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  1. #1
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    Just the 10% ethanol?

    In Phoenix the gas is 10% ethanol all year round. In neighboring counties you can get regular gas without ethanol from May to October. I drove 22 miles this morning at 5:30 am to a QT station with this gas to fill up my 2005 FEH. I hit 0 MTE about two miles from the station and put in 13.74 gallons for a tank of 33.9 MPG. On the trip back home, I drove mostly ICE on at 45 mph and achieved an astounding 57.2 MPG! Traffic was light for most of the way, but I did have to accelerate away from lights a few times when there were people on my tail. With CC at 45MPH, I usually get about 39 MPG on the 10% ethanol gas. Another shorter trip has since dropped my average econ to 48.8 MPG at 39 miles, but it is still light years better than I usually do. How in the world can Ford make the E85 FEH work???


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  3. #2
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    Quote Originally Posted by DesertDog View Post
    In Phoenix the gas is 10% ethanol all year round. In neighboring counties you can get regular gas without ethanol from May to October. I drove 22 miles this morning at 5:30 am to a QT station with this gas to fill up my 2005 FEH. I hit 0 MTE about two miles from the station and put in 13.74 gallons for a tank of 33.9 MPG. On the trip back home, I drove mostly ICE on at 45 mph and achieved an astounding 57.2 MPG! Traffic was light for most of the way, but I did have to accelerate away from lights a few times when there were people on my tail. With CC at 45MPH, I usually get about 39 MPG on the 10% ethanol gas. Another shorter trip has since dropped my average econ to 48.8 MPG at 39 miles, but it is still light years better than I usually do. How in the world can Ford make the E85 FEH work???
    You have an exceptionally good running vehicle in order to achieve that kind of mileage, even if you had no stops on your trip back. See my steady state speed test in my article: http://www.cleanmpg.com/forums/artic...brid--350.html
    These test runs were with a packed HV battery, no AC, no ethanol no head wind for one mile on a flat road.

    Here in South Florida, I've only got 10% ethanol 3 times. All three times my mileage dropped at least 10%. One tank of 10% ethanol continued to reduce my mileage for two additional refills of straight 87 octane. The only reason I could come up with, was during the tank of 10% ethanol, the long term fuel trim data in the Keep Alive Memory had adjusted to the ethanol. Ethanol requires a much more rich fuel mixture, and this screws up this long term fuel trim air/fuel mixture, even after the 10% ethanol mixed gas is gone. This is stated in the shop manual also. You can reset the long term fuel trim to the default settings by disconnecting the 12V ground cable for a least 5 minutes.

    Ford just released 20 E85 FEH vehicles, I think it was to the EPA for testing. Very few locations have E85 available, so they were to areas that sold it. We will see how they do on mileage, but I don't think there is any way they will come close to our mileage.

    Personally, I think the cost of making ethanol will drive the price of straight gas up, because people will want to use better gas and pay more for it. Remember the days when using high octane fuel would give you better mileage and more power in most cars? I paid extra for it then and the oil companies knew we would.

    GaryG

  4. #3
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    I was thinking that my FEH was initially running lean without the 10% ethanol, due to the O2 sensors now indicating less oxygen in the exhaust than before, and would richen up as the computer adapts to the new gas. If this tank stays substantially better for MPG, I may have to think of a refuelling strategy to maximize FE. I don't know if I want to make a 44.2 mile round trip to re-fuel every month unless it pays off big time in tank FE.

    I may park the car this week, though, as the forecast highs are >115 and the A/C in my FEH is barely adequate when it's this hot and dry. The trip back yesterday was at 6:00am, when it was "only" about 85 degrees and I was able to minimize A/C use.

  5. #4
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    An update....and Question for GaryG

    My tank average with the non-ethanol gas has continued to plummet, mostly due to near constant A/C use (high was 116 yesterday.) I did notice today on the way home from work, though, that I was able to attain ~45 MPG while doing 45 MPH w/CC and the A/C on. Now that I have the nav/energy radio, I noticed that I was in Hybrid Drive mode for the entire time. I suspect that is what allowed me to get such great mileage w/o A/C on the return trip from the fill-up with straight 87 octane on Saturday. I know my HV battery was full because I had a brief RPM run-up in L when slowing down for a light. My question to Gary is, those FE numbers in the CleanMPG article, are they with Engine drive only, or Hybrid Drive? I think that there might be a significant difference.

