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Using the Hybrid System Indicator to Improve Fuel Economy

Discussion in 'Gen 3 Prius Fuel Economy' started by Tideland Prius, Apr 24, 2011.

  1. Tideland Prius

    Tideland Prius Moderator of the North
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    Now that the days are getting warmer, I've been playing closer attention to the HSI in an attempt to further improve my mpg on the Gen 3. There are a few places on my commute where P&G wouldn't work (mostly because they're a slight uphill such that my glide wouldn't be of any use because I would lose too much speed for my pulse).

    Then I remembered what the manual said,

    So it basically says you should drive in EV/stealth mode, however I did find that even if the engine is running, staying within the Hybrid Eco Area allowed me to maintain speed up that incline (60kph/38mph) while keeping instant fuel consumption in the 4.0-4.5L/100km area. I found it easier than P&G up that incline. In other words, use the least amount of pedal travel to maintain your speed and I think the Hybrid Eco Area can really help those that aren't familiar or are new to HSD.

    Highway Driving:

    I don't know if I engaged SHM yesterday but I'm going to assume I did given that I had 15 mins (Three 5-Min Consumption bars) of 3.0L/100km (78.4mpg) averages instead of my usual 4.0-4.5L/100km (52-59mpg) if I had used cruise control.

    You could use the Energy Monitor and look for the engine powering the wheels directly without going through the electric motor and the instant fuel economy meter sitting at 2.5L/100km (94mpg). You could also use the Hybrid System Indicator and stay within the Hybrid Eco Area. Using the highway's undulations, I was able to maintain speeds between 81 and 87km/h (speed limit is 80kph/50mph) and on one or two of the inclines where I would drop below 80km/h, I'd just do a quick pulse back up to 90km/h. I was pretty impressed with the results as traffic usually doesn't allow me to experiment with it (no one likes to do 80km/h on that highway) so it was refreshing to know that it's possible.


    In short, I think those without a scangauge can benefit by paying closer attention to the Hybrid System Indicator and staying with the Eco Area or Hybrid Eco area, as the situation warrants, to help improve their mpg.

    Pulse: Within the Eco area

    Glide: Little or no bar showing. It's probably better if the bar was a bit to the right (hybrid eco area) vs. the left towards the CHG area.

    Cruising: Stay within the Hybrid Eco area to maintain speed

    SHM: Stay within the Hybrid Eco area. If you set the cruise control, go back to the HSI screen and see where the bar is. Chances are, it's past the middle line and has exceeded the Hybrid Eco area
     
    #1 Tideland Prius, Apr 24, 2011
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  2. Ferls80

    Ferls80 Performing some hypermiling techniques.

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    Thanks for your post Tideland, I noticed exactly the same thing, while maintaining speed around 72-80 km/h: keeping the HSI filled up the middle, instant fuel economy was around 2,5 l/100km. That's amazing, and Prius can challenge ultra efficient diesel powered European cars around here in this range of speed.
     
    #2 Ferls80, May 1, 2011
  3. 32kcolors

    32kcolors Senior Member

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    That's not what it says. It's saying to drive so that the ECO lights up and as you know, the engine could be running if you're at the far right of the ECO range (and this includes while pulsing). In other words, it's saying to drive ECOnomically.
     
    #3 32kcolors, May 1, 2011
  4. Flaninacupboard

    Flaninacupboard Senior Member

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    The DVD says to pulse at the end of the ECO zone, and then back off the pedal completey (killing the ICE) and gently re-engage the throttle, putting you in stealth, or warp stealth, or SHM. I have found SHM (or at least some operating mode which allows 100mpg at 60mph) remains on until you have maybe 1/2 an inch past the midline of the ECO zone. At that point i pulse a bit (top of ECO zone) and then go back to SHM, i guess you could call it P&SHM.
     
    #4 Flaninacupboard, May 1, 2011
  5. pakitt

    pakitt Senior Member

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    This is what I call "happy mode".
    You can see more about it here (section "Drivetrain – the Hybrid Synergy Drive (HSD)", point 7).
    A pic of the MFD showing "happy mode" here.
     
