"We think that hybrid has
huge potential," says Dr Shiseyuki Hori, executive chief engineer
at Toyota and in charge of the Prius project. He admits that the initial
investment was colossal as absolutely all R&D was carried out in-house.
However he admits that this strategy has been fundamental to the development
of the second-generation model. Additionally, the new car doesn't share
any common platform and almost no common parts with other Toyota products,
explains the hybrid project general manager, Katsuhiko Hirose.
The ground-breaking new Prius, which has won this years car of the year award in North America |
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The car is off course designed primarily to be the world's cleanest family
car and at 65.7 mpg combined fuel consumption and 104g/km of CO2 emissions,
it lives up to this promise. It is also fuel efficient, covering more
than 600 miles on a single tank of fuel. It produces the lowest NOx and
HC emissions of any internal combustion production car in Europe and meets
comfortably not just Euro IV, but Japan and US J-ULEV and AT-PZEV emission
regulations at the same time. And last, but not least, it is the also
easier to dismantle for end-of-life purposes.
The reason for such improvement from the old model is Toyota's self-made
Hybrid Synergy Drive (HSD) technology, which has created one of the most
powerful electric motor for its weight and size. Current-generation hybrids
rely on the petrol engine to produce peak performance, with the electric
motor as an ancillary. HSD, on the other hand, gives the electric motor
a more significant role.
"This technology makes it possible to reach whole new territories
in the automotive field, allowing a total repositioning of the hybrid
vehicle from an 'eco-friendly car' to a 'fun to drive machines'," says Hori.
The problem is that the driver today, no matter how green minded, still
expects some degree of performance from a modern car. HSD delivers just
that. A more powerful 1.5 litre petrol engine works together with a smaller,
more efficient electric motor to deliver performance. At 400Nm from 0-1200rpm,
0 to 62mph acceleration falls below 11 seconds. It's a smoother drive
as the hybrid's advanced control system uses the electric motor as the
main power source. Additionally noise and vibration have been reduced,
although this is less apparent at higher high speeds.
Also new is something called the EV (Electric Vehicle) button, which essentially
mean that when pressed it allows the driver to select full electric mode,
which comes in very handy when stuck in city traffic. The frustration
is at least somewhat subdued knowing that you are delivering zero emissions.
Other new technology includes a high voltage power circuit that supports
the HSD. The circuit inside the power control unit helps both the motor
and generator's voltage to be increased from 274V in the original Prius
to a maximum of 500V in the new model. The high voltage power circuit
increases power by upping the voltage from 202V to a maximum of 500V while
keeping the current constant. Electrical power can be supplied to the
motor by using a smaller current, thereby contributing to increased efficiency.
Although the battery voltage is lower than that of the previous model,
a new converter boosts the total system voltage to 500V when in use.
Additionally, Toyota has been able to increase power supply by 1.5 times
over the original Prius from
33kW to 50kW, even though the motor hasn't increased in size.
Hirose calls the shape: "Triangular Monoform." It is definitely
a larger car from all angels and at 4450mm long, it is 135mm longer than
its parent model. "This is because of aerodynamic packaging," Hori explains. Inside is roomy and subtly modern. It is meant to create
the same atmosphere as a modern living room, says Hori.
Although a much more forward looking car in terms of design than the old
one, you get the feeling Toyota stopped short at some point. This is no
surprise, after all the car will be revolutionary in concept for the average
consumer, therefore to go all the way in terms of styling too, may have
alienated all interested but the true avant guard.
The first generation Prius sold more than 130,000 worldwide since its
launch in 1997. And the new five-door hatchback, branded in the D-segment
and selling at the same price as diesel models in its class, hopes to
beat this record. Sales in Europe are expected to be around 5,000 and
76,000 worldwide by 2004. According to reports from Japan, so strong is
demand for this Prius that Toyota is seriously considering a third shift
at its Tsutsmi factory in Toyota. Sales are running at double anticipated
volumes and the idea is to lift monthly output from 6,000 units per month
to 10,000.
The Prius project may be a technology showcase for Toyota, as Hirose points
out, but it also a true testimony as to how far technology has come, and
how much further it is able to go, if pushed. Perhaps one way to 'sex-up'
hybrid would be to install it in a less accessible, less practical, sportier
car: the Toyota CS&S concept perhaps? No doubt, other carmakers will
follow suite, but it would be interesting to see if the first one in can
keep ahead in the fast lane.
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