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Is the Fisker Karma series hybrid or parallel?

Discussion in 'Electric Vehicles' started by doug, Jan 12, 2009.

  1. doug

    doug Administrator / Head Moderator

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    #1 doug, Jan 12, 2009
    Last edited: Jan 12, 2009
    I think the Karma turned out to be at least in part a parallel hybrid.

    Edit: Or not. Half disremembered a poor article.
     
  2. TEG

    TEG TMC Moderator

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    #2 TEG, Jan 12, 2009
    Last edited: Jan 12, 2009
    Not so sure about that - I think someone may have mis-reported things.

    10 Questions for the Karma’s Henrik Fisker Earth2Tech
    This was the article that may have gotten it wrong:
    Fisker Reveals Production Version of Luxury Electric Car : Gas 2.0
    Further evidence that it is in fact series not parallel:
    Fisker Karma plug-in hybrid car to be unveiled at Detroit Auto Show
    From Fisker:
    http://karma.fiskerautomotive.com/pages/karma
    The above seems slightly ambiguous. It says the gasoline engine turns a generator, but also says it acts as a "normal" hybrid. What does "normal" mean? I imagine some took that to mean parallel, but that is possibly a wrong interpretation.
     
  3. TEG

    TEG TMC Moderator

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    I am fairly sure Karma & Sunset are "Series" hybrids.

    Detroit 2009: Fisker Karma S hardtop convertible unleashed - AutoblogGreen
    My guess is that "Stealth" mode is slightly power limited due to battery pack output limits. If you enable "Sport" mode then the gas motor turns on sooner to supplement current from the pack with generator current to get full power from the dual eMotors. But I still don't think there is a mechanical linkage from the gas engine to the differential. (Please feel free to prove me wrong. I am trying to read between the lines here).
     
  4. donauker

    donauker Member

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    I agree TEG, I believe the parallel came only from a lack of understanding about the "Sport Mode".

    This quote from from Fisker's website.

    The Karma

    Stealth mode is limited due to the maximum power available from the battery pack alone. With the engine generator unit running full electric power is available for maximum performance.
     
  5. TEG

    TEG TMC Moderator

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    Further confirmation today:
    http://www.nytimes.com/2009/01/12/automobiles/autoshow/12elect.html
     
  6. TEG

    TEG TMC Moderator

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    Yeah, I talked about that before here:
    http://www.teslamotorsclub.com/electric-cars/1353-fisker-karma-2.html#post15899
     
  7. TEG

    TEG TMC Moderator

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    #7 TEG, Jan 12, 2009
    Last edited: Jan 12, 2009
    [ mods - can you consider moving all related posts to this topic? ]

    As far as I know the Fisker Karma (and Sunset) are series hybrids where the gas engine only ever drives a generator and has no mechanical connection directly to the wheels.

    There seems to be a long running rumor/mis-interpretation that it is, or can temporarily switch to "parallel" hybrid mode. I think this was started because Fisker touted their "sport" mode as offering full performance when the gas engine is running. This may not be a mechanical linkage, but rather more current available than the battery pack can supply on its' own. The Fisker cars have two large eMotors totalling around 400hp max, so they would need more current than even Tesla's much larger battery pack could supply. For this reason, I think they need gas engine spooled up to provide full eMotor power, but it is still "series" if it has to have all gas engine HP come through the generator.

    Here are some articles that claimed (probably incorrectly) they are "parallel" hybrids:

    24Nov2008:
    Sympatico / MSN Autos (EN): Good Karma: Fisker picks GM Turbo engine to power its luxury plug-in hybrid
    02Dec2008:
    Fisker Reveals Production Version of Luxury Electric Car : Gas 2.0
    11Dec2008:
    Fisker Electric Plugin Car gets 100mpg: The Karma , really.. | The Karma Report.com
    Karma the Car. Fiskers New 4 Seater Electric Plugin Vehicle | Green Car Magazine
    Fisker Karma Production Version Revealed - Gearlog
     
  8. doug

    doug Administrator / Head Moderator

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    #8 doug, Jan 18, 2009
    Last edited by a moderator: Mar 13, 2016
    This video further confirms that the Karma is a serial hybrid:


    (1:13) Fisker: ... gasoline engine in the front that turns a generator, it never turns the wheels...
     
  9. TEG

    TEG TMC Moderator

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    Thanks, Doug. That is about as direct as we could have hoped to get this clarified.

    Remaining question is if the "stealth" mode is performance limited because the battery pack can't output the full 300kW by itself (so it needs the ICE generator to be going at the same time)?

    They seemed to have designed the Karma with the idea that you will use the ICE some of the time. (In other words, it is NOT just a low speed short range commuter car with range extender for emergencies... They don't want a "limp home" mode when the pack is low).

    Volt on the other hand is more optimized for battery only operation, and may be more limited when you have run the pack down. (Volt never had aspirations to be a performance car anyways).

    As with all PHEVs you will need to plug it in frequently if you want to maximize efficiency. Some small minority of owners might only ever "gas it up" and find that it is less efficient than a Prius that way.
     

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