All-electric e-tron concept car from Audi makes its debut at Detroit

(15/01/2010)

Audi is showing an uncompromising purist compact sports car with all-electric drive at the first major auto show of 2010. The Detroit showcar Audi e-tron is the name of this 3.93 metre long and 1.78 metre wide but just 1.22 metre tall two-seater; just a few months after the debut of the Audi e-tron at the 2009 Frankfurt Motor Show, this is now the second electric concept vehicle from the brand.

Coupled with the Detroit showcar Audi e-tron’s low gross weight of around only 1,350 kilograms, high-torque power units driving the rear wheels guarantee commensurate road performance. Two electric motors with a combined output of 204PS and 2,650 Nm (1954.54 lb-ft) accelerate the coupe with ASF-design aluminium body from 0 to 62mph in just 5.9 seconds. The Audi e-tron accomplishes the sprint from 37mph to 75mph (60 to 120 km/h) in a mere 5.1 seconds.

The Detroit showcar Audi e-tron is able to distribute its electric motors’ high torque between the wheels entirely as required. Its “torque vectoring” is the key to a thrilling level of active precision and excellent traction. Thanks also to its low weight, short wheelbase and perfect weight distribution for dynamic handling, the Audi e-tron has all the drivability of a go-kart – agile, good on bends and neutral right up to the very high handling limit.

Lithium-ion batteries, located for an optimal centre of gravity behind the passenger compartment and ahead of the rear axle, make an effective energy content of 45 kilowatt-hours available. This makes an operating range of up to 155 miles realistically possible.

As previously with the first e-tron concept car shown in Frankfurt, Audi again bases all components in this electric vehicle on an integral concept with many revolutionary details: a heat pump as an efficient means of heating up and maintaining the interior temperature. The drive system, power electronics and battery have innovative thermal management – crucial for maintaining a high operating range coupled with outstanding interior comfort.

The vehicle body has a powerful, wide and muscular stance on the road, and looks extremely compact and puristic not least thanks to the typically short sports car wheelbase of just 2.43 metres (95.67 in) – a whole 22 centimetres (8.66 in) shorter than the R8.

The sweeping line of the front end and the flat curved roof immediately identify the two-seater as an Audi. The sides reveal familiar contours: The way the dynamic line is tailored above the sill and the prominent wheel arches, as is typical for an Audi R, combine the front, side and rear into a monolithic entity and strongly emphasize the typical Audi feature of round wheel arches enclosing the large 19-inch wheels. The highly tapered front end gives the Detroit showcar Audi e-tron distinctly wedge-shaped basic proportions.

1.78 metres wide, just 3.93 metres long and 1.22 metres tall – those are the classic proportions of a sports car. That leaves space ahead of the rear wheels for the 399 kilogram battery unit, with converter and power electronics.

The two electric motors, which have their own cooling system, are mounted on the rear axle. This special package, featuring a 40:60 weight distribution, ensures perfect balance, which contributes to the driving dynamics of the Audi e-tron.

The trapeze of the single-frame grille dominates the distinctly wedge-shaped front end and is flanked by two large air intakes. The top of the grille merges into the flat strips of the adaptive matrix beam headlight modules with their clear glass covers. All light units use ultra-efficient LED technology.

The headlights are the core of a fully automatic light assistance system that reacts flexibly to any situation. The new technology recognizes weather conditions and adapts the illumination to rain or fog. The technology at the heart of the light assistance system is a camera that works together with a fast computer to detect oncoming traffic, recognize lanes and measure visibilities, such as in the event of fog.

If there is oncoming traffic, the high beams are turned off in the corresponding section of the illumination field. The cornering light system analyzes data from the navigation system and illuminates corners before the driver steers into them. The Detroit showcar Audi e-tron does not have conventional fog lamps that consume additional power. It intelligently varies the low beams instead; in fog, for example, it produces a wider, more horizontal illumination field, thus significantly reducing the glare from the car’s own lights.

The variability of the headlights is also reflected in their design. The LED elements change appearance and thus the character of the front end of the vehicle depending on the speed driven and the ambient conditions. The innovative lighting technology now offers the Audi designers almost as much design freedom as the shape of the body does.

One design element that is specific to electric vehicles developed by Audi – such as the Audi e-tron – are the air intakes in the single-frame grille and behind the side windows on the C-post. They are closed flush under normal circumstances and opened by retracting slats when additional cooling air is required. The slats above the drive unit then also open to provide a better through-flow of air. These measures, too, maximize efficiency – the concept car is outstanding for an already low drag coefficient that is further improved when the flaps are closed.

Systematic lightweight construction is an even more important prerequisite for efficiency and range with electric vehicles than for conventionally powered cars. Lightweight construction is moreover the key to thrilling handling characteristics. Audi developers focused on a core competence of the company when creating the Detroit showcar Audi e-tron: The body structure is based on Audi Space Frame technology (ASF), with a hybrid design approach adopted. All add-on parts – doors, lids, sidewalls and roof – are made of a fiber-reinforced plastic.

The combination of aluminium and carbon fibre-reinforced composite material guarantees supreme rigidity coupled with low weight. Audi will soon use this technology in a similar form for future production vehicles. Despite the complex drive system layout with two electric motors and a high-capacity battery system, the total weight of the Audi e-tron showcar on display in Detroit is only around 1,350 kilograms.

Two asynchronous electric motors with a total output of 150 kilowatts (204 PS) give the Detroit showcar Audi e-tron the performance of a genuine sports car. The concept car can accelerate from 0 to 62mph in 5.9 seconds if necessary, and goes from 37mph to 75mph (60km/h to 120km/h) in 5.1 seconds. The torque is distributed selectively to the wheels based on the driving situation and the condition of the road surface, resulting in outstanding traction and handling.

The top speed is limited to 124mph, as the amount of energy required by the electric motors increases disproportionately to speed. The range in the NECD combined cycle is approximately 155 miles.

The energy storage unit is charged with household current (230 volts, 16 amperes) via a cable and a plug. The socket is behind a cover at the back of the car. The charging time when the battery is empty is around 11 hours, but heavy current (400 volts, 32 amperes) cuts this to around just two hours.

The battery is charged not only when the car is stationary, but also when it is in motion. The keyword here is recuperation. This form of energy recovery and recharging of the battery is already available on many Audi production models.

Related categories:  Audi   Hybrid and electric car