  6. #5
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    Quote Originally Posted by DesertDog View Post
    My question to Gary is, those FE numbers in the CleanMPG article, are they with Engine drive only, or Hybrid Drive? I think that there might be a significant difference.
    When you are driving with no assist from the electric motors, you are only using the engine for torque, so that was what I used during the test. Prior to each test, I ran the A/C to cool the battery and the cabin. I keep the battery full and did a fake shift in "L" so the battery would not need a charge during the steady state speed test. The A/C was turned off just before the test and the road and direction was always the same for each run.

    If you have a Scangauge, set one gauge to "LOAD". With this gauge, you will see the percentage (0-99%) of load on the engine. With the engine warm, you can see as you accelerate the engine goes to 99% real easy. This is because of the Atkinson cycle engine has very low torque at low RPM's. As you reach 100% load on the engine, the Assist needle will move in the assist direction and your getting electric motor assistance at that point. The engine is now providing energy turning the motor/generator (MG1) to power the traction motor (MG2) for assistance. While in assist, you are gaining in engine RPMs and burning more fuel. The best FE is with no assist, but it's there if you need it at a cost to MPG.

    I'm a big guy at 275 pounds and my Son who wrote down the data is 6'2" 185 pounds. Weight may have hurt the test a little, but not that much for one mile at a steady state speed.

    As far as ethanol, it is an oxygenate which requires a richer air/fuel mixture. The CAT senses higher oxygen and the PCM delivers more fuel to the engine. When the oxygenate is no longer present, the long term fuel trim has to learn to lean each load/RPM map in the KAM. Until all the load/RPM maps are relearned, the PCM will continue to run a rich air/fuel mixture and burn more fuel.

    GaryG

  7. #6
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    Quote Originally Posted by GaryG View Post
    When you are driving with no assist from the electric motors, you are only using the engine for torque, so that was what I used during the test. Prior to each test, I ran the A/C to cool the battery and the cabin. I keep the battery full and did a fake shift in "L" so the battery would not need a charge during the steady state speed test. The A/C was turned off just before the test and the road and direction was always the same for each run.GaryG
    When I duplicate your conditions as best I can, I almost alway get electric assist during the steady state cruise, even with SC LOD at ~82% at 40 MPH. The assist needle is not perceptibly to the right, but the nav display indicates Hybrid Drive, with no arrow between the engine and motor. The arrows go from HV battery to motor to axle, and from engine to axle. I will try to take a picture the next time I do this test. I believe that if you pack the HV battery above 60%, the assist occurs to bleed off charge, like the L run-up. My ultimate point is, I think your data may not be ICE only, but ICE with some electric assist, at least for the 30 and 40 MPH runs. It certainly appears that this is the case for my FEH, and the assist occurs for almost the full mile, yeilding truly impressive FE numbers.

  8. #7
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    Quote Originally Posted by DesertDog View Post
    When I duplicate your conditions as best I can, I almost alway get electric assist during the steady state cruise, even with SC LOD at ~82% at 40 MPH. The assist needle is not perceptibly to the right, but the nav display indicates Hybrid Drive, with no arrow between the engine and motor. The arrows go from HV battery to motor to axle, and from engine to axle. I will try to take a picture the next time I do this test. I believe that if you pack the HV battery above 60%, the assist occurs to bleed off charge, like the L run-up. My ultimate point is, I think your data may not be ICE only, but ICE with some electric assist, at least for the 30 and 40 MPH runs. It certainly appears that this is the case for my FEH, and the assist occurs for almost the full mile, yeilding truly impressive FE numbers.
    My results were what they were in my weather, elevation and barometric pressure. Your results could be affected by your condition also. I conducted three test with CC and three test without at each speed. If your battery was assisting, more than likely it was power from the battery going to the DC/DC converter to run power steering, electronics coolant pump etc.. The 12 volt battery is used for any excess power the DC/DC converter can't supply. The arrows are not always correct to the wheels. An example of this is when you are in neutral and the arrows sometime show regen when MG1 is suppling power to the battery.

