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

Hybrids for Dummies

Discussion in 'Gen 2 Prius Fuel Economy' started by klcroxton, Aug 5, 2006.

  1. klcroxton

    klcroxton New Member

    Joined:
    Aug 5, 2006
    2
    0
    0
    First, I apologize, for I'm sure the answer to this question is already somewhere, but I just can't find it - at least not in terms that I can understand. I keep reading that the most fuel efficient mode on the energy screen is to have no arrows flowing to or from the battery, and just have arrows flowing from the ICE to the wheels (that's dead-banding, right?). It seems to me that means that the ICE is providing all the power, which is what happens in a traditional car. So why would I want to achieve this? Aren't I better off to have the battery providing the power?

    By the way, thanks to the postings here, I was able to achieve the "no-arrow" state yesterday... I'm so proud!
     
    #1 klcroxton, Aug 5, 2006
  2. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,192
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    <div class='quotetop'>QUOTE(keely @ Aug 5 2006, 09:30 AM) [snapback]298186[/snapback]</div>
    1)All the power for a hybrid comes from the ICE...some of that power might, temporarily, be stored in the battery, but ultimately it comes from the ICE (yes, even that energy that comes from regeneration, you had to use the ICE to get up the hill.

    2)Dead-banding is considered most efficient b/c there are no energy loses due to the conversion of energy through the inverter, to the battery and back through the inverter.

    3)Yes, this is how regular cars work, but regular cars run on a less fuel efficient Otto cycle enginer instead of the Atkinson cycle engine used in many hybrids. The Atkinson cycle is not very powerful and can't provide necessary torque or HP for acceleration or passing, but for maintaining speed or very gradual acceleration it can do just fine. The energy stored in the battery is NOT to make you more fuel efficient (not directly anyway), it is to allow you the torque and HP you lose with the Atkinson cycle ICE.
     
    #2 efusco, Aug 5, 2006
  3. hobbit

    hobbit Senior Member

    Joined:
    Mar 23, 2005
    4,089
    468
    0
    Location:
    Bahstahn
    Vehicle:
    2004 Prius
    Model:
    N/A
    "Very gradual" acceleration?! Feh.
    .
    _H*
     
    #3 hobbit, Aug 5, 2006
  4. klcroxton

    klcroxton New Member

    Joined:
    Aug 5, 2006
    2
    0
    0
    Hey, that makes sense! Thanks! One other question, while we are on the topic. In the dead-band state, are there really no arrows to or from the battery? The closest I can get is to have orange arrows from the ICE to the wheels and electric motor, and then a green arrow from the electric motor to the battery. Is this what I'm looking for, or am I trying to get rid of the green arrow to the battery?

    Thanks again for your clear explanation!
     
    #4 klcroxton, Aug 5, 2006
  5. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,192
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    Yea, that green arrow will go away too when you get it 'right'....

    Now, the 'truth'...there's very little use in trying to achieve this other than getting better at knowing the car. I no longer try to dead band. I accelerate moderately and let the hybrid system do it's job. I think there is very very little difference in FE with moderate acceleration allowing the battery to boost the rate of acceleration. It makes for more 'natural' driving, keeps other cars on the road happy, and won't noticably hurt your FE.
     
    #5 efusco, Aug 5, 2006
  6. tripp

    tripp Which it's a 'ybrid, ain't it?

    Joined:
    Oct 23, 2005
    4,717
    79
    0
    Location:
    Denver, CO
    Vehicle:
    2005 Prius
    word. I prefer to accelerate somewhat briskly to get up to the speed limit and then I back off and try to maintain that speed using as little gas a possible. There's a real tempation, I think, when you first get the car to baby it and accelerate really moderately. I find that this hurts FE because you spend a larger amount of time acclerating and less time "cruising". Accelerating is the energy intensive part so you should minimize your time doing it. That's my MO du jour anyways.
     
    #6 tripp, Aug 5, 2006
(You must log in or sign up to post here.)