Volkswagen is continuing to roll out a new line of 'BlueMotion'-badged models in Europe that, the automaker said, are the most efficient and economical vehicles in each of its car ranges.

BlueMotion technology arrived first in the Polo in Germany last summer and the brand will expand with the launch of a Passat version at the Geneva motor show next month.

Applied to the Polo, BlueMotion comprises modifications to an already efficient diesel engine mated to a low kerb weight, improved aerodynamics and longer gearing. The result is an official EU fuel consumption figure of over 72mpg, a potential range of over 700 miles and just 102g of CO2 emitted per kilometre.

The Polo BlueMotion has an 80PS 1.4-litre, three-cylinder TDI engine fitted with electronically controlled, high-pressure direct injection. A variable geometry turbocharger is added to provide high levels of torque from just above idling speeds and improve responses. The modifications increase the engine's output and overall efficiency to allow greater performance while simultaneously using less fuel.

Continuing the theme are the Polo BlueMotion's wind tunnel-developed external modifications which improve aerodynamic efficiency.

A unique front bumper sits below a re-designed grille section to reduce drag. At the rear a pronounced spoiler mounted on the trailing edge of the rear window smoothes airflow further. Finally, a set of 14-inch 'Jerez' lightweight alloy wheels sit at each corner fitted with 165/70 tyres that reduce rolling resistance.

The Polo BlueMotion weighs 1,084 kg and VW claims the weight-saving measures don't come at the expense of safety or comfort - the model has twin front and side airbags for the driver and front seat passenger, ABS with brake assist and Isofix child seat mounting preparation as standard.

New more colourful interior fabrics and finishes unique to the BlueMotion help distinguish it inside from the standard car. A radio CD player, speed-sensitive power steering and central locking are standard.

Production has been tripled since launch due to high demand throughout Europe. Right-hand drive sales start in the UK this summer.

The automaker claims no other vehicle of its size consumes less fuel than the new Passat BlueMotion saloon which returns 55.4mpg (5.1/litres per 100km) and produces just 136 g/km of CO2. 

The Estate (wagon) version consumes 5.2 litres (54.3 mpg) and produces 137 g/km of CO2.  Both versions have a driving range of up to 1,350 kilometres (838 miles) on a full tank.  According to VW, over an average annual distance driven of 15,000 kilometres (9,315 miles), the driver only needs to refuel 11 times a year at an average cost of EUR68 per month.

Volkswagen achieves these low consumption figures through fine tuning of the engine - a 105 bhp TDI engine with a diesel particulate filter.