Audi A1 e-tron 2013 Review - International

You do wonder sometimes about Audi. A little over a year ago, we tested a prototype of its A1 e-tron. It was a plug-in hybrid powered by a big electric motor, a mid-sized battery and a very little petrol-powered rotary engine that was mounted under the rear floor and only ever fired up to charge the battery.

The odd thing was that it felt production ready, so sophisticated were the electronics that ran everything from behind the black box. And yet, a year ago, Audi knew this car would never see a showroom. Instead, this new A1 e-tron hybrid will. Probably. And we’ve tested it, too.

The rotary engine has gone, but the quirks remain. For example, Audi has refused to run with hard-learnt lessons from other car companies. Where Toyota’s Prius has long been able to turn its wheels with either petrol or electric power (a parallel hybrid), most believe a series hybrid, where the wheels only ever turn through electric power, is the way forward.

Audi believes both answers are right, so both answers are found here in the new A1 e-tron, yet there are technical details that suggest this A1 e-tron, too, will never reach production.

For example, this one runs not two, but three motors. And that’s expensive. To compensate, though, it runs only one gearbox and even that has only one gear. That’s right, it has a one-speed gearbox. And one-speed gearboxes are not off-the-shelf items in the car industry, except when they are called “differentials”.

Turning that single-speed gearbox, though, is a combination of two different electric motors and a 1.2-litre three-cylinder petrol engine borrowed from Europe’s VW Polo.

Audi claims that, in concert, they will sling the A1 to 100km/h in nine seconds and use just 23 grams of CO2 per kilometre on the combined cycle.

That’s a set of technologies that deliver the outrageous fuel economy figure of just 1.0L/100km, A1 e-tron development chief, Dr Daniel Boland, told motoring.com.au.

The over-riding philosophy of the car, he said, is that it should work as a plug-in hybrid, it should work as a pure electric city car, it should work on long trips and it should do it all so seamlessly that its owners won’t care what’s happening below the skin.

For starters, it has what Audi calls EM1 (imaginatively, Electric Motor 1), which is a small, disc-shaped 50kW electric motor, with 210Nm arriving instantly when needed. This motor is the support act, behaving as both starter motor to the petrol engine and a generator to charge the lithium-ion battery pack, but never actively driving the wheels.

Then there’s EM2 (figure that one out for yourself), which is the main drive engine with 85kW of power and 250Nm of torque and it’s all supported by a 95kW petrol engine.

The thing with it is that the one-speed gearbox arrangement means not only that Audi has chosen not to run the petrol engine around town, but that it actively can’t run the petrol engine around town. The one-speed gearbox means that it’s way below the petrol engine’s minimum speed up until about 40km/h, so it only every chimes in above 55km/h.

“Its real key is moving to a one-speed transmission, which is why the petrol motor doesn’t drive the wheels at any point up to 55km/h,” Dr Boland said

“Instead, it can be used to provide extra boost into the battery, completely declutched and isolated from the drive gear, then it comes in to help with drive the wheels when it’s needed.”

Between all three motors, the A1 e-tron generates 130kW of power and around 300Nm of combined torque – all of which is useful in a car this size, though Audi is very coy about how much weight all this adds.

“They (the electric motors) are all connected to the combustion engine and the battery is now in the middle of the car for better centre of gravity,” Dr Boland explained.

Like most electric cars, the A1 e-tron looks almost exactly the same as all other models in the range. Inside, it’s still similar, except for its larger display to tell you of the complex goings-on from its array of motors.

It’s still a comfortable unit, though you feel it would be more useful in production as a five-door, rather than the compromised three-door layout. And it would be a hellishly expensive three-door.

It’s also silent, even though it’s technically switched on and ready to go. At light throttle openings, the e-tron just moves silently away. Even the traditional gear whine has been dissipated using noise-cancelling technology.

It moves briskly away, too, when you prod it, but it moves in that surging electric-car way of a hard hit early, leaving the later acceleration to taper away. It’s pretty good on changing throttle openings, it’s terrifically silent and it even rides pretty well.

You know the petrol engine isn’t playing, but you don’t miss it because for a town car the e-tron works perfectly well without it, punching along on plug-in charge thanks to a T-shaped, 17.4kW/h battery that sits beneath the rear seats and stretches up the transmission tunnel up until about where the front seats start.

It’s fairly perky, too, especially because city life offers few opportunities for sustained full throttle. That means the electric motor gets hit hard and fast, then people come out of the throttle in real life and wait for the next traffic light.

In the e-tron, this means it regenerates energy and slings it back into the battery pack to use next time. While the standard car voltage is 12 volts and some high-tech demands are calling for 48 volts, this thing runs voltages in excess of 300 volts, so it soaks up and discharges energy very quickly.

But pure electric mode isn’t all the e-tron can do. It can be driven either in Eco or Sport modes. Go for full throttle in Sport mode and it will punch all the energy available to the EM2 motor. Keep driving quickly and the battery will drain quickly (roughly 12 minutes if it’s being asked to deliver all 85kW all the time), so the three-cylinder ICE motor is asked to fire up to keep juice in the battery.

It does this by using the ICE to spin the EM1 disc, and the surprising thing about it is just how smoothly it executes it. There is no possibility that even an expert driver will feel the engine switch on and off because, unlike most start-stop systems, the three-cylinder engine is eased up to speed by the electric motor, so it’s never actually trying to start from zero rpm. Instead, the little disc spins it up to idle speed first.

It’s an ingenious solution and not only can you not feel it turn on or off (the EM1 also cushions its switch-off), but you can barely hear it. When it runs as a generator, the ICE is whisper quiet and the whole car is one fluid exercise in listening to the tyres and the wind.

That changes above 55km/h. There is no compulsion for the e-tron to start the ICE above 55km/h, though, because the driver can select full electric mode to be good to the environment, to use less fuel or just to sneak up on the people at home.

But Sport mode calls for the petrol engine to help the bigger electric motor to directly drive the wheels. You can hear the petrol engine then, though the performance it delivers is staggering for a three-cylinder engine. With all that electric help, it drives like a big, turbo petrol motor rather than a tiny three-cylinder, because you can’t hear the electric motor providing all the assistance.

Then you push harder still and, over 130km/h, the car runs purely on petrol power. That’s largely because of the single-gear strategy, since the wheels are turning too fast and make the electric motor turn faster than it can manage. So it just shuts off.

The beauty of this car is that it covers all the bases and, in all likelihood, gives Audi plenty of insights into the benefits of a) parallel hybrids, b) series hybrids, c) small petrol motors and d) a combination of all of the above.

Like the rotary A1 e-tron, though, it’s difficult to see all of this technology ever arriving together in an A1 bodyshell in a showroom. A larger car - like an A4 or an A6, where they could charge more money and fit a bigger petrol engine - is a more likely starting point.

Read the latest news and reviews on your mobile, iPhone or PDA at carsales' mobile site…