2008 Chevrolet Equinox Fuel Cell -


General Motors’ fuel-cell effort is more than vapor.BY AARON ROBINSON, September 2006
General Motors wants the world to know that its efforts to build hydrogen-powered cars are more than just vapor. In 2007, the company plans to put a fleet of 100 fuel-cell sports-utilities on the road, some of which will be given to families for everyday use.
It is also continuing work on a surf-board-like vehicle platform called AUTOn-omy that packages the fuel-cell powerplant and its associated batteries and high-pressure hydrogen tanks below the floor.
ZERO TO 100 IN ONE YEAR
GM plans to build 100 fuel-cell test vehicles in third-quarter of 2007 based on its Chevrolet Equinox mid-size sport-utility. The cars will be assigned to three test markets: New York, Washington, D.C., and Los Angeles for three-month loans to families, business, and policy-makers. Except for special silver-green paint, some graphics, and a few interior trim changes, the Equinox Fuel Cell looks essentially stock.
However, inside is GM’s fourth-generation fuel-cell stack, a single 97-horsepower motor with 236 pound-feet of torque driving the front wheels, a pack of nickel-metal-hydride batteries, and three storage tanks holding up to nine pounds of hydrogen (good for 200 miles on an EPA mileage test) stored at 10,000 psi.
The fuel cell, built at GM’s research facility in Honeoye Falls, New York, is about the size of one of its inline-six truck engines turned sideways. Combined with the other equipment, and extra body reinforcements that allow the vehicle to pass government crash tests add about 500 pounds to the standard Equinox’s 3860-pound curb weight.
GM fuel-cell director Byron McCormick promises that the hydrogen-inhaling Equinox will behave much like a regular car. It will start up in sub-freezing temperatures (until now a technical hurdle for the water-generating powerplant) and get to 60 mph in about 12 seconds. However, the fuel cell’s life expectancy is just 50,000 miles owing to corrosion issues inside the stack.
WATER VAPOR FROM THE TAIL-PIPE
The hydrogen fuel cells that GM, Honda, and other automakers are racing to build are not like those that NASA has been launching into space for over 40 years. The auto-motive fuel cell is an electro-chemical processor taking in gaseous hydrogen and pro-ducing water vapor that comes out the tail-pipe.
It uses a concept called “proton exchange membrane” in which hydrogen, a molecule of one proton and two electron (hence the H2 moniker) is forced through a membrane in the fuel cell that strips away its electrons, which become electrical current for the car’s drive motor. As the electrons reunite with the proton downstream, they join up with oxygen in the atmosphere to make H2O, or water, the fuel cell’s only exhaust emission.
Though hydrogen is the most plentiful element on Earth, making it usually involves chemically chipping it out of fossil-fuel hydrocarbons such as natural gas or coal. Currently, the world energy industry produces 15 million tons of hydrogen per year—mostly from hydrocarbons—and used mainly in oil refining, says Phil Baxley of Shell Hydrogen, GM’s fuel partner on the project.