(Los Angelese, December 2, 2009) Volkswagen unveiled a new concept called the Up! Lite based on the same new small family (NSF) mini-car platform as an earlier series of concepts from 2007. The Up! Lite is the fifth concept on the NSF platform and is claimed to be the most fuel efficient four seater car in the world with combined fuel efficiency of 96.4 mpg (US).

The first production models based on the NSF platform are expected to debut in about 2011. The new concept takes the platform to another level by incorporating a new diesel hybrid powertrain and extensive weight saving measures.

Primary propulsion is provided by a 0.8-liter two cylinder TDI diesel engine. This common rail diesel is essentially half of the recently introduced 1.6-liter TDI four cylinder in the European Golf and Polo. This 51 hp engine also appeared in the tandem two seat L1 concept that was shown in Frankfurt last September. In this new application, the two cylinder engine is paired with a 10 kW electric motor in a full hybrid configuration.

The motor can drive the Up! Lite on electricity alone during coast down as well as at low speeds for short distances. As in other hybrids it also provides automatic start-stop functionality and electric boost to the diesel. During passing or other acceleration events the combined output is up to 64.4 hp. The motor is also used to provide regenerative braking capability. Electrical energy is stored in a lithium ion battery pack of undisclosed capacity.

The TDI twin and electric motor both send drive torque to the front wheels through a 7-speed dual clutch DSG gearbox. The dual clutch gearbox allow automatic gear changing without the losses inherent in a hydraulic torque converter.

Efficiency is also enhanced by optimized aerodynamics. A shutter in the grille is thermostatically controlled to manage air flow through the radiator based on engine cooling requirements. At higher speeds, the shutter is mostly closed to redirect air around the car and reduce drag.

Besides the powertrain, the key feature of the up! Lite is the mass reduction provided by the new structure. The body shell of the concept is based on a mix of high strength steels, aluminum and carbon fiber composites. Interior components such as the seats have also been developed to keep the mass to a minimum. Volkswagen has not announced a precise weight for the concept, but it should be under 2,000 pounds. With the low mass and the torque of both the diesel and electric motor, the car should be accelerate to 60 mph in about 12 seconds.