Audi has confirmed details of its more frugal four-cylinder TDI engine, available in the new A6 and A7.

The 2.0-litre unit produces 204PS and emits from 117g/km of CO2, making it ideal for business users.

All versions feature front-wheel drive and a seven-speed automatic gearbox.

The 40 TDI versions can be ordered now, with first deliveries of the A6 expected in September and the A7 due in November,

Entry-level Sport versions are priced from £38,640 (A6 saloon), which is in-line with key rivals such as the Mercedes E 220 d and BMW 520d.

S-Line trim is also available on both models.

Audi says it has worked to ensure the engine is both torque-rich and refined.

In the A6 saloon, drivers should expect average fuel consumption of up to 62.8mpg, while the A6 Avant and A7 can return up to 60.1mpg with CO2 emissions of 122g/km-124g/km.

The A6 40 TDI is around one second slower from 0-60mph than its main rivals, taking 8.1 seconds.

Unlike its rivals, the new 40 TDI engine in the A6 and A7 features mild-hybrid technology.

A small electric motor is able to recover energy during braking or coasting and provide a boost during acceleration. The systems high output can also enable the car to coast with the engine off at speed up to 99mph.

Audi A6 and Audi A7 40 TDI pricing:

Model	Recommended OTR
A6 Saloon 40 TDI Sport	£38,640
A6 Saloon 40 TDI S line	£42,000
A6 Avant 40 TDI Sport	£40,470
A6 Avant 40 TDI S line	£44,100
A7 Sportback 40 TDI Sport	£47,140
A7 Sportback 40 TDI S line	£50,040