The components that make up the e-tron’s hybrid powertrain are not unfamiliar. Its central means of propulsion remains a transversely mounted petrol engine, in this instance a 148bhp 1.4-litre, four-cylinder turbo petrol unit.
Audi says the four-cylinder petrol unit used in the e-tron is one of its most advanced engines. The turbocharged motor, which uses an aluminium crankcase, is claimed to weigh just 100kg, but it isn’t compact enough to allow the fitment of the electric powertrain components without adjustment.
Compared with the standard A3, the e-tron’s engine has been shifted by 60mm or so to the right to help make sufficient space for the extra ancillaries under the bonnet.
Its party piece, though, is thermal efficiency, particularly with regard to getting itself to an optimum working temperature even for those short, low-speed journeys during which it might not be called upon much.
The exhaust manifold, integrated into the cylinder head, is at the heart of its efforts, quickly warming the engine following a cold start. Should that prove insufficient for sudden moments of high load endured during kickdown, the e-tron’s motor features a number of special protective measures, including specially coated piston rings and bearings.