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Forced Regen Button?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by blown240, May 21, 2011.

  1. blown240

    blown240 Junior Member

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    On my old 1st gen Honda Insight, I had a switch that made the car think you were braking. This would turn on the regenerative brake without actually using the hydraulic brakes. It was basically a momentary switch wired in parallel with the brake light switch.

    Is there something like this for a Prius II?
     
  2. qbee42

    qbee42 My other car is a boat

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    No, there is not. Why would you want it?

    Tom
     
  3. blown240

    blown240 Junior Member

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    You use it when you want to just slow down a little, instead of using the brakes, you just have the regenerative brake slow you. The prius already does it to a point, when you let off the gas. This would be a step more than that, more regen, and more brake, but not braking with your foot. Basically more of your kinetic energy ends up in the batteries, instead of heat from the brake pads.

    I am assuming that the prius has more regen when braking then when coasting, but I am new with these cars...
     
  4. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    Even with the foot pressure it will try to use regen first. Only if you go above the current limits, brake too fast, or are under 7mph will the friction brakes even be touched.
     
  5. bisco

    bisco cookie crumbler

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    ^ right. stepping on the brake pedal increases regen before using brakes. so it's probably a more sophisticated method than the manual switch in the honda.
     
  6. ken1784

    ken1784 SuperMID designer

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    The Toyota HSD has more sophisticated regeneration brake than the Honda IMA.
    It applies the regen brake primarily unless it is a hard braking.

    However, if you want a forced regen button, the B-mode switching under 20mph works as desired.

    Ken@Japan

    [​IMG]
     
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  7. qbee42

    qbee42 My other car is a boat

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    The Prius already does this, but you don't need a special button. Just step on the brakes and let it do its thing.

    Tom
     
  8. mikewithaprius

    mikewithaprius New Member

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    Hey OP,

    Here's another graphic with some key details from a Toyota publication regarding the 2004 Prius. The above graphic actually looks a little misleading, especially if you think of the unlabeled x-axis as time. You can see it's more a mix of regen and friction the more you push the brake pedal. A nice, light braking that gently slows the car is the best way to get all the energy available to you. As close to a regen button as you'll get. Still sort of a big button, you just need to push it with your foot :)

    [​IMG]
     
  9. blown240

    blown240 Junior Member

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    Cool. I am glad that Toyota thought of this. The insight wasnt nearly as advanced. Thanks for the replies.
     
  10. xpcman

    xpcman Senior Member

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    I want the opposite. A switch than lets the car coast without any regen.
     
  11. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    That would be nice but too many people would be confused at the lack of "transmission drag" and why the car isn't slowing down. So we will have to live with depressing the throttle just enough to make it a glide.
     
  12. MJFrog

    MJFrog Active Member

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    It has one of those too. It's called 'N' (Neutral). You just have to switch back and forth between it and 'D' to get moving again.
     
  13. serialzombie

    serialzombie Junior Member

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    That's fine to do? Also, what about "Brake?"
     
  14. seilerts

    seilerts Battery Curmudgeon

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    B should only be used when you have reached 8 bars SoC and you are still going downhill. Useful when descending Pike's Peak, but nowhere in the Midwest should it ever be necessary.
     
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  15. qbee42

    qbee42 My other car is a boat

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    Just a minor correction: B should only be used when you anticipate reaching 8 bars...

    If you wait until you hit 8 bars, there is no need for B mode; the Prius will do it for you. The idea behind B mode is to bleed off the excess energy early, forestalling the forced transition to friction braking.

    Tom
     
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  16. psusi

    psusi Junior Member

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    One problem with switching to neutral to coast is that the engine can not be started or stopped in neutral, so if you are over the magic 42 mph where the engine stays on when you shift into neutral, it will continue to idle until you put it back in gear and are under 40.

    Because of this, it is better to just ease off on the gas to gradually slow down instead of shifting to neutral when you are over 40. If the engine is running anyway, you may as well be using it to charge the battery.