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DJP
User Rank
Silver
Wheel-hub motor
DJP   8/24/2012 10:33:10 AM
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Yes, the wheel-hub motor is a very old idea. The Lohner-Porsche from 1901 used it.

Ivan Kirkpatrick
User Rank
Platinum
Re: Novel design approach
Ivan Kirkpatrick   8/24/2012 10:26:56 AM
Computerized control of each wheel's torque for both driving and braking will eliminate any adverse effects on the controls and driving experience.  Torque steer which I eperienced in my 200 Honda Accord under hard acceleration and a curve can be eliminated by appropriate algorithms in the cotrol system.  The same control system can also compensate for loss of power or traction on any combination of wheels.

These systems will evolve and prices will come down once they enter mass production.  The benefits of a computer controlled all electric wheel motor arre very compelling.

I remember the Tom Swift books where he built an atomic powered car with wheel motors.  I think it could fly as well using the Coanda effect on some rotating cylinders near what would be the rocker panels. 

DanielJoseph
User Rank
Gold
Controls and Unsprung Weight
DanielJoseph   8/24/2012 10:19:34 AM
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I am glad to see companies attempting new ideas.   This idea isn't exactly new, (http://www.treehugger.com/cars/electric-mini-0-60-in-4-seconds-it-has-motors-in-its-wheels.html) but who really cares unless there is IP involved.  I hope their efforts bear fruit for others to take it further.  The tough parts to this solution will be the control software (traction control, stability control, failure modes) and managing the effects to the passenger's ride experience from the extra unsprung weight in the wheels.  I'm not a tire expert, but I bet it will take special small tires to handle the extra stresses as they will undoubtedly rely on the tires to absorb some of the energy from bumps.

 

kufman
User Rank
Iron
Re: Novel design approach
kufman   8/24/2012 10:17:35 AM
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With the amount of power they have at each wheel, it should work just fine as an AWD.  After all, they have almost a Prius at each wheel!  This could be a better than any other version of traction control because each wheel can be controlled independantly.  Not something that you can do with 1 power plant and brakes.

I don't think unsprung weight will be much of an issue either.  This is a commuter car not an entry into a F1 race.  

Contrarian
User Rank
Gold
If it seems too good to be true...
Contrarian   8/24/2012 10:02:19 AM
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the SIM-WIL has four motors -- one in the hub of each wheel. Each delivers 65kW of power, giving the car a total output of 260kW


Wow, a compact car with 350 HP on tap?  Those are some serious wheel motors.

The holy grail has always been to put the motor in the wheel but physics keeps getting in the way- coming up with a low mass, high power and high efficiency design is not simple nor inexpensive.


These claims of range and power at this price point do not pass the common sense test.  I'll believe it when I see it, otherwise it's just vaporware.

 

 

Rich Casebolt
User Rank
Iron
Re: Novel design approach
Rich Casebolt   8/24/2012 9:55:37 AM
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The other potential issue, is synchronized control of the four motors ... if a failure occurs and one motor loses power, what does that do to control and handling (and tire wear).  I would think that the AWD traction control systems would face similar problems, so perhaps this problem has been approached there - except that in those systems, you can default back to standard 2WD operation, which I see as less of a problem than inducing a sudden imbalance between the four drive wheels.

Ivan Kirkpatrick
User Rank
Platinum
Time will show....
Ivan Kirkpatrick   8/24/2012 9:52:03 AM
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I think time will show that the idea of wheel motors is pretty compelling.  Given the ability to control the torque at each wheel will improve handling.  It is a tradeoff with the increased unsprung weight but eventually the wheel motors will be much lighter.

The design benefits should not be overlooked in terms of reducing the amount of space taken up by the motor, transmission and other drivetrain components.  Moving all this outboard to the wheel provides more room in the chassis for batteries.

The use of plastics is very significant in that reducing weight of the vehicle is the only first order variable in miles per gallon or in this case range of the vehicle.

I 'm looking for a small two seat commuter car much like this one.  I drive less than 75 miles per day on my daily commute and can park the car in the garage and connect it to a 240 volt charger for an overnight charge.  Five days a week, 50 weeks a year.  My big crew cab pickup with a V8 getting 17 miles per gallon will be relegated to weekend duties around town and long distance trips. I figure the savings in gas expenditures will pay for a good piece of the new car payments.

kf2qd
User Rank
Platinum
How durable???
kf2qd   8/24/2012 9:40:56 AM
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I wonder how durable this system would be. Motors in the wheel where the magnets would also be exposed to all the road shock. I ahve worked with motors where the magnets came loose that were solid mounted with no shock to the motor. Also the cables, the iregular vibration that they would be exposed to going from the frame to the wheel would have to be considerred a harsh environment.

I would favor a mid mounted motor driving 2 wheels through more conventional half shafts. Fewer motors with the motors temselves being isolated from vibration and shock. Also would require few, albeit larger, motor controllers. From experience - the more complex the system, the more likeley it is to fail. More controllers, the more places to fail and the more likelyhood of a failure...


My opinion is that many of the current designs are made t do well in the JDPowers 1 year owner survey, but I would like to know how these designs will do in 5 and 10 years. For $32,000,00 US this car has to last a while to be able to justify the expenditure for all but the wealthy. Byut then, when folks will commit themselve to a $300,000+ house that they can't pay for I guess a $32,000 car they can't pay for seems like peanuts.

ChasChas
User Rank
Gold
Re: Novel design approach
ChasChas   8/24/2012 9:33:21 AM
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Yes, there is the unsprung weight issue, but what about traction control?

True traction control is impossible with only a quarter of the power available for each wheel. No good for an AWD type vehicle meant for snow, slush and mud.

Bunter
User Rank
Platinum
Web site observations.
Bunter   8/24/2012 9:29:35 AM
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Hmmm...looking at the website I'm getting the impression this is still pretty conceptual.  The claimed weight on their pdf was 1580 kg (3483 lb), OK but not amazing and production vehicles rarely seem to make their projected weight.

With EVs I'm taking the stance that I'll believe their mileage claims when several independant testers confirm it and I'll believe their "price" when they can operate profitably at that number without external support.

Best of luck to them, but I'm not getting excited just yet.

Dennis

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