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Thread: EV Timing

  1. #1
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    Oct 2006
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    EV Timing

    With the new Xgauge SoC information, I've been playing around with the minimum amount of letting the SoC go before kicking on the ICE. Most of the time, I've waited till the ICE kicked on by the computer at its lower limits, but now I can see the percentage may be better for timing to start the ICE before that time to go EV with a charge again. What I mean is instead of letting the SoC drop in the 40% range and then a restart will drop the SoC an additional 3-5%, I started kicking on the ICE in the lower 41% range. This left a SoC of around 40.6 to 40.8% after a restart. Increasing speed at 1,600-1,800rpm's after a restart to a speed about 5mph above say a 30mph limit to 35mph and using one FS in "L" to return back in EV at 30mph. Kicking on the ICE sooner at slower speeds has improved my MPG in downtown driving where I have a low SoC, but have to stop at almost every block for a stoplight or sign.

    In the past, I went EV on the second FS in "L" to go EV, but knew it was best to let the ICE shutdown after one FS if the SoC was high enough. Now, I can control that by having a % readout on the Xgauge. Also, I now know that the ICE will kick on at a higher SoC if the speed is higher. An example is the ICE will restart on average at 40 - 40.6% at 30mph, but it with kick on between 41 - 41.4% at 35mph in EV. This higher speed and higher SoC requires a faster FS in "L" so you don't go EV right away. The higher speed requires you to build a higher SoC to maintain a 35mph limit. If you have a restart and drop the SoC to say 40.8% and increase your speed from 35mph to 40mph to go EV again, you need a SoC of more than 43.5% to carry you at 35mph for a fair distance in EV before the ICE starts again. For this reason you may want to kick on the ICE before the SoC gets to 41 - 41.6% at around 42% SoC or even higher.

    The folks with the nav sys had a primitive SoC gauge, but they still had an advantage over those who had nothing. We all can get a Scangauge II with Xgauge capability now and I really recommend it if you want to improve MPG.

    GaryG

  2. #2
    Junior Member
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    Feb 2008
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    Gary, this may be simply a

    Gary, this may be simply a reflection of a software difference in the 2008 version, but I can get my 08 to go EV from D as long as I am:
    1. 40 or just below
    2. Decelerating*
    3. give the brakes one or two taps.
    i.e., no need to be in L.

    * the evidence from attempts to do this action seems to indicate that Ford has a little software routine involving some integral of deceleration rate and time.

    Thanks,
    John

  3. #3
    Guest

    Yes. Part of the trouble is

    Yes. Part of the trouble is the FEH needs 42% or higher to shut down the gas engine. Doing P&G techniques in the 40% range... sometimes you want the engine to shut off at 41%, which is generally, not possible. Thus keeping a baseline of near 42% may be near optimal.

  4. #4
    Junior Member
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    Oct 2006
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    Hi John Tapping the brake

    Hi John

    Tapping the brake pedal in "D" while decelerating to go EV was the first thing that was discovered by the early '05 FEH owners. The reason I use "L" is to pack a regen charge just before going EV. Early on I discovered that after the HV battery got to hot to accept a regen charge in "D" or "L" to go EV, shifting to "N" and tapping the brakes cured that problem. I found the same when the HV battery was to cold to accept to accept a regen charge in "D" or "L"to go EV, shifting to "N" and tapping the brakes works also. I use to get so angry that I could not go EV with the double tap in "D" or shifting to "L" because of this hot or cold battery issue till I discovered tapping the brake in "N". I almost never have a problem going EV under 40mph anymore. Of course if the battery is to full, "N" will prevent a run-up (engine braking) and allow EV by tapping the brake pedal lightly.

    GaryG


  5. #5
    Junior Member
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    Feb 2008
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    Aha! Cunning people, these

    Aha!

    Cunning people, these hypermilers!

    John

  6. #6
    Junior Member
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    Oct 2006
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    After playing with the

    After playing with the single Fake Shift with leaving the SoC at a higher level, I've concluded dropping the SoC as I've always done was better for MPG. Two FS's from the lowest SoC possible at a restart showed a much faster increase of my average MPG. I'm referring to maintaining speeds in the 30-40mph speed range.

    It appears the single FS with a higher SoC is better for downtown driving where stoplights are at almost every block. It's more important to not sit at a light while the ICE is running to reach the ICE shutdown limit for the HV battery.

    Refer to my starting post of this thread for further information.

    GaryG

  7. #7
    Guest

    This story changes somewhat

    This story changes somewhat with those that live in the real winter conditions. When the battery is too cold, shifting into "N" and tapping the brakes will not change anything. The cylinder head temperature needs to exceed 188 degrees and the radiator water temperature exceed 154 degrees for the first time after a cold start prior to any EV mode. Those of you with the Scan gauges can monitor this and report back. There is also the hybrid battery temperature that can play a role in allowing EV.

  8. #8
    Junior Member
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    Oct 2006
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    I agree Billy, all

    I agree Billy, all conditions have to be met before these techniques can put you in EV. In my area, the battery may be to cold to except a combined charge of the generator and regen from the traction motor so tapping the brake pedal in "D" or using "L" will not work for EV. When the CAT is "light-off", coolant temp is around ~154F and the head temp is over ~188F, many times the only way I can go EV is shift to "N" for the double tap. So far, its never failed me to go EV with outside temperature above freezing. However, my SoC very seldom is over 43% at a cold start. This helps warm the HV battery by a drop of SoC to ~32% during the warm-up strategy and having the HV battery rapid charge quickly to above 41.6% where EV is possible. Very seldom in the coldest weather here (33F), I can go EV in 1.5 miles. I take full advantage of the warm-up strategy and my FEH is parked outside with no block heater. The rapid charging from the generator from a ~32% SoC I think is the key to warming up the HV battery from a cold start. Keeping a low SoC (39.6 to 43.5%) continues to keep the HV battery warm and I hear the AC compressor clicking on very often even in the coldest weather here. BTW, many times with stoplights permitting, I reach a current average of 30mpg at the third stoplight 1.8 miles from my home.

    I've overcome the coldest conditions here in south Florida, but the real winter condition would be much more of a challenge to me. Many hypermilers I know do drive in winter conditions as you describe and do overcome those conditions with only a lost of a few MPG average. It's not easy for everyone, but understand it is possible, ask Wayne Gerdes.

    GaryG

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