John, you are the first person I've heard of that does not get a RPM run up at a stop. As for the fuel shut off, the Ford engineer could have meant that fuel above an idle was not being supplied. That would make more sense to me or the ICE would die after instead of idle normal. Remember, these engineers don't understand that some of us are far smarter than they think. By using the term shut off, he may have been triying to make the group understand the ramp up is not caused by acceleration which we all agree. In fact, the eCVT is in a neutral state when this occurs.

Check your scangauge instant mpg, mine shows as if the ICE is at idle coasting and when I stop, it reads still above 0 mpg till I get to a normal idle at 0 mpg.

The FEH eCVT automatic has no manual gear for the ICE to use to slow the FEH down with the axles. The generator and axles are the only way in "L" to cause this effect.

GaryG

 

I have to agree with Ray (Nitramjr) on this part - if you look back at my post #158 my situation could not have been the wheels spinning, there would have been black smoke coming from all four tires . The Tack was up to between 3.5 - 4.0 RPM and I was at a complete stop - this lasted for at least 5 seconds then the ICE shut down. There is more to the situation than has been explained so far. Wish someone form Ford would come on and give his or her insight as to what is happening. Maybe they don't know what is going on either.

John (gasman1) I HAVE noticed that changing to ‘L’ for braking doesn’t seem to be as strong when the battery is full as opposed to when the EV would normally reverse into a generator and therefore put more drag/resistance during that cycle. As you said “When going down a hill, and the HV battery is full... The regen QUITS altogether.... it does NOT keep manufacturing electricity." With the fact the regen Quits when the battery is full - wouldn't that mean that the instant FE would be higher because of less drag/resistance?
Also A BIG 'Thanks for all your help on the 'Points of Interest' while moving modification!!

Can’t really respond to Gary on the different reading on the Scangauge (know that it is more accurate and has a bigger range of FE than my instant bar graph - just don't have the money he has to have one) but it does tell me that it is maxed out when the ICE is revving high and the bar is all the way to the top showing me (not exactly how much) that no fuel is been used when this happens – even when at a full stop.

 

I've had the ScanGauge for less than 1 week, but think it is a useful tool, but not the perfect solution to perfect driving. Every little bit of information does help though.

Anyone with a ScanGauge just needs to realize, that it is simply a display screen, and a calculator with memory. As a display, it is simply showing what is already there. The temperature reading on the ScanGauge can be no better than the FEH itself, since the data on the ScanGauge is coming from the FEH itself. I think it is impossible for the ScanGauge to report better Fuel Economy than the FEH itself, since the data on the ScanGauge is coming from the FEH itself. The ScanGauge can however, give you more resolution ( more digits ).

In the first week I have found one discrepency. One that I think makes the ScanGauge worse.

During engine braking in "Low" position, the Ford's FE reading goes up, usually to max. During engine braking in "Low", the ScanGauge reading goes down, to something very low, like 20 MPG or less.

I "think" ( just a guess, so keep the hate mail to yourself please... ) that the stock display system has been told that engine brake = fuel cut = no fuel being burned = max. fuel economy.

I "think" the ScanGauge does not have this sophisticated programming, thus, interprets 4,000 RPM as using twice the fuel as 2,000 RPM.

Hence, in my first week, the ScanGauge tends to under report FE compared to the stock display. I have not yet re-fueld yet, which is the best measurement.

Also, I monitored the Kw produced / used setting (CAxx.x) on the message center. While using low gear to "engine brake" down a steep hill with a mostly charged battery, the RPM did go to about 4,000 and stay there for 10-12 seconds. During this time, the CA display showed no wattage being produced, nor consumed.

That being said... tonite, on a 1 hour around town round trip, in the 25 -40 MPH range, with outside temperatures of 24-25'F, the Nav screen said 51.1 MPG, and the ScanGauge said 49.5 MPG for just that trip. I used Low Gear setting for most of my stopping or slowing, and "pulse & glide" for intervals between lights.

-John

 

I would add a comment that while the temperature of the battery pack does have an effect on its capacity, the battery doesn't stay at 25F or 0F for very long after start-up. The battery pack has some heating capability of its own (part of the jumpstart mechanism) and by shutting the air door it can prevent cold air from reducing the battery temperature.

And of course, because of the design of the eCVT it's not possible for the wheels to spin the ICE without some energy being directed to the motor/generator to keep it from spinning. That energy can theoretically come from the battery pack or the traction motor.

 

I will agree that it is possible for engine braking to be a result of the wheels turning the traction motor, the traction motor making electricity, the electricity feeding the generator/starter, and the generator/starter turning the engine.

It is also possible for the smaller generator/starter motor to take energy from the battery and spin the wheels.

