Véhicules efficaces: meilleurs, plus propres et sécuritaires
Les nouvelles technologies produisent des automobiles qui sont plus
économiques en essence, plus légères et plus écologiques. Parmi les
avantages, ces autos à "systèmes électricité/ hydrogène"
sont alimentées par des cellules électrochimiques.
On discute des avantages de cette nouvelle technologie tout en jetant
un coup d’oeil à la recherche effectuée au Hypercar Center du Rocky
Cleaner, Safer, Better
Rocky Mountain Institute
news: in the next decade or so, automobiles are probably going to get a
lot more efficient, significantly reducing pollution, greenhouse-gas
emissions and other related environmental problems.
Environmentalists might have a hard time getting their heads around this
development, though, because it’s not being driven by tightened
regulations, fuel taxes, an energy crisis or any other drastic measures
that are usually assumed to be necessary to force car companies to get
serious about efficiency.
No, it all comes down to new technology. Technology that will make
vehicles not only more fuel-efficient and cleaner, but just plain
better. In fact, it’s the better part, far more than the environmental
benefits, that will appeal to most consumers. And consumer appeal is
what is going to get these new cars onto the road and old, polluting
cars off in sufficient numbers to make a difference to the environment.
Yes, these new vehicles are only a techno-fix, and like all
techno-fixes, they won’t really address the deeper problems associated
with driving. But they’re a step in the right direction, and will
probably serve as a stepping-stone to still better solutions.
Today’s automobile is a sophisticated, mature technology. Despite
many incremental improvements during a century of evolution, however,
its design remains fundamentally unchanged. But dramatic advances in
many related fields have set the stage for a new kind of car, a
fundamentally digital creation that improves on its analog predecessors
the way CDs trumped vinyl, and computers displaced typewriters.
The first signs of this revolution are already apparent. Most major
automakers are now readying vehicles with hybrid-electric drive, and
several are developing models powered by fuel cells. These technologies,
along with microelectronics, software controls, and ultra-lightweight
materials, are the enablers of what may prove to be the biggest thing to
hit the auto industry since the assembly line.
Hybrid-electric vehicles combine the best aspects of both
conventional and electric cars. Like a conventional car, a
hybrid-electric car has a power plant (engine); like an electric car,
its wheels are driven by electric motors. It’s a hybrid of the two
because its engine generates electricity to drive the wheels.
Energy from the power plant is therefore sent to the wheels
electrically, via wires, instead of mechanically, via a driveshaft and
other moving parts. (Some hybrids incorporate both types of drive
systems, using them separately or together at different times.)
That overcomes many of the inefficiencies inherent in conventional
cars, and it eliminates the heavy batteries and limited range of
battery-electric cars. In addition, the electric motors can also act as
brakes, recovering much of the energy that’s otherwise lost in
braking. Electric drive also opens the door to even more efficient power
sources, such as fuel cells. Developed in the 1960s for the space
program, fuel cells flamelessly combine stored hydrogen with oxygen from
the air to produce electricity. Unlike the combustion engine in a
conventional car, a fuel cell is more like a battery that, rather than
needing recharging, is supplied with fresh reactants when you step on
the gas pedal.
Fuel cells convert fuel into electricity two or three times more
efficiently than combustion engines, and produce no emissions (except
water). And because they permit the storage of energy in the form of
hydrogen, fuel cells are an integral part of the long-term transition
that society must inevitably make from fossil fuels to renewable energy
sources. Toyota has led the rush to hybrids with its Prius sedan, which
it launched in Japan in 1997. The Prius won’t be available in the
United States until next year, but Honda plans to start selling its
Insight hybrid in the States in December of this year. Nissan, Volvo,
Audi, Volkswagen, and the U.S. Big Three all say they’re developing
commercial hybrids. Meanwhile, Daimler Chrysler has invested $350
million in an effort to mass-market fuel-cell cars by 2005, with Ford
and others in hot pursuit.
(photo: Rocky Mountain Institute)
This new generation of vehicles will be much more fuel-efficient than
today’s cars. Toyota’s Prius, for example, gets 66 miles per gallon,
without any compromise in performance, comfort, or size. Moreover,
electric drive typically provides sportier acceleration, and, combined
with integrated electronic components and software, it makes possible
many new or improved electronic controls and features.
Like computers on wheels, hybrid-electric vehicles, hardware and
software can be made to be upgradable. Has the manufacturer come out
with a more sophisticated computer-controlled suspension? Have a
technician load in the new card, or upgrade the software. Replacing
complex mechanical systems with solid-state electronics and software can
eliminate many causes of breakdowns, and enable remote diagnostics and
repairs of many problems that would send a conventional car to the shop.
The dashboard could be replaced by a user-friendly interface; why have
gauges when you can have a flat-screen display that’s almost
infinitely customizable? In time, fuel-cell-powered vehicles could
actually operate as a small mobile power plants, generating electricity
cheaply enough to sell it back to the grid at a net profit.
Automakers have been slower to embrace another emerging technology:
ultra-lightweight materials. According the Hypercar Center at Rocky
Mountain Institute, a resource-efficiency think tank, making auto bodies
out of advanced composite materials instead of heavy steel can radically
improve the efficiency, capabilities, and economics of hybrid-electric
Hybrid-electric drive and ultralight, low-drag design are both worth
doing in their own right, Hypercar Center researchers claim, but
combining the two yields synergies compounding weight savings and
recovered braking energy that are just too good to pass up. Thanks to
mechanical simplification, indirect weight savings snowball faster in
ultralights than in heavy cars, faster in hybrids than in nonhybrids,
and fastest of all in optimized combinations of the two. The Center
calls its optimized concept a Hypercar.
And contrary to popular perception, cars made of lightweight
materials won’t be more dangerous. In fact, the Hypercar Center has
done extensive research showing that they’d probably be safer. Polymer
composites, materials now used everywhere from rockets to golf shafts
absorb five times more energy per pound than steel. We’ve all seen
Indy cars crash and burn at fantastic speeds, only to watch the driver
limp away, those are composite cars. Special designs can make the most
of composites strength and stiffness, while the significantly smaller
propulsion system of efficient new cars would leave room for extra crush
zones. This should enable cars made of composites to match or exceed the
safety of a heavier car, even if the two collide head-on and note that a
lightweight car fares substantially better than a heavy one in a
collision with a stationary object.
These consumer advantages are only part of the story of the
transition to more efficient cars. The planet and its inhabitants will
also benefit from cleaner air, fewer greenhouse-gas emissions, and a
reduced dependence on oil imported from politically unstable parts of
the globe. And if auto makers stand to make a buck from the transition,
so much the better it’ll happen that much sooner.
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