Tech, in-wheel electric motors for extended range

By James Snodgrass for CNN

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LONDON, England (CNN) -- A British technology firm has showcased a vehicle it hopes will be the future of green motoring -- a car literally driven by its wheels. The hybrid car is powered by four independent electric motors actually inside each wheel.

The Mini QED is an independent project by PML Flightlink, an engineering company in Hampshire, southern England and is not in any way endorsed or supported by BMW, makers of the Mini.

The iconic Mini shape and its interior are the only features of the original car to remain. The engine, gearbox and braking system are nowhere to be seen. Where the engine would normally be -- under the hood -- is the battery pack. And where the gearbox would normally be are three buttons -- one for drive, one for reverse and one for parking.

Power comes from a 300V Lithium Polymer battery pack, which is charged with a 250cc two-cylinder, four-stroke gasoline engine driving a 16kW generator. Unlike conventional hybrid vehicles, such as Toyota's Prius, the gasoline engine is used only for charging the battery and does not directly power the car.

One of the perceived disadvantages of electric vehicles is the lack of range. But the Mini QED retains the fuel tank of the donor vehicle. A full tank should be enough provide a range of 900 miles (1448 km) whilst maintaining a full electrical charge.

At the heart of the technology are the four Hi-Pa Drive electric motors delivering 750Nm of torque. While electric motoring isn't seen as a high-performance option, this powers the Mini QED to a reported 150 mph (241 km/h) with acceleration of 0 to 100 km/h in less than five seconds.

The motors act as generators under braking, returning electrical charge to the batteries. There are no brake pads or discs -- braking is effected by using the motors as generators. So where -- in a conventional car -- rapid acceleration would be inefficient, in the Mini QED much of this energy can be collected under braking.

The wheels effectively become their own engine, their own brakes and their own traction control mechanism.

The wheels are in constant communication with each other deciding 1000 times each second how much torque share is optimum for the current driving conditions. Should one wheel detect a slippery surface and take appropriate anti-skid actions, the other wheels are instantly aware of this and adopt an appropriate compensating strategy to keep the vehicle as stable as possible.

Although conceived as a technical showcase, PML Flightlink's Chris Newman thinks the Hi-Pa Drive motors could appear in mainstream automobiles within years: "The reaction [from motor manufacturers] has been very positive. We hope to see production cars with our technology available to the public in the next 3 years.

"PML are discussing possible investment opportunities which will allow us to reach mass production of the Hi-Pa drives systems in the next 2 years."

Newman estimates that, in mass production, the technology should add only 10 to 15 per cent to the price of a standard petrol version of the same car.

PML has produced two Mini QED vehicles in partnership with Synergy Innovations. The two cars took eight months to engineer, following a four-year product development program.

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