FWD and AWD comparison and info

[daniel-crotty]

Recent posts raised another point that I keep forgetting to ask.

Say you want to drive on the interstate at 70mpg. 2wd is going to be an X energy drain. Throw on another motor and that goes up. But now you are driving with 3 instead of two, so one would think that all 3 have to work less.

So, are you actually taking that big energy hit? I am guessing that there is more drain, but it may not be as big as people are thinking. Ignore the “more weight” or address it. There has also some talk about having 3wd and having the 3d turned off.

Anyone know? humm… may be a new post for this. People may never see this or replies.

[Mike-Mars]

I presume that the efficiency hit is mainly due to the friction of the motor. I don’t think there a way around that other than installing a clutch between the wheel and the motor, which a) would be expensive and add to maintenance costs, and b) make it impossible to use in-wheel motors.

[raymond-nettleton]

1.) With the weight distribution and torque vectoring the 2WD should be pretty good for ice and an inch or 2 of snow. Adding the 3rd drive motor won’t improve performance by 33%. Maybe 15%

2.) Deep snow is going to suck for either. The wheel pants are going to take a beating with ice chunks and lane build up. The center wheel will be ploughing snow regardless.

3.) The tesla semi actually has a clutch to prevent the unused motors from spinning. This is even more energy saving than free wheeling.

4.) I suspect any range it is 90% due to additional clearance, not AWD.

[TxAg82]

With all of the discussion of right to repair would it also be possible to change to AWD with a parts kit or salvage from a damaged car?

[george-hughes]

I’m hoping someone associated with Aptera will figure out that if you have to do things differently with services including insurance and especially recycling if you have a multi-generational vehicle.

Knowing the modular nature of Aptera (and encouraging it as well), recycling and recertification of components captured from the waste-stream would ease the availability of parts.

That said, this might be a way for an ad-hoc Aptera related business to blossom. The idea is that folks with an interest in being parts/recyclers of Aptera establish and join an Aptera parts clearinghouse. The great news is that Aptera, while it will likely take off quickly, has the advantage of a clean slate meaning there are zero wrecked Aptera in any junk yard anywhere. Statistically, the attrition rate (vehicles that are removed from service) will follow distribution.

This suggests the development of Aptera EV recycling and repair centers that if they somehow gain official status of recyclers for the brand, would also seek to recertify and reuse the various components

…Or is the insurance company auction model the best way to handle this particular waste stream?

[paul-hackett]

Let me pose the question again. Is it possible and cost efficient and therefore “really” possible to design the Aptera “AWD”/3wd” version to select “2wd or AWD”? And if it is possible would it be possible to electronically accomplish the same affect as locking differentials when in AWD/3wd? Someone early in this post mentioned living in Colorado, as I do, where my 12% grade driveway at 7,100′ at least 6 times a year gets hammered and I mean beyond a foot of snow. I plow it with a F250 with front and rear differential lockers, and I’ve plowed through more than 24″ up hill with only the rear differential locked. But my question goes to the following point: even after I plow I typically have to wait a day or two before I can drive my front wheel drive Prius on my driveway or the roads. I just think it would be great if I could drive my Aptera up the driveway after I’ve plowed it but there’s still snow falling and there’s an inch or two on the roads between the county plows, and it would seam to me that if there was an electronic “selector” that would allow me to tell the electric wheel motors to continue to turn and in effect turn off “traction control” that would be huge and allow the ability to drive on “plowed” snowy road and judiciously get me up my driveway. And I should add as I’m sure many on this forum know, even in a 23 year old F250, I have the ability to electronically switch on the fly from 2wd to 4wd; as long as I have the front hubs manually locked. 🙂

• This reply was modified 3 months, 1 week ago by  Paul Hackett.

[joshua-rosen]

The only way to disconnect a permanent magnet motor is with a clutch. How would you implement a clutch with an in wheel motor? It sounds complicated assuming it’s possible at all. They chose permanent magnet motors because they are more efficient than induction motors, the standard motor arrangement is 2WD so those motors have to be permanent magnet. There is only one motor in back, replacing it with an induction motor is theoretically possible but then you would add supply chain complexities by having two different motors. Better to keep manufacturing as simple as possible and pay the efficiency penalty for having a third motor in AWD.

[paul-hackett]

Thanks Josh, I was just curious if it was feasible at this time. I’m happy to stick with AWDx3 and a relatively small loss in overall efficiency with the AWD option.

[craig-graber]

Is there an advantage selecting All wheel Drive over just front wheel drive if one motor fails, will the vehicle be able to limp home on either just the front or just the rear motor(s)?