In E-mode, only the 114-hp rear electric motor propels the vehicle and the TDI engine is shut off and decoupled from the drivetrain.

ENGADGET: VW unveils CrossBlue plug-in SUV with iPad mini headrests and 85MPGe efficiency (eyes-on)

With the Chevrolet Volt, Chevrolet accounts for more than 50 percent of all plug-in electric vehicle sales in the United States and Spark EV builds on Chevrolet's proven electric motor and battery development programs.

ENGADGET: Chevy details 2014 Spark EV: under $25,000, 0-60 in 8 seconds and a 20-minute fast charge

Last week, the plant celebrated Spark EV motor production, marking the first time a major U.S. auto manufacturer has designed and built both a complete electric motor and drive unit for a modern electric vehicle in the United States.

ENGADGET: Chevy Spark EV rated most efficient retail car with 82-mile range, 119 MPGe

PowerBox Concept hybrid, for example, shown at the L.A. show, looks a lot like a standard sports utility vehicle (SUV) but combines a supercharged V-6 engine that runs on compressed natural gas and an electric motor that provides added power for acceleration and passing.

FORBES: The Hybrids Are Coming

The exterior also utilizes a flat underbody (including a large front flat floor cover, electric motor area undercover, front undercover and rear diffuser with fins) to help manage airflow under the vehicle.

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