Buick LaCrosse with eAssist gets big mpg numbers

Buick is taking an interesting tack with the standard drivetrain in upcoming 2012 models. GM has developed Buick's eAssist system that mates an Ecotec four-cylinder engine with mild hybrid tech and a six-speed automatic to create amazing mpg numbers for cars of this size and class. The best part is that the Ecotec four with eAssist is the "base" engine in the LaCrosse, meaning you don't necessarily pay more for high mpgs. Early estimates show that the LaCrosse, Buick's large sedan, equipped with eAssist is expected to post mpg ratings of 25/city and 37/highway. These numbers will help GM meet its fuel economy requirements and prove that the government's recent fuel economy requirements are attainable. And, with $5 a gallon gas looming, consumers will appreciate it too. The mild hybrid system adds 15 hp to the 2.4-liter Ecotec four that gets its power from lithium-ion batteries mounted in the trunk (see pic below). The Buick LaCrosse with eAssist uses typical hybrid tactics to maximize fuel economy like regenerative braking, Eco-gauges in the instrument cluster, and engine shut-off tech. The LaCrosse also received some under body aerodynamic tweaking to reduce airflow turbulence to improve efficiency. What you get in effect is a large sedan that will seat five comfortably, yet get fuel economy typical of much smaller cars. Looks like a "win-win" to me. You can get your own Buick with eAssist (the Regal gets it too) later this year.

Source: Buick - Press release and pics (2) after the jump. Video post.

Press Release:
LaCrosse with eAssist Delivers Fuel Economy of a Small Car

Buick uses electrification and other improvements to get estimated 37 mpg highway
As gas prices go up, so does purchase consideration for more fuel-efficient cars. And the new 2012 Buick LaCrosse with eAssist™, a luxury sedan that comfortably seats five adults, delivers highway fuel economy on par with compacts like the Mini Cooper.

LaCrosse with eAssist, which goes on sale this summer, uses a variety of technological advances and body enhancements to deliver estimated segment-leading fuel economy of 37 mpg on the highway and 25 mpg in city driving without sacrificing passenger comfort. The fuel economy ratings await EPA certification.

Not only is the luxury sedan expected to be more fuel efficient than competitors like the Acura TL, Lexus ES350 and Lincoln MKS, it also expects to beat smaller hybrids, including the Lincoln MKZ Hybrid, Toyota Camry Hybrid and Lexus HS Hybrid on the highway, while offering more rear leg room than any of them.

Buick LaCrosse with eAssist
Acura TL
Lexus ES350
Lincoln MKS
Lexus HS Hybrid
Lincoln MKZ Hybrid
Toyota Camry Hybrid
25 city / 37 hwy
18 city / 26 hwy
19 city / 27 hwy
17 city / 24 hwy
35 city / 34 hwy
41 city / 36 hwy
31 city / 35 hwy

LaCrosse is the first in its segment with a four-cylinder, six-speed powertrain, the first with HiPer Strut suspension for improved ride and handling, and is now has the new standard eAssist technology.

“LaCrosse with eAssist is the smart choice for those who want great fuel economy and performance in a luxury vehicle,” said Tony DiSalle, U.S. vice president, Buick marketing. “LaCrosse with eAssist is an excellent value, costing thousands less than competitors with similar technologies, and its fuel-efficient powertrain comes standard on four-cylinder-equipped models.”

Program engineers improved the fuel economy of the outgoing four-cylinder, six-speed 2011 model by 25 percent by implementing a number of improvements. Chief among them was the introduction of the electric assist (eAssist) system that is mated to a 2.4L Ecotec direct injection four-cylinder engine and a next-generation six-speed automatic transmission.

The eAssist system uses a state-of-the-art 115V lithium-ion battery system and latest-generation 15-kW electric motor-generator to enable regenerative braking, which takes place anytime the driver is off the throttle. Regenerative braking provides up to 15 kW of electricity to charge the battery to power all of the vehicle’s electrical systems with recaptured energy instead of fuel, which dramatically reduces the need to load the engine with the generator.

The system uses power stored in the battery to provide 15 hp of electric power assistance in various driving scenarios, delivering more than three times the power provided by the previous-generation belt-alternator-starter system.

“The additional 15 hp provided by electric assist allowed us to lower LaCrosse’s gear ratio without sacrificing reserve acceleration and performance,” said Steve Poulos, global chief engineer of the eAssist system. “For example, when climbing the grade of an overpass, a normal vehicle will downshift and lose some fuel efficiency, but LaCrosse with eAssist maintains gear for improved performance and increased efficiency.”

eAssist also enables LaCrosse’s Ecotec engine to shut down fuel delivery in certain deceleration conditions, which saves additional fuel. While in fuel shut-off mode, the 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 motor-generator unit spins the engine, bringing it to a smooth stop – properly positioned for a smooth restart.

“All Buick automatics do some deceleration fuel cutoff when the driver is not on the accelerator,” said Daryl Wilson, LaCrosse lead development engineer. “But eAssist allowed us to take the decel fuel cutoff all the way down to zero speed, which resulted in a significant fuel economy increase.”

Program engineers also improved LaCrosse’s underbody aerodynamics by strategically placing underbody aero panels. Tires were optimized for performance and fuel economy, and 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 and engine warm-up. All of these technologies increase the effectiveness of 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, helping the driver attain 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.

“All of these improvements deliver significant fuel-efficiency gains Buick customers will appreciate,” DiSalle said. “With eAssist, Buick customers don’t have to trade a premium driving experience for efficiency.”

The eAssist system also comes to Buick Regal in late 2011.

About Buick
Buick is a modern luxury brand offering vehicles with sculpted designs, luxurious interiors with thoughtful personal technologies, along with responsive-yet-efficient performance. Buick is attracting new customers with its portfolio of award-winning models, including the Enclave crossover, LaCrosse sedan and Regal sport sedan. The new Buick Verano compact sedan and a small crossover will join the portfolio in the next few years. Buick’s sales continue to increase in North America, and it remains a best-selling brand in China, with continuing record growth. Learn more about Buick cars and crossovers at www.buick.com, on Twitter @buick or at www.facebook.com/buick.