    When I stated I packed the battery, I meant I raised the charge above the cut off point of the small generator which is 53%. Regen only allows up to the set limit of 60%, and can't exceed that point. By raising the charge above 53%, it assured me that it was unlikely the battery would need the engine and MG1 for an additional need to charge during the mile test. The engine and MG1 charging would have resulted in lower test MPG. Also, during my test I had to watch speed, OD, the road, traffic and the SG to call out start and the average at the end of one mile.

    The bottom line is that if assist improved your mileage, the battery would need to be recharged after the assist. This would result in more engine load and more fuel to replace that energy.

    GaryG

  9. #8
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    I checked the short term fuel trim, and it is at 0%. The long term fuel trim, however, is at -8.6% ...pretty rich. I will now start monitoring this at every fill-up from now on.

  10. #9
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    Quote Originally Posted by DesertDog View Post
    I checked the short term fuel trim, and it is at 0%. The long term fuel trim, however, is at -8.6% ...pretty rich. I will now start monitoring this at every fill-up from now on.
    Desertdog, are you getting that reading from the dash information center by pushing down on the trip OD reset and turning the key ON, or did you use a diagnostic tool?

    Stoichiometric air/fuel (14.7:1 for gasoline) is determined by the PCM, but the oxygen sensors can only indicate rich or lean. The fuel control strategy must constantly adjust the desired air/fuel ratio rich or lean to get the oxygen sensor to switch around the stoichiometric point. The desired air/fuel control parameter is called short term fuel trim where stoichiometric is represented by 0%. Richer (more fuel) is represented by a positive number and leaner (less fuel) is represented by a negative number. Normal operating range for short term trim is +/- 25%. Short term fuel trim values are not retained after the engine is turned off.

    While the engine is operating in closed loop fuel, the short term fuel trim corrections can be learned by the PCM as long term fuel trim corrections. These corrections are stored in keep alive memory (KAM) in tables that are referenced by engine speed and load. Learning the corrections in KAM improves both open loop and closed loop air/fuel ratio control. Advantages include:

    Short term fuel trim does not have to generate new corrections each time the engine goes into closed loop.

    Long term fuel trim corrections can be used both while in open loop and closed loop modes.

    Long term fuel trim is represented as a percentage, just like short term fuel trim, however it is not a single parameter. There is a separate long term trim value that is used for each RPM/load point of engine operation. Long term fuel trim corrections may change depending on the operating conditions of the engine (RPM and load), ambient air temperatures, and fuel quality (% alcohol or oxygenates). When viewing long term fuel trim PID, the values may change a great deal as the engine is operated at different RPM and load points. The PID displays the long term fuel correction that is currently used at that RPM/load point.

    This is why a reading of -8.6% doesn't make much sense to me. This would be a leaner air/fuel than stoichiometric, not richer and at what RPM/load was this reading taken, idle?

    Sorry to the group for being technical, but I thought this would help those interested in the subject. When you take the ground cable to the 12 volt battery off for 5 minutes, you reset KAM to the default settings for fuel trim and other things.

    GaryG

  11. #10
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    Good point about the short term trim, I looked at it with the engine off. The long term trim varies a little around -8.6%, but not that much. As fas as the negative numbers, everything I see on the web indicates that negative is richer and positive is leaner, which I agree seems counter-intuitive.

    I am using my scan guage, sending 0106 for short-term and 0107 for long-term.

    Interestingly enough, absolute fuel pressure is reported, but relative is not. Ambient temperature is reported and seems pretty accurate, my guess is that it's coming from the battery vent.

    When I finish figuring out what all things can be read with the SC2 for the FEH, I'll post a table if anybody's interested.

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