LOS ANGELES - Buick unveiled the 2012 LaCrosse with eAssist, a new fuel-saving technology that increases fuel economy by 25 percent compared to the four-cylinder/six-speed powertrain in the 2011 LaCrosse. The eAssist technology provides class-leading highway fuel economy of 37 mpg, while maintaining the luxury, performance and value expected from Buick's flagship sedan.

The eAssist system becomes the standard powertrain on LaCrosse starting next summer. The system uses a state-of-the-art lithium-ion battery system and electric motor-generator to enable regenerative braking capability to improve LaCrosse fuel economy by an estimated 25 percent.

Mated to a 2.4L Ecotec direct injection four-cylinder engine and next-generation six-speed automatic transmission, the eAssist system uses power stored in the battery to provide needed electrical boost in various driving scenarios, optimizing engine and transmission operation. An advanced 115V lithium-ion battery and latest-generation 15-kW motor-generator unit help increase fuel economy through:

• Regenerative braking, which provides up to 15 kW of electricity to charge the battery.

• Providing up to 11 kW (15 hp) of electric power assistance during acceleration.

• Automatic engine shut-off when the vehicle is stopped.

• Aggressive fuel cut-off during deceleration down to zero vehicle speed, enabled by the torque smoothing provided by the motor-generator unit.

• Intelligent charge/discharge of the high-voltage battery.

Buick LaCrosse with eAssist technology also features improved underbody aerodynamics and tires optimized for performance and fuel economy, as well as active control of front-end airflow that improves aerodynamics and engine warm-up. Electronically controlled shutters in the lower grille close at higher speeds to push more air over the vehicle, which increases aerodynamic efficiency to enhance fuel economy.   All of these technologies increase the eAssist system's regenerative braking capability, while also improving the vehicle's efficiency while driving.

LaCrosse with eAssist includes an ECO gauge on the instrument panel that continuously responds to driving behavior, enabling the driver to drive with maximum efficiency. It also features a hill-assist system that captures brake pressure to help the driver more comfortably accelerate from a stop on a moderate or steep grade. It does this by greatly reducing the tendency of the vehicle to roll backward with the engine in shut-down mode.  

While the eAssist system shares the same basic belt-alternator-starter configuration of previous BAS designs, it delivers more than three times the power and is much more capable than the previous-generation BAS system, according to the automaker.