Imagine filling up your gas tank once—
and then ignoring it for the next 640
miles. Or if you drive less than 40
miles a day, imagine never filling it up again. That's the promise of the Chevy Volt, GM's latest concept car, unveiled at last month's North American International Auto
Show in Detroit ().
A 16-kW lithium-ion battery pack
powers the Volt, though the system only uses 8 kWh (with a state of charge
between 80% and 30%). Fully charged, the
Volt gets 40 city miles of pure electric vehicle range. When the battery is depleted,
the car's 1-L, three-cylinder turbo-charged
engine kicks in to recharge it. Drivers who
travel about 60 miles a day can get up to
150 mpg.
When they get home, drivers simply
plug the car in to a typical 110-V outlet for
about six and a half hours to replenish the
day's energy. Drivers who forget to charge
the vehicle or who are traveling great distances would get 50 mpg just by using the
engine to convert gasoline into electricity,
for a total range of 640 miles.
"We have an on-board charger, so all you
really need is a conventional extension cord
that connects to a port on the front fender,"
says Nick Zielinski, vehicle chief engineer.
"We wanted to make it as easy as possible."
GM currently is working on a battery
with JC-Saft and Cobasys/A123 for the
Saturn Vue Green Line of plug-in hybrid
sport utility vehicles. Researchers say the
results of this work may be applicable to
the Volt's battery system. They also expect the Volt's battery to have a 10-year life
span or 4000 recharge cycles, with a production-ready model by 2010 to 2012.
E-FLEX INNOVATION
The Volt
also uses GM's E-flex technology, a family of
propulsion systems that fit onto a common
chassis. GM is preparing separate gasoline,
ethanol, bio-diesel, and hydrogen systems
that will drive the Volt and recharge the battery when it is depleted ().
"We can tailor the propulsion to meet
the specific needs and infrastructure of a
given market," says Larry Burns, GM vice
president of R&D and strategic planning.
"Somebody in Brazil might use 100%
ethanol to power an engine generator
and battery. A customer in Shanghai
might get hydrogen from the sun and create electricity in a fuel cell."
Designing a chassis with this kind of
flexibility was a challenge, but Zielinski
and his team had the advantage of experience. "What we're doing on E-flex is
expanding the work we've done on the EV1, building on what we've done for the
last 10 years on the EV-1, Sequel, and
Equinox fuel-cell vehicles," he says.
Again drawing on their EV-1 experience,
which broke all kinds of ground in relation
to safety and even inspired many federal
standards, GM's team sized and set all of
the electrical system's components for
optimum protection. For example, placing
the battery down the center of the vehicle
isolates it evenly from front crashes, rear
crashes, and side crashes.
GM showed two versions of the Volt
during the NAIAS. The first mockup,
which wasn't a running vehicle, showed
off the interior and exterior styling
enabled by the E-flex system. The second, a chassis display, revealed how the
battery will be laid out. While GM hasn't
announced any specific dates for test trials or mass production, its designers
don't think the Volt is a novelty—or a toy
for the wealthy.
"The Volt will have a reasonable price
but still offer reliability and performance," Zielinski says. "So much depends
on battery development, though we're
very confident we can deliver the battery
pack."