FFH and neutral coast

Discussion in 'Ford Hybrids' started by SD3_Driver, Sep 18, 2011.

  1. lolder

    lolder Well-Known Member

    All true but the ICE doesn't turn above 38; it's 47 mph. No Dash Mode display or sensation including the Engineering Test Mode page that displays RPM show the ICE turning between 38 and 47.
     
  2. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Take a look at the electric usage. You'll see a drain arrow appear when coasting in N above 38mph or so. To back that up, you'll find that the SoC drops quite a bit faster at higher speed glides in N as well. The RPM sensor is only active when the engine is actually using fuel.
     
  3. lolder

    lolder Well-Known Member

    There's no drain arrow above 38 in D, it's charge. The RPM gauge in "Enlighten" dash mode appears and disappears but the RPM display in the Engineering Test Mode ETM ( enterred by holding RESET and SET-UP for five seconds after turning key on ) page ( hit RESET five times for page with tachometer ) is active all the time and can show zero and briefly even some rpms between 0 and 1000 as the ICE stops and starts. There is no physical feeling that the ICE is ever turned below 47 and I can feel it when it is turned above 47 in "N". The car is smooth but not that smooth. The ETM tachometer page shows 0 rpm below 47 mph and about 1000 rpm above 47 in N with a slight discharge arrow. Pressing the accelerator pedal amply then yields a slight charge arrow and about 1150 rpm so the injectors are not completely cut off even then. The state of charge increases with all D coasts above about 25 mph unless there's very heavy AC load. The state of charge does drop coasting in "N" above 47 and the ICE is apparently being electrically turned then. You are certainly a senior member of these forums but are you basing the FFH operation on the FEH? My FFH was built 5/09 and I have owned it since 7/09.
     
    Last edited: Sep 29, 2011
  4. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Okay, let me recap here (again, READ my posts instead of skimming). We purchased a FFH for my wife in April of 2010. I don't now nor have I ever owned an FEH, though I have driven one twice. My statements are based on actual experience, not associations with another vehicle.

    We have been speaking of coasting in N for the entire thread and I've been very careful to qualify my statements. When coasting in neutral between the speeds of 38mph and 47mph (assuming the car is warmed up enough that the car is EV capable in this speed range) the engine will be off but turning via electric power. You can see it as a power drain on the SoC gauge. The RPM gauge only reports something greater than zero when the engine is actually consuming fuel.

    Above 47mph the only way you can get the engine to not use fuel is to enter DFCO. There is no engine off glide of any sort above 47mph. Once again, the RPM gauge only shows anything other than zero when gas is being consumed. Because of this design choice there is no such thing as Warp Stealth (the mode in Toyota hybrids above normal EV range) in the FFH (or the FEH either, for that matter).
     
  5. lolder

    lolder Well-Known Member

    I've read a lot of your posts and you are undoubtedly an authority and I see you've had an Insight also. If you look at the Tachometer page in the Engineering Test Mode, it displays RPM continuously at about a twice per second rate from 0 to max. It may even show a RPM between 0 and 1000 when the ICE is stopping or starting when the fuel is always cut off. The "Enlighten" dash display shows a coarse RPM gauge when the ICE is running and only an EV gauge when the ICE is OFF. I see no indication including a discharge arrow on the HVB gauge that indicates the ICE is turning between 38 and 47 in N or D.
     
  6. GaryG

    GaryG Well-Known Member

    You must not have a SGII programmed to read SoC in your FFH. Any time you are in "N" and EV, with the key On, the HV battery is discharging. The reason it's discharging at a fairly quick rate is because "N" does not provide any regen with MG2, and the battery is discharging while running the 12V loads. You may not see the arrows on the OEM gauges, but you will see the SoC dropping on a SG11 in 10th's of one percent. My '09 FEH does not go EV above 40 mph, so it does not have the programming to protect the electric motors by spinning the engine like Sean is talking about with MG1.

    From what Wayne Gerde has reported from his reviews of the '10 FFH, it uses much more battery SoC at 47mph in EV than below what I think I read at 40mph. Now I'm hearing Sean say it's 38mph and I have no reason to disagree. If this is the case, the only additional power lost could be from MG1 spinning the engine to protect the electric motors from over RPM damage. This makes perfectly good sense to me.

