I never said you always get fuel cut in Drive, just that it is possible.
In L coasting, you get fuel cut any time the engine ramps up to use up the regen. As you know, this is strong regen, 4000 RPM, and you get a lot of slowing. A 7% grade is not steep enough to maintain speed in L.

However, for a perlonged coast in D, I don't have an exact number, but maybe 30-60 seconds into the coast, the FEH will go into fuel cut mode and continue the coast with very mild regen. Fuel-cut in Drive will keep the engine rpm at about 2000 at 65 mph, with 0.0L / 100km on the display, for as long as you like. On the steeper parts I could use the brake pedal to increase regen, and rpm, and slow more... keeping fuel-cut mode. I could brake, release, brake, release as many times as I wanted, and as long as I did not tap the gas pedal, I could keep fuel-cut for the entire hill.

Here's where you may wish to consider the LGA all over again.
After a time ( 30-60 seconds ) the FEH will go into fuel cut during a coast in drive.
However, you don't have to wait that long. Now when I see a downhill section, I will shift to L, get the rpms up along with fuel cut mode. Then I shift to D and loose most of the RPM and regen, and still maintain fuel cut mode for as long as I do not touch the gas pedal! This is the best discovery I have found in probably 1 year.

This is probably of little use to drivers in flat areas, but for mountain drivers like myself, this is a really cool find. You "basically" for all practical purposes get EV ( zero fuel used ) for long sections of downhill at any speed, even 75+ mph.

Now with practice, I can evoke fuel-cut... at high speed, almost as easily as the brake tap evokes EV below 40.

Oh... I've taken fuel cut down to about 15 MPH, then the fuel injectors fire back up ( for me ) below this speed.

This is something I had wondered about for a long time, but never really tested. Hats off to the Ford engineers for not missing a chance to save even more gas on long downhills. For 2 years I've ALWAYS said I get better MPG in the mountains than the flat prarie. Now I have a clue why.

And for people who always say "Why won't the engine shut off when I don't need it coasting down the highway?" Well guess what? It does. It just does it without telling you!
-John

 

How long does it take for L to trigger the fuel cut (I don't have the nav, and it sounds like the SG has trouble detecting this)? I'm wondering if this could help me with hills we have around here. Not talking about 10 miles at a 7% grade here ... these are rolling hills 1/8 - 1/4 mile or so, up and down. I usually take the downhills in N. But if L forces the fuel cut quickly, perhaps L at the top, and then to D would be a better option on the downhill side?

-- Rick

 

Yes... it should have been clear already.... I said you get OPEN LOOP in Fuel-Cut mode... both in L and in Drive.

Open Loop does not exactly mean fuel-cut.
You can have open loop without fuel cut,
But I do not think you can have fuel cut without open loop.
You get Open Loop at WOT also.

Please see "Open Loop" and "Closed Loop" defined in previous post #22 in this thread.

Fuel cut works on flat roads also. But I do not think it will save much.
I did notice today on a flat road, once I got into fuel cut mode in Drive, I was able to coast "deadband".... that is, without any energy flow arrows, or any noticeable "charge" needle movement... but I still think I had some additional slowing going on. So this would only be good if there was a downgrade to cancel out the slowing. I was going pretty slow... 30-40 range, but it was right after a cold start ( 39'F) so EV was not an option.
I still do not know if this will be a help for the first few minutes before the car warms up or not. I've only spent one 10 mile drive experimenting on flat roads at low speeds. I'm mostly proving what is possible. At this point, I cannot say if it is a good thing or not yet.

This new "fuel-cut" technique is for sure good for MPG at highway speeds on hills. Rick, I think you should for sure try it. Neutral coasting down hills will get you about 100 MPG. Good, but not as good as using zero fuel. And DO use metric to tell if you are getting it, if you do not have any other instruments. 0.0L / 100km is zero fuel burned. You should see this in EV also. Coasting in N will usually show 1.x L being burned.

I think this is totally cool to see 0.0L of fuel being used at highway speeds!!! And no messy FAS!

 

I switched my econ dash gauge to metric and had a chance to check fuel usage a couple of times on the way home tonight. The first time was shortly after starting up and things were still cold so I couldn't get EV yet. Just before going down a 1/4 mile or so hill at around 25-30MPH (city street), I shifted to L and had a run-up.

