1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Concerned

Discussion in 'Gen 3 Prius Main Forum' started by Johnnyc, Apr 28, 2011.

  1. Johnnyc

    Johnnyc New Member

    Joined:
    Apr 28, 2011
    8
    0
    0
    Location:
    Billerica
    Vehicle:
    2010 Prius
    Model:
    II
    I had my 2010 Prius for a little over a month and experience a couple of times the issue of acceleration. I was going only about 15 mph and it felt like I got a push from someone behine me. What can I do about this?
     
    #1 Johnnyc, Apr 28, 2011
  2. 32kcolors

    32kcolors Senior Member

    Joined:
    Jul 14, 2009
    5,683
    953
    124
    Location:
    Redondo Beach, CA
    Vehicle:
    2010 Prius
    Model:
    V
    You need to educate yourself on how regenerative to friction braking works by visiting various topics in this forum.
     
    #2 32kcolors, Apr 28, 2011
  3. Johnnyc

    Johnnyc New Member

    Joined:
    Apr 28, 2011
    8
    0
    0
    Location:
    Billerica
    Vehicle:
    2010 Prius
    Model:
    II

    Is this a real problem that could cause accidents?
     
    #3 Johnnyc, Apr 28, 2011
  4. Paradox

    Paradox Prius Enthusiast / Moderator
    Staff Member

    Joined:
    Sep 22, 2005
    29,110
    8,589
    201
    Location:
    USA
    Vehicle:
    2014 Prius v wagon
    Model:
    Five
    IMO, no. And the car is not accelerating.
     
    #4 Paradox, Apr 28, 2011
  5. Johnnyc

    Johnnyc New Member

    Joined:
    Apr 28, 2011
    8
    0
    0
    Location:
    Billerica
    Vehicle:
    2010 Prius
    Model:
    II

    thank you a thousand times. I love my car and didn't want any problems driving it.
     
    #5 Johnnyc, Apr 28, 2011
  6. Flaninacupboard

    Flaninacupboard Senior Member

    Joined:
    Apr 25, 2010
    1,297
    213
    0
    Location:
    Midlands - UK
    Vehicle:
    2010 Prius
    Model:
    N/A
    just over 30k miles on mine so far and i haven't crashed it once.

    If you are braking moderately at fairly low speeds (15-25mph) and go over a bump/drain/loose gravel/ice/pothole (you should be able to see all these things on the road) then you will get a momentary reduction in braking force while the car switches from regenerative braking to friction braking.

    If you stomp the pedal (or were already stomping on it) then friction braking is immediately engaged and stopping distance is not affected in any way. the only way i can see this causing an accident is if someone feels it thinks "i am pressing the wrong pedal!" and either comes off the brake completely, or worse, then stands on the accelerator.
     
    #6 Flaninacupboard, Apr 28, 2011
    1 person likes this.
  7. Felt

    Felt Senior Member

    Joined:
    Jul 4, 2009
    1,624
    603
    0
    Location:
    Mountain West
    Vehicle:
    Other Hybrid
    You can sometimes replicate the sensation when cruising to a stop with a light brake pedal, and the front wheel hits a pot hole. The regenerative brake reacts to the change in resistence, and momentarily gives the sensation the car might accelerate. Press the brake pedal a bit harder, and the sensation ceases. And, of course you are now beyond the pot hole.

    36k miles, and no issues to date. It is just a sensation that is different ... but I think normal with any vehicle with regenerative brakes.
     
    #7 Felt, Apr 28, 2011
  8. pakitt

    pakitt Senior Member

    Joined:
    Aug 10, 2009
    2,173
    1,311
    0
    Location:
    Colorado
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Same here.
     
    #8 pakitt, Apr 28, 2011
  9. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

    Joined:
    Oct 28, 2010
    7,744
    6,542
    0
    Location:
    Redneck Riviera (Gulf South)
    Vehicle:
    Other Non-Hybrid
    Model:
    N/A
    Concur.

    Don't be concerned.
    The "other UA" issue that you've been hearing about is the "I mashed the accelerator instead of the brake" form of unintended acceleration, which isn't what you're experiencing, and is nothing to worry about.

    Greetings and Welcome Aboard....(In case somebody forgot to do so..) :welcome:

    Relax and enjoy your car! :cool:
     
    #9 ETC(SS), Apr 28, 2011
  10. Sporin

    Sporin Prius Noob

    Joined:
    Dec 10, 2010
    576
    293
    0
    Location:
    Vermont, USA
    Vehicle:
    2010 Prius
    Model:
    II
    I agree that this can be a little startling the first time it happens to you but as noted, you aren't accelerating, and just keep pushing the pedal to stop the car.

    Once you've had it happen once and know what it feels like it won't be so jarring when it happens again.
     
    #10 Sporin, Apr 28, 2011
  11. 32kcolors

    32kcolors Senior Member

    Joined:
    Jul 14, 2009
    5,683
    953
    124
    Location:
    Redondo Beach, CA
    Vehicle:
    2010 Prius
    Model:
    V
    OP is talking about the perceived acceleration (which doesn't actually happen) that occurs during regenerative to friction braking transition, not UA. Takes some time to get used to if you live in an area full of potholes or road imperfections.
     
    #11 32kcolors, Apr 28, 2011
(You must log in or sign up to post here.)