Volkswagen is set to expand its BlueMotion range of fuel misers with the launch of several new models based on the latest Passat sedan and Golf and Polo hatchbacks. The new cars will appear in production trim at this month’s Frankfurt auto show and sadly, the chances of any of these ultra-frugal hitting U.S. showrooms are next to nil.

The highlight of the stand will be the Passat BlueMotion, which for 2010 adopts a 1.6-liter common rail diesel engine developing 104 horsepower. The new engine, replacing the existing 2.0-litre TDI unit currently fitted to the Passat BlueMotion, allows the new car to return 54 mpg on the combined cycle--up from the 48 mpg achieved by the outgoing car. This means that the total range for the 2010 Volkswagen Passat BlueMotion is 840 miles from the one tank.

The engine, however, is only part of the story. The car’s fuel economy also benefits from the results of aerodynamic changes with a new front bumper, sill extensions, a lower ride height and relocated air ducts behind the grille elements. The result is less aerodynamic drag leading to less loading on the engine and greater economy.

The most efficient model remains the Polo BlueMotion, which gets by with a fuel economy rating of 71 mpg, while the Golf BlueMotion rates in at 62 mpg.

All three models are due to go on sale in Europe early next year with prices and specifications due to be announced nearer the time.