edatoakrun
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The introduction of in-wheel motors for BEVs/PHEVs. When?

Wed Apr 17, 2013 12:36 pm

This has been discussed before, but I thought it might be time for a dedicated thread, as IMO, this will be a major advance in PHEV/BEV engineering and design.

At 68 lbs for 75 kW, this would already seem to be a practical proposition for larger 4wd PHEVs (ICEV front wheel drive, electric rear?) and 2wd and 4wd BEV trucks/SUVs where the unsprung weight penalty of IWMs is not as significant as it is for smaller vehicles.

Protean Electric will introduce its production in-wheel motor at the 2013 Society of Automotive Engineers World Congress in Detroit.

Protean’s new production motor provides a 25% increase in peak torque compared with the previous generation’s design and can deliver 1,000 N·m (735 lb-ft) and 75 kW (100 hp), not quite keeping pace with the new industry benchmark.

Other features of Protean’s in-wheel motors include:


•Mass of only 31 kg (68 lbs) per motor.


•Up to 85% of the available kinetic energy to be recovered during braking...


http://www.electric-vehiclenews.com/201 ... wheel.html
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Sublime
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Wed Apr 17, 2013 1:28 pm

What I found most impressive about it, is they claim the inverter is packaged in with the motor too.

So popping the hood of the LEAF, like 80% of what you see there, would either be unneeded (tranny) or in the wheel (motor, inverter).

Plus an independently controlled motor per wheel opens the door to better handling and tighter turning radiuses thanks to torque vectoring.

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GeekEV
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Wed Apr 17, 2013 2:37 pm

There was a thread on the Tesla Forums about this. Apparently it's a bad idea because it increases unsprung weight which is detrimental to handling...

http://www.teslamotors.com/forum/forums ... ub-engines

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TonyWilliams
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Wed Apr 17, 2013 4:19 pm

GeekEV wrote:There was a thread on the Tesla Forums about this. Apparently it's a bad idea because it increases unsprung weight which is detrimental to handling...

http://www.teslamotors.com/forum/forums ... ub-engines


I'd like to think the same concept can be used on each wheel with a half shaft, mounting the motor solid to the body. Perhaps the motors for the right hand side wheels are on the left to make a long enough shaft for u-joint / constant velocity joint angles.

edatoakrun
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Wed Apr 17, 2013 4:24 pm

GeekEV wrote:There was a thread on the Tesla Forums about this. Apparently it's a bad idea because it increases unsprung weight which is detrimental to handling...

http://www.teslamotors.com/forum/forums ... ub-engines



Why the multiple advantages of IWMs outweigh that one significant disadvantage, which does cause a "small performance deficit", according to Lotus engineering.

http://www.proteanelectric.com/wp-conte ... namics.pdf

As I mentioned in my OP, the first applications will be probably be in larger vehicles for which the superior load capacity, drive train efficiency, and/or 4WD performance, outweigh the disadvantage of higher unsprung weight.
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SteveInSeattle
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Wed Apr 17, 2013 8:25 pm

If there was the slights variation in motor speed between the two sides, there would be immediate uncontrolled turning. Are the electronics of EV's sufficiently developed to prevent this?
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planet4ever
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Wed Apr 17, 2013 8:32 pm

SteveInSeattle wrote:If there was the slights variation in motor speed between the two sides, there would be immediate uncontrolled turning. Are the electronics of EV's sufficiently developed to prevent this?
If you are talking about synchronous motors, like the LEAF has, that shouldn't be any problem at all, should it? In fact I would think the bigger problem would be dealing with differences in wheel speeds when turning.

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RegGuheert
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Thu Apr 18, 2013 3:13 am

planet4ever wrote:If you are talking about synchronous motors, like the LEAF has, that shouldn't be any problem at all, should it? In fact I would think the bigger problem would be dealing with differences in wheel speeds when turning.
Our SL trim level LEAF certainly has a system for detecting steering position. You can see this sensor in action when backing as it creates curved lines to show where the car will go. It seems rather accurate so far. Assumedly these or similar sensors could be used to adjust for differential wheel speeds to allow a higher power level to be directed to the outer wheel(s) when turning.
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DaveinOlyWA
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Thu Apr 18, 2013 5:11 am

Several technologies controlling the rotation of individual wheels so have to think its not a major challenge.

More interested if smaller lighter motors are out there. Seems like a lot of weight here. Granted a lot of weight is replaced bythis but we are talking X2 or X4?
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DoxyLover
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Re: The introduction of in-wheel motors for BEVs/PHEVs. When

Thu Apr 18, 2013 1:28 pm

planet4ever wrote:
SteveInSeattle wrote:If there was the slights variation in motor speed between the two sides, there would be immediate uncontrolled turning. Are the electronics of EV's sufficiently developed to prevent this?
If you are talking about synchronous motors, like the LEAF has, that shouldn't be any problem at all, should it? In fact I would think the bigger problem would be dealing with differences in wheel speeds when turning.

Ray

But each motor has its own inverter.
Sublime wrote:What I found most impressive about it, is they claim the inverter is packaged in with the motor too.

Therefore, the motors are not automatically synchronous to each other. In any case, you just need to do an electronic emulation of a differential.
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