All Electric Audi A2 Concept

In Audi by Jonathan Humphrey

  • All-electric four-seat concept weighing just 1,150kg with the help of multi-material hybrid construction
  • Lithium ion battery-powered electric motor mounted within sandwich floor delivers 116PS and 270Nm, permitting 9.3-second 0-62mph time and governed 93mph top speed
  • 124-mile range following 1.5-hour 400-volt charge or 4-hour 230-volt charge
  • Shift-by-wire, brake-by-wire and steer-by-wire contactless technology
  • Adaptive Audi dynamic light across profile of car and in the cabin, LED matrix technology for headlights and tail lights

A highly-charged atmosphere is guaranteed on the Audi stand at the 2011 Frankfurt Show as the futuristic A2 concept is confirmed as the third all-electric Audi design study to take the limelight for the Vorsprung durch Technik brand. Although more familiar in form than the two radically styled urban concept electric studies, the four-seat A2 concept is similarly forward-looking. Its exceptionally weight-conscious and space-efficient packaging is achieved using state-of-the-art multi-material hybrid construction, and its space-age specification includes contact-free battery charging, ‘by-wire’ steering and braking, LED matrix lighting technology and a semi-autonomous running mode.

Advanced Audi ultra-lightweight construction techniques limit the weight of this latest technology study to just 1,150kg. For the first time it unites hybrid multimaterial construction, in which very different materials are combined with one another, with the Audi Space Frame (ASF) construction principle. The superstructure is made largely from aluminium, complemented by add-on parts in Carbon Fibre-Reinforced Polymer (CFRP).  The 18-inch alloy wheels also shave off around 2kg each compared with conventional equivalents thanks to cladding technology which greatly reduces the amount of material used.

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The Audi A2 concept is a purely electric vehicle. A lithium-ion battery mounted in its sandwich floor stores 31 kWh of energy, 24 kWh of which is usable. The electric motor is transversely mounted in the front, and delivers 116PS of peak power (80PS continuous) and 270 Nm of torque (160 Nm continuous) to the front wheels via a single-speed transmission.

This power output permits a 0-62mph acceleration time of 9.3 seconds and a top speed of 93mph, the latter electronically limited in the interest of driving range, which stands at 124 miles according to the European driving cycle test.

It takes roughly 1.5 hours to fully recharge the battery with 400 volt three-phase current and approximately four hours with 230 volt household current. The Audi A2 concept is also designed for the new contactless charging technology (Audi Wireless Charging).

The charging socket and the cooling water connection are concealed at the front of the car behind the upper portion of the single frame grille. The lower section of the grille acts as an air inlet, and incorporates highly efficient cooling elements made of graphite foam. The lightweight mineral is an excellent conductor of heat from the water to the ambient air. Eight blocks with six graphite elements each are located in the central air inlet.

McPherson strut front suspension and a torsion beam rear axle provide agile handling with the help of steering and brake systems which are purely electric (steer-by-wire and brake-by-wire), requiring no mechanical or hydraulic connection to the steering wheel or the pedals, respectively.

Semi-autonomous driving

The A2 concept can also cruise ‘semi-autonomously’, a benefit designed specifically to take some of the strain out of driving in slow-moving traffic. Two large inward-pointing touch-sensitive pads are used to control all the car’s key operating functions bar the turn indicators and the windscreen wipers, and if both these touch pads are touched simultaneously the car enters this ‘semi-autonomous’ mode. In this mode, the driver can manually intervene and regain full control of the vehicle at all times, as is currently the case with the Adaptive Cruise Control with stop & go function on which the new technology is based.

Another highlight of the A2 concept is the matrix beam LED headlights. An entire bundle of small light-emitting diodes arranged one above the other produce the low beam and high beam light. Microreflectors enable the precise positioning of the light. The LEDs can be switched on and off independently to illuminate the road perfectly in any situation. Numerous mini-LEDs set in the lower section of the headlight produce the daytime running light.

The adaptive tail lights also use matrix beam technology. The system uses a sensor to detect how good visibility is and adjusts the brightness accordingly.

