Ford has attempted to trump GM's Chevrolet Volt plug-in with a hybrid electric plug-in version of the Edge crossover that combines a hydrogen fuel cell generator with lithium-ion batteries.

The vehicle is built on a flexible powertrain, an architecture that will enable Ford to use new fuel and propulsion technologies as they develop without redesigning the vehicle.

"This vehicle offers Ford the ultimate in flexibility in researching advanced propulsion technology," said Gerhard Schmidt, vice president of research and advanced engineering at Ford. "We could take the fuel cell power system out and replace it with a downsized diesel, gasoline engine or any other powertrain connected to a small electric generator to make electricity like the fuel cell does now."

The new HySeries Drive powertrain uses a real-world version of the powerplant envisioned in the Airstream concept unveiled earlier this month at the 2007 Detroit motor show.

The plug-in hybrid is powered by a 336-volt lithium-ion battery pack at all times. The vehicle drives the first 25 miles each day on stored electricity alone, after which the fuel cell begins operating to keep the battery pack charged. This provides another 200 miles of range for a total of 225 miles with zero emissions.

When the battery pack is depleted to approximately 40%, the hydrogen fuel cell - supplied by Ballard - automatically turns on and begins generating electricity to recharge the batteries. Like a conventional vehicle, the Edge hybrid will go until it runs out of fuel - in this case via a 350-bar hydrogen tank that supplies 4.5kg of useable hydrogen.

The HySeries Drive name is derived from the powertrain's structure: a hydrogen fuel cell-powered series hybrid drivetrain. This highly innovative approach reduces the size, weight, cost and complexity of a conventional fuel cell system by more than 50%. It also promises to more than double the life of the fuel cell stack.

This flexible powertrain architecture enables the use of new fuel and propulsion technologies as they develop and become available without the need to redesign the vehicle and its control systems.

Ford said that, certainly, many significant technical hurdles need to be overcome before a vehicle such as this Edge can become a reality. Fuel cell vehicles remain expensive, costing millions of dollars each. And the single biggest hurdle to plug-ins remains the cost of lithium-ion batteries. Much work also needs to be done to make fuel cells more durable and to create a hydrogen infrastructure.