The 2017 Buick LaCrosse made waves with its attractive design and impressive build quality at its unveiling at the 2015 Los Angeles auto show.

For 2018, the large sedan gets a new standard powertrain which happens to be a mild-hybrid system, referred to as eAssist by General Motors.

Like the mild-hybrid system offered on the previous-generation LaCrosse, the new setup pairs an inline-4, in this case a 2.5-liter mill, with a small electric motor-generator powered by a 0.45-kilowatt-hour lithium-ion battery.

The electric motor isn’t powerful enough to drive the car on its own. Instead, it aids the engine under high-load situations and recovers energy under braking. It also provides smoother engine starts than a conventional starter motor, making the fuel-saving engine stop-start feature much more refined.

EPA-rated fuel economy hasn’t been released but Buick says the eAssist powertrain should be 19 percent more efficient in city driving than the LaCrosse’s existing 3.6-liter V-6. Power and torque figures also haven’t been released.

Other changes for the 2018 LaCrosse include expanded availability of all-wheel drive, plus a 9-speed automatic for V-6-equipped models. A handful of new colors have also been added to the options list.

The 2018 Buick LaCrosse lands in showrooms this fall. Thanks to the new standard powertrain, pricing will start at $30,490, down from the 2017 model’s $32,990 starting price.

Buick also sells a LaCrosse Hybrid in China. This model pairs a 1.8-liter inline-4 with a more powerful electric motor and bigger battery. However, there are no plans to sell it outside of China just yet.