How to use "B" gear?

Discussion in 'Gen 3 Prius Main Forum' started by ibmoses, Jun 4, 2014.

  1. ibmoses

    ibmoses Junior Member

    Joined:
    Jun 1, 2014
    109
    22
    0
    Vehicle:
    2013 Prius
    Model:
    Two
    Greetings!
    2013 Prius "two" newbie here from North Alabama :)

    Car salesman explained the "B" gear as a "Jake Brake" like a Tractor Trailer type truck has....
    Owners manual is pretty vague on how and when to use it.

    I have already mistakenly somehow been driving around for a couple of moments in D with the B still
    braking(I think).

    Thanks for any tips or advice. I am still learning obviously.Love it so far.

    Figured out how to use the savings calculator function.
    Saving $4.00 per day(approx.) compared to the vehicle the Prius replaced.
     
  2. CaliforniaBear

    CaliforniaBear Clearwater Blue Metallic

    Joined:
    Oct 9, 2012
    1,174
    285
    0
    Location:
    Northern California
    Vehicle:
    2012 Prius
    Model:
    Plug-in Base
    Going down a long hill with the battery already fully charged there may be some advantage using B to reduce the need for friction brakes. However, the computer automatically does much the same thing in that situation. I guess B gives you the control.
     
  3. Nora

    Nora Member

    Joined:
    Jul 7, 2013
    128
    44
    0
    Location:
    CO
    Vehicle:
    2013 Prius
    Model:
    Two
    Other than trying to figure the gear out, the only time I've used B is when going downhill on slick snow at low speeds. On a steep hill, B kept the car at a nice, slow speed without having to rely on the brakes. I have found the brakes and traction control to be just great in the snow, but using B kept it even more under control. The only worrisome part is that I have to look briefly to figure out where B is, since I hardly ever use it. A brief glance only feels a bit scary in icy conditions, I don't think looking away is actually all that risky.
     
  4. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,050
    6,317
    1
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    As mentioned, the car will use engine Braking when the big battery is "full". The advantage of B mode is to use engine Braking from the top of a hill you know will fill the battery. Some people try to use it below 22 MPH, where it does not use the engine, but the pedal is just as effecive and warns cars behind you that you are slowing.
     
  5. hill

    hill High Fiber Member

    Joined:
    Jun 23, 2005
    16,076
    5,962
    54
    Location:
    South OC So Cal & Nashville, TN
    Vehicle:
    2004 Prius
    Model:
    IV
    I've looked into the disassembled synergy drive ... and darn if I simply never was able to find that "gear". But I'm having the same issue with our EV too.
    (smidge)
    .
     
  6. ibmoses

    ibmoses Junior Member

    Joined:
    Jun 1, 2014
    109
    22
    0
    Vehicle:
    2013 Prius
    Model:
    Two
    Am I imagining things or does the vehicle allow you to accidentally leave "B" engaged while driving in "D" (that cant be a good thing):)
    Thanks

    Bert
     
  7. Troy Heagy

    Troy Heagy Member

    Joined:
    Apr 21, 2013
    1,218
    4
    0
    Vehicle:
    2013 Prius
    Model:
    One
    Why are salesmen so stupid? This guy shouldn't even have a job at a Toyota dealership.
     
    pauerbach and Merkey like this.
  8. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    13,282
    6,822
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    It will let you leave it in 'B' fulltime. The only thing that gets hurt is your overall MPG. The car will be just fine.
     
  9. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,050
    6,317
    1
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    Quick check, in B you can't use cruise control.

    I try to call it B Mode, as there are no actual gearing changes, just software spinning the engine with no fuel.
     
  10. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    519
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    Forgive me, but what exactly is stupid about the salesman's comment?

    My understanding is B mode primarily changes the valve timing to create engine braking, which in a layman's terms would seem to be more or less what a jake brake does?
     
