Audi launches new and extremely frugal versions of the A1 and A3. Made by OCD specialists to be as economical as possible, these models are known as CoD – or Cylinder-on-Demand – and feature a 1.4 liter TFSI four-cylinder engine that can turn itself into a two-cylinder in 13 milliseconds.

This engine delivers 140PS and a maximum of 250 Nm of torque, which results in acceleration times of 7.9 and 8.0 seconds in the A1 and five-door A1 Sportback equipped with S tronic transmission. Those numbers for the A3 and A3 Sportback with manual gearbox are 8.3 and 8.4 seconds.

Top speed of both models is 132 mph. And as for the fuel economy, the A1 does up to 60.1mpg, equating to CO₂ output of 109g/km. The Sportback versions are slightly less frugal.

The cylinder deactivation system in these models is carried over from the bigger S models. It uses sleeves called cam elements, each of which carries two different cam profiles. An actuator controls the cams, which depending on the style of driving can shut down or restart individual cylinders by controlling exhaust and intake valves.

Audi CoD models carry an £850 over their regular 1.4 TFSI 122PS equivalents.