In-Wheel Electric Motor

[SHRED]

Wow.

Protean markets its in-wheel motor for both hybrid and all-electric applications. Each unit sits in the space behind a wheel, supplying power exactly where, and when, the driver requires.

It's certainly powerful, with each motor alone producing 75 kW (100 horsepower) and 735 pounds-feet of torque.

Each also weighs "only" 68 pounds which probably isn't so good for unsprung mass--all the weight not supported by the car's suspension, affecting handling, steering, responses and ride quality. Protean does say that the extra unspring mass can be compensated for in other ways though, reducing the effects of significantly heavier rolling stock.

And with claimed economy improvements of up to 30 percent (depending on battery size), the benefits may offset the negatives for many. Protean also says up to 85 percent of the vehicle's kinetic energy can be recovered when braking.

http://www.greencarreports.com/news/1083562_protean-launches-production-in-wheel-electric-motor

[BlueStreak]

1. It is interesting and an impressive amount of integration

But Protean has been hyping this for years now and nobody has taken them up on it. It seems ideal for a world of fuel cells where there would be no gas engine to integrate with.

One big concern is that this is a HUGE amount of unsrprung mass -- more than doubling the unsprung mass of conventional cars. The upshot is that this could become a real safety issue because it can be hard to keep the tire in contact with the road as unsprung mass goes up.

Rather than going for ridiculous amounts of horsepower per wheel, I think they would be better off concentrating on reducing the mass and cost. Instead of 100 HP per wheel, a much more compact 30 HP package would be dandy for most normal transportation needs.

[Gregorian]

2. Not new. There's a Mini Cooper from several years back this this configuration.

From 2006

http://www.worldcarfans.com/10607246585/pml-builds-640hp-electric-mini

[BlueStreak]

3. Actually that may be the company I was thinking of

The Cooper was done by Synergy Innovations. This Protean company seems to be a Shanghai outfit. My guess is they just ripped off the work of Synergy Innovations.

[wtmusic]

4. Yikes.

Impressive, but 270 lbs of unsprung mass sounds like a handling nightmare.

[jmowreader]

5. If you want to do this right, look at a military Hummer

The military Hummers (and the civilian H1, but not the H2 and H3) have the brakes bolted to the side of the differential, and power is transferred to the rim of the wheel via a half-axle. If they did something similar with this - putting the motors and brakes along the car's centerline and using half-axles to connect the wheels - all that weight becomes sprung.