I got 19 MPG in a 2005 FEH but I was towing this:


The tow was from NE Iowa to NE Colorado.
I went to a certified truck scale along I80 in Iowa near the start of the trip.
The Truck scale rounds to the nearest 20 pounds.

My FEH as loaded with me inside ( no trailer ) = 4,040 pounds
The U-Haul as loaded by itself ( no FEH ) = 2,620 pounds
Tounge weight on my FEH = 200 pounds

Total combined weight = 6,660 pounds ( and I have the scale ticket if anyone is interesed to see it ).

Total miles = 857.4
Total gallons = 44.98
Average MPG = 19.06
Average Speed = 56.41 MPH ( incl. brief in-town drives to get gas/food )

I had a head wind the first 225 miles and net 18.8 MPG that segment.
I had a side/diagonal tail wind for the middle part of the drive and net 20.4 MPG that segment.
The last 190 miles were uphill from the Nebraska state line to the Denver area, and that segment net me 17.2 MPG.

At no time did my water temperature get above a "nominal" 191 degrees.
( Well, the first 30 miles I forgot I had my winter radiator block on, and my water got up to 197 which reminded me to take the radiator block off! )
At no time did my transmission, or either generator motor get hot.
Outside air was 50's and 60's most of the trip.

Below are ScanGauge photos of the "hottest" part of the day:
The first one shows typical flat road parameters.
The second one showest modest uphill of 5% slope.



MCo = Traction Motor Coil Temperature in degrees F
GCo = Generator Motor Coil Temperature in degrees F
HP = ICE Horsepower
CVT = eCVT transmission temperature in degrees F
fWT = Engine Water Temperature in degrees F
fIA = Intake Ait Temperature in degrees F ( usually 10 over ambient )

-John

 

Nice info.

Any idea what Ford's temperature specs are on the generator & traction motor?

For reference what do you see in these numbers for idle, and power on cruise w/o a trailer or heavy load inside?

It'd be nice if you tow a similar load but with out the windage this one had to see what numbers you get.

I've been over that stretch of I-80 many times. Its a good choice for this kind of info.

 

The temperatures were very typical for w/o a trailer.

I think the Ford Manuals say the electric motors will "shut down" and put a warning indicator on your dash if they exceed 225'C.

IIRC, 225'C = about 440'F.

That seems very hot, but I work with large industrial motors (100 to 1000HP) and 300 degrees F is often typical operational conditions.

Of worthy note, the "inverter" temperatures for the motors on my FEH were so cool, like 128'F I didn't look at them very often.

This is a very well built automobile and I am very impressed with its performance. Starting had good, but slower acceleration as expected.
Braking was very good and very smooth and NOT much different.
Without a rear-view mirror, for the most part, you wouldn't have known there was a trailer back there.

I was able to back up the driveway in the photo in EV mode with no difficulty.
In fact, I was only pulling 16 amps out of the HV battery.

I could go zero to 25 MPH from a stop-sign in EV with the 2620 pound trailer.

P.S. when you think about it, cool motor temperatures are not surprising. The ICE does 99% of the work when towing... just like it does on the highway without towing. The battery boost is just that, for an occasional boost. The motors were ~190 degrees not from any sort of use, but simply because they are bolted in close proximity to the engine.

 

I agree, it is quite well built. The numbers you mentioned don't bother me... but it is always nice to know what spec they built these things to. I've spent a career around propulsion machinery, some geared turbine and some diesel electric.

In my mind the technology, MG1, MG2, and the inverters, is well known & understood (the AC Generators with rectified output on diesel locomotives are far larger) so I don't expect much problem with these. I consider the planetary gear setup, with two electric machines, to be a quite elegant solution to the CVT problem.

Do you really think there is that much heat conduction over from the engine? With the traction machinery cooling circuit I would have thought the whole transaxle assembly would have benefited. But having electrical stuff around those numbers is probably about right for a fully warmed up engine & transaxle.

If you look at water cooled aircraft engines they only put the cooling jacket around about the upper 30-40% of the cylinder. The amount of heat to be gotten rid of from the lower 70% skirt area was found to be so low as to not be worth the weight.

When I get home I'll pull out the shop manuals and see what I can figure out to add to the discussion.

 

What's interesting is that with higher ICE power, higher rpms, & slightly higher OAT the transaxle temps went down just a little.

Any idea why?

 

You might as well have labeled this: Don't try this with a Ford Escape! The FEH is not recommended for towing, and the 4-cylinder is only rated to tow 1500 pounds. You were grossly overweight, and a hazard on the road with the vehicle overloaded like that!

http://www.fordvehicles.com/assets/p...ailerGuide.pdf

 

 

Even so, he was way over that amount.

 

i think johns findings show that the feh could well handle the load. regardless what ford says the scan g shows that the vehicle was handling the load just fine.i have always gone beyond factory specs with every ford i ever owened. and never had a problem.

 

The issue is twofold: Vehicle guarantee and insurance coverage.

If you are within the manufacturers guarantee period then towing beyond the recommended limits means no coverage if a failure is logically related to the towing. They will have to show a connection if you end up in court, but they have enormous resources to put on showing that connection.

If there is and accident claim and the insuror specifies some limits on the vehicle & tow, then there may not be coverage. The bigger deal here is the liability issue.

I just rented a U-Haul 5x8 trailer (for towing behind my Suburban) and it notes its empty weight as 900 lbs. So it would be of little use behind the FEH.

In the end I believe Ford was very conservative in the 1000 lb limit. Given the higher ratings of the other versions there is sufficient mass in it as a tow vehicle to control the load. The issue is the power available for good towing.

This post shows that there are sufficient reserves in the engine & powertrain. Note that the planetary gearset of the transaxle is a far stronger set of gears when compared to a standard gearbox.

I doubt that Ford will change the limits of those FEHs on the road, but I expect that they will begin raising the towing limits on newer models as they gain more experience.

You always tow at your own risk. Just ensure you understand just what those risks are.