Audi e-bike Wörthersee Concept
Set to debut at the 2012 Wörthersee Tour, the Audi e-bike Wörthersee is a sport bike technology concept that explores new limits in terms of design, lightweight construction, networking and electric mobility.
Each component of the electrically-assisted bike was created by Audi designers. The frame, swinging arm and wheels are made of carbon fiber.
The frame weighs only 1,600 grams and makes use of bionic principles derived from nature; the 26-inch wheels weigh 600 grams (1.32 lb) each and have large-area blade-pattern spokes.
The electric motor is a 2.3 kW permanent magnet synchronous machine; it is located at the lowest point on the frame and drives the bottom bracket shaft directly, delivering a maximum torque of 250 Nm.
The lithium-ion battery is housed in the frame; it weighs about 5 kg (11.02 lb) 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 complete bicycle weighs only 21 kg (46.30 lb), equivalent to a power-weight ratio of 9 kg (19.84 lb) per kilowatt, or 7 kg (15.43 lb) per hp.
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.
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 upside-down principle; it is air-sprung, with 130 mm (5.12 in) of travel. LEDs are used for powerful lighting: the front light is integrated into the handlebar, the rear light into the seat.
The Audi e-bike Wörthersee will be unveiled at this year’s Wörthersee Tour, the 31st meet for Audi, VW, Seat and Skoda fans; trial biker Julien Dupont and downhill specialist Petra Bernhard will demonstrate their stunts and streetbike skills.
From the official Press Release:
“When developing the Audi e-bike Wörthersee we drew on motor racing design principles for inspiration,” explains Hendrik Schaefers, one of the designers at Concept Design Studio Munich.
“The e-bike appears incredibly precise, highly emotional and strictly functional. Indeed, the design effort focused on its function as a sports machine. All design elements are thus firmly aligned to the technical features.”
The lithium-ion battery is incorporated into the frame and needs 2.5 hours to fully charge.
On long trial tours, only a few simple steps are required to remove the battery and replace it with a charged one.
The frame and the swinging arm that holds the back wheel are made of carbon fiber- reinforced polymer (CFRP).
The same material is used for the 26” wheels, which feature an innovative “Audi ultra blade” design with broad flat spokes for an optimized transmission of pedal power.
“We were able to demonstrate with the choice of materials just how closely design goes hand in hand with expertise in ultra lightweight construction,” Hendrik Schaefers comments.
Homogeneous LED light strips round out the frame and create the immediately recognizable Audi light signature. For extreme tricks and stunts the seat can be lowered to run flush with the frame itself. At the press of a button, the seat then rises up and the biker can adopt a comfortable position.
Connectivity and riding modes
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 cyclist’s smartphone hooks up by WLAN to the computer – when you start cycling, for example, the immobilizer is deactivated. Video images of the trial drive or of a trick, as recorded via the in-helmet camera, are uploaded to the Internet in real time via smartphone.
“Each trick performed successfully is then awarded success points, and as the number of points awarded grows, the cyclist receives awards and the challenge level rises, too.
“The rankings table in the Internet means you can measure yourself against other bikers and your friends.
“And where they happen to be comes to you via Facebook status reports that pop up on the Audi e-bike Wörthersee display.”
The cyclist can choose between a total of five cycling modes – pure muscle power, the electric motor alone, or pedaling supported by the electric motor.
In the “Pure” mode, the drive power is purely the product of the cyclist’s legs, while in “Pedelec” mode you are supported by the electric motor that then makes speeds of up to 80 km/h (50 mph) possible and gives you a range of 50-70 kilometers (31-44 miles).
If you select “eGrip”, the Audi e-bike Wörthersee runs solely on the electric motor and can reach a top speed of 50 km/h (31 mph). The cyclist then controls forward momentum using a gripshift and can configure the power as desired using the computer.
When performing wheelies, an electronic control system support the rider when performing tricks and back-wheel biking. Different modes can be set using a smartphone or directly on the e-bike – either “Power Wheelie” mode, with adjustable wheelie angle for less skilled bikers or “Balanced Wheelie” mode for sporting challenges.
In “Balanced Wheelie” mode, the electronic control system maintains the rider’s balance, by compensating the biker’s movements forwards or backwards via the electric motor.
This means the rider can influence the bike’s speed by shifting weight: if you lean forwards the bike picks up speed, and if you lean back it slows. You select “Training” mode if you want to keep your performance constant for training purposes.