Behind the wheel: fuel-cell vehicles
We recently had the
chance to drive some fuel-cell
vehicles that aren’t for sale to the general public, giving us a
behind-the-wheel view of the possible future. Many of these research
vehicles impressed us and show the promise, and appeal, of electrically
powered cars, in this case through fuel-cell technology.
A potential alternative to gasoline-engine-powered
cars, these electric vehicles produce their energy on board via a chemical
reaction in a fuel-cell stack. Hydrogen is consumed in the process, with water
as the only tailpipe emission.
In spring 2007, we drove the impressive Honda
FCX sedan. It has since been renamed the FCX Clarity, and was shown at the Detroit auto show.
Since then, we drove a hydrogen-powered
BMW 7 Series, which is propelled by an internal combustion engine rather
than an electric motor.
This past fall,
we hosted an unusual guest here at our track in Connecticut. For a few hours, we got to
experience the Chevrolet
Equinox FC fuel-cell vehicle. It looked like a regular Equinox, except for
the slightly raised floor that was concealing three hydrogen tanks and a symbol
of a blue water drop on the shifter. The tanks hold 4.2 kilograms of compressed
hydrogen at 10,000 psi. The claimed range is 200 miles. That translates to
about 48 mpg in terms of gallon-of-gas-equivalent (gge) consumption. (One kg of
compressed hydrogen is about equal to one gallon of gasoline in terms of energy
density.) With the electric propulsion, the Equinox FC was much quieter than a
regular Equinox V6. There was a noticeable, but unobjectionable, whine when accelerating
on a highway ramp and the vehicle felt responsive. The car kept making all sort
of whirrs and fan noises after we parked it and left a small puddle of water
under its tailpipe.
Late last year, at the EVS23 (Electric Vehicle
Symposium) in Anaheim, CA, I drove several electric
vehicles. Also on hand, were several other fuel-cell vehicles. I
sampled them on a short driving loop and some of them were quite impressive:
Nissan
X-Trail: The X-Trail is a small SUV that was never
offered for sale in the United
States. This fuel-cell version had a tank of
compressed hydrogen at 10,000 psi and a relatively long claimed range of 300
miles. The tank holds about four kilograms of compressed hydrogen, which
translates to 75 miles-per-gallon-of-gas-equivalent (mpgge). The X-Trail was
quiet and refined. From a standstill, it launched decisively and kept
accelerating smoothly. It handled and rode soundly. All that was happening
underneath was rather transparent without intruding into the cabin. The car was
free of strange and unpleasant noises.
Toyota Highlander FCHV: Based
on the previous-generation Highlander, this fuel-cell vehicle is able to propel
itself only on battery power, without drawing directly on energy from the
fuel-cell stack and depleting the hydrogen. That’s the reason for the H (for
hybrid) in the FCHV name. It has a claimed range of 350 miles, and Toyota says it can sprint
from 0-60 mph in 10.5 seconds. The compressed hydrogen is stored in two tanks
under the floor at 10,000 psi. With a little more than four kilograms of
compressed hydrogen, it would consume 88 mpgge. It drove like a Highlander
hybrid, which is quite slick with a comfortable, quiet ride and smooth acceleration;
The hum of the traditional V6 engine was conspicuously absent.
Mercedes-Benz
A-Class: The A-Class is the smallest Mercedes (not
counting the Smart-branded products) and was never offered in the United States.
The company boasts that through its fleet of 60 A-Class fuel-cell vehicles, it
covered over four million test miles in four years. The A-Class stores 1.8
kilograms of compressed hydrogen in two tanks at 5,000 psi. It has a claimed
100-mile range, which translates to about 55 mpgge. The design of the A-Class
fuel-cell research vehicle dates back to 2002. From behind the wheel, it
felt rather slow and noisy. The stiff ride was probably inherent to the
A-Class. The slow acceleration and noisy whirs and swooshes, however, were
attributable to the fuel-cell conversion. Mercedes is now in the midst of
phasing its fuel-cell efforts into the larger B-Class. (Read the B-Class
first look. Our B-Class road test is available to online subscribers.) The
B200 we tested is sold in Canada
but not in the United States.
Hyundai
Tucson: The Tuscon fuel-cell vehicle has three tanks of
compressed hydrogen at 5,000 psi and it holds 3.5 kilograms of the gas. This
small SUV has a claimed range of 190 miles, which translates to 54 mpgge. Kia
also featured the same technology in the essentially identical Sportage. The Tucson didn’t feel as slick as the Nissan or Toyota but better than
the Mercedes-Benz A-Class. It drove pretty much like a regular Tucson, which is pleasant enough.
Acceleration wasn’t quite robust and the vehicle was considerably noisier that
a regular Tucson.
Bottom line
In the effort to wean us off petroleum and slow global warming, at this point,
it is safe to say that in the long-term future we will see vehicles powered by
either hydrogen or electricity (or some combination of both). Automakers are
reluctant to put all their technology eggs in one basket and are developing more
hybrids and plug-in hybrids, which are likely to proliferate in the short-term.
For now, electric vehicle development is mostly relegated to the aftermarket or
specialized manufacturers.
Before these cars of tomorrow reach consumers,
there are several obstacles to each technology as they race to go mainstream.
For example, hydrogen lacks storage and delivery infrastructures; the fuel
stacks (which use expensive platinum) are costly and may not last as long as
gasoline engines; and the public remains skeptical. Further, batteries for
plug-in hybrids or electric cars are still too expensive, and effective thermal
control strategies have not been verified.
At this year’s Detroit Auto Show, GM Chairman
and CEO Rick Wagoner said he expects fuel cells to be the long-term solution,
while plug-in hybrids will fill the gap in the medium term. Some electric-car
advocates and environmentalists, however, have suggested that fuel cells are
just a distraction from development of battery electric vehicles.
It’s too early to tell who is right. But we’d
like to hear your opinion on fuel-cell and electric cars. Let us know what you
think by posting your thoughts in the Comments section below.
—Gabe Shenhar
Learn more about fuel cells and alternative
fuels in our fuel economy special section.
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http://blogs.consumerreports.org/cars/2008/01/fuel-cell-cars.html
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