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Some naive owners may be using the B instead of the D

Discussion in 'Gen 2 Prius Main Forum' started by roperld, Sep 2, 2006.

  1. richard schumacher

    richard schumacher shortbus driver

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    <div class='quotetop'>QUOTE(Ichabod @ Sep 3 2006, 08:43 PM) [snapback]313742[/snapback]</div>
    No, it is not a waste of drag: it's to keep you from overheating your brakes. "B" is meant to be used as an alternative to riding your brakes. If you're riding the brakes then you are already "wasting" energy: you *have* to waste it because the battery can't absorb the energy fast enough. All that excess downhill energy has to go somewhere. "B" gets rid of that excess energy without burning up your brake pads.
     
  2. lowspeed

    lowspeed Member

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    <div class='quotetop'>QUOTE(richard schumacher @ Sep 5 2006, 10:29 AM) [snapback]314501[/snapback]</div>
    I really don't get the purpose of B... once you filled up the battery the car goes to engine braking automatically.

    its just there to make the stick look a little more sophisticated then just forward and reverse...
     
  3. Frank Hudon

    Frank Hudon Senior Member

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    you just need to get it on a hill. One that I was on on holidays and it's not the longest or steepest has a sign at the top that says gear down 8 1/2% grade for 5Km's. At the first switch back the battery was at 82% BSOC and the ICE was at 4300 RPM and I was in B to keep the speed under 80 Km's per hour. There are steeper hills and longer hills but that's one of the better ones to see the value of B.
     
  4. sew1more

    sew1more New Member

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    [1)No b-mode, braking with brake pedal only....Since you'll be regenerating at a rate of around 60 amps you'll charge the battery to the green range within around 1/2 mile....at that point regen will drop off dramatically and then the ICE will begin to be spun by MG1 to



    What's ICE?
     
  5. efusco

    efusco Moderator Emeritus
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    <div class='quotetop'>QUOTE(key @ Sep 9 2006, 09:29 PM) [snapback]317198[/snapback]</div>
    Internal Combustion Engine...the gas engine. MG= Motor Generator--the electric motors


    <div class='quotetop'>QUOTE(lowspeed @ Sep 9 2006, 07:37 PM) [snapback]317154[/snapback]</div>
    No, it doesn't. The ICE does spin rapidly..propelled by MG1 to spill excess charge but does not do any braking.

    The other point is to delay and minimize the need for the friction brakes on very long grades. Excessive use of the friction brakes can lead to overheating and, potentially, failure.
     
  6. jburns

    jburns Senior Senior Member

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    <div class='quotetop'>QUOTE(bradysplace @ Sep 4 2006, 12:40 AM) [snapback]313807[/snapback]</div>
    Cruise is for convenience. A decent driver can easily beat cruise control milage.
     
  7. IsrAmeriPrius

    IsrAmeriPrius Progressive Member

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    <div class='quotetop'>QUOTE(key @ Sep 9 2006, 07:29 PM) [snapback]317198[/snapback]</div>
    An essential ingredient for mixing a dry Martini.

    :lol:
     
  8. lowspeed

    lowspeed Member

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    <div class='quotetop'>QUOTE(efusco @ Sep 9 2006, 10:49 PM) [snapback]317202[/snapback]</div>

    It definitely starts braking with the engine once the battery is topped off ... happened to me a couple of times. switching to B didn't make it feel any different.
     
  9. NuShrike

    NuShrike Active Member

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    B is no different from 2/1 (under the D) in your normal automatic. I wonder how many more people are just as confused about what 2 and 1 is for.
     
  10. Ichabod

    Ichabod Artist In Residence

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    To be fair to those of us who have been confused, there are a lot of things internally different with "B" than with putting an automatic into a different gear ratio. Personally, I always knew it was for engine braking, but it does help me to know its relationship to battery SOC and friction brakes. "B" also feels less aggressive than downshifting in most automatics I've driven.

    Without this thread I wouldn't have know that the regen braking will stop and leave you with only friction brakes if your battery is fully charged.
     
  11. Charles Suitt

    Charles Suitt Senior Member

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    :unsure: GEEZ....

    QUOTE: [Underline added] "A decent driver can easily beat cruise control milage."

    I suppose that means I'm an "INDECENT" driver. Cruise Control does a good job for me. I'm not compulsive about MPG to the ultimate. Seems arbitrary "labels" are categorically inaccurate. :eek: :unsure: ;)
     
  12. mhellmer

    mhellmer New Member

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    To B or not to B?

    This is a good discussion. (Not only did my sales guy tell me what B was for I did RTM so I would have found out anyway.)

    How much braking power does MG provide before the friction brakes kick in? Is there an way to tell by feel or otherwise. I have a 1/2 mile steep grade I go down once a day and I feel compelled to use B because otherwise I would be more or less riding the brake to check my speed most of the way down. In B I might have to tap the brakes a couple times. If staying in D and riding the brakes does not employ the friction brakes then I'd rather do that since I hate the sound the ICE makes in B at 55-60 MPH.
     
  13. stanleyjohn

    stanleyjohn New Member

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    I would use B in the winter when i am going down a snow covered road for better control.Its a bit like using low gear in a non hybrid car.
     
  14. tomdeimos

    tomdeimos New Member

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    <div class='quotetop'>QUOTE(stanlwyjohn @ Sep 11 2006, 06:10 PM) [snapback]317985[/snapback]</div>
    Winter is the last place you should use b mode. It brakes on 2 wheels and defeats the proper operation of the ABS system.
     
  15. stanleyjohn

    stanleyjohn New Member

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    thanks tom! shows how much i know about the B :unsure:
     
  16. jburns

    jburns Senior Senior Member

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    <div class='quotetop'>QUOTE(Charles Suitt @ Sep 11 2006, 03:37 PM) [snapback]317899[/snapback]</div>
    Been taking sensitivity training again? All I did was state a fact. If you want to discuss it fine. Your personal insecurities are irrelevant to the topic.
     
  17. curtissac

    curtissac New Member

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    <div class='quotetop'>QUOTE(Ichabod @ Sep 11 2006, 01:47 PM) [snapback]317855[/snapback]</div>
    Not exactly. What you desribe would amount to coasting, which the car will not do unless you select "N."

    In "B", the system will use compression braking from the ICE when the batteries reach full.
     
  18. Soylent

    Soylent The v isn't a station wagon! It's just big boned

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    B mode is very important in the mountains, because excessive use of the brakes downhill will cause them to overheat, which causes them to fail. Then all you can do is pile into a Run-away Truck Ramp to stop!
     
  19. ken1784

    ken1784 SuperMID designer

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    <div class='quotetop'>QUOTE(Soylent @ Sep 12 2006, 10:06 PM) [snapback]318243[/snapback]</div>
    Are you talking about the Prius case?

    Prius is designed to prevent the overheat of your brake.
    Have you ever been a long downhill in D and ever realized what was happening?

    Ken@Japan
     
  20. DonT

    DonT New Member

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    I did as well do my do jillegence. I rented PRIUS while visiting relatives in Ct. after driving from Fl. the yr b-4 w/ our Dodge Van. Van=24mpg :( Prius=46-50mpg. We all should know already that most of the time hiway is ;LOWER than the city because my "MACHINE" sips the gas. LOL. I could go on but we have storms in my area of Fl. It's afternoon, what else is new. Take care. thanks for reading me. Regards, DonT
     
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