Buick is adding an eAssist system to its LaCrosse sedan.

Buick is adding a new eAssist mild hybrid system to its flagship LaCrosse sedan for the 2018 model year.

The 2018 LaCrosse eAssist will use a 2.5L four-cylinder engine and a 0.45kWh lithium-ion battery pack to delivery 19 percent better city fuel economy than the standard V6-powered LaCrosse. Buick didn't announce official economy figures, but that should net a city rating of about 25mpg.

Likewise, Buick didn't announce performance figures for the new eAssist system, but promises a 9 percent jump in torque compared to the brand's previous mild hybrid system.

"Executing innovative technologies in an approachable and meaningful way is core to Buick," said Duncan Aldred, vice president, Global Buick and GMC. "By adding the eAssist system to the LaCrosse, our technology flagship, we are making electrification accessible to our customers as we chart our course to the future of mobility."

The eAssist four-cylinder will stand as the LaCrosse's new point of entry, dropping the sedan's starting price to $30,490 from $32,065.

Meanwhile, Buick will expand the availability of all-wheel drive and the company's new nine-speed automatic transmission on V6-powered LaCrosse models. The 2018 LaCrosse will also have three new exterior colors — Satin Steel Metallic, Dark Slate Metallic and Red Quartz Tintcoat.

The 2018 LaCrosse range will arrive in Buick showrooms this fall.