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Electrified roads could
power cars from the ground
up
Greased lightning (Image: DreamPictures/Photodisc/Getty)
THE cars of the future could be powered by electrified roadways. Such
technology would allow electric cars to forgo their heavy batteries, which
not only add to a vehicle's weight, increasing the energy needed to move
it, but also force it to sit idle while recharging.
The idea has been around for decades. Previous attempts used an
electrified coil in the road to create an electromagnetic field that interacts
with a coil attached to the car. "Since the coils must be exactly aligned
face-to-face to achieve a high energy efficiency, such schemes may be
useful for [charging] vehicles in a parking lot, but never very effective for
cars while running," says Masahiro Hanazawa at Toyota Central R&D Labs in
Nagakute, Aichi, Japan.
Hanazawa and Takashi Ohira at Toyohashi University of Technology, also in
Aichi, are developing a system that transmits electric power through steel
belts placed inside two tyres and a metal plate in the road. "Our approach
exploits a pair of tyres, which are always touching a road surface," says
Hanazawa.
To test how much energy would be lost as electricity travelled through the
tyres' rubber, Hanazawa and Ohira set up a lab experiment in which they
put metal plates on the floor and inside a tyre. "Less than 20 per cent of
the transmitted power is dissipated in the circuit," says Ohira. The team
presented its work in May at the International Microwave Workshop Series
on Innovative Wireless Power Transmission in Kyoto, Japan.
With enough power the system could run typical passenger cars, says
Ohira, and the team are now developing a small-scale prototype to prove it.
He admits, however, that the system's energy loss is "much higher than
regular batteries".
John Boys, an electrical engineer at the University of Auckland, New
Zealand, notes that with this system, the metal pads on the road would
need as much as 50,000 volts to power the car, the same voltage used to
operate tasers. "You wouldn't want to step on that," he says.
What's more, at the energy levels needed, the electric plates would
produce a large magnetic field that would "cause significant radio-frequency
interference that might create chaos with all manner of electrical systems",
says Boys.
It would be expensive to "rip up the roads and install the necessary
infrastructure", says Daniel Friedman at the University of New South Wales
in Sydney, Australia. But he adds that one way around that may be to limit
metal plates to main highways, and then run cars on other roads using small
batteries.
Electrified roads could power cars from the ground up - tech - 13 September 2011 - New Scientist
power cars from the ground
up
Greased lightning (Image: DreamPictures/Photodisc/Getty)
THE cars of the future could be powered by electrified roadways. Such
technology would allow electric cars to forgo their heavy batteries, which
not only add to a vehicle's weight, increasing the energy needed to move
it, but also force it to sit idle while recharging.
The idea has been around for decades. Previous attempts used an
electrified coil in the road to create an electromagnetic field that interacts
with a coil attached to the car. "Since the coils must be exactly aligned
face-to-face to achieve a high energy efficiency, such schemes may be
useful for [charging] vehicles in a parking lot, but never very effective for
cars while running," says Masahiro Hanazawa at Toyota Central R&D Labs in
Nagakute, Aichi, Japan.
Hanazawa and Takashi Ohira at Toyohashi University of Technology, also in
Aichi, are developing a system that transmits electric power through steel
belts placed inside two tyres and a metal plate in the road. "Our approach
exploits a pair of tyres, which are always touching a road surface," says
Hanazawa.
To test how much energy would be lost as electricity travelled through the
tyres' rubber, Hanazawa and Ohira set up a lab experiment in which they
put metal plates on the floor and inside a tyre. "Less than 20 per cent of
the transmitted power is dissipated in the circuit," says Ohira. The team
presented its work in May at the International Microwave Workshop Series
on Innovative Wireless Power Transmission in Kyoto, Japan.
With enough power the system could run typical passenger cars, says
Ohira, and the team are now developing a small-scale prototype to prove it.
He admits, however, that the system's energy loss is "much higher than
regular batteries".
John Boys, an electrical engineer at the University of Auckland, New
Zealand, notes that with this system, the metal pads on the road would
need as much as 50,000 volts to power the car, the same voltage used to
operate tasers. "You wouldn't want to step on that," he says.
What's more, at the energy levels needed, the electric plates would
produce a large magnetic field that would "cause significant radio-frequency
interference that might create chaos with all manner of electrical systems",
says Boys.
It would be expensive to "rip up the roads and install the necessary
infrastructure", says Daniel Friedman at the University of New South Wales
in Sydney, Australia. But he adds that one way around that may be to limit
metal plates to main highways, and then run cars on other roads using small
batteries.
Electrified roads could power cars from the ground up - tech - 13 September 2011 - New Scientist