The Jeep Wrangler is famous for its ability to tackle brutal off-road conditions. It's also known for the fact that, generally, it doesn't change too much. Today's flat-sided Wrangler is clearly a descendant of the boxy Jeep that slogged through the battlefields of World War II.

But Jeep will soon undergo one of the biggest transformations of its 79-year history. At the CES technology show in Las Vegas next week, Fiat Chrysler Automobiles will unveil plug-in hybrid versions of the Jeep Wrangler, Cherokee and Compass. The plug-in models will bear a new 4xe badge, which is a play on the term 4x4 used to denote four-wheel-drive vehicles.

Fiat Chrysler CEO Mike Manley has said previously that a plug-in hybrid Wrangler will go on sale later in 2020.

Jeep will unveil a plug-in hybrid version of the Jeep Wrangler. A purely gasoline-powered Wrangler is shown here.

Fiat Chrysler currently offers two plug-in hybrid models, the Chrysler Pacifica Hybrid minivan and the Jeep Commander PHEV, a crossover SUV sold in China.

Batteries in ordinary hybrid vehicles are charged as the vehicle drives, particularly during braking, and that power is then used to turn the wheels together with power from the car's gasoline engine. In most hybrid vehicles, the electric motors can even drive the vehicle by themselves in situations where not much power is needed, such as at low speeds.

Read More