing greenwashing spin like "gas saved".
    .
     
  7. usbseawolf2000

    usbseawolf2000 HSD PhD

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    They are doing it with MPG. Electric miles are added to the MPG to emphasize on the "gas saved". What happened to the "gallon per year" measurement? The real-world data probably killed the idea.

    We need a new term to differentiated the two types of MPGs.

    Corded MPG - Volt displays this and it includes the electric miles divided by gallons consumed.

    Cordless MPG - Non-hybrids and cordless hybrids display this. Miles driven by gasoline divided by gallons consumed.

    Corded MPG has strings (pun intended) attached. Prius PHV prototype also shows Corded MPG but it also openly shows EV/HV miles ratio.
     
  8. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    Its funny you mentioned that. The only reason that the Volt is the first American car I'd consider buying is because of this.
     
  9. Trollbait

    Trollbait It's a D&D thing

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    If the clearance is really that low, and not just bolted on ground effects for air flow, do new owners get instruction on how to clear speed bumps? Like with the 'Vette. Does the quick braking and acceleration have a large affect on EV range and fuel economy?
     
  10. tpfun

    tpfun New Member

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    The study takes the source of the energy into account. Read it.
     
  11. SageBrush

    SageBrush Senior Member

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    ^^ yes, which is why the paragraph you quote has all the conditionals. I have to admit some confusion about you. Stupid, or just a troll. Maybe both.
     
  12. tpfun

    tpfun New Member

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    [​IMG]
    Look at chart in Fig 6 of the study which clearly shows for distances of 21-45 miles between charges (daily commute), the PHEV40 (Volt) is the best (min GHG's).

    Don't shoot the messenger.
     

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  13. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Why would you consider a vehicle with 3" ground clearance in Illinois? :confused:

    Sorry but it is not Volt. They are all Prius plug-in conversions with different EV range.

    Electricity consumption is very low (200 Wh/mile even for structural factor +2). This high efficiency is probably due to the blended depletion strategy.

    We know Volt consumes 360 Wh/mile per EPA rating. We should refer to DOE report for Volt's GHG emission because they used series hybrid architecture for PHEV40. That report said Volt's GHG emission is higher than PHEV20 or HEV (cordless hybrid).

    Figure 6 highlights the path/potential for Prius PHV when the battery becomes more affordable.

    [​IMG]
     

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  14. tpfun

    tpfun New Member

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    The hypothetical series architecture for the PHEV40 in the DOE report is not the Volt.

    No, that's not what it says. Read it.
     
  15. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Volt is a series hybrid except in certain situation, the gas engine also powers the wheels. It was done to improve 5-10% MPG in the CS mode. CS mode is utilized only 33% of the time (GREET model). Therefore, the DOE report is accurate within 1.65% to 3.3% and it does say PHEV40 (Volt) emit higher GHG.
     
  16. Skoorbmax

    Skoorbmax Senior Member

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    At its current price the Volt is nothing more than a proof-of-concept. It's not a consumer vehicle, really. The Prius absolutely is and the Leaf is priced such that I would say it is, too, as long as you're ok with its limited range. The volt is so expensive that only real techaholics or early-adopters (for the sake of saying they are one) would buy one. It has too many drawbacks, the two notable ones being incredible cost and terrible fuel economy when run on gas (premium at that). If its cost would come down $10k it would be a pretty impressive piece of kit, certainly. Same price as a Leaf and though less EV none of the range anxiety. Really quite worthwhile then. As it is now though it's just kind of meh.
     
  17. MattD

    MattD Member

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    I just posted a review on the Volt in the Prius PHV forum, you should check it out.
     
  18. tpfun

    tpfun New Member

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    Here's another comparison point.
    Video 1 shows the lack of traction control in the Prius.



    Here's the Volt

    [ame=http://www.youtube.com/watch?v=_bg-Yzjge3E]YouTube - Volt Handling in Snow[/ame]
     
  19. Flaninacupboard

    Flaninacupboard Senior Member

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    You do realise you're comparing a 7 year old design (gen 2) with a brand new design in the volt. the gen3 would have got up that hill no problems at all.

    The driver also didn't help. they were clearly applying a LOT of throttle, judging the way the wheels span up when it lost traction.
     
  20. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Gaining momentum is the right way to do it. However, if you need to start moving from a dead stop, can Volt do this? Remember, under the snow is ice.