HCH-II - SAHM "Super Highway Mode" (70-90 MPG)

Discussion in 'Honda Hybrids' started by msantos, Jul 27, 2008.

  1. armadaman

    armadaman Active Member

    Does this mode exist in a 2000 Insight with MT ?
     
  2. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Armadaman:

    ___Your Insight 5-speed has lean-burn and with the OEM iFCD, you will see the jump in FE at lower speed highway cruise. There may be an IGN component but with the 150 mpg bar graph, it is relatively easy to hold and maintain your fuel miser in that fuel efficient region without much work other than a very light amount of footwork :)

    ___Anyone with an Insight 5-speed want to watch IGN while entering and exiting Lean-burn for us please?

    ___Good Luck

    ___Wayne
     
  3. armadaman

    armadaman Active Member

    Wayne,
    Thanks again for your help.I can tell I have alot to learn and will learn with all the knowledge
    of the members of this site.
     
  4. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Armadaman:

    ___I hope you will be teaching us in the very near future as you have two of the best fuel savers on the planet sitting in your drive. I know at least a thousand of us would like to be in your shoes and thank you for owning such fine pieces of fuel saving propulsion technology! If I could only be so smart to have done the same…

    ___Good Luck

    ___Wayne
     
  5. Harold

    Harold Well-Known Member

    I'm not sure about the scan gauge, Owlmaster. That is a big jump in FE, so we should see the differance? I,m going to try anyway, before I take the plung! H:D
     
  6. owlmaster08

    owlmaster08 Well-Known Member

    Let me know how it goes!...I don't drive much these days since I bike commute to work. I haven't even used 1/4 of a tank since I moved here 5 weeks ago :p

    70+mpg is extremely alluring though....If you think it's worth the plunge I'll take it too :)
     
  7. Harold

    Harold Well-Known Member

    I am going on a trip on the 11th Aug. too Saskatoon[flat lands]. I will give it the old one-two out there. I will let you know how I make out. H
     
  8. shifty35

    shifty35 Well-Known Member

    Wayne, you can redeem yourself by getting on a waiting list for a Prius-III or Honda Global Hybrid now...
     
  9. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Ben:

    ___Someday... when I have some distance to drive. The Wife, definitely ;)

    ___Good Luck

    ___Wayne
     
  10. owlmaster08

    owlmaster08 Well-Known Member

    Ok, I had a Physical Readiness test today so I drove instead of biking. I usually get about 52-56 mpg on this 8 miles commute. It's a somewhat decent amount of traffic down a 6 lane road with lots of lights, speed limit 45mph. Today I decided to try to do either "SAHM" or the "mid3s"? Uusally I try to pulse and glide the whole way...Anyways, I kept my speed about 35-45 mph, and ended up with 62.7 mpg going there, 62.8 coming back! I thought pulse and glide was THE way to go, but this looks a lot better! (or I suck at P&G, lol)

    Again, I didn't know what I was achieving for sure, but it worked :p I won't be driving again though for a while, back to the bike :D
     
  11. Harold

    Harold Well-Known Member

    That is a big bump in FE! Could you notice a change in FE when SAHM kicked in? Must be much easier driving with SAHM than Pulse and Glide as well. H
     
  12. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Owlmaster:

    ___Because of the HCH-II’s poor acceleration performance you may have to bury the SoC and jump on the pedal to get P&G to work properly. IN the review HCH-II, I did not have the time to find out. I have driven Terry Honaker’s HCH-II to > 100mpg but with the review vehicle, I was only using a 4-bar SoC and holding. Less assist affinity there but still gentle on the pedal. The results were less by almost 20% but the feel of a gentle more gentle pulse felt much better for the vehicle’s longevity. Like I am supposed to care about a review vehicle but I hate it when these press vehicles are abused by the likes of C&D, R&T types who could give a $&*! About anything but their publications.

    [​IMG]
    Std. high load P&G after burying the SoC to 3-bars and forced charge on each pulse.

    [​IMG]
    Gentle P&G while holding a 4-bar SoC.

    ___All that being said, I saw a segment with the aFCD at 82.2 while traveling 85 to 90% slower speed Interstate into a Chicago neighborhood pre-rush using SAHM on my very first drive.

    ___Temps are even more of a consideration with the HCH-II and SAHM. In the 60’s and low 70’s, SAHM will allow 75 +. In the high 70’s and low 80’s, 80 + driving under the same constraints in my experience.

    ___Good Luck

    ___Wayne
     
  13. msirach

    msirach Well-Known Member

    SAHM is a winner! I was able to use a Scangauge for 1 day when I started back to work this week. I've got to quit loaning them out! I had the rear control arms changed yesterday and 4-wheel alignment (warranty) and it seemed to come in and stay at a higher speed much easier. I was flying blind though without the Scangauge.
     
