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Is it Prudent to Neutral at 60 mph Down a Hill ?

Discussion in 'Gen 3 Prius Main Forum' started by PriusNeckBeard, Nov 8, 2016.

  1. PriusNeckBeard

    PriusNeckBeard Active Member

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    I stopped using neutral Today. Sigh. I really enjoyed the easy glide.

    I had been using it pretty much like a manual transmission, sort of:

    If I wasn't pushing the gas pedal I.e. had enough acceleration and wanted to coast), I would just lift my foot off the gas pedal and shift into Neutral.

    If I needed to slow down, back into Drive, foot not on pedal. Sends to allow things a bit.

    Need to slow down further?
    Push the brake pedal down some or a lot (still in Drive).

    Honestly I thought it was going great, smooth rides, and it seemed reduce gas use (increase mpg)

    But now I m giving up on it I guess.
    There's some sort of deal with 62,mph, or whether or not the engine is running when I go into Neutral or something.

    I can't quite figure it out, mostly because I'm getting conflicting information this thread and some of the other Neutral threads I tried reading, so I can't tell what's fine and what's risky, exactly.

    Wish I could is Neutral. It's nice.
     
  2. Maarten28

    Maarten28 Active Member

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    I have a different experience. B mode definitely makes a difference and as long as you keep the HSI indicator within the charge area, you are not using the mechanical brakes, so you can ride the brakes with no adverse effect.
    Sure, other cars have multiple stages of decelleration without braking (selecting a lower gear) that the Prius does not have so you will have to use the brake pedal more. But that only means you're more in control of the car.
     
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  3. PriusNeckBeard

    PriusNeckBeard Active Member

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    Just to confirm - OTHERS CHIME IN PLEASE -
    Is it true that when you apply brakes in B mode, that mechanical brakes cannot be engaged ??
     
  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    No.
    B adds engine braking to help keep both the rotors and battery cooler, but both will still be used until the battery 'fills up', Then you will have friction and engine braking.
     
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  5. fuzzy1

    fuzzy1 Senior Member

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    No.

    The whole electrical / reg-gen / engine compression braking system (~60 kW) doesn't have anywhere near the power handling capacity needed for hard or panic braking (500+ kW). Such braking will always be mechanical.

    Any mechanical lockout would also violate NHTSA safety requirements for how the brakes must perform in case of electrical or control failure.
     
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Agree with all the other responders, ie: B just adds engine braking, reduces the need to brake, any kind of braking.

    My sense too, is it's not that black and white: that there's always a bit of conventional braking mixed in with the regen braking, it's not either/or. I know when I've washed the car and it's sat a day or two, giving time for the rotors to get surface rust, I can hear the brakes scrubbing a bit, for the first block or two, even when the displays are showing regen as well.
     
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  7. The Electric Me

    The Electric Me Go Speed Go!

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    Prudent?
    No.
    About the only thing I used neutral for in my Prius was going through a drive through car wash.

    Just drive the car with the recommendations Toyota provides. By this I mean the only shifting going down a big hill Toyota recommends is into B not N.
    Quit trying to outsmart the the software and the hardware that makes up Hybrid Synergy Drive.
     
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  8. DonDNH

    DonDNH Senior Member

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    No. You will engage your brakes whenever your demand to slow down exceeds the maximum of regen capability. Makes no difference whether you're in D or B.
     
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  9. charlesinoc

    charlesinoc meep meep :-)

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    This is why I love my 2011 Gen 3 Compared to other vehicles in the same class. On long down hill sections when braking is required to maintain speed at posted limit? I engage the cruise control and it effortlessly maintains the set speed without having to engage the brake. (Unless of course it's an 8% grade or worst, then I engage engine braking).
     
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  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Mostly? I put it in D and go. Need to slow: I step on the brake.
     
  11. solrunner

    solrunner Member

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    I've been using N briefly sometimes when I want to coast, and not have to lightly push down on the accelerator to prevent the "artificial braking" that automatically happens.

    Does anyone else find it annoying that when you take your foot off the gas, the car automatically slightly brakes (visible on the energy monitor)? So you have to slightly push down on the accelerator to prevent it from regenerating and slowing down the car. I would rather the car just coast 100% with no energy consumption / regeneration.
     
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    It's doing a bit of regen, very slight, only increases if you actually touch the brake. I find it a good balance, usually does not get in my way. If I really want to coast a bit further, I'll touch the gas slightly, as you mentioned.
     
  13. drysider

    drysider Active Member

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    This is the way all cars work. Take you foot of the accelerator and the engine compression slows you down. The Prius gives the option of not slowing down if you want to use it.
     
  14. PriusNeckBeard

    PriusNeckBeard Active Member

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    Meaning what..that to maintain constant-ish speed down a hill, it will engine brake ?
     
  15. PriusNeckBeard

    PriusNeckBeard Active Member

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    Yes ! I find that annoying. I preferred it when I was using Neutral -- I would just glliiiiiide along, at a more constant speed, as you said. So nice.

    I've since decided that:
    While I CAN coast in neutral below 60 mph, in a gen 3 (less in a gen 2) -- (if I understand this thread correctly),
    it's not really worth it.
    It's fun, and I like it,
    but I'd rather think about the radio, focus on conversation, etc, than keep an eye on the shifting stuff.

    Footnote:
    Remember, you can only do the neutral thing down a hill in a few states.
    I'm in Ohio, so I'm allowed. FYI.

    Honestly it makes sense.
    IMO most people shouldn't do this...only the attentive obsessives who used to drive stick in a neutral-legal state.

    Having driven stick shift, I treated the Neutral like a manual shift car - constantly shifting into neutral to coast, then out of neutral to give it gas or brake. It was cool.

    But I'm over that now. :0
     
  16. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    US regu!ators insisted the Prius work like other cars. So Toyota added some engine braking. Just imagine the whining we would hear if it did not emulate other cars.
     
    #36 JimboPalmer, Nov 17, 2016
    Last edited: Nov 17, 2016
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  17. PriusNeckBeard

    PriusNeckBeard Active Member

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    LOL! :) :)
     
  18. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    They have been working for a decade to make sure it was as loud as other cars in parking lots, despite no evidence that if needs to be louder.
     
  19. AKCoffee

    AKCoffee Junior Member

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    Interesting... I n-glide my PiP a lot sub 62mph.
     
  20. AKCoffee

    AKCoffee Junior Member

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    Control regen by dumping it back into D and feathering the brake.