The L1 in the Volkswagen L1 Concept stands for 1-Liter — the idea being that this roughly 170 mpg hybrid can travel 100 km (62 miles) on just 1-liter of diesel fuel. It's close, but actually needs 1.38-liters to cover that distance. Still, its fuel efficiency is still good enough to make current hybrids look like gluttons.
The chassis is tiny with passengers sitting in tandem like a motorcycle or more accurately a glider with which it shares its style of canopy entry. The focus here is clearly light weight, good aerodynamics and gentle acceleration. Power comes from an 800cc two-cylinder turbo-diesel making 20 kW (about 27 horsepower) when in "ECO" mode, or 29 kW (38 horsepower) in "Sport." An interesting twist is the inclusion of a 7-speed twin-clutch transmission that has an integrated hybrid assist called E-motor that comes in the form of a 10 kW electric motor and secondary clutching mechanism. A small lithium-ion battery is stored in the front of the car and drives the electric motor when it best suits conditions to improve efficiency. It can propel the L1 in pure electric mode for short distances, but the system is used mainly to support the start-stop feature of the diesel engine and aid in acceleration. A lot of attention was paid to the restarting of the diesel and trying to make it as seamless as possible. The E-motor also recoups energy during slowing.
The chassis itself is very light being made of a carbon fiber reinforced plastic and aluminum monocoque. The entire vehicle weighs just 839 pounds. Combined with a drag coefficient of 0.195 it's easy to see how the little car, which sits lower than a Lamborghini, can achieve its high fuel economy. It's narrow, long and low with little to know appendages to interrupt air flow. Even rearview mirrors have been replaced with tiny cameras. As a testament to the L1's ability to cut through the wind this little under-powered fuel sipper is still capable of hitting 100 mph.