No arguments here!

It's a fairly simple AWD setup. It's front wheel drive until there's any wheel slip. The rear driveshaft and rear differential are "along for the ride" and spin freely as the rear wheels turn.

If one of the front wheels slips, even by a small amount, the center clutch locks up and engages the rear driveshaft. Not sure if the center is still a viscous coupling like the old one or a mechanical clutch. Most systems are viscous so my money's on that. It's electronically controlled but activated by the mechanical action of wheelslip.

The rear diff, like the front diff, is open. There's no limited slip on either. That means: If one side of the vehicle is on ice, the front wheel on the slippery side will slip. Center diff locks instantly and power goes to the rear. Since the rear diff is open, the rear wheel on the slippery side will slip, too.

In the real world, it's possible to get stuck if one front and one rear tire are on slippery surfaces. It's not likely, as "some" power makes it to all wheels. But it's possible.

Ford calls the system 4WD but says it is "generally similar to AWD, though tuned to take advantage of the off-road characteristics of an SUV." Whatever THAT means.

 

No, it uses an electric clutch to engage the rear driveline of wheelspin/slip is detected at the primary, front, drive wheels. Much like the old Aerostar system.

 

If you have a scangauge with xgauge, you can program an indicator for AWD mode, I think. I have an FWD FEH, so I can't verify it. For those that do, try this xgauge and let us know if it works:

TXD: 07E0221101
RXF: 046225110601
RXD: 3401
MTH: 000100010000
NAM: AWD

Should display ON or OFF

 

Don't we have a form of traction control, that is part of the re-gen/ABS brake system? The owner's manual seems to imply it. If so, then the traction control should take care of side-to-side power distribution.


I think that an AWD system is always driving all the wheels, even though it might change the percent of power going to each as conditions require.

Ours is a "on demand" 4WD system because there are times (actually most of the time), there is no power going to either rear wheel.

 

I love the i4WD. I have gone through some very high snow. One time for fun I pulled into my driveway and I didn't think that I would make it. I parted the snow and made it up the drive without a problem. I think we have best 4wd hybrid on the marked. I think my car will go through anmost anything nature and lake effect snow can throw at me.

 

As I understand it, the FEH has no traction control. For other Escape models, that is an integrated part of the stability control system that could not be made to work correctly on the Hybrid. I don't think the regen/ABS has any traction control capability (unfortunately).

 

Here is a Ford Media link that details the intelligent AWD system. http://media.ford.com/products/press...423&make_id=92

I did not see any side to side capabilities-only the ability to vary power front to back.

 

No, the FEH is FWD unless there's slip. Under normal conditions, no power goes to the rear. When slip is detected, the center coupling locks and directs power rearward. The old system used something called a "rotary blade" coupling which was a sort of lockable fluid coupling. It directed some power to the rear all the time and could be locked into a simple 50/50 F/R power split. Ford positioned it as a substitute for true off road 4WD, since the idea back then was that SUVs had to be fairly off-road capable.

Regarding traction control: While the FEH doesn't have it, it does have a system to limit the MGs spinning too fast. Conveniently, this limiter acts as a sort of "virtual" traction control in some conditions.

The details: If momentary (like a few degrees of rotation) wheel spin occurs, the 4WD coupling on 4WD models locks and power is directed to the rear. If additional slip occurs (like when the rear wheels slip, too), or if the vehicle is a FWD, the computer reduces MG power output. It does this because allowing the MGs to spin up without significant load can damage them. This all happens in milliseconds and is pretty hard to detect.

While not a true traction control system, this spin-limiting design does also aid traction like a real (brake based) traction control system: By cutting power to the driven wheel(s) when wheel spin is imminent.

 

Then what's the traction-control-active indicator on the dash for? I am sure that if Ford could have saved itself a light bulb, it would have.

 

From the little knowledge I have side to side "power" would be controlled mechanically by the differential. It has to be that way since in going around a corner one wheel has to turn faster than the other.