Issues with battery tech aside, electric motors allow for the creation of much simpler vehicles, without the need for exhausts, cooling systems, or complex lubrication schemes. The next logical step for electric vehicles is to move the electric motors into the wheel hubs themselves, replacing driveshafts, transmissions, and differentials with much lighter wires and switches. The primary problem with this configuration is the huge jump in unsprung weight that comes with mounting heavy electric motors inside of the wheels. Michelin Tires thinks it may be a step closer to solving this problem with its Active Wheel technology, unveiled at the 2008 Paris Motor Show.
The Active Wheel system consists of the wheel and tire combination, an electric motor, an active suspension system, and disk braking system all integrated into a 95-pound package. Essentially, every element of the power train and suspension has been compacted. Smaller 14.4 pound electric motors can be used because there will be two to four of them sharing the load. Use of an electronically controlled active suspension system allows for a smaller, shorter travel suspension that can be optimized for road conditions.
The Heuliez Will--a prototype based on the Opel Agila--has been built in a partnership between Michelin, coachbuilder Heuliez, and the telecommunications company Orange. This front wheel drive prototype features an unsprung weight of 77 pounds per wheel on the front axle and 53 pounds per wheel on the rear axle (thanks to the omission of rear wheel motors). Michelin points out that the similarly sized Renault Clio features an unsprung weight of about 84 pounds at all axles, so the Active Wheel has already saved weight there. Offsetting the weight gained by the addition of the battery pack with the weight saved by the removal of the engine, fluids, differentials, transmission, and full fuel tank, and the final tally is a Heuliez Will that's 165 pounds lighter than the Opel Agila upon which it is based.
The Heuliez Will also seats five, features two trunks--one in the back and one in the front where the engine used to live--and thanks to the contributions of Orange, features in-car high speed Internet and live traffic monitoring and navigation. The two in-wheel electric motors deliver 41 horsepower to the front axle (can you even still call it an axle?) and up to 82 horsepower for short sprints and merging. The Heuliez Will should hit 62 mph from a dead stop in 10 seconds and will have a max speed of 87 mph. Three lithium ion battery configurations are available offering ranges of 90, 185, and 250 miles. Based on these specifications it should be pretty clear that the Heuliez Will is designed for urban living and commuting, not long road trips or performance driving.
The first batch of Heuliez Wills are testing now on the streets of France. Heuliez anticipates that they will be able to make the vehicle available in Europe, with the Active Wheel tech in place, for a limited release in 2010 and to the public by 2011 for an estimated price of 20,000 to 25,000 euros.
Those looking for a few more thrills, a few more kilowatts, and a much more exotic aesthetic should look for the Venturi Volage, which also features Michelin's Active Wheel system, but with a 0-60 time of about five seconds and a top speed of 93 mph. The Volage will see a limited production run--also in Europe--in 2012 for a yet unnamed price.