Buick Regal Hybrid

Buick Regal Hybrid

The eAssist powertrain employs a direct-injection 2.4-liter inline-four gasoline engine rated for 182 hp and 172 lb-ft of torque. A motor-generator unit is attached the engine’s accessory belt, offering up to 15 hp and 79 lb-ft of assistance under acceleration, and regenerative braking during deceleration.

GM expects fuel-economy ratings of 25/37 mpg (city/highway) for the LaCrosse eAssist, versus 19/30 mpg for the 2011 LaCrosse four-cylinder. eAssist is also slated to appear on the 2012 Buick Regal later this year.

Four-cylinder models of the 2012 Buick LaCrosse come standard with a new mild hybrid drivetrain, called eAssist, with a 2.4-liter inline-four and electric motor/generator working together for up to a claimed 37 mpg. Buick has now revealed how much the economy gain costs, as the 2012 LaCrosse eAssist is priced from $30,820 after destination charges.

If buyers don’t want to go hybrid, the 2012 LaCrosse can now be ordered with a direct-injection, 3.6-liter V-6 engine at no extra cost. Thanks to a few small revisions for the 2012 model year, the engine now produces 303 hp and 264 lb-ft, improvements of 23 hp and 5 lb-ftover last year’s six-cylinder engine.

The eAssist power pack contains the lithium-ion battery pack, the integrated power inverter and 12V power supply. It is located in a compartment between the rear seat and trunk; and it is surprisingly compact and lightweight, weighing only about 65 pounds (29 kg). Trunk space is slightly reduced when compared with 2011 models with the four-cylinder/six-speed powertrain, but still offers 11.1 cubic feet (314 liters) of storage. A quiet electric fan cools the power pack, drawing air from a vent located in the package tray, behind the rear seat.


The eAssist system's electric induction motor-generator is mounted to the engine in place of the alternator to provide both motor assist and electric-generating functions through a unique engine belt-drive system. The induction motor-generator is a high-performance, compact induction motor that is liquid-cooled for increased performance and efficiency.

Next-generation six-speed

The eAssist system works with Regal's direct injected 2.4L Ecotec four-cylinder and next-generation six-speed automatic powertrain combination. In the Regal with eAssist, the engine is rated at 182 horsepower (136 kW) and the next-generation Hydra-Matic 6T40 takes transmission technology to the next level with features designed to enhance powertrain efficiency.

Significant internal transmission changes to clutch controls and hardware provide reduced spin losses while improving shift response and time. The added electric power provided by the eAssist system allows for higher gearing to improve steady state efficiency without impacting acceleration performance or driveability. The system's ability to provide some electric assistance at cruising speeds allows the driver to accelerate lightly or ascend mild grades without the transmission downshifting.

An auxiliary, electric-driven transmission oil pump is added to the 6T40, which keeps the transmission primed and the fluid flowing when the engine shuts down at a stop. That keeps the transmission ready to perform when the driver accelerates, for a seamless, uncompromised driving experience.