Cadillac Plans Plug-In Hybrid CT6 Sedan

General Motors Co.'s Cadillac unit is adding a plug-in hybrid powertrain for its top-of-the-line CT6 luxury sedan due later this year.

GM says the system, which borrows technology from the Chevrolet Volt extended-range hybrid, can travel 37 miles in electric-only mode. The hybrid CT6 will deliver more than double the fuel economy of the conventionally powered car, according to the company.

The powertrain consists of an 18.4-kWh lithium-ion battery made up of 192 prismatic pouch cells, two electric motors with three planetary gears, and a 2.0-liter turbocharged 4-cylinder gasoline engine. The plug-in system makes 335 hp and 432 lb-ft of torque, according to Cadillac. The hybrid's output compares with 265 hp, 335 hp and 400 hp for the conventional engine choices for the CT6.

The hybrid will use a new rear-drive electric variable transmission. Cadillac claims the gearbox delivers better drive quality than competitive plug-in powertrains.

The plug-in CT6 also be equipped with regenerative braking, including an on-demand feature that provides instant braking when the accelerator is released. Cadillac, which is using the same technology in its ELR electric coupe, likens the effect to downshifting a manual transmission when entering a corner.