Five laser diodes produce the rear fog light. When visibility is good, their light is invisible. In the fog or rain, however, it strikes the water particles in the air and becomes clearly visible as a floating triangle.

Audi dynamic lights in profile

Each flank of the Audi A2 concept is also embellished by a band of light that connects the headlights with the tail lights.These Audi dynamic lights are produced using light-emitting diodes and light guides. When in standby-mode, the several centimetre-wide band is coloured black, but when the holder of the key to the Audi A2 concept approaches, it lights up blue and intensifies illumination of the door handles. These are inset into the band and extend when the driver swipes a hand over them.

The dynamic light shines bright orange when the A2 concept is driving. It pulses on the corresponding side when indicating a turn, and when braking, a red pulse of light runs along the flank as a warning for other road users.

Despite a ‚footprint‘ spanning just 3,804 millimetres in length, 1,693 millimetres in width and 1,494 millimetres in height, the A2 concept offers seating for four and space for luggage in a cabin that perfectly reflects the philosophy behind the Audi A2 concept. It is light, clean, open, and spacious with intuitive controls. The dashboard is split into two sections, with the semi-circular left section enclosing the driver’s area. Audi dynamic light runs along the edges in two separate arcs from the doors to the cockpit, welcoming passengers in a manner similar to the light band on the exterior.

The architecture of the interior takes advantage of the possibilities afforded by the electric drive system. There is no centre tunnel; the console between the front seats can be lowered to allow free passage through the vehicle. Heating and cooling air flows indirectly and draft-free through a perforated surface beneath the windscreen.

The steering wheel of the Audi A2 concept is flattened at the top and bottom, with a single spoke connecting the ring to the impact absorber and the two large touch pads controlling many functions protruding inwards.

An open, shell-like section serves as the steering column and extends horizontally into the cockpit. On the far end is a seven-inch display flanked by two secondary displays with the speedometer and the power meter.

When the driver pushes the button to activate the electric drive, an animated band of light encircles the driver and passenger, and two touchpads unfold to the right of the steering wheel.The small touch surface on the left is for shifting gears (shift-by-wire); the larger one on the right is reserved for the air conditioning and media functions.

Evolution of MMI Touch

The retractable console between the seats includes an additional touchpad for entering letters and numbers and for secondary functions – a further development of today’s MMI touch. A docking station for the iPhone completes the control concept.

The show car has all of the Audi connect technologies on board. The Bluetooth online car phone connects it to the Internet via a Universal Mobile Telecommunications Standard (UMTS) module, a Wireless Local Area Network (WLAN) hotspot lets the passengers surf and e-mail from their mobile devices, while a fast data connection delivers specially prepared news and information to the vehicle. The services currently offered by Audi are of course also available for navigation: the Google Earth-enhanced mapping, Audi online traffic information, Google Points of Interest (POI) search via voice control and Google Street View.

The opaque glass roof of the show car is finished in flat Electric White, and becomes transparent at the push of a button. When an electric voltage is applied, small particles integrated into the glass align so that the light can pass through the glazing unhindered. When the glass roof is darkened, however, it blocks the infrared component of the sunlight almost completely, effectively shadowing the interior. This is a further contribution to efficient temperature management in the purely electric powered Audi A2 concept.

Cut-outs in the backrests of the four individual seats give them a sporty look and make them incredibly light. They have an aluminium chassis and the developers used a polymer blow-moulding process for the shells. Three struts connect the seats with the floor for more foot room in the back, and there are storage bins beneath the fold-up seat cushions.

A console with storage bins is located between the rear seats. Folding these seats forward reveals a fixture for the fork of a special city bicycle. The luggage compartment of the Audi A2 concept has a sandwich floor. A fold-up frame with two solid, high-load nets covers the lower load level.

The colours and materials in the interior support the impression of lightness and functionality. The large areas from the door top shoulders to the floor are covered in a tough material with a neoprene surface feel. A ribbed material made from recycled polyester covers the central floor area. Aluminium elements accentuate the cockpit.