    GaryG
     
  7. lolder

    lolder Well-Known Member

    I misspoke. In N coasting below 47 there is discharge for the reasons you state, not because it is spinning the ICE. The ICE is NOT turning below 47 mph. The RPM limit for MG1 occurs at a road speed of 47 mph. In D coasting, it is charging above and below 47 mph, ICE off or on. The FFH uses more SOC at 47 in N because it is spinning the ICE.
     
  8. lolder

    lolder Well-Known Member

    In the FFH, there is an Engineering Test Mode ( ETM ) displayable on the right side of the panel enabled by holding ReSet and Set-Up buttons on the steering wheel for five seconds while turning key to start. It has 10 separate pages of various digital readings scrollable by pressing the ReSet button. For instance, fuel level is displayed to three places ( .750 = 3/4 ). Page 5 has Tachometer with 4 digital places ( 1243 RPM eg. ). It is active all the time on page 5 of the ETM and displays 0000 when the ICE is off. I'm pretty sure it is driven by the crankshaft position sensor, not the fuel computer. It shows 0000 rpm below 47 mph. Check it out
    The Forum at Fordfusionforum.com has been pretty quiet lately as there are very few being sold because of Japan parts problems ( and new competition ) so there are few newbies and almost no problems. 2012 production has apparently not started yet and there are few on dealers lots.
     
  9. SD3_Driver

    SD3_Driver Well-Known Member

    Ok, i'm getting a little confused here... so it is better to coast in gear above 47mph and coast in N below 47mph in ev mode...:)
     
  10. lolder

    lolder Well-Known Member

    Coasting in N below 47 stops the HVB charging due to non-braking programmed regen drag so you are eliminating those round trip EV cycle losses. But, you won't recoup regen braking energy unless you remember to go to D before you brake. I think that's cumbersome. You can coast in D below 47 mph in EV and modulate the accelerator pedal so that neither the Up or Down arrows appear in the HVB gauge. This reduces the EV cycle looses almost as much as the use of N. This is easier than you might think. Because of the round trip generator-charge-discharge-motor EV cycle losses, EV is useful only in three situations: acceleration assist of the lower HP Atkinson ICE, regenerative braking, low power cruising below about 35 mph. where the ICE efficiency drops off and cycling between EV and ICE is more efficient. The latter case can also use P & G and null the arrows for further gains. This is the closest to old manual P & G and can be done in D simply with pedal movement. All these methods cause varying degrees of road distraction. Use of N frequently will interfere with the Ford HVB management plan. That gives me pause to use it.
     
    Last edited: Sep 30, 2011
  11. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    I'll see if I can get a shot of the arrows at some point.
     
  12. SD3_Driver

    SD3_Driver Well-Known Member

    OK, got it... have to try and see if any gains... quick question.. does the curb weight of the car includes the weight of the fuel in the tank? Or do I have to add to get the real weight of the car?..
     
  13. lolder

    lolder Well-Known Member

    Full fuel and oil, no passengers or cargo.
     
  14. SD3_Driver

    SD3_Driver Well-Known Member

    OK thanks, so my avg weight for the car is 3900 pounds ( weight of 150 pounds + 30 additional) and losing a gal and a half every normal week...:)
     
  15. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    I had a chance to drive the wife's FFH to Church and back tonight (Choir practice :p) so I got the phone camera fired up and ready to shoot.

    Here's a shot of the drain arrow while in a N glide. I watched more carefully and the faint outline of the drain arrow is visible all the way down to 35mph, then it disappears:

    [​IMG]
    (Note selector in N, very low ACC load due to only fan on 1, drain arrow on SoC gauge, and speed over 40mph)

    For this reason, I prefer to keep speeds at 34mph or lower, but that isn't always possible. The SoC will decrease noticeably faster when using higher speed glides in neutral. Still, that can be counteracted by proper management of the SoC using regen strategically and paying attention to the pulse rates with P&G. I'll describe my techniques below and then share the results from tonight's driving. I didn't use AC or the stereo, the windows were all rolled up, and I had the vent fan set to 1.

    Firstly, on the highway I don't use glides in N. They may help in some areas but in most cases I believe the better approach is simple DWL. I typically manage low 50's in warm weather at speeds between 55 and 60mph. As mentioned earlier, there is no Warp Stealth or Warp Neutral (terms Prius drivers will be familiar with).

