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According
to the original plan revealed at its launch in 2010, General Motors
should have already delivered 170,000 copies of Volt Mk1 by this time.
Unfortunately, the plug-in hybrid car (or range-extending EV, as
insisted by GM) has been proved less popular than expected, with only
77,000 units sold to date. This means the second generation needs to
work harder.
From its exterior, you can already see GM has made quite a lot of
changes. Its body gets much sleeker, with a roof line flowing smoothly
from the nose to the hatchback tail. The front end design is perhaps
too flashy and not as tasteful as the old car's, but meanwhile, it has
ditched the gimmicky black stripes at the top of the doors. You might
say the whole exterior design now gets closer to conventional cars, but
that is perhaps something GM did deliberately after consulting the
successful story of Tesla Model S.
A bit disappointing though, despite of the streamline shape, its drag
coefficient is unchanged at 0.28. It should have been lower.
While
Tesla can afford an all-new platform dedicated to EV architecture, the
mainstream Volt has to keep production costs under close guard. That's
why the Mk2 is still derived from the Delta II platform of the
conventional Opel Astra / Buick Verrano and Chevrolet Cruze. It gets
slightly larger – wheelbase is stretched by 10 mm to 2695 mm; Length
and width are up by 85 and 20 mm, respectively. Only the roof is
lowered, yet by merely 5 mm. Sadly, all measurements of passenger space
are virtually unchanged from the old car. The only exception is the
rear seat, which has been converted from 2 individual seats to a bench
seat. Nevertheless, as the T-shape battery still occupies a large part
of the central tunnel, the middle rear seat is best reserved for
emergency use.
Up front, the new interior looks remarkably different from the old car.
Bascially, its architecture gets closer to the mainstream Opel and
Buick, with the exception of twin-LCD, one occupies the instrument pod
and another at the floating panel above the center console. Both of
them are quite large at 8-inch. Underneath the console screen is now
the controls for air con and ventilation. It answers one of the
criticisms of the old car, i.e. drivers need to use the touchscreen to
adjust HVAC. In short, the new cabin trades Sci-Fi theme for
practicality and cost sharing.
Despite
of the larger dimensions, the new Volt is 105 kg lighter than the old
car. This must thanks to the use of more high-strength steel, aluminum
bonnet and tailgate as well as improvement to its battery and
powertrains.
The lithium-ion battery pack now offers 18.4 kWh instead of 17.1 kWh of
usable energy (note: the battery of Mk1 was originally rated at 16kWh,
then gradually improved). It is made up of 192 cells, a third fewer
than before, so to cut 14 kg of weight, reduce costs and enhance
reliability.
The petrol range-extender engine has been changed from the old 1.4
Ecotec iron-block unit to a new 1.5-liter Ecotec all-alloy unit with
direct injection, variable cam phasing and on-demand oil pump. Its
output is lifted from 84 to 101 hp. We don't care about its torque
output as it rarely drives the wheels. Its main mission is to recharge
the battery when the latter depletes.
The Voltec II electric powertrain is also improved. Previously, it
employed a large motor for propulsion and a small motor primarily for
generation. Now it employs 2 motors of closer sizes, and they can
provide propulsion together. Total output is unchanged at 149 hp, but
maximum torque is improved from 273 to 294 lbft, while efficiency is
enhanced by 12 percent. Moreover, the motor/transmission unit and
smaller power electronics shave 45 kg. The motors are integrated with
the planetary CVT and differential in the front transaxle.
Front-to-rear weight distribution is 60:40, much like a conventional FF
car.
According to early road tests conducted by C&D and MT, the new car
is about 1.5 seconds faster to accelerate from 0-60 mph, taking less
than 8 second now. In other words, it’s fast enough for most consumers.
Top speed is limited to 98 mph, but a BMW i3 is 5 mph slower still.
GM claims it will travel 53 miles before the range extending engine
fires up, up from 35 miles of the original Volt. This means 90 percent
trips of its typical owners can be accomplished without burning a
single drop of oil. When the gas engine kicks in, the EPA fuel economy
is still a good 42 mpg combined, thanks to the engine that always works
in Atkinson combustion cycle. With a full tank of fuel, the total range
is extended to 420 miles.
In urban driving, the performance feels lively as the electric motors
offer good torque at low speed. As expected, the driving experience is
extremely calm and relaxed as the electric motors make so little noise
and no vibration at all. The suspension is markedly improved from the
old car’s, being more composed over undulations. Another big
improvement is the brakes, whose pedal feel is linear and natural,
unlike many hybrids or EVs with regenerative braking.
The new car turns into corner more responsively, too. However, it is
still
no driver’s car. Push it beyond the rather low grip levels of its
Michelin energy-saving tires and it will run into terminal understeer.
When the
petrol motor kicks in, the Volt becomes less impressive. Not only the
noise is quite intrusive after you have got accustomed to the serene
environment, but the engine rev and noise are oddly irrelevant to the
speed of the car. There is no mechanical connection between the
four-cylinder and the front wheels, remember.
After the first generation Volt, the Mk2 no longer sounds
ground-breaking. However, its technology definitely gets more matured
and
better suited to mainstream production. It is not only more practical
to use in all aspects but also gets cheaper. The base price is
US$34,000 at its home market. Factor in federal tax break and it
becomes just $26,500. In California it is slightly cheaper still. With
the arrival of Volt II, plug-in hybrid cars are finally a practical
choice for ordinary consumers. The
next generation Toyota Prius had better to be good, because it no
longer enjoys any cost advantages against the Chevrolet.
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