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GREEN cars are winding their way to an
era of less polluted Istreets. General
Motors (GM), the world's largest automobile 'manufacturer, has announced
'that it would begin selling the Electric
Vehicle (Ev) I electric motor cars in Los
Angeles, San Diego, Phoenix and Tucon
in the us from late 1997. It will be the
first car in recent tirnes,to @have been
specifically design@d by a big car-maker
to run on electricity.
The Evi, under development since
1990, can accelerate to 96 kmph in 8.5
seconds and ultimately run at 128
kmph. It can seat only two people at a
maximum travel range of 144 km in
town, after which the car must be
recharged. Given the fact that the average us commuter travels 71 km daily,
each refill can take care of two days.The
two-seater EvI will weigh 1,060 kg, 40
per cent of which consists of 26 lead-
acid batteries. The contraption will cost
us $35,000. GM is also producing an electric pick-up truck.
To help compensate its heavy
weight, and to maximise the distance it
can cover, the Evi will be equipped with
low-rolling-resistance tyres, an aluminiurn chassis, a wind-cheating plastic
skin and a regenerative braking system
that helps to recapture energy that is
normally lost when the brakes are applied.
EvI's owners will have two ways of
recharging its batteries. Those without
access to a 220-volt power supply (most
American domestic circuits are 110
volts) will have to do it the hard,
15-hour way by plugging into a normal
socket, in the boot (dickey). But the preferred method is more ingenious: use of
a paddle-like contraption that is inserted into a 'small slot in the car's nose.
This operates by induction, eliminating
the risk of sparks that might ignite the
hydrogen released during recharging. At
220 volts, the paddle can give an Ev1 the
electrical equivalent of a full tank in
three hours. It looks likely that the use of
electric cars will have to await developments, in battery technology to replace
the bulky lead-acid batteries of today.
Even recent variants such as lithium,
nickel-metal hydride (NMH) or sodium
sulphur batteries (being used by the
Ford company in its Ecostar van) hold
just a fraction of the energy in an equivalent weight of petrol or diesel. The
search for better batteries has been
going on for decades and manufacturers
are yet to come up with anything viable
Several possibilities are being studied. GM seems to favour the NMH
battery, which functions much like
the n'ickle-cadmium (Nicad) batteries
found in many domestic appliances.
Early tests suggest that fitting NMH batteries to the Ev I could boost its range to
more.than 250 km on a single charge.
In addition, NmH batteries, which do
not rely on sulphuric acid as an electrolyte, are expected to last up to 10
years, whereas the Evl's'lead-acid batteries will have to be replaced every two
to three years. The NMH, however, is difficult and expensive to manufacture.
Energy Conversion Devices, a firm in
Michigan, usA, has promised commercially viable NmH batteries by the end of
But the dominance of petrol and
diesel is unlikely to be challenged, until new fuels, such as hydrogen, move from
the test bench to the test track, or
batteries become lighter and more
powerful. Meanwhile, car-makers can
continue to produce limited numbers of
vehicles powered by alternative fuels,
secure in the knowledge that their main
business can roll on unchallenged.