Hybrids are now an accepted part of our vehicle landscape, with electric cars powered by lithium-ion batteries on the horizon. But General Motors and other manufacturers are also looking much further ahead, toward a future where our personal transport—what we might call “a car”—is powered exclusively by hydrogen fuel cells.
GM has spent a decade working on fuel-cell cars, with several concept vehicles along the way: the HydroGen1 of 2000, and the AUTOnomy and HyWire concepts revealed in 2002. The most recent push came five years ago from CEO Rick Wagoner’s challenge to Larry Burns, GM’s global head of research and development: Completely reinvent the automobile for the 21st century, unburdened by any legacy technologies.
In Burn’s words, GM wants to “take the automobile out of the environmental debate.” With emissions of nothing more than water vapor, hydrogen fuel cells eliminate carbon fuels altogether. That is, they eliminate them from the vehicle. Instead, the debate over the types of energy used to generate hydrogen shifts from GM and other carmakers to the natural resources and power industries.
GM’s latest fuel-cell car, the Sequel concept, was unveiled at Detroit’s January 2005 North American International Auto Show. Less than two years later, it’s a drivable prototype (two of them, actually), now called the Chevrolet Sequel. Last week, GM let selected journalists—among them this Spectrum reporter—drive it within the guarded confines of the U.S. Marine Corps' Camp Pendleton in California.
Tanks: A Lot
Outside, the Sequel is a sleek, stylish SUV. You wouldn’t give it a second glance at the mall parking lot. But underneath, it has little in common with today’s cars beyond wheels and tires. Its “skateboard” aluminum chassis is built around three long, heavily reinforced canisters that hold 8 kg of hydrogen. That mass of hydrogen contains the same energy as 8 gallons of gasoline, though GM’s latest fuel cell uses energy twice as efficiently as a gas engine.
The Sequel’s power electronics are mounted in a package with the front electric motor; “productionizing” fuel-cell vehicles will require major reductions in the size and weight of these componentsPhoto: John Voelcker
The 73-kW fuel cell in the Sequel is a sealed box in which hydrogen passes through a membrane to react with oxygen, producing water and giving off energy. It’s that energy that powers the three electric motors that move the vehicle: One 65-kW motor in the front, plus individual 3-phase permanent-magnet 25-kW wheel motors at the rear. Total traction power is thus 115 kW. Those rear motors also act as generators, so when a driver hits the brakes, energy that would have been lost is used to recharge a 65-kW lithium-ion battery pack stored within the “skateboard” between the rear wheels.
The steering wheel, accelerator, and brake pedal aren’t mechanically connected to the wheels or powertrain. Instead, a set of computer processors evaluates what you asked for—and then tells the car how to do it most efficiently. This “by wire” control technology not only reduces weight by eliminating mechanical components, it also maximizes safety by letting the car weigh what it’s being asked to do against external factors (such as traffic, weather, vehicle proximity, etc.).
Integrated rear-wheel motors allow regenerative braking on the Sequel, and the suspension arm includes a steering knuckle for up to 5 degrees of rear-wheel steeringPhoto: John Voelcker
Behind the Wheel
Having drive-by-wire controls means driving the Sequel runs the risk of feeling like a video game—compelling but not quite “real.” But in fact, GM’s engineers (spread across Warren, Mich.; Honeyoye Falls, N.Y.; Torrance, Calif.; and Mainz Kastel, Germany) did so much simulation work to make it feel real that … it actually does.
Behind the wheel, it drives and steers like a heavy SUV: Press the accelerator, and it accelerates. Turn the wheel, and it changes direction. The only difference is that the slight whine of the electric motors increases continuously—there’s no change in engine note as the transmission shifts, because there’s no transmission. And the brake-pedal feel is so natural that I completely forgot I wasn’t getting feedback through a hydraulic system but an electric simulation using pistons and quite a lot of software.
The Sequel weighs 2170 kg (4774 lb), at the high end of the range for a 4-to-5-seat SUV. It will do the 0-to-60-mph sprint in less than 10 seconds, with a top speed of 145 km/h (90 mph). Most important is its range of 300 miles (480 km)—like a normal car—meaning that the Sequel travels roughly twice as far on the same energy content as a conventionally powered SUV.
We won’t see Sequels at our dealerships any time soon, though. Each of these concept cars probably costs one million dollars or more, although “productionizing”—figuring out how to lower weight, reduce complexity, cut costs, and improve reliability—is a standard part of technology innovation. As the shape of the world’s hydrogen infrastructure becomes clearer over the next decade, the component costs will fall and carmakers will know more about how fuel cells perform in the real world.
