(November 20, 2013) TOKYO — Volkswagen introduced the XL1, the world's most fuel-efficient production car, to the streets in 2013. This plug-in diesel hybrid for two people is being produced in a limited volume and has a European combined fuel consumption figure of 261 mpg as well as a carbon-fiber body and chassis.

Now, Europe's largest carmaker is applying the experience it gained from this technological showpiece and is applying it to a high-volume production vehicle. Volkswagen is presenting this new car at the Tokyo Motor Show: a plug-in hybrid version of the up!, called the twin up! concept car. The four-seater shares certain parts of its drive system with the XL1 — including its diesel engine, electric motor, and DSG dual-clutch automatic transmission.



Since all new Volkswagen vehicles are configured to accept alternative drive systems as well as conventional ones, it was easy to install the compact plug-in hybrid system in the twin up!. The only modification made in the production version was to lengthen the extremely short front overhang by 1.2 inches.

The twin up!'s 55 kW (74 horsepower) drive unit — consisting of a 35 kW (47 horsepower) 0.8-liter TDI Clean Diesel engine, a 35kW electric motor, a seven-speed DSG transmission, and the power electronics — is mounted at the front of the car. Installed at the back, behind the rear seats and under the trunk, is the "fuel storage system:" an 8.6 kWh lithium-ion battery, the 12-volt battery for the electrical system, and an 8.7-gallon fuel tank.

The car attains impressive efficiency thanks to a combination of good aerodynamics (0.30 Cd), a low unladen weight of 2,657 pounds, lightweight plug-in drive components, and low rolling resistance 165/65 R15 tires. In all-electric mode, for example, the twin up! has a driving range of 31 miles.

The twin up! highlights the fact that efficiency and driving fun will not be mutually exclusive in the future. In the city, in electric mode, the twin up! accelerates from 0 to 37 mph in 8.8 seconds on its way to a top speed of 78 mph. In hybrid mode, the car delivers 159 pound-feet of torque, a high number for such a small car. Out of town, the twin up! goes from 0 to 62 mpg in 15.7 seconds and reaches a top speed of 87 mph.