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MAZDA IBUKI CONCEPT VEHICLE MAKES NORTH
AMERICAN DEBUT AT CHICAGO AUTO SHOW
- Design Concept Hints At Future
Generation MX-5 Miata -
CHICAGO — Chicagoans and others will
have the opportunity to peek into the legendary past of the Mazda
MX-5 Miata, as well as its possible future, when the Mazda Ibuki
concept makes its North American debut at the 2004 Chicago Auto
Show. The Ibuki suggests one possible approach for a future MX-5
Miata model.
Recognized in the Guinness Book of World
Records as the best-selling, two-seat sports car of all time, the
Mazda MX-5 Miata re-established for enthusiasts around the world
the concept of the lightweight convertible sports car. Launched
in 1989, its 15-year legacy lives on in the Ibuki concept, which
clearly showcases Mazda's current efforts in both design and
technology.
"The aim of this concept was to
further refine the fun-to-drive spirit that can be derived from a
lightweight, convertible sports car," said Truman Pollard,
chief designer of Mazda North American Operations. "At the
same time, the design team has worked to advance the true
roadster identity and further refine the levels of comfort and
safety in a vehicle with the top down."
In an effort to more fully realize oneness
between car and driver—a oneness that was the overall intent
of the original MX-5 Miata—the Ibuki design team has
borrowed from the advanced front-midship engine layout of Mazda
RX-8, although in this case employing an inline four-cylinder
engine.
Overall vehicle proportions have been
defined by extremely short front and rear overhangs that
confidently signify the extreme fun-to-drive spirit achieved by
the innovative engine layout. The overall shape is clean and
simple, reminiscent of the original Mazda MX-5 Miata, with a wide
and stable stance, pronounced fenders and the elegant use of oval
shapes throughout the design.
Isao Tohda, a key member of the Ibuki
development team who also played an important role in the
development of Mazda RX-8 says, "We aimed for a sports car
that offers the sort of fun felt from being in firm control of
one's own driving. With Mazda Ibuki, our primary theme was to
minimize the car's yaw inertia moment, and to take Mazda's own
sports car values to the absolute extreme."
THE ULTIMATE ROADSTER DESIGN
Mazda Ibuki has an overall length of 143.3
inches, measures 67.7 inches in width, 48.4 in height and rides
on a wheelbase of 91.7 inches. The overall length is 12.4 inches
shorter than that of the current MX-5 Miata. A key design feature
is a 15-inch reduction in the combined front and rear overhang
lengths, as compared to the current MX-5 Miata.
With the exterior, Mazda capitalizes on
these compact dimensions and the benefits of a twin backbone
frame to give concrete support to driving functions. The oval
body shape evokes a look of tension in repose, and the 18-inch
wheels and run-flat tires accentuate the car's well-planted
stance. The body form also communicates the snug yet comfortable
fit that both driver and passenger enjoy.
Front and rear views inherit the familiar
look of the first-generation MX-5 Miata married to a more
futuristic design. The radically curved windscreen conceals the
front pillars and gives occupants of the Mazda Ibuki a wide field
of view as well as a distinctive character.
"Sports car design is a question of
expressing the car's frame, and begins by supporting driving
functions," said Moray Callum, director of Mazda's Design
Division. "With the Ibuki concept we aimed to visualize, as
simply as possible, the car's compact size and the undeniable
excellence of its super front-midship layout. The results can be
seen in a contemporary design that also manages to evoke the
familiarity of the past MX-5 Miata. As we work to develop the
future direction of the Roadster, it was very important for the
Mazda design team to fully understand and appreciate the original.
The purity of the original design is particularly interesting to
us."
LIGHTWEIGHT, HIGH-RIGIDITY TWIN BACKBONE
BODY STRUCTURE
For Ibuki, Mazda engineers developed a twin
backbone body structure. Based on the high-mount backbone frame
concept employed with Mazda RX-8, the structure comprises an open
body frame with extensive reinforcements and a rigid lower
backbone frame located beneath the transmission tunnel. This
unique construction, featuring upper and lower backbone frames,
helps the Ibuki concept achieve extremely high rigidity—a
level of stiffness comparable to that of a closed body structure—while
maintaining the extremely low weight demanded of a sports car.
ULTRA-LIGHTWEIGHT DESIGN
In addition to the lightweight, high-rigidity
body structure, Mazda Ibuki employs lightweight materials at key
strategic points. Reinforced plastic is used for the fenders,
bonnet, rear floor panel and door outer panels. Brake discs and
door inner panels are made of aluminum. The propeller shaft and
power plant frame are of carbon fiber, while the wheels are
magnesium alloy. This judicious use of lightweight materials
keeps overall vehicle weight low.
In addition to carefully choosing
lightweight materials, the design team has also employed
recyclable materials such as fiber reinforced plant-based plastic
wherever possible.
SUPER FRONT-MIDSHIP LAYOUT
Essential to the success of the Mazda Ibuki
concept is the super front-midship layout that places all
critical powertrain and accessory components within the wheelbase.
The power unit, including the engine,
radiator and key parts of the cooling system, is located towards
the rear of the engine compartment, well behind the front axle.
