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I've completely changed my strategy...

Discussion in 'Gen 2 Prius Fuel Economy' started by gnagel, Jul 10, 2006.

  1. gnagel

    gnagel New Member

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    I've had my '06 Prius for about three months now. My life-to-date mpg is about 56 mpg. I'm pleased with that performance, but I must admit that it was taking quite an effort to get there. At first, my approach was to maximize the usage of the electric motor. I tried to keep only yellow arrows on the display for as long as possible. Of course, this caused my battery to drain rather quickly. So, I would see fluctuations in mileage---but was still able to average about 56 mpg.

    Over the past 1,000 miles or so, I changed my approach. I tried to go into stealth mode (no arrows) for as long as possible. I figured that this would minimize battery drainage---and it did. Of course, the car loses speed rather quickly at times, so I would accelerate back to a desired speed and then let the car go right back into stealth mode. My mileage increased slightly.

    Over the past 500 miles or so, I have once again revised my approach. I am going with almost the opposite approach from where I started. Rather than try to maximize the use of the electric motor, I am trying to minimize it! I try to use the gas engine as much as possible and to minimize the yellow arrows. For some reason, the best that I can ever do is to have yellow arrows moving from the electric motor to the battery with no yellow arrows moving in the direction of the front tires. I have never been able to eliminate the yellow arrow entirely. Of course, I try to avoid green regeneration arrows all the time.

    Anyway, I am seeing improved mileage while driving at faster speeds! My last tank came in at 62 mpg. Does any of this make sense?
     
    #1 gnagel, Jul 10, 2006
  2. OriginalGT

    OriginalGT New Member

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    <div class='quotetop'>QUOTE(gnagel @ Jul 10 2006, 01:49 PM) [snapback]284051[/snapback]</div>
    I have been able to do what you are saying by accident a couple of times. On acceleration, I would get to about 35 MPH, then release the gas so that I can feather into battery only mode. If I "missed" that battery only mode, I would hit what I call a "sweet spot" where I am running on ICE with battery charging. The MPH at this point would soar all the way to the 60s for as long as I could hold the gas pedal at that spot. It seems weird to me that running on ICE would yield that kind of gas mileage, but now that I read your post I must not be imagining things.
     
    #2 OriginalGT, Jul 10, 2006
  3. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
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    I think you have bounced between all schools of thought in the high-mileage arena.

    First of all, to make sure we are all speaking the same language, "stealth" usually refers to movement generated by battery power. When you are coasting with no arrows, that is refered to as "feathering" or "glide" as in Pulse&Glide.

    And what you described in your second part was, in fact, pulsing and gliding. Many people use that technique to achieve impressive numbers. I don't know about Orland Park, but up here in Northern Chicagoland, there are way too many hills for me to properly P&G. Not to mention that it is few and far between that I can actually maintain sub-40 MPH on level terraine.

    Your mileage is great! Keep it up. My lifetime - after two years - is 48.5 so you've gotten me beat so far. We'll see how you fair come winter. Bwa-ha-ha-ha :D
     
    #3 TonyPSchaefer, Jul 10, 2006
  4. troe

    troe New Member

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    <div class='quotetop'>QUOTE(gnagel @ Jul 10 2006, 03:49 PM) [snapback]284051[/snapback]</div>
    My learning curve is much like yours, I often find the "sweet spot" where I can get as much as 88 MPG sustained from the ice. That is at about 45-50 MPH on flat roads, but when below 41, pulsing and gliding is the best. I am at 63 MPG dispayed on this tank ;)

    [​IMG]
     
    #4 troe, Jul 13, 2006
  5. gnagel

    gnagel New Member

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    <div class='quotetop'>QUOTE(pcflorida @ Jul 13 2006, 09:59 AM) [snapback]285619[/snapback]</div>
    That "sweet spot" is exactly what I finally discovered. It allows me to maintain a nice speed while achieving very high gas mileage.

    I've also discovered that one of the keys to maximizing the impact of pulse and glide is to accelerate (pulse) properly. I used to pulse by accelerating rather quickly. This resulted in low mpg during the acceleration stage and also drained the battery---the yellow arrows would be moving away from the battery at that point. Now, I try to accelerate using the gas engine as much as possible and try to keep the yellow arrows from the battery either neutral (blank) or moving in the direction of the battery. This allows me to recharge the battery while pulsing and also helps achieve readings of 35-40 mpg during the acceleration stage versus 10-15 mpg under my old approach.

    Of course, I try to glide whenever possible.

    My gas mileage continues to improve as I learn these techniques. I am now at 64 mpg on my current tank while driving at much more constant and higher speeds!
     
    #5 gnagel, Jul 13, 2006
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    Sounds like you've found the P&G method on your own! Yes, it does seem odd that minimising battery use and using the engine more actually saves more fuel because the battery will have to recharged somehow and if you don't have a hill to do it, then the engine will be charging it.
     
