What is the 2012 Buick Regal’s eAssist all about?


Buick RegalAutomotive technologies are appearing on new vehicles faster than customers can absorb them. Hybrids, electric power, handling dynamics, lane departure warning systems and more rapidly are replacing mechanical systems that we all loved and easily understood. Which means now you need to do even more research before spending your hard-earned cash on a new vehicle.

In 2012, Buick introduced a feature called eAssist, first on the 2012 Buick LaCrosse eAssist, and now on the Regal sedan. GM claims this fuel-saving technology will help improve overall fuel economy by 25 percent over Buick’s non-eAssist inline four-cylinder engine even when mated to a six-speed transmission.

For the 2012 Buick Regal with eAssist, EPA estimated fuel-economy numbers are 26 city/37 highway. On a recent round trip between Los Angeles and San Diego, we achieved over 31 mpg on the highway; an impressive number that, while not at the maximum 37 mpg, was still closer than what we’ve seen with other manufacturer’s mpg claims, especially since we were driving under normal highway conditions (no hyper mileage attempts).

So what exactly is eAssist?

First, keep in mind that fuel economy improvements aren’t achieved from one specific vehicle feature. Rather, it’s a lot of elements contributing incremental fuel savings that add up to the bigger savings.

For example, the 2012 Buick Regal eAssist uses lightweight alloy wheels and low-rolling-resistance tires to help reduce weight and vehicle drag, or air resistance. There’s also an optimization mode for the air-conditioning system so the driver can choose to reduce cooling effort to save fuel economy. The U.S. Department of Energy conducted a study on the impact of air conditioning on fuel economy in 2000, and at the time reported that the energy needed to operate a vehicle’s air-conditioning compressor could be even more than the power required to move a mid-sized vehicle at a constant speed of 35 mph.*

Another area where fuel-economy savings can be realized is body design. Smoothing the airflow above, below and around the vehicle to reduce drag also assists in raising mpg figures. Buick’s Regal features a sleek design with a low 0.30 coefficient of drag (Cd). For comparison, the Chevy Volt gets a 0.28 Cd, while the Tahoe sits at 0.36 Cd. And yes, lower is better here!

Buick designers and engineers also improved the underbody aerodynamics to keep the air flowing freely from nose to tail under the vehicle. Nooks and crannies on the undercarriage disturb air flow and create turbulence, which causes drag and reduces fuel economy.

Another new technology on the Buick Regal eAssist that you’ll see on a few other vehicles (and more in the future) is called Start/Stop. This is a fuel-shutoff feature that shuts off the engine when the vehicle comes to a full stop, and then starts it again instantly as soon as you release the brake pedal. This can lead to a fuel savings of up to 15 percent, depending on the vehicle. In our Buick Regal, the Start/Stop function was smooth, quiet, and unobtrusive. As the Regal is one of the quietest vehicle’s we’ve tested, when stopped and the engine in shut-off mode, you could hear the proverbial pin drop on the thick carpet.

The Regal also features a deceleration fuel-shut-off feature, which, in certain circumstances, shuts off the fuel feed to the engine when you take your foot of the accelerator as you coast to a stop. When you think about how often you do this during a daily drive, the fuel savings, although incremental, accumulates quickly.

Regal IP

Buick Regal eAssist ECO gauge

The Regal also features an ECO gauge located on the instrument panel that does a great job of monitoring driving behavior, so you instantly can see if you are achieving the best possible fuel economy and driving efficiency.

The actual eAssist includes a state-of-the-art, 115-volt, air-cooled, lithium-ion battery system and an electric 15-kilowatt induction motor generator that are paired with the Regal’s 2.4-liter Ecotec direct-injection four-cylinder engine. The transmission is a six-speed automatic, which also incrementally helps with fuel economy by providing two overdrive gears. Horsepower output for the eAssist Regal is listed at 182, and torque at 172. In addition, the maximum electric generating power is 15 kW, and max electric motor torque is 110 lb-ft.

The Regal eAssist uses the gas engine for the majority of its motive force, while the eAssist system uses the power stored in the battery to provide electrical boost in various driving situations, which helps optimize both engine and transmission operation. Basically, when you are demanding more power by pushing the accelerator pedal to the floor (freeway onramps, hill climbing, lane merging), the electric boost to the powertrain provides that needed juice without having to use more gas to get the vehicle moving faster.

In addition, the Regal eAssist, like other hybrid and electric vehicles, uses regenerative braking, which, as you apply the brakes to slow down the vehicle, converts the mechanical energy into electrical energy, which can be fed back to the charging system for the battery.

eAssist powerflow screen

There’s a lot going on as you accelerate, decelerate, and brake the Regal. Is there a way to keep track of what’s happening? You bet there is. The Regal features a readout in the 7-inch touchscreen that shows the state of the vehicle’s power flow. You can see when the vehicle is using the electric assist system to add power to the engine, or when the energy flow during regenerative braking is going back to the battery.

Obviously, since weight also has an effect on fuel economy, the eAssist power pack is a relatively light 65 pounds. It’s compact, and is located in a compartment between the rear seat and trunk, with only a minor concession to trunk space. The eAssist Regal offers 11.1 cubic feet of cargo room compared to 14.2 without the battery pack. There’s a quiet electric fan that cools the power pack, and it draws air from a vent located in the package tray behind the rear seat.

11.1 cubic feet of cargo volume with the battery located on the right rear still allows for a fold-flat second-row seat.

The liquid-cooled motor generator is mounted to the engine, and replaces the alternator because it provides the electricity needed for regular functions via a unique engine belt-drive system.

How much is this technology?

While we know the price for some hybrid models and electric vehicles are at a premium, the Buick Regal is one of the more affordable, high-mileage, near-luxury sedans on the road that you will actually enjoy driving. Another advantage is you can add the eAssist to even the base level Regal, for $2,000. With a base price of $27,535 and eAssist, you can have great fuel economy, a quiet comfortable ride, and state-of-the-art technology for under $30,000.






* Impact of Vehicle Air Conditioning on Fuel Economy, Tailpipe Emissions, and Electric Vehicle Range, October 21, 2000, National Renewable Energy Laboratory, Golden, Colorado.