In the pursuit of optimal economy Audi has added a new mild-hybrid drivetrain to the A6 and A7. Equipped with the 2.0-liter, 204ps 40 TDI unit, this is the first time a four-cylinder has been fitted in the five-door coupe.
The key component behind the MHEV system is a belt alternator starter (BAS) connected to the crankshaft which, in this application, can recover up to 5kW of power during deceleration and store it in a separate lithium-ion battery housed in the rear of the car.
The 40 TDI can also coast with the engine running at idling speed between 54km/h and 159km/h. As soon as the driver accelerates again, the BAS restores power.
The 2.0-liter unit in both A6 and A7 sportback applications offers fuel economy of 3.7l/100km and CO2 output from 117g/km, while the A6 Avant has a potential of 3.9l/100km, corresponding to CO2 production of 124g/km.