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

Underclocking the Prius and other Hybrids

Discussion in 'Gen 2 Prius Main Forum' started by Mardikes, Apr 28, 2006.

  1. Mardikes

    Mardikes New Member

    Joined:
    Mar 24, 2006
    50
    0
    0
    After owning a 2001 Prius and a 2002 Prius, we sold both and bought a 2006 Highlander Hybrid and have on order a 2006 Prius.

    I find that in driving the HiHy, that one really has to watch the acceleration. The car has incredible power, but more than we want or need. The single most important factor for me for MPG is how heavy my foot is.

    These vehicles are bascially computer driven. When I put my foot on the gas, it is not mechanically increasing the gas, but instead inputting information to the computer to increase speed.

    The computer already limits the maximum speed one can drive.

    It also limits the maximum torque of the combined power to avoid destruction of the transmission, which basically is a limitation on maximum acceleration.

    It seems to me that it would be easy to basically reprogram the computers to reduce that maximum acceleration.

    One would need to limit the maximum acceleration from both the engine and the motor, otherwise the computer would put excessive strain on the battery and motor system instead of the engine.

    It seems to me that this would possibly increase MPG. I am sure it would for the HiHy, probably less so for the Prius.

    In essence, similar to computer that can be modified to make them faster -- overclocking-- we would be modifying the hybrid to make them slower, at least as to acceleration -- underclocking.

    Now Toyota might not like to do this. For example, if someone does not know the vehicle is underclocked, then the person driving may not be impressed with the potential power of the vehicle. To solve this one might have a warning on the dashboard stating that the vehicle has been underclocked by the owner.

    If this is possible, it might make sense for the Sierra Club, National Resources Defense Council and other green groups to lobby Toyota to allow these modifications.

    Thoughts?

    George

    P.S. I would prefer to focus this posting on the technological issue of whether the reprograming could be done, not alternative work arounds, like being more careful at driving (I cannot control all of the drivers in our family) or using cruise control (not realistic in the city).
     
    #1 Mardikes, Apr 28, 2006
  2. Frank Hudon

    Frank Hudon Senior Member

    Joined:
    Jan 11, 2004
    4,147
    18
    0
    cheaper and easier and no potential problems is to reprogram your foot.
     
    #2 Frank Hudon, Apr 28, 2006
  3. mikepaul

    mikepaul Senior Member

    Joined:
    Dec 2, 2003
    1,763
    6
    0
    Location:
    Columbia, SC
    Vehicle:
    2004 Prius
    I use the cruise control as often as possible, highway or not. I rarely see where my foot does better. Maybe there are horror stories of old-school cruise sticking and causing accidents, but with throttle-by-wire that hardly seems an issue.

    I say stick with as much computer control as you can, and hope for improvement...
     
    #3 mikepaul, Apr 28, 2006
  4. highroute

    highroute New Member

    Joined:
    Apr 9, 2006
    94
    0
    0
    Location:
    Oakland CA USA
    <div class='quotetop'>QUOTE(Mardikes @ Apr 28 2006, 09:26 AM) [snapback]246672[/snapback]</div>
    If it were that simple and had only the effects that you've listed, why wouldn't Toyota already have done this during its years of research into hybrid propulsion?

    Or, to put it another way, maybe Toyota has already done this, and the hybrid drive's current settings already reflect that balancing act.
     
    #4 highroute, Apr 28, 2006
  5. Mardikes

    Mardikes New Member

    Joined:
    Mar 24, 2006
    50
    0
    0
    <div class='quotetop'>QUOTE(Frank Hudon @ Apr 28 2006, 09:30 AM) [snapback]246674[/snapback]</div>
    Believe me, that is really hard for the HiHy. It just does not take much pressure to start it racing and I have pretty good control of my right foot from drumming. Besides, I cannot control other members of the family when they drive the vehicle.


    <div class='quotetop'>QUOTE(highroute @ Apr 28 2006, 09:44 AM) [snapback]246683[/snapback]</div>
    Yes, they have already done this to a certain extent. At least in having maximum power without destroying the transmission. My thought is to back off a bit more.

    I can see no technological reason they could not reprogram the Prius to do 0 to 60 in 14 seconds. What effect on MPG would it have if they did so?

