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G3 vs. G2 Regenerative Braking?

Discussion in 'Gen 3 Prius Main Forum' started by Blind Guy, Jun 17, 2009.

  1. Blind Guy

    Blind Guy New Member

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    To Those Who've Owned Both a G2 and G3;

    Toyota's Press Release of Jan. 12, 2009 says "a newly developed electronically controlled Regenerative Braking System has been adopted, with Control Logic optomized to enhance regeneration".

    Is there a difference between the quality and affectiveness of their respective brakes (since the G3's are 4-Wheel Disks), and their regenerative braking systems, is the G3's stronger, touchier or more responsive etc....or is the G2's better?

    Curious
    David (aka Blind Guy)
     
  2. dogfriend

    dogfriend Human - Animal Hybrid

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    I don't have a G3, but its important to remember that the regenerative braking only works on the front wheels - it is the retarding force created by MG2 that slows the car during regenerative braking. So the type of rear brakes (drum or disc) have no influence.
     
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  3. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    dogfriend, that's true up until the driver demands more force than regeneration can provide (quick or emergency stops). I've found braking in the G3 much improved in those situations.
     
  4. dogfriend

    dogfriend Human - Animal Hybrid

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    Yes, but that's friction braking, not regenerative.

    I can believe that the G3 friction braking is better or that the regen braking has been improved in some respects, but the rear brake type (disc or drum) can't have any effect on regen braking.
     
  5. ken1784

    ken1784 SuperMID designer

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    It looks the 3G Prius regen braking is more efficient than 2G one.

    I saw seven regen marks on the G3 and we saw max three and a half on the G2 in 5 minutes.
    Had anyone seen more than that on the G2?

    Ken@Japan

    [​IMG]

    [​IMG]
     
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  6. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Wow, 7 regen cars. That's 350Wh. I have never seen it in my 06 Prius.
     
  7. CtrlAltDelete

    CtrlAltDelete New Member

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    My wife has an gen II and I have a gen III. In the few weeks that I've had my gen III, its much easier to regen. Taking the same trip in both cars, I can easily double or triple the amount of energy captured with the gen III compared to the gen II. This is just from normal driving; and its just something I noticed one day when I saw all the little cars staked up.
     
  8. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    I think the higher RPM of MG2 (despite it's smaller size) thanks to reduction gearing allows for more effective (read MAX) regen up to a lower speed. I've seen more regen on my bars as well.
     
  9. mosttoysrk

    mosttoysrk New Member

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    It is interesting how different the G2 and G3 cars feel (at least for me) when you coast. The G2 Prius creates an immediate drag sensation when you coast almost as if you downshifted in a normal car. The G3 just glides like crazy without slowing down, when you gently touch the brake on the G3 you see the regenerating scale increase.
    This is probably why the pulse and glide technique works on a G3 vs not so much on a G2.
    I tend to gently touch the brake pedal if I want to obtain the largest regenerative effect in a G3 where you didn't have to do this in a G2.
     
  10. Judgeless

    Judgeless Senior Member

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    It would be great if the display gave feed back when you are using friction braking compared to regenerative. It would make me lighten up on breaking. It would also generate more energy and save on brake pads.

    I do not own a Prius yet and the car might already do this.
     
  11. wfolta

    wfolta Active Member

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    I've asked about this but got no answer. My hope would be that friction braking begins at the far left side of the "CHG" section of the main display, but no one's confirmed this for me yet.

    So I generally try to brake -- when I have the option -- so that I see a tiny bit of gap in the CHG section. I'd love to know the answer, but unless it comes from a factory manual I don't see how anyone could test it.
     
  12. Judgeless

    Judgeless Senior Member

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    It would be even better if you could feel it in the brake pedal. As you press the pedal down it would be smooth until you pressed hard enough to start using friction brakes. The pedal can give a slight knock as feed back to tell you friction braking has started.

    Most highway braking is because traffic is slowing down. If you keep clear distance you could use regenerative braking most of the time.
     
  13. DetPrius

    DetPrius Active Member

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    Came looking for the same answer Judgeless and wfolta are looking for but it looks like nobody knows yet. I can't feel when the friction brakes are kicking in, if I am pressing hard enough at times to cause them to engage. I also wondered if it was at the point the CHG area is filled while braking. Would really like to know this one...
     
  14. wfolta

    wfolta Active Member

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    Still no answer. :( Personally, I think the HSI display needs two more indicators:

    * A red circle to the left of the CHG area to let you know you'd gone into friction braking.

    * A "bullseye" where the ECO indicator is (useless, redundant indicator) where the center indicates that the engine is spinning, and the outer circle indicates cylinders firing.
     
  15. FlipStylee270

    FlipStylee270 New Member

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    Is it better to see 10%-20% CHG bar at for a lenght of time, or 70-80% CHG for shorter... Meaning, is it better to brake early, where theres really not much braking but just regen braking, or shorter brake distance with 80-90% CHG?

    Does each wH cars equal to 1 bar in the recharge?

    If I'm on EV and use up 1 battery bar, how many cars does it take to bring that 1 bar back, like "recapturing" energy?

    Thanks in advance!

    (This is out of topic, but if we somehow placed prius on a Dyno that would simulate a regen glide, would it be the same as plug-in vehicle?, wouldn't it be nice if the traction battery would be charged before you roll out of the garage using this silly method?)
     
  16. clooch

    clooch Junior Member

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    imho the gen lll is touchier upon regen, it seems harder to glide as well.

    this is my $ .02 worth :D
     
  17. Vincent

    Vincent Don't Wait Until Tomorrow

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    Subjective answer to the original question:

    1. Battery SOC is always higher in my Gen III vs my Gen II.
    2. Brakes feel more responsive on the Gen III.

    There's a much more noticable George Jetson type regen whine when applying the Gen III brakes that bothered me at first, but is now part of all the other "normal" Prius noises that I don't hear any more.