The GM fuel-cell revolution

General Motors is working on revolutionizing the way cars are built and sold over the long term, and it demonstrated this in its futuristic fuel-cell-powered Chevrolet Sequel concept car that we drove near New York City recently. The car combines two futuristic technologies, and it would give buyers as well as GM a lot more choices about what kind of car they want.

The Sequel is based on GM's "skateboard" architecture, with all-electric mechanical systems sandwiched into a rolling chassis, which can accept a wide variety of vehicle body styles. Since it's all electric, the powertrain would simply act as a generator to supply electricity to the motor that turns the wheels. This could be anything from a traditional gasoline- or ethanol-burning engine to a fuel cell or simply extra batteries for a pure electric car.

GM calls this technology "e-Flex," and it would also allow plug-in hybrids to charge off household current and run as an electric car for some part of driving duty. Plug-in hybrids are battery electric cars with a gas, diesel, or ethanol-powered generator (or a fuel cell) that can extend the car's range to 300 miles or more, while improving fuel economy.

The "skateboard" chassis has no mechanical link between the driver controls for steering, braking, and acceleration. On our brief drive, some of these controls failed while being monitored via laptop by a mechanic riding along with us.

GM has made a tremendous commitment to fuel cells, with reportedly more than 650 engineers focused on this future energy source. However, GM's approach depends on a high-pressure, 10,000-psi hydrogen refilling infrastructure. Today, the small number of hydrogen refueling stations operate at 5,000-psi, and most new facilities being constructed use the lower pressure.

Clearly, all manufacturers navigating the hydrogen highway face challenges before fuel-cell vehicles roam Main Street, although as demonstrated on our recent drives, this innovative technology shows tremendous promise and now depends more on infrastructure development than radical powertrain breakthroughs.

The final blog in the series will further explore the reality of using hydrogen to power cars today.

--Eric Evarts