Audi
e-bike Worthersee Concept
One
of the highlights on the Audi stand at the 2012 Wörthersee was the bicycle
technology concept known as the Audi e-bike Wörthersee, a sport bike that does
not fit into any of the usual categories. It is neither a pedelec nor a
conventional bike, but is best described as a high-end pedelec made by Audi for
sport, fun and tricks. The Audi e-bike Wörthersee combines the Audi brand's
principal competences - design, ultra, connect and e-tron and explores the
limits of what is technically feasible in terms of design, lightweight
construction, networking and electric mobility.
This
show bike is futuristic at the very first glance - a bike for tomorrow and
beyond. All its components, even the pedals, have been shaped by Audi's
designers, for instance the 26-inch wheels made from CFRP that weigh only 600
grams each and have innovative large-area blade-pattern spokes.
The
Audi e-bike Wörthersee's ultra-light carbon-fiber frame weighs only 1,600 grams. It makes use of bionic principles derived from nature. Material
reinforcements are needed only at the points where loads actually occur. The
swinging arm for the rear wheel is also made of CFRP. All in all, the Audi
e-bike Wörthersee represents the full extent of the brand's expertise in
ultra-lightweight design.
The
rear wheel is driven by a chain. The electric motor is a permanent magnet
synchronous machine; it is located at the lowest point on the frame and drives
the bottom bracket shaft directly. Maximum torque at the rear wheel is in the
region of 250 Nm. Peak output from the electric motor is 2.3 kW a new top value on the e-bike scene. The complete bicycle weighs only 21 kg, equivalent to a power-weight ratio of 9 kg per kilowatt,
or 7 kg per horsepower - another record-breaking value.
The
lithium-ion battery is housed in the frame; it weighs about 5 kg and
operates at a voltage of 48 V. Its capacity is 530 Wh and it can be fully
recharged from a 230 V supply in two and a half hours. As an alternative it can
be easily detached from the bike and replaced by a recharged battery.
The
rider of the Audi e-bike Wörthersee can choose between five programs; these
either support use of the pedals or permit electric-only travel.
In
the 'Pure' mode the rider only propels the bike by means of the pedals. In the
'Pedelec' mode the rider is assisted by the electric motor; a top speed of up
to 80 km/h can be reached and the action radius is between 50 and 70
kilometers . In the 'eGrip' program the Audi e-bike Wörthersee
can be ridden with the electric motor providing all the necessary power; in
this case at speeds up to 50 km/h. The rider controls the power output
from the electric motor at a twistgrip and can configure it at the on-board
computer.
In
'Wheelie' mode the power flow is electronically controlled in order to assist
the rider when the front wheel is in the air. Alternative operating modes are
available, and can be selected by smartphone or directly at the e-bike: either
'Power Wheelie' with an adjustable wheelie angle for less skilled riders, or
'Balanced Wheelie' for those with more experience. In the latter mode the
rider's balance is maintained electronically: as his or her weight is displaced
forward or back, this is counteracted by either braking or accelerating the
electric motor.
In
this way the rider can influence the speed when riding on the rear wheel only
by shifting his or her weight. Leaning forward speeds up the bike, leaning back
slows it down. If the rider wants to use the pedals and maintain a constant
power input, the training mode can be chosen. The electric motor then makes
good the extra power needed when riding into the wind or up a hill, so that the
rider's performance can be kept constant for training purposes.
The
Audi e-bike Wörthersee has a varied specification. The nine-speed hydraulically
actuated gear shift has a very rapid sequential action, similar to the R tronic
transmission in an Audi R8. The two disk brakes are also applied hydraulically.
Seat height can be continuously adjusted at a handlebar control, even while the
bike is being ridden. The front fork uses the more complex 'upside-down'
principle; it is air-sprung, with 130 mm of travel. LEDs are used for
powerful lighting: the front light is integrated into the handlebar, the rear
light into the seat.
The
on-board computer is located in the frame top tube and operated using a
touchscreen. Among the functions it provides are riding mode selection,
recording trick sequences and adjustment of various e-bike functions such as
electric pedaling assistance and lighting. The display shows road speed,
distance covered, state of battery charge, energy consumption and slope angle at
any given moment.
The
rider's smartphone communicates by WLAN with the bike's computer. The antenna
is integrated into the front brake line. To ride the bike, the immobilizer is
deactivated at the smartphone; the bike is then ready for use. In addition, by
way of the interface between the bike's computer and the smartphone, video
images recorded while riding or even complete trick sequences can be
transmitted to the Internet or the trainer. Every trick performed successfully
qualifies for success points. As the number of points increases, the rider is
rewarded and at the same time the challenge level rises. The total Internet
ranking can be compared with friends or other riders. The rider can locate them
by way of Facebook entries that can be shown on the Audi e-bike Wörthersee's
display.