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UFE (concept car: Ultra
Fuel Economy)
Daihatsu has remained faithful to the compact car, attaching priority
to friendlier coexistence between cars, humanity, and the global environment;
and to ensure cars will retain their attraction for a long time to come,
Daihatsu has extended the challenge to the development of a new powertrain.
Daihatsu's involvement with electric vehicles goes back almost four
decades, giving it the longest experience of any Japanese motor manufacturer.
With a diverse range of electric vehicles to its credit, including concept
cars, commercial models and special vehicles, Daihatsu's quest for a
more fuel efficient, super-clean engine has already led to the presentation
here at Geneva of two concept cars: the hybrid Move EV-H in 1998 and
the Move EV-H II in 2001.
For 2002 we are unveiling a hybrid UFE that sets a next-generation ultra
fuel economy standard by running 55 km on a litre of petrol.
Fuel efficient technology
In the search for aerodynamic advantage, we have realized a drag coefficient
of Cd 0.25, placing the UFE's aerodynamic characteristics among the
world's best. Also contributing greatly to enhanced fuel economy is
a reduced body weight. An ultra-light vehicle weight of 630 kg has been
achieved by adopting a resin composite body complemented by the extensive
use of aluminium in the brake system, seat frames and elsewhere. And
a high fuel economy hybrid system of two-motor type has been adopted
that incorporates a highly efficient, direct injection petrol engine
into the powertrain.
The UFE has made next-generation ultra fuel economy a reality by linking
all other technology and systems in the vehicle to fuel efficiency.
Examples of features contributing to reduced electricity consumption
are the twin-bulb HID headlamps, LED rear combination lamps, and electric
power steering. Also essential for fuel economy have been the development
of low rolling resistance tyres and the adoption of hydraulic adaptive
regenerative braking. This wealth of advanced technology has realized
an astonishing fuel efficiency of 55 km/litre (Japanese 10-15 mode,
Daihatsu test data).
Powertrain
The power unit utilizes a hybrid system combining the two electric motors
with a direct injection petrol engine, and compact, lightweight, highly
efficient AC synchronous motors both the generator and drive motor.
The generator, combining with a planetary gear mechanism, functions
as an electronically controlled continuously variable transmission.
All equipment down to the inverter has been integrated into a single
compact unit.
This hybrid system enables the engine to be controlled so that it operates
on the high efficiency line at all times; automatically switches modes
between "motor only", "series" and "parallel"
according to the conditions of the battery, road speed and acceleration
etc. The hybrid system also stops the engine when the car is stationary
to avoid wasting energy. A direct injection petrol engine was chosen
to provide the sought-after ultra fuel economy and low emission level.
The UFE has a regenerative braking system in which the motor acts as
a generator during braking, converting kinetic energy into electricity
to be stored in the battery. The regenerative braking system is very
effective in urban traffic conditions where acceleration and braking
are frequent. The braking system combines regenerative brakes and conventional
hydraulic brakes in an optimum way to recover energy most efficiently.
The battery for the hybrid system is a compact nickel metal hydride
battery carried under the rear luggage compartment floor. To achieve
world leading fuel efficiency of 55 km/L (Japanese emission mode), the
UFE also reduces electricity consumption in all areas including its
12-V electrical system, uses aluminium alloys to cut weight , and is
constructed to decrease Cd and reduce rolling resistance.
Safety technology
The UFE is richly endowed with technology for safety on the road. Notably,
the vehicle carries various active safety systems (brake control for
reducing impact, cruise control for following vehicle [across the entire
road speed range], speed control in entering curve, lane keeping system),
together with night vision capable of identifying objects out of reach
of the headlamp beams and an advanced front-lighting system that shifts
the beam in the steering direction, all developed as our own original
technologies.
The vehicle is also provided with diverse impact safety functions including
impact-safe body with new frame structure TAF (Total Advanced Function
body), dual SRS airbags, SRS curtain shield airbags and SRS side airbags,
dynamic support head restraints, knee airbags, and so on.
Exterior and interior design
We have created a super-aerodynamic body form that combines a cut-tail
teardrop silhouette providing the required aerodynamics with the latest
in parts technology to give an exterior design with superb aerodynamic
characteristics. As a result, Cd 0.25 has been achieved. The interior
design creates an interior space with a flowing image, extending the
basic geometric lines of instrument panel like the bird wing towards
the wall-integrated rear lounge seats.
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