The Audi E-tron Spyder is a concept sports car capable of rushing from standstill to 60 mph in just 4.4 seconds. It also has the potential to sip fuel at a rate of 108 miles per gallon.
That’s because this car is a plug-in hybrid with a diesel engine. Audi first constructed an all-electric concept in coupe form, the E-tron. While following the tradition of calling open-top cars "spyders," the company decided to send this variant down a somewhat different path. A diesel hybrid is still not quite ready for prime time due to a number of reasons. There’s still some resistance to diesel from American buyers (who constitute a considerable proportion of many car companies’ target market) and technical issues such as a less-than-seamless bump whenever a diesel engine suddenly starts up while driving. The E-tron Spyder is the laboratory and testing ground to overcome at least some of these obstacles.
Neither diesel engines nor electric motors and battery packs are known for being light. To mitigate this, the Spyder’s two-seater body is fashioned from carbon fiber panels set over a specially made aluminum spaceframe, similar in principle to an Audi A8 production sedan. Curb weight is a relatively trim 3,190 pounds, distributed in an ideal 50:50 fashion front to rear. For some frame of reference, a V8-engined Audi R8 Spyder weighs 3,858 pounds.
One attribute for which both diesel engines and electric motors are renowned is torque, that thrust from low revs as the throttle pedal is pressed and the rate of acceleration goes up and up. The Spyder has 738 pound-feet of it, which is a considerable amount, especially in a car this light. An electric motor per front wheel provides the equivalent of 44 hp and 129.5 lb-ft; a lithium-ion battery pack is also housed in the nose. A mid-mounted 3.0-liter, twin-turbo V6 engine provides 479 lb-ft, along with 313 horsepower.
In any diesel-powered production-model Audi, there’s hardly a murmur under acceleration. Since this is a prototype without noise insulation, the V6 emits a metallic, ear-rattling bark that underscores a turbine-like whistle from the electric motors. It’s a new soundtrack for enthusiasts to get acquainted with, but it’s not unpleasant. Anyway, driving through populated areas can be handled in stealthy electric-only mode, up to 31 mph or a range of 31 miles.
In this particular car, an example of Audi’s C-tronic transmission – a continuously variable transmission (CVT) – is deployed, interacting solely between the combustion engine and the rear wheels. No mechanical connection exists between the two separate forms of locomotion, just a series of computerized relays that determine how much muscle can be applied to each wheel for maximum traction. Audi calls it "torque vectoring." Everyone else would call it superb acceleration, grip and handling. There’s a neutrality to the chassis that Switzerland would be proud of – the car retains a fine balance from corner to corner.
An instrument panel set into a clean-lined, sculpted dash has just one dial that’s so futuristic it doesn’t have a needle, just a thin green line arcing around it to indicate how much energy the system is consuming, or flick to another "page" and it will display road speed.
No other plug-in hybrid has such a cool way of offering access to its socket. With the press of a button, the four-ringed symbol at the nose sinks down and then back into the body. On the right rear flank, the fuel cap is reached in much the same way. But those are just two of a whole drawing board-full of design details to delight in. The LED light clusters compete with vents, understated door handles and the subtly sensual lines of the body to grab the attention. The intricate-yet-elegant 20-inch wheels are forged aluminum, as is the flat-bottomed steering wheel that’s also partly dressed in grey neoprene. If this car ever became a production reality, though, safety regulations will demand that those door mirrors be substantially bigger, no matter how sleek they look right now.
Perhaps wondering about production is beside the point. What we can take from the E-tron Spyder, and what Audi can also take from it, is that a diesel hybrid can be a workable proposition and the technology could one day soon find its way into a mainstream sedan to offer that cake every driver wants to have and eat too: more power and better consumption.