Showing just how versatile the little SMART fortwo can be, the DaimlerChrysler-owned company has developed four vehicles using various experimental drivetrains to power the cars. The most impressive is the fortwo cdi diesel-electric hybrid that combines a 20kW electric motor with a 40-hp diesel to achieve an impressive 81 mpg. The hybrid can power the vehicle from a stop on its batteries, assist with acceleration, regenerate power via braking and also features a new shift delay bridging technology that has the electric motor provide propulsion for the few tenths of a second between manual shifts. It's a very trick way to provide smooth acceleration in a vehicle with a stick, and while it does improve acceleration to 62 mph by nearly two seconds over a conventional diesel, it still takes 17.8 seconds.

SMART has also developed a fortwo micro hybrid that uses a belt-driven starter generator and 61-hp gas engine to achieve a 5-percent reduction in fuel consumption, a fortwo ev with a 41-hp all-electric motor and range of 62 miles, and finally a fortwo cng that has the ability to run on either gasoline or natural gas thanks to two separate fuel tanks hidden in the car's underbody.

[Source: SMART and GreenCarCongress]

[Thanks Adam H. for the tip]