    #5 pakitt, May 1, 2011
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    The Hybrid ECO area is the area where the engine is most likely off. The ECO are you speak of is the entire HSI bar (not including PWR of course).


    Anywhoo... these are my results on the highway today... 80km/h speed limit (50mph)

    [​IMG]
     
    #6 Tideland Prius, May 22, 2011
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  7. pakitt

    pakitt Senior Member

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    Wow - 3.2! is that including warm up? and did you drive 80km/h on the MFD or true 80km/h? (ie. 85-88km/h on MFD)? was it 100% highway or did you have a little bit of city before getting there? (trying to understand the 5min column at the beginning, showing less than 5L/100km.
    PS: flat or hilly terrain?
     
    #7 pakitt, May 24, 2011
  8. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    i dont hyper mile much, but what i do varies on speed, if driving a 40 mph road, i will accelerate to just past the center line which runs gas and charges. then for the glide option i will try to stay in the 25 % or halfway between charge and the center line.

    this allows the glide to last much longer and account for the constant but slight elevation changes that most of my driving contains
     
    #8 DaveinOlyWA, May 24, 2011
  9. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    i dont hyper mile much, but what i do varies on speed, if driving a 40 mph road, i will accelerate to just past the center line which runs gas and charges. then for the glide option i will try to stay in the 25 % or halfway between charge and the center line.

    this allows the glide to last much longer and account for the constant but slight elevation changes that most of my driving contains
     
    #9 DaveinOlyWA, May 24, 2011
  10. ken1784

    ken1784 SuperMID designer

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    The "happy mode" description is misleading.
    If the MG1 continues to charge the battery, the battery will soon be overcharged.

    Ken@Japan
     
    #10 ken1784, May 24, 2011
  11. Tideland Prius

    Tideland Prius Moderator of the North
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    The car was driven earlier in the day to the airport (~50km round trip) and then parked for a few hours before this trip. The airport trip was on the previous tank.

    80km/h on the speedo.

    there's probably 2-3km on either side of the highway trip to get to the destination and to home. It's a round trip (but the Consumption screen is the return trip hence the better mileage for the first 5 min consumption. I was at my destination for about an hour)


    How much battery would that use? I'm trying to balance between battery usage and maintaining speed.
     
    #11 Tideland Prius, May 26, 2011
  12. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

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    i try to use as little battery as possible so i only see less than 6 segments when i am driving for extended periods at say under 30-35 mph.

    now, not sure that this is best method, but what i will do is pulse up to get over half way point on HSI to engage motor, then drop back down to the 25% area (halfway between center and regen) this will extend charging to battery while engine is running and still get me into the 60-99 mpg range

    doing this frequently gives me characteristics of glide where speed will bleed off slowly. problem is, i live in area where there is literally no flat areas or large changes in elevation. its one gentle slope after another so typical glide is not really possible.

    i am doing same driving pattern with the Leaf and have had good results.

    on typical 40 mph road, i will maintain whatever speed i need to regen as little as possible. this requires speed variance from 33 to 47 mph on my daily commute but has increased my efficiency from low 5's to high 5's and once a 6.0 MPK (miles per Kwh). but i run at 0 kwh going down and try to maintain (traffic permitting) 10-15 kwh going up

    [​IMG]

    sorry for blurriness. now weather does play a part in the increase but i think the driving is also contributing
     
    #12 DaveinOlyWA, May 28, 2011
  13. Tideland Prius

    Tideland Prius Moderator of the North
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    Yeah but rolling hills will actually help moreso than flat land. The numbers above were achieved on an undulating highway.
     
    #13 Tideland Prius, May 29, 2011
  14. pakitt

    pakitt Senior Member

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    Why is it misleading? I am sorry but need to disagree or I do not understand your comment.

    "happy mode" is very difficult to maintain (especially if the road is not flat or a constant incline); if the battery starts to be full (about 5-7 bars), then I have noticed you start having the "dance of charge" - where the HSD computer calls into action the MG2 every now and then, to use some of the charge and reduce the SoC, and then start again charging it when it is around 6 bars. It is often a very quick "to and fro" between the battery, MG2 and MG1.

    "happy mode" is clearly not "forever" (like all other modes for that matter).
     
    #14 pakitt, Jun 1, 2011
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