Audi has approved a new strategy to build a range of eco cars. They will be clean, low CO2 cars, dubbed internally E1 to E5 and spanning everything from a small city car to sports cars.

Audi E1- The E1 electric car is the smallest clean Audi and is based on Volkswagen’s NSF family. That’s essentially the sub-Polo mini car based on the VW Up concept, which will also be badged as a Seat and Skoda.

Audi E2 – Audi’s eco sports care will be the iteration of the VW BlueSport concept car – and it’ll be a mid-engined sports car aimed at the Mazda MX-5 family. Clean aero, light weight and a string of stingy powerplants will ensure the E2 is a clean, green sports car.

Audi E3 – Audi are relaunching the A2, renamed as E3. It will again use aluminium-intensive construction and be based on the cost-efficient MQB matrix due for the 2011 A3 hatch.

Audi E4 – There’s a new name and a second chance for the Audi Roadjet concept which quietly disappeared after its debut at the 2006 Detroit auto show.

Audi E5 – By 2014, Audi plans another green sports car. This should come as good news for enthusiasts worried about the future of fast cars.