Audi A8 Hybrid Concept
Power like a big V6, fuel economy like a modest four-cylinder unit – Audi presents the A8 hybrid as a technology concept. Its two propulsion units – a 2.0 TFSI and an electric motor – develop a total output of 180 kW (245 hp) of system power and 480 Nm (354.03 lb-ft) of torque. This enables the Audi A8 hybrid to accelerate in 7.6 seconds from zero to 100 km/h (62.14 mph) and to achieve a top speed of 235 km/h (146.02 mph). Yet its average fuel consumption amounts to only 6.2 liters (37.94 US mpg) per 100 km – the CO2 equivalent is 144 grams per km (231.75 g/mile).
The combustion engine of the Audi A8 hybrid is the 2.0 TFSI – a high-tech powerplant. This four-cylinder unit, which has been named “Engine of the Year” five times in a row since 2005, is an example of Audi’s downsizing philosophy. It combines direct fuel injection with turbocharging and the AVS Audi valvelift system, which regulates the valve lift in two stages. In combination with the adjustable intake camshaft, the Audi valvelift system improves cylinder charging and ensures spontaneous and powerful torque build-up. The 2.0 TFSI delivers 155 kW (211 hp) and 350 Nm (258.15 lb-ft); the torque value remains constant from 1,500 to 4,200 rpm.
In the crankcase of the four-cylinder unit, which has a displacement of 1,984 cc, two balancer shafts offset second-order inertial forces to ensure virtually vibration-free and pleasantly quiet operation that goes well with the luxurious character of the A8. All components are optimized to minimize friction. The flow-rate-regulated, pressure-controlled oil pump further reduces fuel consumption.
A hydraulically operated wet clutch links the 2.0 TFSI with the electric motor. Its control requires the utmost precision, and a great deal of know-how has been expended to achieve its smooth, precise and swift operation. The synchronous motor, which is continually excited, also serves as a generator that develops 33 kW (45 hp) of power and 211 Nm (155.63 lb-ft) of torque. Its full power is available practically right from standstill and contributes to a sportily powerful start-up. Since an electric motor also develops heat, its housing is furnished with cooling ducts. Interposed between the electric motor and the wheelset of the eight-speed tiptronic, which is controlled entirely by electronics, is an additional cut-out clutch. In conjunction with the electric unit, this functions as a torque converter. The propulsive power of both drive systems is applied to the road through the front wheels.
The hybrid drive is designed for fully electric-powered driving up to 65 km/h (40.39 mph) and for a distance exceeding two kilometers – especially well-suited for driving in the city or residential suburbs. When conditions permit, the driver can also select the electric mode by actuating a separate e-key in the cockpit. Both the display screen of the instrument cluster and the large monitor of the MMI operating system on the dashboard present all momentary power flows in brilliant graphics.
This near-production concept car has 21-inch, two-colour wheel rims styled with highly three-dimensional surface areas. The exterior paint job of the A8 hybrid is in “Prism Silver” with “Spectra Flair” as an accent color – a rainbow effect that’s accentuated in reflected light along creases and seams on the body. The prominently located “hybrid” lettering on both front fenders leaves no doubt about what kind of car this is. The accentuation of its width by a prominent low horizontal spoiler edge and a chrome strip conveys the vehicle’s solid stance on the road.
The engine compartment cover with its high-gloss finish and the glass cover of the battery in the trunk also provide visual links to hybrid technology. And the illuminated doorsteps bear the “hybrid” insignia as an elegant touch to underscore the electric aspect whenever the doors are opened – using LED technology to minimize energy consumption.
Source: Audi press