[John]

This could be very cool. Independent torque controlled high powered all wheel drive and extreme mechanical simplicity. It could be a huge leap forward in terms of vehicle dynamics. It could do full regen with proper brake bias not just fore and aft but also left and right if braking while cornering. It could do active yaw control with the drive assisting the turning of the vehicle possibly even using a combination of Regenerative Braking and drive on the inside and outside wheels to aid vehicle turning. The computer could dial down the torque to any wheel when excessive slip is detected. All manner of new things could be done that aren't currently possible with today’s cars. It could put the electric car firmly out in front in terms of drivability and nimbleness and surefooted safety.

[JRK5150]

Yeah, this is cool! Traditionally, converting a car to electricity has been a bit of a compromise, but this could actually make the cars perform better in every way. Also, with no engine or transmission, vehicles will be left with a large, empty engine bay that could be filled with a generator... extra batteries... fuel cell... the options are endless!

[mattW]

It would also make a conversion to a series hybrid ridiculously easy. Just swap the wheels and add a battery pack/controller while keeping the existing engine (or downgrading the size). It could be fitted pretty easily to just about any vehicle with the space for batteries.

The only problem would be designing the motors for such low rpm and sensing/controlling the 4 wheels at once.

[Dennis]

To make such a motor you would need the following:

• Vacuum Pressure Impregnation System (VPI)

• Oven

• High temp Resin

• Metal press with dies needed to cut out the stator and rotor steel sheet laminates

• Thin steel sheets on large rolls

• Enamel coated copper wire

• Furnace for melting copper or Aluminum

• Special metal casting machine to cast the rotor bars of either aluminum or Copper into the rotor...

• Nomex paper

• Coil winding machine (unless you want to do it by hand)

• Induction heating device to heat the inner race of the bearings such that it expands to fit over shafts.

• Test equipment such as insulation testers...

This undertaking is not exactly what I call easy. Maybe you can outsource the rotor design and stator design?

[JRK5150]

Anyone else in the central Florida area? I think I'd like to start developing this into a working concept. I don't have a problem with fabrication, so my plan is to get a small, fairly aerodynamic piece of junk and mount conventional AC motors at each wheel. We could use this to develop the controller setup. After we have the controller designed and programmed, we could post free plans and software online for everyone to use. Then we could work on developing the actual motor. I'm looking around locally as well, to try and find others to help.

[JRK5150]

Would developing this in stages be the best idea? Rather than jumping head first into the entire project with all of it's complexities, maybe the best idea would be to break it down into steps.
For instance, step one could be to mount two conventional AC motors to the rear wheels of a front wheel drive car. This could be used to develop the control system without the extra complexity of four wheels or the need for complex algorithms for steering wheel motors. It would allow for the main controller to be developed as well as the basic programing for the wheel motor controller.
Step two could be designing and building the actual wheel motors. With the basic control system in place and wheel motors built, we would have a simple 2wd conversion for light cars. This would also be nearly a bolt on hybrid setup for most front wheel drive cars.
Step three could be to add the front wheel motors and work out the added complexities of four motors working together as well as steering inputs. This would open the door for heavier, all electric conversions as well as true hybridization.
This seems to be the quickest way to having this technology on our cars. Does this make sense or am I just over thinking it?

[Wirecutter]

Originally Posted by mattW

The only problem would be designing the motors for such low rpm and sensing/controlling the 4 wheels at once.

I have to agree with Manntis about the unsprung weight issue. A wheel-hub motor would be fine for something like a forklift or some kind of industrial vehicle where weight isn't as much an issue, and the "road" surface is very smooth. What I always thought of when I considered a "4 wheel - 4 motor" vehicle is having the motors mounted inboard and shafted to the wheels.

Back to mattw's comment, though - I read that this sensing and controlling of motor speed is one of the things that makes the Wrightspeed X1 so stinkin' fast. The AC Propulsion controller used in the X1 is modified to provide traction control. It will sense wheel speed of the driven and undriven wheels, and allow the driven wheels to spin only slightly faster than the undriven wheels. The effects of limiting the amount of slip allowed between the tire and the road surface is already well proven with ABS. I would imagine the algorithm gets slightly more complicated when dealing with turning and attempting to power slide, because at such times, front and rear wheels need to turn at different speeds. But I would also imagine that the performance of such a car would feel absolutely marvelous.

Ok, well it's a cool idea, but I admit a little problematic for a vehicle with all wheels being driven. You'd have to come up with another way of measuring the ground speed of the vehicle.

-Mark

[mattW]

Have you guys seen this:
Siemens VDO eCorner Project
That wheel does just about everything!

[unclematt]

Originally Posted by Wirecutter

I have to agree with Manntis about the unsprung weight issue. A wheel-hub motor would be fine for something like a forklift or some kind of industrial vehicle where weight isn't as much an issue, and the "road" surface is very smooth. What I always thought of when I considered a "4 wheel - 4 motor" vehicle is having the motors mounted inboard and shafted to the wheels.

Back to mattw's comment, though - I read that this sensing and controlling of motor speed is one of the things that makes the Wrightspeed X1 so stinkin' fast. The AC Propulsion controller used in the X1 is modified to provide traction control. It will sense wheel speed of the driven and undriven wheels, and allow the driven wheels to spin only slightly faster than the undriven wheels. The effects of limiting the amount of slip allowed between the tire and the road surface is already well proven with ABS. I would imagine the algorithm gets slightly more complicated when dealing with turning and attempting to power slide, because at such times, front and rear wheels need to turn at different speeds. But I would also imagine that the performance of such a car would feel absolutely marvelous.

Ok, well it's a cool idea, but I admit a little problematic for a vehicle with all wheels being driven. You'd have to come up with another way of measuring the ground speed of the vehicle.

-Mark

The whole "unsprung weight" issue is overblown in my opinion. Yes, we should design them as light as possible, but in my research I have found that most manufacturers found that when much of the weight is removed that is associated with the regualr drivetrain that the wheel motor ends up weighing only slightly more by comparison. I am NOT interested in mounting motors to shafts. That defeats part of the purpose of doing wheel motors in the first place.

[unclematt]

Originally Posted by mattW

Have you guys seen this:
Siemens VDO eCorner Project
That wheel does just about everything!

Their concept is a good one, but they still use friction brakes, which is unneccesary and weighty. They also do not offer them to the public at any price, so they are vaporware for the moment.