  11. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    519
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
  12. Troy Heagy

    Troy Heagy Member

    Joined:
    Apr 21, 2013
    1,218
    4
    0
    Vehicle:
    2013 Prius
    Model:
    One
    Diesel engines don't have a throttle valve, so they don't have natural engine braking. Instead an additional device must be added called a "Jacobs Brake" (the trademarked name). Prius does not have an extra device like that.
     
  13. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,050
    6,317
    1
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    I do not think we have disagreed with the salesman. I think we have been elborating on "the manual is vague on when to use B"
     
  14. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    519
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    The Prius also does not have natural engine braking, and so B-mode implements a change in valve timing (as a jake brake does) to create engine braking. It is implemented in electronics instead of hydraulics but it would seem that the overall effect is similar. Maybe he should have called it an "e-Jake Brake" instead ;)

    Rob
     
  15. ibmoses

    ibmoses Junior Member

    Joined:
    Jun 1, 2014
    109
    22
    0
    Vehicle:
    2013 Prius
    Model:
    Two
    So basically the "B" mode can be used at any time, except in reverse.

    There is a pretty steep mountain I go off each day...I can use it going down that mountain to control the vehicle speed withougt damaging anything?
    Its about a two mile stretch where the B mode would be engaged....should I also select N or leave it in D?
     
  16. Troy Heagy

    Troy Heagy Member

    Joined:
    Apr 21, 2013
    1,218
    4
    0
    Vehicle:
    2013 Prius
    Model:
    One
    In all the cars I've owned, I never used B or L (or shift down in gear). In my hybrids even when coming off the Rockies, I just use the regen braking to fill the battery. Or friction brakes. I see no need to use B..... ever.
    Really? Well I just learned something new. I thought the 1.5 and 1.8 engine would have braking just like any other gasoline car. After all it has a throttle valve which closes-off the cylinder & creates the vacuum brake effect.

    Comparison/contrast:
    - In my Honda hybrid's lean burn engine, 3 of the pistons "decouple" from the camshaft and stop moving. That's its method of decreasing engine braking to 25% of normal.
    - Also instead of "B" for going down mountains it uses "L".
     
    #16 Troy Heagy, Jun 4, 2014
    Last edited: Jun 4, 2014
  17. energyandair

    energyandair Active Member

    Joined:
    Jun 9, 2009
    905
    335
    0
    Location:
    Victoria BC Canada
    Vehicle:
    2010 Prius
    Going down mountains is what its designed for. You may also have to use the brake. The main benefits are that your brake pads will last a whole lot longer and brake fade is much less likely.

    B is a separate choice from N D and R. You can't be in be in more than one of them at the same time.

    In general, when going forward you should be in D except for long downhill sections where B is better. I would avoid N for normal driving.
     
  18. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

    Joined:
    Oct 17, 2010
    38,243
    26,986
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    When we took a test drive the salesman suggested to put it in B, fwiw.

    My take: if you never put it in B, the car will do just fine, for almost anything you can throw at it.
     
    CaliforniaBear likes this.
  19. JimboPalmer

    JimboPalmer Tsar of all the Rushers

    Joined:
    Apr 14, 2009
    12,050
    6,317
    1
    Location:
    Greenwood MS USA
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    I wish they had called it L, many people know when to use L. (almost never) Toyota was too honest, as it does not use lower gearing. B for Braking was a poor choice as MANY people confuse it with B for Battery, thinking erroneously that it is helping charge the battery more. It isn't.
     
  20. energyandair

    energyandair Active Member

    Joined:
    Jun 9, 2009
    905
    335
    0
    Location:
    Victoria BC Canada
    Vehicle:
    2010 Prius
    I think that you are right around Vancouver and most other places. The only large descents I can think of around Vancouver are coming down from the North Shore ski slopes and IIRC, those have enough tight bends that you need to use friction braking anyway.

    I think that B really offers a significant benefit when you have relatively high speed descents measured in thousands of vertical feet.
     
Loading...