|How much could the energy consumption of cars be reduced if all the stops were pulled out for efficiency? Volkswagen’s visionary goal of bringing to the market a production car with a fuel consumption of 1.0 liter per 100 km was reached with the most fuel-efficient hybrid ever: the XL1, a diesel-electric plug-in hybrid. VW claims it is the most fuel-efficient hybrid ever. The XL1 concept car will be exposed this week at the Qatar Motor Show. When January 26-29, 2011