It is possible for the engine only, by itself to spin the wheels.
And ( most people disagree with this ) it is possible for the wheels to spin the ICE.

Everything is so interconnected, there are more possibilites than flavors of ice cream. ( Probably... I haven't actually counted. )

As an expereinced FEH driver knows... the FEH ICE will not run less than 1000 RPM.

Has anyone been able to drive or idle at 650 RPM? 750 RPM? I doubt it.

I speak from experience on this one... expereince that many of you have not had.

I have actually run out of gas. I know, not good to do on a regular basis, but I did it when the car was new, so there shouldn't have been any "gunk" in the bottom of the tank yet to foul things up. But I digress....

When I ran out of gas, I kept the car in Drive, and coasted to a stop.
The RPM, as I coasted, slowly dropped.... 900, 800, 700, 600, 500, 400, 300, 200... you get the idea. This is the only time I have ever seen tach hover in this low of a range. The only explanation I can think of is, the wheels were spinning the ICE. This may not happen often, this may not be prefered. This may have happened because the car entered some sort of fault mode. The car said "Stop Safely Now". After I stopped, I could use EV, but flooring it produced a computer limit of 22 MPH. ( I thought it was 20 MPH, but the manual says "limp home" mode = 22 MPH )

So if the wheels CAN spin the ICE when you run out of gas, why can't the wheels spin the ICE to slow you down in Low gear?

Someone said something about the "one-way clutch". I think this only means that you cannot use the ICE to run in reverse. As you already know, only electricity can power the FEH in reverse.

-John

 

John, lets try to find out together what was happening during your coast down in RPM's. This has led you to believe that the ICE is used to slow the FEH down and a few of us are having a hard time understanding that to be the case. My thoughts on that is, you were in the drive mode when an error occured (out of gas). The PCM takes control and shuts down everything including the eCVT and electric motors. The PCM still sees the tach sensor on the crankshaft which is turning the motor from the drive mode it was locked in from when the error code was sent to the PCM. In this situation, I agree, the wheel were turning the ICE. Under normal conditions, I don't think this is posible though.

We agree the Traction motor (ring gear) is using the wheels (regen) to charge the battery in "L" and braking. Something is giving the generator moter a signal to start the ICE with the generator/starter motor. I also have the nav sys as you know, and have seen this happen when the SOC (state of charge) was not complelely full. The signal is most likely coming from the Traction Battery Control Module (TBCM) or PCM due to overcharging or over heating. I've read that there is a Rapid Discharge (RDC) signal that comes from the TBCM to the Transaxle Control Module (TCM) to perform a rapid discharge. This could be the reason the ICE starts and burns off energy and the tracting motor stops charging. If the wheels moving had anything to do with the ICE ramp up, the eCVT would not go into a neutral mode like it does IMO. If the eCVT was not in a neutral state, the FEH would speed up, which it doesn't.

As far as burning fuel, I only confirmed this with the scangauge at a stop about a week ago. I do agree after reading up on this, the PCM can stop the fuel injectors but I don't see that happening on the scangauge instant mpg readings.

The One Way Clutch (OWC) prevents the engine from turning counter clockwise under normal conditions. Both Elec motors can operate in reverse which would be a problem for the ICE.

GaryG

GaryG

 

There are a few diagrams in the Helms workshop manual that illustrate various ways that power can be split. There are only a few, so they don't cover all the bases.

One diagram shows mechanical energy (ie 'torque') flowing FROM the wheels INTO the ICE during rengerative braking, if the torque provided by the wheels exceeds the amount the generator/battery can accept.

Comments?
-John

 

--

 

One thing is for sure. The only way the wheels can spin the ICE is if the motor/generator holds itself steady. If the motor/generator was not getting any power to brake itself, it would spin freely (up to 40 MPH anyway when the computer forces the ICE on) and the ICE would not spin at all (since the ICE has compression resistance and an electric motor doesn't. Therefore some current has to be applied to the fields of the motor/generator to slow it or stop it from moving, or even drive itself "against the current" coming from the wheels, so to speak. The field current can come from either the traction motor or the battery pack. So yes, some electrical power is being consumed in spinning the ICE.

The whole thing is a constant balancing act between the ICE and the motor/generator. Since the traction motor is essentially hard-wired to the driveline (i.e. it's on the "output" side of the power-split device) its role in life is more straightforward. Either it's contributing torque or it's subtracting it from vehicle motion.

I agree the one-way clutch mechanism on the ICE is not clearly explained at all, just that it exists. My thought is it might be there to allow some slippage when the engine starts up.

 

Steve, I totally respect your imput, but have not heard from you much lately. You can offer much from your past post. I'm not running this show and don't want to be. Matter of fact, thinking of taking my mpg and running at this point. No posting, no time reading and no time answering is what my wife wants.

GaryG