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Hypermiling for dummies

Discussion in 'Gen 3 Prius Fuel Economy' started by octavia, Sep 5, 2009.

  1. octavia

    octavia Active Member

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    Ahhhh.... The ancient art of hypermiling. I've heard mention of this wise and mysterious technique but alas, what is it? Where does a young prius pup find such wisdom in the great vast world of priuschat?

    (I've done a search and can't seem to find a thread that explains what it is and how to do it)
     
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  2. royrose

    royrose Senior Member

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    Here is a link to a hypermiling web site, not Prius specific. The link is to their intro page. Read that, then go to their home page for more info.

    Welcome to CleanMPG Primer - CleanMPG Forums

     
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  3. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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  4. octavia

    octavia Active Member

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    :) thanks!! :)
     
  5. ken1784

    ken1784 SuperMID designer

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    "Pulse & Glide" is the key technique for Hypermilers.
    Following is a copy of my post for Gen3 Prius specific.

    -----
    In Japan, we have been discussing how to pulse&glide on the 3G Prius.

    Our conclusion is we don't have to be so sensitive for the zero amp (no energy flow) gliding and a weak battery use is acceptable, therefore 0-25% zone on the HSI screen is acceptable.
    Also, a slow acceleration is not good for the ICE efficiency, therefore 75-100% zone is recommended for pulsing.

    Ken@Japan

    [​IMG]
     
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  6. anne1965

    anne1965 Gotta love the game...

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    I find the battery to be depleting too much when I do this. Therefore, I glide with as close to 0 amp as possible, and pulse less powerful to maintain the battery level. I mainly do P&G on the last 2.5 km coming home from work and do not want to park it with an almost depleted battery to prevent the 3-min recharge penalty.

    What is your experience?
     
  7. rachaelseven

    rachaelseven New Member

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    My experience is similar. If I don't keep my glides near zero, I gradually deplete the battery and end up with really crappy mileage on the next trip, especially if its a short trip, since I have to do so much recharging while the engine is cold. I do the pulse right up to the top of the ECO range, as suggested here, but I try to glide at 0 or just slightly positive or negative, depending on the battery SOC.
     
  8. octavia

    octavia Active Member

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    Thank you, this is helpful.

    Coming from a point of knowing nothing about this, it can be hard to really understand the in-depth threads written and contributed to by those of you who already understand and have been doing this for a while. Y'all are fine tuning things and I am still trying to figure out what the heck is going on!

    I knew nothing of it until a few days ago.

    I've been driving my friends Gen II. I've noticed that I can effect the kind of mileage I get by how I drive. I've (not knowing that "hypermiling" exists yet) been experimenting to try and improve the mpg. I keep edging it higher and higher. My friend noticed the higher numbers and asked me if I was hypermiling. " Hyperwhat?" ...
    I had NO CLUE there was a term for what I was, in a very primitive way, trying to do.
    I was very proud when I got it to 45.1 Then.... My friend drives it and knocks it back down to 44.something. :)
    I'm frustrated that I can't force the battery to kick in when it is full or near full and the darn thing is still sucking gasoline.

    As you can probably tell, I'm still at a very beginner level with this, hence the name of the thread. :)
     
  9. SageBrush

    SageBrush Senior Member

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    Octavia, good to see another person intrigued by hypermiling. I'll take a bit different tack, though, and suggest that the first stage to enlightment is learning to minimize brake use by anticipatory driving. This has very little to do with hybrid per se, but is essential to 60+ mpg fuel economy in the Prius.

    Once you are coasting to red lights, turns, and cars ahead with you and only requiring minimal braking, you are ready for Pulse and Glide (P&G).

    Cheers, and have fun!
     
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  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    When you finally get your Prius, it would help if you could measure not only PnG performance but also the equivalent, steady-speed performance. The key is to make sure the block times, the start and stop times, match over the same distance.

    GOOD LUCK!
    Bob Wilson
     
  11. octavia

    octavia Active Member

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    I've read this several times Bob, and still have no clue what you are talking about. I'm still in the "read about it" and experiment stage. :)
     
  12. royrose

    royrose Senior Member

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    I would agree about anticipatory driving.

    I would add that you don't always have to "Pulse" in order to "glide". If you find yourself going downhill, even a gradual slope, you can often back way off the pedal, giving just enough electric or gas power to maintain speed. You will see the instantaneous mpg meter go to 100 and stay there for quite a while.
     
  13. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Sorry, let me explain. Let's assume you have a regular, daily commute. Try to run two sets of tests:

    • one week - PnG. Fill the tank on Sunday evening and then fill on Friday evening. Using a trip meter distance and fuel receipt, this becomes your PnG baseline. Be sure and record the elapsed times on each leg. The commuting distance divided by the time for your legs are your 'miles per hour' PnG speed. This is the equivalent speed if you drove at a constant speed and your average speed at the end of the week should be the same.
    • next week - Using the 'miles per hour' from the PnG speed test, use the cruise control to run the exact same route. Be sure and fill the tank again on Sunday evening so you'll have the same fuel consumption measurement. At the end of the week, fill the tank and calculate the MPG and read out the average speed.
    The typical problem with PnG is the average speed is less than the posted speed limit. The first week's test (assuming speed limit compliance,) defines the "block to block" time, the speed used to drive PnG on the weekly travel. Then the second week, the same route is used with the equivalent, constant speed. This should be less than the posted speed limit, assuming PnG was posted speed limit compliant.