  14. owlmaster08

    owlmaster08 Well-Known Member

    This is very interesting...Looks like Wayne can really P&G :p. I feel embarrassed now hehe. Before I would just call this continuous gassing "feathering" the gas pedal as Tarabell called it I think. The key from what I see is you get up to a speed, let off on the gas a little, then easily reapply a little. When you let your foot off the FE bars go to max. When you reapply they go down a little. If you don't reapply enough, your bars stay really high but you slow down too much. If you apply too much all your FE bars drop like a rock. You have to be pretty easy with it or you slow down to much or you kick it back to normal driving. I think this is right? (If I am wrong let me know :) )

    I have done a couple trips this summer P&Ging that I have gotten 70 mpg on, about 15-20 miles or so, but 103 is crazy! For heavier traffic it looks like SAHM is the way to go, now that I understand it better. I may have to jump on getting a Scangauge, it looks like a worthwhile investment for a HCHII hypermiler now. Now that I have a real job that makes money I can splurge a little :D
     
  15. msantos

    msantos Eco Accelerometrist

    Well, while my vacation continues, my short trip with the family to Hecla island is now over. So, I just managed to get the pictures out of the camera.

    Now, our trip to Hecla was devoid of any significant hills but the car was really loaded. The tires were pressed at 50 psi and temps on each tire varied from 28C and 32C depending on which side was being hit by the sun. The fuel tank was full on departure and the ambient temps were very good too as 24C-27C and the winds were very light.

    Also, it helped a lot that my wife was riding the back seat with my daughter ready to take the shots as needed.

    Now, the SAHM mode was very hard to sustain while the SoC was less than ideal. This is because the LOD would climb due to this constant micro regen. Anyway, the following is a picture of my short lived attempts to keep the mode on (I was averaging a measly 67 MPG). :(

    [​IMG]

    Sometime later, more like towards the end of the trip to our destination I decided it was time to take another snapshot (after my wife woke from her short nap). So she grabbed this one in the midst of a good run (at this point the SG was reading 100-120 MPG as per SG-II and my wife got the high point).

    [​IMG]


    Now, a short diversion from the technicalities of Fuel Efficient driving::p

    I just wanted to prove to myself that it is VERY possible to load up an HCH-2 with 2.5 people, a 7 person tent, two full size inflatable beds, grill and stove, electric cooler, chairs, 2 sun umbrellas, and food for 4 days and 3 nights. Just don't ask me how I did it. By the way, there's literally no space left in the trunk and one of the seats (the front passenger seat) was fully load with cargo too. Yes, that is a CleanMPG window sticker. Thanks Mike, I took your advice concerning its placement. :D
    [​IMG]

    Anyway, back to the goods on the SAHM...

    The following picture is something that I took by myself during our return from our camping trip. I took many but this is the only one that came up the least blurry. This time I did not want to bug my wife as she was playing scrabble with my daughter and man was that ever a long game which left me to take the shots on my own (I was getting 98+ MPG as per SG-II in this stretch). :rolleyes:
    [​IMG]

    The following snapshots were captured on the driveway right after our return. The next shot is that of the aFCD showing the B trip meter which was reset just before our departure.
    [​IMG]

    The next image is that of the ScanGauge summary for the day upon our return from our trip. This included a bit of slow driving inside the provincial park due to some road works and reduced speeds. There was also another detour on highway 8 that forced us to take up a slower but more traffic laden alternate route. All in all it was only a 35-45 minute penalty.
    [​IMG]


    Conclusions:
    Well, this SAHM is very finicky especially regarding the more detrimental variables. This includes head winds and the weight of the vehicle both of which I managed to experience in the recent attempts. On my way there, we were very heavy and it was VERY easy to drop off the mode. This required huge amounts of concentration and a very steady foot... and by the way, if you just started reading this, then I will remind you that cruise control does not apply here. ;)

    When I first tried this mode on my way to Hybridfest 08 I arrived to Madison with a cramp on my right ankle like I never had in my life before... and I did that type of driving for the better part of the 14 hour trip.
    This time on a much shorter trip I arrived with a sore ankle which dissipated quite quickly but still it is something I would consider before doing it regularly.

