Selectable AWD? Has this been asked?

[pb3]

It occurred to me -- what's preventing a feature to allow the driver to switch from AWD to RWD-only when the former isn't needed?

This would potentially save a lot of energy even if the front wheels can't "freewheel" per se.

OTA feature upgrade?

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[generaltso]

The front motor is a permanent magnet type. I don't believe that will be possible in software.

 

[EVer]

I don’t believe the front motors can free spin

 

[pb3]

I don’t believe the front motors can free spin

I wondered about that. But what if they got enough juice to match the speed of the rears without actually adding any "torque"? Wouldn't that save energy?

 

[VegStang]

Might be one of the drawbacks from having the motor in-line, but I like the idea. I'll assume that Ford will make this as efficient as possible when my inputs don't require the torque or for traction.

 

[dbsb3233]

I wondered about that. But what if they got enough juice to match the speed of the rears without actually adding any "torque"? Wouldn't that save energy?

No, because whatever torque the front motor adds means less the rear motor has to add, and vice versa. It likely adds up to about the same kWh usage either way. Maybe a tiny difference but negligible. And Ford likely tunes that to balance it for the best efficiency anyway.

 

[ChasingCoral]

No, because whatever torque the front motor adds means less the rear motor has to add, and vice versa. It likely adds up to about the same kWh usage either way. Maybe a tiny difference but negligible. And Ford likely tunes that to balance it for the best efficiency anyway.

If anything, you want the smaller front motor to do the heavy lifting when cruising, reducing the work by the bigger rear motor.

 

[dbsb3233]

If anything, you want the smaller front motor to do the heavy lifting when cruising, reducing the work by the bigger rear motor.

It's geared the opposite way though (front at 10.0:1, rear at 9.05:1). Not sure it really matters when always engaged though. What probably matters more is the efficiency of the motors at different RPM points. They could have different "sweet spots" for the RPM ranges they're most efficient at.

I really don't know enough about it though. More just kinda speculating.

 

[ChasingCoral]

It's geared the opposite way though (front at 10.0:1, rear at 9.05:1). Not sure it really matters when always engaged though. What probably matters more is the efficiency of the motors at different RPM points. They could have different "sweet spots" for the RPM ranges they're most efficient at.

I really don't know enough about it though. More just kinda speculating.

Yes, I agree with your earlier assessment that it might have made sense for maximizing highway range to have a lower gear in front. The gearing on those two motors was probably optimized using the simulators.

 

[SnBGC]

The front motor has a higher rpm limit so it can have a steeper gear compared to the rear motor. Benefits are more torque multiplication for acceleration and RPM increase for regeneration. It looks like the front motor is responsible for the majority of the regeneration on AWD vehicles. You can get a clue to this by looking at all the cooling plumbing shown in the owner's manual and from the factory photos of the chassis assembly.

The 10 to 1 ratio up front means the motor turns 10 times for one wheel rotation. That is opposite of what most people mean when they say "highway gear"

 

[trutolife27]

If anything, you want the smaller front motor to do the heavy lifting when cruising, reducing the work by the bigger rear motor.

fact

 

[Jimrpa]

Silly question: isn’t there some kind of clutch-like mechanism in the propulsion units (whatever those things from borg-Warner) are called) that would essentially disconnect them from the drive shafts on command?

 

[SnBGC]

Silly question: isn’t there some kind of clutch-like mechanism in the propulsion units (whatever those things from borg-Warner) are called) that would essentially disconnect them from the drive shafts on command?

Nope.

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