Buick again dips its tire into the green waters of hybrid and electric vehicles with the 2012 Regal with
Regal’s eAssist battery system is designed to provide power assistance to the internal combustion engine, rather than store energy for all-electric propulsion, a feature Buick equates as being closer to an extension of the conventional internal combustion engine than a replacement for it.
What is eAssist?
That eAssist system consists of what the company says is a state-of-the-art lithium-ion battery system, electric induction motor-generator and 15 kW of regenerative braking capability, all working to improve fuel economy. Buick is marketing the Regal with eAssist as the more affordable choice for consumers seeking hybrid style in the mid-size and full-size luxury sedan categories.
Answering consumer demand for lighter batteries, the Regal’s battery pack is just 65 lbs. and located in a compartment between the rear seat and trunk which, while slightly reduced compared to 2011 models, still offers 11.1 cubic feet of storage.
The power pack is cooled via electric fan, drawing air from a vent behind the rear seat. The eAssist system’s electric induction motor-generator is mounted to the engine in place of the alternator. According to the company, this provides both motor assist and electric-generating functions through what Buick says is a unique engine belt-drive system. The induction motor-generator is compact and liquid-cooled for increased performance and efficiency.
Regal sports a 2.4L Ecotec direct injection four-cylinder engine rated at 182 horsepower, as well as Buick’s next-generation six-speed automatic transmission.
Storing Power with eAssist
Power stored in the eAssist system’s 115V air-cooled lithium-ion battery provides the necessary electrical assist in a variety of driving scenarios, in an effort to optimize engine and transmission operation. Fuel efficiency is improved with the electric boost to the power train system during heavy acceleration and uphill driving. The vehicle also features a hill-assist system that captures brake pressure to help drivers accelerate more comfortably from a stop on moderate or steep grade by reducing the vehicle’s usual tendency to roll backward with the engine in shut-down mode.
While in fuel shut-off mode, the induction motor-generator unit continues spinning along with the engine to provide immediate and smooth take-off power when the driver presses on the accelerator. Then, as the vehicle comes to a stop, the induction motor-generator unit spins the engine, bringing it to what Buick says is a smooth stop, positioned for a smooth restart.
eAssist Combined with Transmission Changes
Significant internal transmission changes to clutch controls and hardware are designed to provide reduced spin losses while improving shift response and time. The added electric power provided by the eAssist system is targeted at allowing 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 means light acceleration or ascent up low grades can be accomplished without the transmission downshifting.