    On the way back from Hecla the HCH-2 was much lighter and It was definitely easier to keep the mode on without bleeding the speed.
    The MPG results:
    The odd stuff here is that I had two scangauges both working on slow rate mode and one of them was displaying the iMPG while the other was displaying the iLHK and the values did not agree. The MPG values were outrageously high when compared to the iLHK. Either that or the iLHK were very understated.
    In the end the SG-II average MPG was much higher than the the HCH-2 instrumented aFCD and if my past experience is any indicator, the actual fuel economy is somewhere between the SG-II aFCD and the HCH-II aFCD. :rolleyes:

    There are a few other oddities that I will have to think about before posting any further. But for now these are the raw results.
    Cheers;

    MSantos
     
    Last edited: Aug 8, 2008
  16. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Great pics and awesome mileage! :)
     
  17. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Manuel:

    ___I cannot wait to get into an HCH-II again as your road pics made it a sight to see! Great and I mean great job as that is the highest family vacation FE possibly seen here in the US and possibly the planet!@

    ___Good Luck

    ___Wayne
     
  18. msantos

    msantos Eco Accelerometrist

    Hi Wayne and Sean;

    Thanks, but I don't really have good news especially since I checked the actual achievement at the pump. :(

    As I expected both scangauges were way off the real mark. In fact, the car's own aFCD was off too and by the widest margin I had ever seen.

    I went to the pump this morning and filled the tank up to the first click (as I always do at the same gas station). In total, I consumed 14.2 Liters (3.75 gallons US) to cover a distance of 423Km (256.62 Miles). This places the actual fuel economy performance at 3.4 l/100km or 69.2 MPG US.

    As usual the instrumented mileage performance is to be taken with a BIG grain of salt and in this case make that a truck load of it !!!
    And here's the worse part: The scangauges were not in agreement with each other either !!!

    Here are the details (I did not reset the tanks, so these are just the details for the day trip):

    Left Scangauge II (3.0X)
    Trip distance= 127 miles (204 km)
    Trip fuel used= 1.58 gallons (5.98 Liters)
    Trip duration= 3.6 hours
    Trip MPG=80.3 (2.94 lhk)
    Right Scangauge II (3.15 -W XGauge)
    Trip distance= 192 km (119.3 miles)
    Trip fuel used= 5.75 Liters (1.52 gallons)
    Trip duration= 3.0 hours
    Trip MPG= 2.9 LHK (81.1 MPG US)
    As I mentioned before, what is worse is that while on route the iMPG display on the left gauge did not agree with the iLHK on the right gauge. In fact, the discrepancy appeared so large that I wondered if there was an interaction issue between the two that prevented one of them from computing accurately... or it was just the fact that both scangauges had differing firmware revisions. :confused:

    But still, when operating in this SAHM mode the scanguage MPG readings are too optimistic and unrealistic. Also surprising is the HCH-II's aFCD as it too, overestimated the MPG performance when usually it is the other way around.
    There is no question that this mode creates some very unique operational scenarios where the instrumented display of the fuel used is just fraught with a lot of calculated error... so much so that it becomes nothing but a weak estimate at best and really nothing to boast about.

    A usual, nothing beats a hand calculated assessment of actual FE.

    Cheers;

    MSantos
     
  19. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Manuel:

    ___Was that top off to top off? In the HCH-II review vehicle, she had about 75 - 80% highway with most sitting in “SAHM” and the top off to top off actual yielded 73.2 mpgUS vs. the 71.5 mpgUS displayed per the OEM aFCD. I saw the same large ScanGauge-II error with 0% offset and a reset ScanGauge-II which read 83.4 mpg over 503 miles for the week long drive.

    ___At times, the ScanGauge-II's iMPG would read an Insight like 100 – 115 mpgUS at 40 - 55 mph in a lot of areas while under “SAHM” when I know it would not be possible to receive Insight like fuel economy from the somewhat heavy 4-door sedan. Maybe the iCDTi but not the DSI which proved to be the case with the top off to top off fill yielding 73.2 over 503 miles.

    ___While you were out on vacation, we missed you around here too :D

    ___Good Luck

    ___Wayne
     
  20. msantos

    msantos Eco Accelerometrist

    Hi Wayne;

    Yes, that was top-off to top-off, all done at the same pump (Shell).

    I am not terribly disappointed at the actual mileage I got at all - well kind of. Now that I think about it, I missed the 70MPG mark by a small bit and even though the weather conditions were very good and the roads were almost ideal, the car was still very loaded at least on the first trip. I guess I failed to bring up the mileage high enough on the return trip to bring it over the 70 MPG mark. But I did notice that my return trip yielded better results perhaps on the account of the car being somewhat lighter. Wind was negligible and the AC was running strategically mostly in electric so it too should not have been a hindrance.

    In retrospect, this "mode" will really work far better for people commuting on the highway over a good enough distance... on a properly setup car with not too much weight on it. I figure that under these scenarios getting 80+ runs on a regular basis should be doable if the diligence and conditions are there.

    I guess the key for me is also to not get overly excited about the SG-II mileage being reported, either instant or averaged but instead use it as a relative measurement of potential success. As always, the measurement of actual fuel used while still not full proof is still king in my books. :)

    I'm still on vacation but since I am closer to urban centers, being online is easier than being at a remote location where mobile communications are non-existent. ;)


    Cheers;

    MSantos
     

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