Immediately reset the econ gauge, it went to 0.0L, and I shifted to D. RPM's reduced (not sure how much), and 0.0L was maintained until I got to the bottom of the hill. Foot was off the gas the entire time and then I did brake to stop. Econ was at 0.0L until I accelerated away from the stop sign.

I had similar results once I got on a two lane highway closer to home. I had a run-up after shifting to L. This time speed was 50-55mph and I went downhill around 1/4 mile or so. Reading was 0.0L until I pressed the gas and started up the next hill. Unfortunately I had traffic following pretty close after that, so I didn't get a chance to try again.

I didn’t have Loop Status set on the SG. I’ll try that over the weekend and report back on Open/Closed.

-- Rick

 

Thanks Rick. That is exactly what I found out and reported earlier.
GaryG is going to have to learn that I only report tried and true data...

 

Now we seem to be getting somewhere! In my TCH, I can, like you, on downhills sometimes provoke fuel-cut operation (what you call ICE run-up) by moving the gear-shift to 'B' (Braking = 'L'). The ICE revs up to 3000+ rpm, open-loop. If I then move the gear-shift back to 'D,' the fuel-cut mode often continues at ~1000 rpm, still open-loop. The open-loop readout of ScanGauge, together with its > 0 rpm indication, is a sure sign (under these circumstances) that fuel-cut is in effect.

Stan

 

GaryG — A good question. I wasn't completely clear in what I said. Fuel-cut in the TCH only happens under specified prior conditions. See the document I attached to my Post #7. This basically requires the vehicle to be at operating temperature, and to have been under ICE power at speed for at least 10 seconds in 'D.' Then, if you release the accelerator pedal completely and start coasting, the TCH immediately (well, within seconds) goes into fuel-cut mode, open-loop at ~1000 rpm. However, what I was referring to in my Post #37 is that, if warmed up and the above procedure doesn't trigger fuel-cut mode, then sometimes (I haven't investigated whether this will always occur, hence I say "sometimes") switching to 'B' and back to 'D' will trigger fuel-cut. I hope this clears things up.

The FEH appears to be so similar to the Toyota hybrids (after all, Ford is paying royalties to Toyota for licensing their patents) that many (most?) of the things I have found seem to correspond to what you're also finding with your FEH/MMH's. That's why I felt motivated to comment in this Newsgroup too.

Stan

 

I'm not sure how often I will be able to take advantage of this though. I was lucky the first time since it was cold and I was pretty sure I wasn't going EV and I had been using L a few times to get the battery charged.

I'd feel better if I knew the SoC. Then I might have a good indication if a run-up was possible as I crest a hill. I know coasting in N is not as good, but it always works and I wouldn't lose momentum trying to get the fuel-cut with L (near home I have a lot of smaller rolling hills on 2 lane highways). With longer downgrades it seems like a better approach.

I'm taking a short road trip on Saturday with some longer grades down from the bluffs along Missouri river and I'll see how that goes.

-- Rick

 

I was able to test the ICE run-up again yesterday, this time on a longer downgrade: Approx 1 mile plus an additional ½ mile level.

After the run up started, I reset the dash econ gauge which went to 0.0L/100km. I shifted to D for about a ½ mile. I then shifted to N for the rest of the glide. Econ stayed at 0.0L the entire time until I shifted back to D and pressed the accelerator.

It took at least ¼ mile down hill before I had the run-up. So again, I’m not sure how often this will be useful, at least for me. One thing I did learn though was to not be worried about a run-up in RPM when I shift to L. It always alarmed me before and I’d shift out of L as soon as possible (the first few times it happened I was even wondering if there was something wrong with the car).

By the way, I noticed something the other day coasting in N. I had just started out and was coasting down in the parking garage at work. Someone came up behind me, so I pushed on the gas and the RPM stayed the same. I forgot I was still in N. My FEH hadn’t though … it saw absolutely no need to rev up the ICE if it was still in N! Similar to not going into reverse if you accidentally shift to R on the highway.

-- Rick

 

Rick, what was your speed?

Are you talking instant Econ, or average Econ?
If you had more than zero, but less than 0.1L it would still read an average of 0.0L.

0.0L in neutral works, if you are in EV.

If you are seeing 0.0L in N with engine spinning, how is that possible?
Try a few more times if you can, and see if you can get consistant results.