The carmaker claims efficiency figures of 188mpg and CO2 emissions of 35g/km for the petrol/electric hybrid drivetrain according to the ECE standard for plug-in hybrid cars.

The drivetrain uses a modified 148bhp 1.4-litre TFSI unit and a 75kw electric motor. This is integrated into a newly designed six-speed “e-S tronic” transmission that sends power to the front wheels.

Combined, the two power units generate 201bhp of system power and 258lb.ft of system torque, giving a 0-62mph sprint of 7.6 seconds and a top speed of 138mph.

The car can run on petrol power alone or exclusively on electric power for up to 31 miles at speeds of up to 80mph. In hybrid mode the driver can run both units simultaneously. When the driver stops accelerating in this mode, both motors temporarily deactivate, eliminating motor braking torque and allowing the car to glide to conserve fuel and recuperate energy. 

According to reports, a production version of the A3 e-tron is expected late in 2014.