Volkswagen has created what it calls the world's most economic car, running for 313 miles on a single gallon of diesel.
The two-seater XL1 has an 0.8 litre two-cylinder TDI engine, E-motor, 7-speed dual-clutch transmission (DSG) and lithium-ion battery. The company says it emits just 24 grams of CO2 per kilometer.
"Despite the very high levels of efficiency, developers were able to design a body layout that offers greater everyday practicality, incorporating side by side seating rather than the tandem arrangement seen in both the first 1-litre car presented in 2002 and the L1 presented in 2009," says Volkswagen.
"In the new XL1, wing doors make it easier to enter and exit the car. Further progress has been made by manufacturing body parts from carbon fibre reinforced polymer parts (CFRP), a technique used in Formula 1 car construction."
The lightweight materials used include magnesium for the wheels, ceramics for the brake discs and aluminium for dampers, steering system and brake calipers.
The prototype, to be unveiled at the Qatar Motor Show this week, accelerates from 0 to 100kmh (62mph) in just 11.9 seconds, and has an electronically-limited top speed of 99mph.
"Yet these numbers alone do not tell the whole story: since the XL1 weighs just 795kg, the drive system has an easy job of propelling the car," says Volkswagen.
When full power is needed, the electric motor, which can deliver 100 Newton metres of torque from a standstill, works as a booster to support the TDI engine (120 Newton metres torque). Together, the TDI and E-motor deliver a maximum torque of 140 Newton metres in boosting mode."
The company reckons it should go on sale in 2013 at an 'affordable' price.