Super Highway Mode (SHM) and Hybrid System Indicator (HSI)

Discussion in 'Gen III 2010+ Prius Fuel Economy' started by Tideland Prius, Jul 27, 2010.

  1. Tideland Prius

    Tideland Prius Moderator of the North
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    So I was trying out SHM the other day, (after 5 years lol) and trying to get a hang of it. I had to use the car's standard gauges as I don't own a Scangauge. I followed the suggestion on cleanmpg about pulsing to about 90km/h and then SHM-ing to 80km/h using the Energy Monitor as a guide (arrow from engine to wheel only. If there are arrows to the battery, it should flicker from battery to wheels from time to time).


    On the 2010, the red arrow for power from the engine is pretty hard to read at a glance so I was playing around with the HSI and seeing if I can find a suitable substitute.


    It appears that if you want to push SHM, 1/4-1/2 of the Hybrid ECO area (That would be the dark green bar on the left side of the HSI) is filled. You can go all the way to the midway point (thus filling up the Hybrid ECO area) if you want to maximise distance on SHM but use a little more fuel.



    Now I have nothing to confirm this other than guessing that I am in SHM and then looking at the HSI and corresponding what I'm seeing on the MID with what I'm feeling and seeing on the instant FE gauge (usually reads about 2.0-2.5L/100km or 94-117mpg US).


    Can anyone with a Scangauge confirm? it might be useful to Gen 3 owners that don't have a Scangauge to achieve SHM.

    TIA!
     
  2. spiderman

    spiderman wretched

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    The only way I see those numbers is when the grade is slightly downhill @ highway speeds. I have that going into work and can get upwards of 70+ mpg. However outbound, I generally get the upper 40s. I still need to get a good GPS w/ elevation to see what the actual numbers are.
    The SG is fun, coming down a hill just before home I can get numbers like 1850mpg on up to 9999. lol

    p.s. we all need to start a fund to raise $ for a ScanGuage for TP! I'll throw in a buck.
     
  3. Tideland Prius

    Tideland Prius Moderator of the North
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    Really? not even on a flat road with no wind? It's true I only get it going one way on that highway (undulating.. it's an odd highway where it's below ground but open at the top and surface streets bridge across it without a "hump" (IOW, the highway is like a huge canal but slightly dips at "intersections" and rises slightly in between).

    This is why I like L/100km. I can see numbers down to 0L/100km (EV). Makes it easier than 99.9 which is about 2.35?


    lol...
     
  4. Dan bo

    Dan bo Prius Fan

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    I don't have a Scanguage, but I have been able to get this "SHM" once in a while and would agree with what you have said above. I haven't been able to sustain it for very long and need to pay more attention to when it is happening.

    Dan
     
  5. Prius42

    Prius42 New Member

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    Tideland,

    I really tried to get the red arrow to go just from the ICE to the wheels without the to/from battery indicator doing anything, and I just can't get it. How tricky is this? However, I do note that when the ICE is fueled, i.e. not gliding, and below the center-line of the HSI, the ICE is running below 10 kW. This is pretty inefficient, even if the instantaneous fuel economy shows some high number. You'd still be better off running at 15-20 kW and accelerating, and then go into glide. Am I missing something?

    p.s. I'm in for $1 for Tideland's SG.
     
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    It is very tricky. I've managed to do it a handful of times and when I do get to that state, they don't last very long. It'll end up charging the battery or having the battery drive the wheels.

    Hmm.... so... what I'm seeing is not SHM then?? The thing about 15-20kW and then gliding is that I'm travelling at highway speeds (50-56mph). Below 70km/h, I'll glide (since that's the Gen 3's threshold anyway)
     
  7. Prius42

    Prius42 New Member

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    You should be able to hold highway speeds with 15 kW. On flat ground, I can accelerate up to 60 mph or so at 15 kW. At 55 mph I get 62 mpg holding steady at 15 kW. At 20 kW I get ~52 mpg at 55 mph. Sorry about the english units... but you get the idea. The HSI is almost the perfect tool for driving at peak efficiency since above the center line it is almost entirely an ICE power meter. 15kW is the right edge of the little lighted "ECO" label. 20 kW is the center between the HSI centerline and the "power" region. 15 kW is the peak of the efficiency curve according to the discussion by hobbit and the BSFC curve here:

    Sweet spot refinement

    Even at highway speeds you can sort of glide. The unfueled ICE spins at ~1000 RPM, as you know, and it takes about 1.5-2 kW to keep it spinning. If you apply the gas pedal very lightly you can counteract the ICE drag with the traction battery and MG2. It is very delicate as slightly more than where the HSI starts to taper towards "charge" causes the ICE to kick on at about 5 kW which is extremely inefficient. You just want a very small amount of green bar showing on the HSI. I've been working on a pulse and glide kind of highway driving where I run the car in binary between 15 kW and glide. This doesn't always work since you still have hills, and you don't want to be a traffic impediment. Here is Hobbits description of using the HSI for maximum efficiency:

    HSI
     
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  8. bisco

    bisco cookie crumbler

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    i'm in for a buck!:D
     
  9. Colonel Ronson

    Colonel Ronson New Member

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    i averaged 65mpg driving 67mph in a 75 zone for about 60 miles. MPG meter was constantly moving back and forth between the 75mpg mark and the 50mpg mark.
     
