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.

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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

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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