Don Terrill’s Speed-Talk

No transmission, drive shaft, differential, axles, or conventional breaking system required.
http://www.proteanelectric.com/technolo ... ology.aspx

http://www.worldcarfans.com/10607246585 ... ctric-mini
0-60mph in 4.5 seconds.

Interesting idea, I've seen other wheel motor setups before but they did not have braking . Looks like it would add a lot of unsprung weight to the suspension. Leaves more room in the body for batteries though...

New take on a very old idea, undoubtedly a lot better than the old Lohner-Porsche.

steveD wrote:Interesting idea, I've seen other wheel motor setups before but they did not have braking . Looks like it would add a lot of unsprung weight to the suspension. Leaves more room in the body for batteries though...

Ditto... tremendous increase in unsprung weight. Their selling point is that it doesn't require a redesign to existing bodies, BUT I'd rather see a redesigned body with the motor mounted inboard for a net reduction in unsprung weight, since the brakes would be removed from the hubs also.

Brakes are capable of a tremendous "power output"... Even a ZR1 brakes faster than it accelerates. Can these motors even come close?

I couldn't guess what the motor weighs. It may be made from various light weight materials and should be a lot less unsprung than a solid axle suspension. I thought about the unsprung weight too but they say it isn't significant.
http://www.proteanelectric.com/faq/8/fr ... 2/faq.aspx
“While perceptible differences emerge with increased unsprung mass, on the whole they are small and unlikely to be apparent to an average driver. The nature and magnitude of the changes appears to be nothing that cannot be overcome by the application of normal engineering processes within a product development cycle.”

Brian S wrote:“While perceptible differences emerge with increased unsprung mass, on the whole they are small and unlikely to be apparent to an average driver. The nature and magnitude of the changes appears to be nothing that cannot be overcome by the application of normal engineering processes within a product development cycle."

The underlined portion above probably was not written by the engineer responsible for taking out the mass. I think they also forgot the "money" part.

FWIW, during the development of the C5 Corvette "lightness" was important...it's still about the lightest vehicle with its performance. At that time (mid 1990s) engineers could spend $10 on part cost per kilo they removed. IOW, if you could take 4.4 lbs out of the floorboard by making it a balsa wood/fiberglass composite, you could spend $20 more on it. That's GM's cost, not the selling price. That is rarely practiced in the OEM world. The 2011 $204K Porsche Speedster weighs 3388 lb. That's about 180# more than a standard C6 and about 55# more than a ZR1 which costs half as much, but twice as much as the standard C6. I guess the $10/kg ante was raised a lot for the ZR1.

I worked on a project that used prototypes from this same company in an F150 pickup truck as a demonstrator for a hybrid vehicle.

These motors were capable of around 400 ft-lbs of torque at the wheels, flat curve and impressive (i.e., not just 400 ft-lbs at zero rpm)

However the major obstacle was that the motors were quickly ruined as soon as the vehicle hit even the slightest of bumps at any kind of speed. They're still working on that problem, last I heard. It's been about a year since I've had any updates though.

I wonder why it's not mounted in the vehicle with half shafts to the wheels. With no brakes in the wheels there wouldn't be much weight there.

avengerengines wrote:I wonder why it's not mounted in the vehicle with half shafts to the wheels. With no brakes in the wheels there wouldn't be much weight there.

that is exactly what was being planned for "Version 2.0" of the truck I worked on. Lack of funding killed the project though.

Probably for the same reason that you don't see many(or is that any?) cars with the brakes mounted inboard. I know it's been done at the rear though, but not sure of the front.

RobsonCNC wrote:Probably for the same reason that you don't see many(or is that any?) cars with the brakes mounted inboard. I know it's been done at the rear though, but not sure of the front.

Oh, some lovely cars such as Citroëns and the early 70's Audi 100 had inboard front disc brakes...

Quite a few Jaguars over the years have had inboard rear disks.
It is complicating, but I'd like to see more manufacturers do it, as it pays significant dividends in ride quality.

Tesla's competator looks a bit like a Jag and it uses 4 motors.
http://www.worldcarfans.com/1080710756/ ... motor-show

It seems to me braking forces are best controlled at the wheel. Where are brakes mounted on Indy cars?
Nothing prevents the electric motors from being mounted inboard (hybrids do it) but I think diameter would be somewhat limited.
Does a large diameter stator increase torque? I also noticed these motors also don't turn at a very high rpm.

PMW is a sister company.
http://www.printedmotorworks.com/in-wheel-motors/

Brian S wrote:It seems to me braking forces are best controlled at the wheel. Where are brakes mounted on Indy cars?

If the brakes are mounted at the hub, then the suspension has to deal with brake torque as well as the longitudinal force slowing the car.
With in-board mounted brakes, those forces can be separated.

The Dark Side of Will wrote:If the brakes are mounted at the hub, then the suspension has to deal with brake torque as well as the longitudinal force slowing the car.
With in-board mounted brakes, those forces can be separated.

I agree, but the forces will be transferred through CV joints and half shafts. If there is a joint or shaft failure during hard braking you may lose control, especially if it's a front wheel. Inboard brakes will use a smaller diameter rotor than can be mounted outboard so more clamping force is required.