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Michelin to Commercialize Electric Active Wheel Technology

Michelin’s Active Wheel integrates brake disk, electric motor and suspension motor. Click to enlarge.

Michelin’s Active Wheel, an in-wheel system comprising a brake, 30 kW (40 hp) electric traction motor and electric suspension motor system, will be used in the Heuliez-produced WILL electric vehicle (battery or fuel cell), due to be available to fleet owners in 2010. The WILL grew out of a concept developed by Heuliez and Michelin and features networked services innovated by Orange.

Michelin has shown earlier versions of the Active Wheel in concepts before, such as the Michelin/PSI Concept HY-LIGHT Fuel Cell Vehicle shown at the 2004 Challenge Bibendum in Shanghai. (Earlier post.) The two-wheel motor WILL is its first application in a series production-intent vehicle. The partners showed the WILL at the Paris Motor show in October. Venturi Automobiles also showed an application of the Active Wheel in the premier of its four-wheel motor Volage.

The electrical suspension system in the Active Wheel features an extremely rapid response time—3/1000th of a second. All pitching and rolling motions are automatically corrected.

The WILL. Click to enlarge.

The Michelin-Heuliez-Orange WILL. The WILL, a front-wheel drive electric vehicle, seats five and features two trunks (front and rear). The model presented at the Paris Motor Show was a five-seat family car with lithium-ion batteries. Four versions will be available starting in 2010: battery or fuel-cell powered, for commercial or family use. Users will be able to choose from among three energy modules that offer driving ranges of 150, 300 or 400 kilometers (93, 186 or 249 miles). Depending on their needs, drivers will have the option of changing from one module to another on the same vehicle whenever necessary. In this way, the partners say, WILL’s driving range can evolve to suit each user’s needs, at any time.

The first WILL is scheduled to hit the road this year, followed by other models for testing different solutions, notably in terms of energy supply and interior design. By 2010, Heuliez’s assembly lines in Cerizay, France, will be ready to begin producing the car, with a first-year output target of several thousand vehicles. Michelin will supply all the Active Wheel assemblies. This project has received financial backing from Oséo.

Venturi Volage. The Volage is a four-wheel drive two-seater roadster featuring four Active Wheel systems. As shown at Paris, the Volage uses a 45 kWh lithium polymer battery pack weighing 350 kg. The Volage accelerates from 0 to 100 kph in less than five seconds, has a range of approximately 320 km (199 miles) and a top speed of 150 kph (93 mph).

(A hat-tip to GreenPlease!)



Peace Hugger

Looks like a game changer


The dual trunk could be very handy for such a small vehicle.

The driving ranges are pretty impressive too.

This could be an ideal city car.


I really think that having the motor in the wheel changes the game design wise. I see much more aerodynamic vehicles in our future.

This concept would further benefit from a composite wheel technology which would further reduce the sprung mass.

very interesting how they keep the motor so small. compared to almost all of the other in wheel motors which seem to take up the whole interior volume with the rim, this one is a small unit. makes me wonder if there wont be torque transfer issues, but i agree it looks to be on the right track. (in fact, why on include two such motors (snaller?) in each wheel? better redundancy and power transfer, etc)

electircally actuated, elecronic, in wheel, stability and anti roll machanism, is briliant.
This is the game changer.
wouldnt be surprised to find in in high end sports cars soon led by closed wheel racing.


Here's the new game ... car companies become nothing but coach builders. Drivers can keep the coach and change the wheels if they want better performance. Or, keep the wheels and upgrade the coach. This paradigm could lead to infinite variety in automotive design creating a truly consumer/fashion based coach business leaving the technology to the wheel builders. Bravo!


They probably have a tranmission in the motor, no ? Either some planetary type or harmonic drive, perhaps.


It seems that this type of active wheels could easily be scalable to suit any size of vehicle. Ways will be found to make it as light as possible. To go from 2WD to AWD would become an easy choice.

Once mass produced (in various sizes) on automated assembly lines, it could become a customer exchangeable component (just like tires). This would mean the end of motor mechanics.

Modular standardized e-power packs (ESSUs or battery packs or modules) could also become customer exchangeable. Every vehicle could be built to accept 2 to 6 battery modules. Customers would buy and install as many modules as they can afford or require.

The end of personal transport pure ICE vehicles may be closer than we think.

Michelin, with large factories in a few dozen countries, could become a major active wheels manufacturer.

Let's hope that major car manufacturers will use similar solutions within a few years.

A four to five passenger e-car at less than one tonne should be possible.


My first thought goes to maintenance. I mean a regular tire isn't exactly something u just throw around now they have to go into ur wheels to do tune ups, or the equivalent. Also prob needs some kind of gunk guard.

Overall i like the idea especially modularity. Then like previously mentioned aerodynamics becomes less hindered by not having to worry about having a huge block up front.

This article also implies that all safety regs have been passed. Impressive


There does not appear to be any mention of it, but
this has got to require some type of external cooling.
Even at 95% efficiency the motor is going to disipate
1500 watts. Thats about a frying pan. At 160 degress
ambient, the motor would glow cheery red without any


Friction brakes dissipate orders of magnitude more than 1.5 kW, so air cooling should be sufficient.