    George
     
    #5 Mardikes, Apr 28, 2006
  6. ScottY

    ScottY New Member

    Joined:
    May 18, 2005
    1,250
    7
    0
    Location:
    Long Island, NY
    Vehicle:
    2005 Prius
    <div class='quotetop'>QUOTE(Mardikes @ Apr 28 2006, 12:52 PM) [snapback]246685[/snapback]</div>
    You can go from 0 to 60 in 14 sec, just don't step on gas that much. :p
     
    #6 ScottY, Apr 28, 2006
  7. hobbit

    hobbit Senior Member

    Joined:
    Mar 23, 2005
    4,089
    468
    0
    Location:
    Bahstahn
    Vehicle:
    2004 Prius
    Model:
    N/A
    Given that some people do 40 mpg and some push 70 mpg in identical
    cars, there's a lot to be said for driving style. Up at that level
    some very subtle things can have a pretty radical effect on fuel
    usage. [A bird poops on the hood, and there goes your average!]
    .
    _H*
     
    #7 hobbit, Apr 28, 2006
  8. PriusDad

    PriusDad New Member

    Joined:
    Apr 16, 2006
    48
    0
    0
    <div class='quotetop'>QUOTE(Mardikes @ Apr 28 2006, 09:26 AM) [snapback]246672[/snapback]</div>
    I swear I saw this somewhere, but can't remember where... I thought the Toyota hybrids (because of the electronic accelerator) had a sensitivity adjust. You may want to ask the service department at your Toyota dealer if such an adjustment exists, and if they can make it for you or tell you how to do it.

    Peter.
     
    #8 PriusDad, Apr 28, 2006
  9. tomdeimos

    tomdeimos New Member

    Joined:
    Feb 16, 2004
    995
    2
    0
    Location:
    Lexington, MA
    Just fix the accelerator so you can only push it down half way.
     
    #9 tomdeimos, Apr 28, 2006
  10. V8Cobrakid

    V8Cobrakid Green Handyman

    Joined:
    Jun 6, 2004
    3,790
    152
    0
    Location:
    Park View, Los Angeles, CA. U.S.A
    Vehicle:
    2004 Prius
    Model:
    N/A
    the RX400h and the HyHi are running the same specs right? If so... just get up to speed a little quick. not too quickly. then cruise. i know the 400h will cruise a lot longer than a normal car.. so get up to speed an cost behind other cars. It's not too hard to get over 30mpg in these vehicles... if you don't want o have fun punching it. :)
     
    #10 V8Cobrakid, Apr 28, 2006
  11. nerfer

    nerfer A young senior member

    Joined:
    Mar 1, 2006
    2,507
    236
    28
    Location:
    Chicagoland, IL, USA, Earth
    Vehicle:
    Other Hybrid
    Model:
    N/A
    <div class='quotetop'>QUOTE(highroute @ Apr 28 2006, 11:44 AM) [snapback]246683[/snapback]</div>
    People regularly reprogram this chip in other cars, usually for more HP and acceleration than what the manufacturer intended. I'm sure it can be done in hybrid Highlander as well, but might require somebody cracking the code. The HiHy is intended for a different audience than the Prius, one where performance has a higher relative weight and economy is lower. It would be a hard sell to get Toyota to make their big strong SUV drive like a dog (in some people's eyes). They probably took the optimum values and added a good bit for the American market. Chances are if you took the appropriate computer chip for the same vehicle sold in say, Singapore, it would behave differently.

    I'm just wondering why they haven't come out with an economical minivan yet. Seems to me this would be the next logical market - people who want economy, but need something to take 3 kids and sports gear.

    nerfer
     
    #11 nerfer, Apr 29, 2006
  12. Frank Hudon

    Frank Hudon Senior Member

    Joined:
    Jan 11, 2004
    4,147
    18
    0
    <div class='quotetop'>QUOTE(nerfer @ Apr 28 2006, 10:36 PM) [snapback]247081[/snapback]</div>
    I doubt that the NA market is really ready for that. Maybe in a year or two when high gas prices are still with us, maybe then, but to do it now when all the marketing is revolving around HP and acceleration, the "economy" market just doesn't exist. At least in the numbers to make it economically viable for the manufacture.
     
    #12 Frank Hudon, Apr 29, 2006
  13. hobbit

    hobbit Senior Member

    Joined:
    Mar 23, 2005
    4,089
    468
    0
    Location:
    Bahstahn
    Vehicle:
    2004 Prius
    Model:
    N/A
    A Prius would take three kids, sports gear, *and* a dog. See the
    "screw the truck" thread.
    .
    _H*
     
    #13 hobbit, Apr 30, 2006
(You must log in or sign up to post here.)