Compared to the current MX-5 Miata, the engine is located about
15.8 inches more rearward and 1.6 inches lower. To achieve this
position, Mazda's design team moved the air conditioner unit
behind the seats, an innovative idea that creates space within
the dash section for part of the engine.
At the back of the car, the rear-mounted
air conditioner unit, fuel tank and main exhaust muffler are
located ahead of the rear axle. The super front-midship layout
allows substantial weight reduction in the front and rear
overhangs, enabling a 15-percent decrease in yaw inertia moment
compared with Mazda's current MX-5 Miata. This decrease in the
yaw inertia moment can be felt in the natural and linear
handling, and superior control at the limit of tire grip. The
ultra low yaw inertia moment in itself promotes the kind of
driving fun expected of a lightweight sports car.
This layout also assures an adequate
crushable zone, making a significant contribution to safety
including the protection of pedestrians in accidents.
INTERIOR INTEGRATED WITH EXTERIOR
The high-mount backbone frame presents an
axis that integrates interior and exterior design. The interior
expresses the strength inherent in the backbone structure that
extends forward beyond the dashboard towards the bonnet and
rearward to the cowl aft of the seats. This smooth continuity of
interior and exterior is further emphasized in the smooth joining
of the rear cowl and interior, and the way the passenger seat
integrates with the body and creates a sense of unity between
interior and exterior.
INDEPENDENT LEFT/RIGHT REAR-MOUNTED AIR
CONDITIONING SYSTEM
Locating the air conditioning unit behind
the seats confers two major advantages. First, it allows the
engine to be mounted much further to the rear. Second, it helps
enable improved independent left/right zoning so that occupants
can obtain comfortably warm or cool air according to their
individual needs, even when driving with the top down.
Spot-cooling zones provide cool air for the
neck, the back and pelvis, and thighs, three areas of the body
particularly sensitive to temperature change. Louvers are
installed in the rear cowl section (for the neck), within the
seatbacks (back and pelvis) and upper part of the center console
(thighs).
For cold weather driving, a heating zone
traps warm air between the occupants' waist and lower extremities.
Warm air is directed to the thighs from a louver in the top of
the center console. In this way, occupants enjoy a comfortable
cabin environment during convertible driving, regardless of the
season or weather.
BALANCED, RESPONSIVE ENGINE
Mazda Ibuki is powered by a new,
lightweight and compact 16-valve MZR 1.6-liter inline four-cylinder
engine equipped with sequential valve timing and lift for both
intake and exhaust valves. The engine features an integrated
electric hybrid motor that improves acceleration and partly
serves to control engine vibration, allowing use of a lighter
flywheel for heightened response.
At low engine speeds, the electric hybrid
motor provides torque assistance to boost acceleration from a
standing start. Additionally, when the car is stationary, the
hybrid motor automatically stops the engine from idling to save
fuel and reduce emissions. The motor then restarts the engine
automatically when the driver is ready to accelerate. Also,
during deceleration the hybrid motor functions as a generator,
using regenerative braking energy to recharge the battery.
Mazda Ibuki features a six-speed manual
transmission. The transmission weighs less than the current MX-5
Miata gearbox and has reinforced synchronizers to give a decisive
yet smooth shift feel—a hallmark of the original MX-5 Miata—with
extremely short, precise throws.
NEW PROPOSALS FOR SAFETY AND EASE-OF-USE
In an effort to advance safety in
convertible vehicles, the Ibuki design team has installed a four-point
active roll bar into the front pillars and rear cowl section that
instantly lifts up under impact sensor control to reduce
occupants' injuries in the event of a rollover.
Powerful LED headlamps give improved
visibility, and a keyless entry by ID card is provided. Other
innovations include a unique side-parting boot offering a wider
opening and easier access. In addition, a new audio system that
combines the seat air conditioner ducts and speaker in one,
delivers much clearer sounds. This feature enhances the
convertible driving.
Mazda IBUKI Main Specifications
Dimensions
Overall length: 143.3 in. (3640mm)
Overall width: 67.7 in. (1720mm)
Overall height: 48.4 in. (1230mm)
Wheelbase: 91.7 in. (2330mm)
Track front/rear: 58.7 in./58.9 in. (1490mm/1495mm)
Occupancy: 2
Engine
Type: MZR 1.6L in-line 4-cylinder DOHC,
direct injection with dual S-VTL and hybrid motor with idle-stop
function
Horsepower: 180 @ 7500rpm (estimated)
Torque: 180 lb-ft @ 6000rpm (estimated)
Transmission
Type: 6-speed manual
Suspension
Suspension system front/rear: Double
wishbone/multi-link
Brakes
Main brake system front/rear: Ventilated
disc
Steering
Type: Electric power assist rack and pinion
Wheels and tires
Tires front/rear: 215/40R18 (run-flat tires)
Wheels: 18 X 7.5J
Mazda North American Operations (MNAO) is
responsible for the sales and marketing, customer service and
parts support of Mazda vehicles in the United States.
Headquartered in Irvine, Calif., MNAO has more than 700
dealerships nationwide.
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