Henry Gibson

No highway electric car should be allowed on the road, sold or advertised without a built in engine powered battery charger and fuel tank. Such devices can be very small, high performance and very low weight. The OPOC engine is just one example already used in a hybrid electric vehicle. Even smaller lower powered ones are acceptible similar to the multispeed generator system in the Honda portable power system EU1000is. Such small units can be engineered for very high power, but in many cases they will rarely be used. Their cosmetic purpose purpose is to eliminate the limited range comments like the ones in this article. Their useful purpose is to eliminate the fear of limited range in the consumers mind and to dramatically reduce the cost of the vehicle by allowing the use of much smaller and cheaper batteries. A very long life fuel, such as butanol, can be kept in the tank in case the engine is seldom used by a particular owner, but ordinary gasoline can be used when necessary.

Most people do not know that only four or five kilowatts or less is required on the average to keep up with traffic flow in city traffic. Even very low energy batteries allow fast acceleration after a stop or recovering energy whilst stopping. EFFPOWER makes such batteries with lead chemistry. Lithium is not needed for plug-in-hybrid cars nor is any other new battery technology. Low first cost and low operating costs are what is required.

No new electric wheels are needed to make an electric car possible, but they might give such a car better performance. CSIRO already has an electric wheel. ..HG..


I just confirmed that the function of the electric suspension motor is to produce electric braking energy. What I don’t understand is why a separate electric motor is needed for regenerative braking? Why can’t they just use the same motor for driving and regenerative braking?


The point is that the text indicates that the
motor input is 30 KW continuous. If you ride around
with your breaks dissipating even a faction of
that power, they will fail catastrophically, in
only a few minutes. An induction motor can not
operate over 200 degrees F for very long, the
control electronics, and most wire insulations
will fail at those temperatures.


According to the photo, second motor is for actuating active suspension, not for traction.


Thank you. So it is mainly about thermal management. By having one motor for traction and another only for regenerative breaking you will have more efficient regenerative braking because the regenerating braking can be on for many more seconds before the critical temperature is reached that will necessitate a switch to ordinary friction brakes. The traction motor can’t be used for regenerative braking for many seconds because it is on almost constantly and therefore is hotter than the dedicated regenerative braking motor that only is on when the driver brakes and therefore has time to cool more between the brakes. That makes sense. Another reason could be efficiency gains from specializing the electric motors to respectively traction and regeneration which is probably more efficient than one motor doing both even when ignoring the thermal advantage.

Is it possible that the extra motor is there to provide power generation via suspension as in a recent GCC post? Then the drive motor would be providing both motive power and regeneration.


IMO, these motors should be liquid cooled, to maintain power density at the very least.

Adding a range extender is a mistake, IMO. While batteries may be expensive, these costs can be partially offset by the simplicity of a pure EV architecture.

If we could somehow get motor efficiency to 97% air cooling will be viable as heat dissipated will be proportional to vehicle speed and therefore air flow over the motors.


Ah, let them recycle the heat in the future iterations.


Nick, the motors are rated at 30kW continuous. But if you were to drive around continuously applying 30kW to each front wheel in a vehicle that size, you'd find yourself exceeding the speed limit by rather a lot, quite quickly.

For point of reference, conventional mid-size passenger cars with decent aero need around 5-8kW continuous to maintain 55mph...


It is a space saver, obviously.
But it requires 4 motors at least (2 per wheel).
One stronger motor like in Mitsu MiEV electric should be much cheaper to build.
This design may have many reliability issues, especially if driven in salted snow.
Suspension travel is limited.

Probably more suitable for a smooth race track than for everyday vehicle.


Cute ! One more brick in the puzzle.

Reliability may be an interesting concern though. Shocks, vibrations, heat, cold, etc. A wheel is pretty exposed. I'm curious to see how this arrangement will fare compared to a more "sheltered" engine under the hood.


Motor heating is not an issue. Let’s assume continuous load 8 kW. In case front wheel drive it would be 4 kW per wheel. Since 5% of power will be transformed into heat then heat output per wheel would be 200 W. This can be easily cooled down by air flow at 40 mph. In case 4 wheel drive it would be only 100 W/wheel heat output.


Motor heating is not an issue. Let’s assume continuous load 8 kW. In case front wheel drive it would be 4 kW per wheel. Since 5% of power will be transformed into heat then heat output per wheel would be 200 W. This can be easily cooled down by air flow at 40 mph. In case 4 wheel drive it would be only 100 W/wheel heat output.


Sorry but I think that I got it all wrong. There is presumably no regenerative function in the electric suspension motor. To quote “While the drive motor transmits power to the tire, the other (the "electrical suspension motor" in the diagram) controls torque distribution, traction, turning maneuvers, pitch, roll and suspension damping for each wheel independently. A standard brake disc fits between the motors.” See

Presumably a much more sophisticated suspension system than normal is needed to make the system more durable. So regenerative power is included in the drive motor as well?

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