► Tech secrets of Audi Q8► Electric drive, virtual cockpits► Tech to be shared with new A8Audi has shown the Q8 Sport concept twice now, though it did at least go to the trouble of re-painting it yellow for Geneva. Big deal, you say. But this car is a big deal, not only as a design preview for 2018’s Q8 SUV but because its key tech will appear on production Audis before the end of this year, first in the form of the new A8 saloon.Bringing the promise of increased efficiency with an impressive turn of speed is the mild hybrid powertrain, which in the Q8 concept combines a 0.9kWh lithium-ion battery under the rear luggage compartment and a modest 26bhp, 125lb ft electric motor sandwiched between the more conventional elements of the powertrain, a 3.0-litre, twin-turbo petrol V6 and eight-speed Tiptronic transmission. Energy flows between motor and battery via the car’s 48-volt system, with the motor wearing many hats: starter motor, generator under braking, additional power unit for hard acceleration and sole power source in traffic. The aim is the grunt of a V8 with the efficiency of something more modest. The V6 summons 436bhp alone but, when the powertrain chimes in…