Volkswagen is producing the XL1, what it calls “the world’s most efficient production car,” in its plant in Osnabrück, Germany. Yes, it is a production plant. Yes, it is producing the car. But as for how many are being built, well, all we could find out at this early stage (the vehicle was officially announced on February 1, 2013) is that it is likely to be “thousands of vehicles”—over a multi-year period.
That notwithstanding, the plug-in hybrid vehicle undoubtedly lives up to that fuel efficiency claim. According to VW, it returns a European combined fuel consumption rating of 261 mpg.
To get there, the car is extremely light. It has a curb weight of 795 kg—or 1,753 lb. This is largely a function of the use of low-mass materials in the construction of the two-seater, primarily carbon fiber-reinforced plastic (CFRP). For example, the monocoque, which provides structure for the passenger compartment, weighs just 89.5 kg.
The skin is CFRP. VW engineers have calculated that the mass for the CFRP structure is 1.8 kg/m2, and that if a steel body was used, the mass would be 5.1 kg/m2.
In addition to which, the XL1 uses aluminum for crash energy management (in addition to the inherent capabilities of the CFRP: they don’t build Formula One cars out of composites simply because they’re light). Aluminum crash tubes with cross members are used at both the front and the rear of the car. Aluminum impact beams are located in the doors.