    Second, manage the SoC by avoiding electrical assist when the engine is on. Use a pedal "blip" to get the engine started when you want to pulse -- this will avoid the extra drain of running purely electric for a short stretch and then smoothing the engine start. It is nice programming and certainly pleasant to experience but it uses power unnecessarily. Once the engine is started you can start out with a slightly heavier pulse because the spin up will get engine RPM up higher than you actually need it, but back off after the initial press. The idea here is to pulse with no drain or charge arrows. On engine start you will almost always see at least a brief moment of charging as the RPM drops after the "blip" -- use it for that extra power off the start. Using P&G with N glides at 34mph and below I see minimal deviation of the SoC doing this.

    Thirdly, when using N I pulse to speed (without arrows if possible) then let my foot off the accelerator; as soon as the red bar on the PWR meter meets the top of the EV demarcation line I shift to N. The engine will cut off if everything is warmed up and you simply throw the lever into N at 47mph or lower while releasing the pedal at the same time but it will idle for a few seconds. Waiting for it to DFCO down to the EV PWR level cuts the fuel use and gets instant engine off when you shift.

    Fourthly, if you have to use steady state speeds, use the lowest pedal pressure needed to maintain speed above 47mph and at speeds under that, try to park the PWR meter's red bar right on top of the EV demarcation line while maintaining speed. This will raise your instant FE and also add some charge to your SoC.

    How does all of this work in the real world? I took my favorite through town route to Church and back this evening. The way there has a slight net elevation gain with a truly annoying and quite tall hill towards the end. The route there has a steeper incline than coming back so it is a bigger hit when going to Church. I also had heavier traffic on the way in (rush hour, in fact) throwing a monkey wrench into light timing with a large amount of unpredictable cross traffic with bad sight lines. Here's the result for that trip out:

    [​IMG]
    (60.1mpg over 16.6mi at 81F, fan on 1)

    Coming back the traffic was lighter and the route has a slight elevation loss, but the temperature was lower and I now had the headlights on (fan still on 1). Net SoC usage for the round trip was zero ending at 50% per the in-dash gauge. What did it look like?

    [​IMG]

    The average at the top right is actually the tank average -- this is the first time I've driven on this tank and it was at 41.3mpg when I left the house (my wife really doesn't hypermile so I'm quite happy with her mileage). You can see I pulled it up 1.1mpg over the round trip. You can also see 9 of the 10 2min bars maxed out with the 10th just barely under the 60mpg mark. SoC is nicely at 50% (where it was when I left the house). Here's the average for that trip:

    [​IMG]
    (71.5mpg over 16.6mi at 76F)

    There was no appreciable wind for either trip. Round trip ends up calculating out to 65.3mpg over 33.2mi.

    Hopefully the above is of some use to other FFH drivers.
     
  16. lolder

    lolder Well-Known Member

    Nice post. As you said, the secret to getting into the 60's and 70's mpg at lower speeds is avoid the charge-discharge arrows in P & G. You can see how the demo in 2008 got 81 mpg. The general rule to avoid EV mode ( and eliminate those losses ) is evident here.
     
  17. lxmike

    lxmike Well-Known Member

    Sean, i checked and the ffh is rated at 39 combined so yes your wife is indeed a hypermiler even if she doesn't try to be one.
     
  18. lolder

    lolder Well-Known Member

    In a recent test over an eight mile level road going both ways and AC off, I got 79 mpg. using P and G in "D" between 25 and 35 mph keeping the HVB arrows off. With CC on on a previous test I got 64 mpg. cycling between ICE and EV at about a 50 % duty cycle at 30 mph. Starting and ending vehicle states were the same in all tests. Somebody might be able to calculate EV cycle efficiency from that data. I've previously read it was 70 %. Off hand it looks to be 81 %, from this single point data. Don't hold EV mode in such high esteem, it's a convenience.
     
  19. SD3_Driver

    SD3_Driver Well-Known Member

    I tried that this week and (for me) is really hard to get the arrows to not show up, it did get me to the low to mid 50's instant MPG at 30 to 40 MPH range, but the arrows were present almost all the time, so, how do you do that????????:confused::confused:
     
  20. GaryG

    GaryG Well-Known Member

    I hypermile my '09 FEH totally different using EV and pulsing with a heavy charge. After 4 or 5 P&G segments, the battery SoC is up around 45 - 46% when I go EV at around 30mph and set the CC. I burn the SoC down to ~43.3% and then do a "N" glide to as low as 20mph depending on any traffic behind me. The '09 FEH is good for 75 - 80mpg using this technique. My acceleration rate is between 12 - 15mpg during my pulse. I'm limited to the roads that have these speed limits and traffic for ideal conditions, but can still pull tanks over 60mpg.

    GaryG
     

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