  10. Tideland Prius

    Tideland Prius Moderator of the North
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    Thanks a bunch!

    whohoo! I'm up to $3 lol ;)

    ahh... I haven't tried at anything above 60mph. Above that, I'm usually enjoying my DRCC :D
     
  11. HI MPG

    HI MPG Active Member

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    Everytime I see this thread, I think of KITT and the Super Pursuit Mode. Haha
     
  12. Prius42

    Prius42 New Member

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    Yeah, I wish I could do that too, but silly Toyota decided that (at least in the US) I had to choose between the solar sun-roof (which I dearly love) and the "advanced technology package". Oh well, they could have made yet more money off me by letting me buy more toys...
     
  13. Tideland Prius

    Tideland Prius Moderator of the North
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    On the flipside, I wished I had the LED headlights. (i.e. current package + LEDs like the UK or Aus) but then again, their prices are a lot higher!
     
  14. Tideland Prius

    Tideland Prius Moderator of the North
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    Any luck with comparing the HSI to a Scangauge for SHM?
     
  15. macman408

    macman408 Electron Guidance Counselor

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    What should I look for on my SG? I might be able to try it out next weekend.

    I'm not convinced I've ever hit SHM though, so no guarantees. Plus the ease of DRCC is very, very tempting.
     
  16. Tideland Prius

    Tideland Prius Moderator of the North
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    I know. It's one reason why I cruise above 100km/h.

    Umm.... this..

    New Prius - "Super Highway Mode" Technique (SHM). - CleanMPG Forums

    and see how that relates to the HSI bar graph. I'm thinking IGN 15 is close to the middle bar. I don't know where IGN 14 would be.
     
  17. macman408

    macman408 Electron Guidance Counselor

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    Well, I didn't do any super-thorough testing, maybe 20 minutes total or so, and I'm not terribly acquainted with adjusting my driving to get a targeted IGN value, but here's what I can tell you: I doubt you'll be able to get anything resembling a correlation between the HSI and the IGN. You are correct that IGN 15 can be close to the middle bar. It might also be 16, or 14, or 13, or 12, or 25... (15 might be more common than some of the others, though.) Sometimes reducing the go pedal increased the IGN value, sometimes the IGN value would decrease.

    Your best bet might be to take your $3 so far and buy a ScanGauge. :D

    Barring that, I'd say just go with your gut; if you think you're at or near 14-15 based on your experience, fuel economy, etc., then you probably are. The HSI can help that feedback a bit, but, like many other things (RPMs, battery amps, etc.) it's not a direct indicator.
     
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  18. Tideland Prius

    Tideland Prius Moderator of the North
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    Thanks for the update. I was just trying to see if we can squeeze more usefulness (is that a word?) out of the HSI to help the newbies. Toyota does mention to keep it in the Hybrid ECO area (the darker green area) for electric motor driving.
     
  19. Tideland Prius

    Tideland Prius Moderator of the North
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    So I refuelled and decided to take the opportunity to try SHM again on the same undulating highway but I recorded both ways to even out the terrain.

    This is what I got

    [​IMG]


    3.2L/100km = 73.5mpg US = 88.1 Imp. mpg. :cheer2:

    I think I nailed, right? right?


    I used the HSI (still no scangauge) and basically took the bar up to the middle line (so I filled up the Hybrid ECO area, the dark green area). and I'll ride until I drop below 80km/h (50mph) which is the speed limit and then pulse up to 90km/h (56mph). It's a narrow one but the undulations going west are spaced well enough that I can do that. Coming back east, I would let it drop to 75km/h if necessary. I also used the YouTube MAX mpg Driving Tips to pulse up grades (iMPG = speed in mph) - a little harder to do since at 50mph, you peg your iMPG at 50mpg which is a nice tick on your meter. On mine, it's 4.7L/100km (that's 50mpg) but my bars are in 0.5L/100km increments so I have to flicker between 4.5 and 5.0L/100km.
     

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  20. mikewithaprius

    mikewithaprius New Member

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    Wow, Tideland, that's great! Those Gen III's seem really great on the highway, congrats on super highway moding it to the max.
     
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