Mini Cooper

"Weve sort of reinvented the wheel," says Chris Newman of PML Flightlink, the small British electrical-engineering company that has produced a remarkable electric Mini.

Outwardly, only the oversize wheels protruding from the bodywork distinguish the PML prototype from a standard-issue Mini Cooper. It is those wheels that also separate this prototype from all other electric and hybrid cars available today.

But the company is confident that it has a better solution amid the electric-and-hybrid-vehicle debate. Hub motors are not new, but PML claims its motors have the best power-to-weight ratio in the industry. PMLs motor unit, including the miniature Hi-Pa drive inverter, weighs 53 pounds, and the complete wheel assembly, including the tire, is only 4.4 pounds heavier than a regular Minis, so the effect on unsprung weight is small.

To produce the vehicle, PML starts with a new, dealer-purchased Mini and then removes the engine, the transmission, and the brakes. Under the hood go a 300-volt lithium polymer battery pack and a series of 135 supercapacitors that boost top-end power as well as electrical power. Each wheel motor is electrically controlled and requires no transmission or differential. The motors also act as the brakes, taking the cars kinetic energy and converting it to electrical energy. At this stage, PML has not developed a way past legal requirements that call for a mechanical backup brake system. Under the rear floor, in space liberated by removing the original exhaust system, is a 250cc twin-cylinder four-stroke gasoline kart engine that, when required, will run at constant speed to recharge the batteries. PML expects the electric power will last about four to five hours at an average speed of 50 mph before the gas-powered generator fires up to refill the batteries. Fuel consumption is claimed to be about 65 mpg. The batteries can also be charged from a household electrical supply.

This 640-hp Mini exists just to get our attention. According to PML, the Mini cost about $350,000 to build, but the motors and their casings were handmade. Mass-producing the motors and control systems could bring the price down substantially, and only two of the powerful motors would suffice in most applications. PML hopes to hook up with a car manufacturer or investor seeking to enter the electric-car business.