The Economist gives a surprisingly upbeat assessment of the future of electric cars in this week’s article The electrification of motoring. I hope they’re right. It seems clear enough that if the battery cost comes down, then a lot can be simplified out of a car. This is looking pretty far down the road, but consider this scenario. If you put the motor into the wheel itself (something that is possible with an electric motor), then you can remove the engine under the hood, the transmission, the drive shaft, the gas tank, and the emissions controls, muffler, and exhaust. Not only does that free up a lot of space, but, as the article points out, it changes the car so drastically that the competitive advantage of existing car companies is much diminished. As a result, we’re likely to see some new players in the automobile industry.
Michelin has already built such an in-wheel motor, dubbed the Active Wheel. It may be a while before it goes mainstream, but it already works in the lab. Check it out.
Rambles Blog at Star Chamber 
Rocky Mountain Institute was pushing this idea 15 years ago, along with a series-hybrid drive train in which the ICE simply drives an electric generator. Can anyone explain why in-wheel motors haven’t already caught on? What’s the down-side?
The big problem, as I understand it, is the unsprung mass of the wheel. The car feels different (worse, apparently) when all that weight isn’t riding on top of the suspension springs. Other problems (as cited here) are cost and the high-frequency pounding the wheels must absorb. As is so often the case, there is a trade-off in up-front vs. running costs, and people just hate up-front costs. But the motors are getting smaller and better and cheaper, and at some point, switching will become a no-brainer.
RMI’s Amory Lovins is one of my heroes. He gives a great talk about all the energy you lose on the way from the piston to the wheel. As he puts it, the negabarrels of crude we have in the Detroit formation make us the Saudi Arabia of consumption.
I hope you and Amory are right. In the early 90’s he predicted that by now we’d all be driving lightweight carbon-composite series-hybrid cars that get over 100 miles per gallon. He was partially right about the hybrid part, but the rest is happening a whole lot slower than he predicted.
At least things are going his way. He was quoted in the Economist last year: “Yes, my ideas do sometimes have a slow burn of a decade or two before they catch on.”
As long as we’re on the subject of electric cars, don’t miss the new video by They Might Be Giants: Electric Car.
I don’t think a decade or two is going to do it for in-wheel motors. Dr. Porsche first built one of these in 1898.
http://www.cartype.com/pages/2417/lohner_porsche__1899
Unsprung weight really does matter. The wheels just won’t stay on the ground when you go over the bumps if they weigh too much. In a small car, even the weight of the brakes has a pretty negative effect on the handling.
This conversation got me thinking about inboard brakes. See http://blog.garritys.org/2009/09/inboard-brakes.html for some reax.