A new 3-door Volkswagen Polo B-car scheduled to bow in production form at the Frankfurt auto show will include a diesel-propelled model promising the world’s best fuel economy for its class.

Volkswagen AG says the diesel Polo will achieve 71 mpg (3.3 L/100 km), using the auto maker’s BlueMotion technology. The fuel economy number is equivalent to 87 g/km of carbon-dioxide emissions.

The Polo BlueMotion will come in both 3-door and 5-door models, with sales beginning in Europe later this year.

Volkswagen also will show at Frankfurt a new entry-level model for the Polo range. The 3-door receives longer doors than its 5-door stablemate, while restyled side windows and C-pillars convey the coupe-like proportions popular in vehicle design today.

The entry-level Polo Trendline will start at E12,150 ($17,306), Volkswagen says, and include two higher trim levels – Comfortline starting at E14,150 ($21,155) and Highline beginning at E15,900 ($22,648).

The Polo BlueMotion is one of six engine variants for the Polo line, which also includes two additional diesels and three gasoline engines. Also for the first time, Volkswagen will offer its 7-speeed, dual-clutch gearbox on top-of-the-range Polo models.

The auto maker also intends to soon add a fourth gasoline engine, featuring turbocharged direct-injection technology with optional DSG.