    #6 Tideland Prius, Jul 13, 2006
  7. mextaco1

    mextaco1 New Member

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    You are not using A/C, so you drive around iLL in misery!! Doing alot to save $20 month!
     
    #7 mextaco1, Jul 13, 2006
  8. gnagel

    gnagel New Member

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    <div class='quotetop'>QUOTE(mextaco1 @ Jul 13 2006, 08:47 PM) [snapback]285983[/snapback]</div>


    I only use the A/C when its hot outside. In Chicago, we've had only five days so far over 90 degrees. Although, next week is expected to be a warm one!

    I guess the poem is supposed to be humorous. But, it doesn't make a whole lot of sense:

    I do use the A/C---when it's hot outside.
    I'm not driving around in misery---I love driving my new Prius.
    I'm not "doing alot"---just learning how to maximize the mpg of my new car.
    I'm saving more than $20 per month---I'm not sure how you are computing the savings, but at $3.25 a gallon, it doesn't take long to save $20!
     
    #8 gnagel, Jul 14, 2006
  9. micheal

    micheal I feel pretty, oh so pretty.

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    <div class='quotetop'>QUOTE(mextaco1 @ Jul 13 2006, 10:47 PM) [snapback]285983[/snapback]</div>


    Why do you really care if the person is or isn't driving around in misery? I don't use the A/C driving around in West Texas, even on 100+ days. The reasons for this is many, including a slightly better mpg, enjoying the feel of fresh air, a desire to not be so spoiled to always require A/C, and because it rarely is misery. It doesn't really matter though what the reasons are, it is my choice.

    As far as your thinking gnagel, it does seem to be counterintuitive to try and minimize battery usage, but it does seem to have better mpg. My thoughts on why is because in and of itself, the small ICE is very efficient when maintianing a 35-50mph speed and as others have said, if you deplete the battery, it has to be recharged somehow. I only try to use the battery when I know I will be making up the charge by a long hill or coasting stop, and try to keep the battery at least at 4 bars. Anything less than 4 seems like the ICE works harder to recharge the battery. I probably saw a jump of about 5 mpg doing this rather than trying just the battery.
     
    #9 micheal, Jul 14, 2006
  10. gnagel

    gnagel New Member

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    Well said.

    I usually prefer to leave the A/C off whenever possible--both at home and in the car--for the reasons which you stated.

    I find that I use the A/C the most when I have passengers in the Prius. Most people have been spoiled by rarely experiencing fresh air. Living in Chicago, I look forward to the summers and try to avoid sealing myself away from the outdoors.

    But, as you said, the reasons really shouldn't matter. It's still a free country, isn't it? And, anything to reduce our dependency on foreign oil should be encouraged.
     
    #10 gnagel, Jul 14, 2006
  11. jkash

    jkash Member

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    I certainly used the AC today on the way home. It was 108 degrees in the San Fernando Valley this afternoon. One of the reasons I got the Prius was to get a car that the AC actually worked. My old car was a Honda Civic VX. The AC didn't work when it got over 90 degrees. It also lugged the engine really badly. I am much happier in the summer since I got my Prius. Of course, I am much happier just driving my Prius than any car I have ever had.
     
    #11 jkash, Jul 14, 2006
  12. ServoScanMan

    ServoScanMan Member

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    I drive 10 miles one way to and from work. Its 50% surface streets and 50% highway. On a section of highway there is a gradual downhill slope and a long uphill slope. On the downhill slope I accellerate gently up to 62mph and as I transistion going into the up hill portion I lift the throttle and feather back into it. The MFD shows 99.9mpg for about a half mile. After that the mpg starts to drop and I start slowly backing off the throttle. As I decel to 40mph I try to keep the mpg above 70mpg. I have noticed that you can run the ICE with green arrow to battery and the MFD will show high mpg. I thought it was a fluke at first but after reading this thread I guess it's not.

    BTW, I now have 3 round trips to and from work on this tank and the MFD is showing 61mpg. I haven't been using the AC this tank to learn what the impact would be. For me the AC cost me about 5mpg.
     
    #12 ServoScanMan, Jul 15, 2006
  13. micheal

    micheal I feel pretty, oh so pretty.

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    <div class='quotetop'>QUOTE(gnagel @ Jul 14 2006, 10:34 PM) [snapback]286522[/snapback]</div>
    It is interesting to see how so many of us go from our houses with a/c to our cars with a/c, to our offices with a/c and then repeat. Course, I probably would still be one of those if our primary car hadn't had it's a/c do the nice swan dive of death and helped me realize that running the a/c isn't as necessary as I had conditioned myself to believe.

    There really is something about the fresh air that I find invigorating. Naturally there are always conditions that mitigate this, here it is the high frequency of blowing dust (makes it hard to keep the MFD clean). In other places I have lived, the humidity in the summer would make it a sweaty time!
     
    #13 micheal, Jul 16, 2006
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