    Using PnG saves fuel but the problem is very few report the relative fuel savings of taking the exact same trip at the same, equivalent speed. If PnG is kept within the posted speed limits, each trip will have an average speed less than the posted speed limit.

    Our first Prius is an NHW11 (2003) and before trying PnG in traffic, I went to a low-traffic, route over at Redstone Arsenal and tested PnG versus the equivalent, cruise control, constant speed. When these results gave only an 11% performance improvement, I decided it was too much work for too little gain given the routes I have available:
    [​IMG]

    Others may have routes more conducive to PnG and for them, it works. But the only routes I have available that would be safe for PnG would add at least 11% more distance. It really is a question of what routes are available. In my case, 90% of my driving is on cruise control. As you might tell from my signature, my NHW11 results meet my requirements.

    Now my wife has a 2010 (ZVW30) Prius but I don't use it for commuting to work. But I do use it in the evening and on weekend for the various errands she sends me on. Thanks to the improved warm-up and overall improved performance, the ZVW30 is a great choice for ad hoc errands. It seems to have nearly 25% improved PnG performance but in my case, the errands seldom include PnG safe routes.

    Bob Wilson
     
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  14. sparkyAZ

    sparkyAZ übergeek

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    with some practice you will get much better at it. I regularly hit mid-50s in my Gen II and sometimes 60mpg even though my commute is 80% freeway (65-70mph) driving and i'm not always light footed. The prius has unique modes that are unlike any other vehicle. The most interesting is the "glide" mode, where you have no power from either the gas engine or electric motors going to the wheels, and no power being regenerated. This feels like you are free-floating along. You will probably read something about the "hybrid paradox". Basically, you want to operate the ICE (internal combustion engine) in it's most efficient operating mode, and then glide along. To get the best mpg, you want to avoid using the electric motor except for starts and stops. It's all about managing the gas pedal and braking.

    While you can do a lot with the stock instrumentation, there are some limitations. On the Gen II, it would be great if you could have the Consumption bar graph and the energy flow screen in one display. Fortunately, there are aftermarket products such as the Scangauge (www.scangauge.com), that allow you to watch your engine loading, rpm, charge current limit, traction battery current, and other advanced parameters. Also, you can tell how close you are to topping out the regen and going to the mechanical brakes, which saves on brake wear. Plus, it's another cool gadget to add to the Prius :)

    Good luck with your quest to learn more - learning the proper way to drive the Prius is quite habit forming and it can turn into quite a fun hobby!
     
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  15. Dan.

    Dan. MPG Centurion

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    I think Ken's nailed it here. Pull up the HSI display and Pulse with the bar somewhere over "AVG" and glide as close to CHG as possible without actually being in CHG. So using Ken's display, glide on the left part of his "glide" zone and pulse right about in the middle of his "pulse" zone.

    For highway cruise, keep it right under the "O" in ECO. The trick to highway is to keep the HSI as rock steady as possible. If you have to go past the "O" that's ok, but pick a spot on the HSI and stay there for your whole highway drive. This is called DWL and it means you will loose one or two MPH as you go up a hill and gain one or two MPH going down the other side. Kinda like a roller-coaster. If you move your position on HSI on the highway you'll get about a 7 second penalty in MPG, so really try to hold it steady. This is the main reason why Cruise Control on the highway yields less than optimal results. It bounce throttle all over the map to maintain speed. If you can maintain throttle and bounce speed around a bit instead you will get much better numbers. Unfortunately DWL isn't very useful to someone in Colorodo or Virginia since there isn't really much flat-land to maintain constant throttle. For rolling topology you need high-speed pulse and glide which is a bit more advanced.

    11011011
     
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  16. jay_man2

    jay_man2 jay_man_also

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    That graphic did more to help me push my mileage up than all the charts and spreadsheets another poster could ever create. After all, this is the hypermiling for dummies thread, not the hypermiling for engineers who can put together the most confusing graphs and charts on this earth thread. :pound:
     
  17. octavia

    octavia Active Member

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    Bingo!
    My hope is that once I really "get it" and have figured out how to do it myself. I can edit my op with a translation for the rest of "my people"

    :p
     
  18. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Always, feel free to ask. I'm quite willing to break things down into easier to easier concepts. For example,
    What is a calibration curve?
    Understanding drag and vehicle efficiency?
    How to conduct an experiment and quantify the effect?
    Who is Ralph Coleman?
    But I fully understand that these are foreign concepts to folks not used to science and engineering. Still, these are not that hard to understand and I'm patient.

    Bob Wilson
     
  19. bwilson4web

    bwilson4web BMW i3 and Model 3

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    You see the problem is measuring the effect. Of course if there is no need to measure the effect compared to a baseline, then of course it doesn't matter. That is why medicine uses double-blind tests including that wonder drug, "placebo." <grins>

    Bob Wilson