Under the hood of the Equinox Fuel Cell SUV, one of 100 to be tested by members of the public next year; a hydrogen fuel cell and the electric motor it powers are hidden beneath this coverPhoto: John Voelcker
Next Year: 100 Fuel Cell SUVs
To start learning, GM will put fuel-cell cars into the hands of live consumers roughly a year from now. (Honda did this already—once—providing its small, Fit-sized FCX hatchback to the Spallino family of Redondo Beach, Calif., in June 2005, a ceremony that received a remarkable amount of media attention.) Chevrolet will loan 100 Equinox Fuel Cell SUVs for three to 30 months to “teachers, engineers, firefighters, government officials, business partners and media” in California, New York, and Washington, D.C.
These vehicles don’t have all the technical frills of the Sequel, which is a full concept car. Absent the special paint and trim and revised front-end styling, you’d be hard-pressed to tell an Equinox Fuel Cell from its gasoline equivalent. But GM is especially proud that these highly modified vehicles comply with all 2007 Federal crash and safety regulations and more, including a 50-mph angled side impact directly into the hydrogen tanks—without any leakage.
The fuel-cell Equinox promises a range of 200 miles (320 km) per 4.2-kg tank of hydrogen. Top speed is 100 mph (160 km/h), and GM quotes a 0-to-60-mph time of 12 seconds. It expects the fuel cells to last 50 000 miles (80 000 km), and notes they are “freeze durable”—which is to say they generate power in less than 15 seconds at temperatures down to –20 degrees Celsius (important for the U.S. Northeast, among other markets).
GM will garner feedback on all facets of the Equinox Fuel Cell vehicles’ performance from operations data downloaded via the cellular phone in each car’s OnStar system. And it will announce similar trials for Europe and Asia later on.
OK, But Where Do You Get H2?
The broader question is, How and where do you refuel? Right now there are only several dozen places on the planet where civilians can buy gaseous or liquid hydrogen for automotive use. And naturally occurring hydrogen is a tricky substance: Because it’s the smallest and lightest molecule, it escapes easily through tiny spaces other molecules can’t pass through. So you need heavily armored and very secure storage tanks—in the car and on the ground—as well as aircraft-quality hoses and fittings to fill the tanks.
GM is working with Shell, among other partners, to increase consumer availability of hydrogen for automotive use. (The OnStar navigation system in each Equinox Fuel Cell will let drivers work out how far it is to the nearest hydrogen source, no matter where they are.) There are regional and national test projects around the world, using whatever local energy source makes the most sense: Geothermal in Iceland, nuclear in France, natural gas in several places.
And that’s the great thing about hydrogen: You can make it a lot of different ways. Just apply electricity to water molecules in a device called an electrolyzer, and two components result: hydrogen and oxygen. You can do much the same with natural gas, producing hydrogen and carbon dioxide (which would need to be trapped, since venting it into the air would contribute to global warming).
That electrolyzer is basically a fuel cell running in reverse. Companies with good fuel-cell technology also have the means for efficient electrolyzation. One vision is that owners top up their car’s hydrogen fuel cells by plugging in the hose of an electrolyzer that connects to the home’s water pipes. It’s mounted on a garage wall and fills the tank with hydrogen in the wee hours, when demand for electricity is lowest, so the price is cheap.
Would such an electrolyzer say “Chevrolet” on it? Larry Burns, the head of R&D at General Motors, shakes his head. CEO Wagoner “made it clear that we’re in the business of providing personal mobility, not garage appliances.”
Would GM license their technology to other companies to make garage appliances—meaning you might never have to visit a “gas” station? Burns smiles. “Now that’s a very interesting question,” he says.
By design, the Chevrolet Sequel and Equinox Fuel Cell will slot seamlessly into today’s suburban culture of malls, freeways, subdivisions, and football practice. If the average soccer mom’s Jeep Grand Cherokee were replaced with the Sequel—without telling her it was a fuel-cell vehicle—she might never know the difference.
So, one question: What does it mean if the car of the future arrives … and we hardly notice?
Editor's Note: General Motors provided airfare and one night of lodging to Spectrum’s reporter.
About the Author
John Voelcker covers auto technology for IEEE Spectrum, Popular Science, and other media. His automotive blog can be found on RoveSite.com. He is executive editor of ROVE and the founder of Profuse Media, a consultancy specializing in the interactive media business.