Detroit show: Audi shows off all-new e-Tron

AUDI has taken the wraps off a new iteration of its high-performance e-Tron eco-supercar, a smaller and lighter version it describes as an “uncompromising purist compact sportscar with all-electric drive”.

While the inaugural version shown at the Frankfurt motor show last September was an R8-sized supercar which stunned the world with its phenomenal performance claims – output of 230kW and 4500Nm, acceleration from 0-100km/h in 4.8 seconds, 60-120km/h in 4.1 seconds, for example – the Detroit show car has emerged as a somewhat less aggressive and, were it to reach series production, a more affordable contender.

It also shows that the Audi is considering a range of applications for its zero-emissions electric drivetrain, and provides a look at another market segment niche the prestige German manufacturer looks set to enter before long.

Unlike the all-wheel drive Frankfurt model, the Detroit e-Tron drives the rear wheels only through two electric motors that have a combined output of 150kW of power and 2650Nm of torque, enabling the 1350kg aluminium space-frame coupe – 250kg lighter than the first e-Tron – to reach 100km/h in a claimed 5.9 seconds.

The 60-120km/h benchmark is devoured in 5.1 seconds.

Top speed is limited to 200km/h because, according to Audi, the amount of energy required by the electric motors increases disproportionately to speed. The driving range is approximately 250km, with recharging times ranging from two hours (via a 400-volt outlet) to 11 hours, the latter using 230-volt household current.

The tale of tape is no less interesting, with the Detroit two-seater measuring 3930mm long, 1780mm wide and 1220mm high – smaller in all dimensions than not just the R8 but the TT as well, and resting on a shorter (2430mm) wheelbase, too.

The wheelbase is 220mm shorter than the R8 and 38mm shorter than the TT, a characteristic of the car that, according to Audi, has assisted the designers to create a powerful, wide and muscular stance on the road and at the same time a compact and ‘puristic’ look.

The short wheelbase, low weight and the 40:60 front/rear weight distribution achieved are also said to contribute to neutral, agile, go-kart-like handling.

The 399kg 45kWh lithium-ion battery pack is positioned ahead of the rear wheels and behind the passenger compartment, while the two electric motors, which have their own cooling system, are mounted on the rear axle.

Torque is distributed selectively to each rear wheel based on the driving situation and the condition of the road surface, which the manufacturer claims results in outstanding traction and handling.

High levels of grip are also guaranteed with the use of 19-inch wheels on 235/35 front and 255/35 rear tyres – a unique profile for the Detroit version – while the latest e-Tron also has a more advanced braking system, with an electro-mechanical set-up that can recover energy.

A hydraulic fixed-calliper brake is mounted on the front axle, while two electrically actuated brake-by-wire floating-calliper brakes are mounted at the rear. By virtue of being isolated from the brake pedal, the e-Tron’s electric motors can convert the entire deceleration energy into electric current and recover it.

The body structure is based on the familiar Audi Space Frame (ASF) but with a “hybrid design” that includes add-on parts – doors, lids, sidewalls, roof, etc – made from fibre-reinforced plastic.

Aluminium and carbon-fibre-reinforced composite material also contributes to the low weight.

The chassis has triangular double wishbones made of forged aluminium components at the front and rear axles. The steering is via an electro-mechanical system that varies in boost according to speed.