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2018 Buick LaCrosse eAssist Hybrid

Taco Winter

Electrification is perhaps the automotive buzzword today, but General Motors has been offering various hybrids for more than a decade. The Buick division launched its first such vehicle back in 2012: the LaCrosse eAssist, a hybrid version of its large sedan that continued through the 2016 model year. When the third-generation LaCrosse was released for 2017, the technology was absent from the order sheet, but Buick reupped on the hybrid for 2018. The four-cylinder eAssist now is the entry-level power plant. Unlike many eco-themed vehicles that telegraph their gree leaning powertrains, however, the LaCrosse keeps its electrification on the down low.

Take a walk around the LaCrosse and there are only four badges in sight: the Buick tri-shield logo on the grille and the center of the trunklid, Buick spelled out on the left side of the trunklid, and LaCrosse on the right side. There’s nothing else on the rear or on the body sides to indicate that this car has hybrid technology under the skin. Not even a funky color choice like bright green, chrome yellow, or electric blue. Our test car was white with chrome wheels—classy but conventional.

The same aesthetic carries through to the interior. There’s no weird dash arrangement for the sake of being different, no strangely patterned or colored trim, no oddball shifter. The one thing that hints something environmentally friendly is going on is a tiny digital leaf on the right side of the gauge cluster; it acts as the needle on a meter that ranges between ACCEL and BRAKE. Seeing such labels might seem silly considering how elementary those tasks are in any car, but it denotes the two areas where the eAssist system comes into play.

This branch of GM’s family of green machines can be traced back to Saturn—remember that brand?—which launched the Vue Green Line SUV for the 2007 model year. The Green Line introduced the belt-alternator-starter (BAS) system. The BAS technology has been applied to many GM vehicles since then, incrementally improving through the years and eventually being marketed as eAssist. It uses automatic stop/start and a small amount of electric assist and regenerative braking to boost fuel economy.

In the LaCrosse, the hybrid system consists of a 2.5-liter inline-four gasoline engine, an electric motor/generator, and a 24-cell 0.5-kWh lithium-ion battery pack. The electric motor, which GM calls the Motor Generator Unit (MGU), takes the place of a conventional alternator and is belt driven or belt driving, depending on its mode. Regenerative braking collects energy, the MGU converts it to electricity, and it’s stored in the air-cooled battery pack.

When the LaCrosse comes to a stop, the gas engine shuts off and the battery powers the rest of the car’s functions, such as the infotainment and HVAC systems. It’s then used to restart the engine when the brake is released and can also provide additional torque when the driver presses the accelerator. Buick claims it provides 9 percent more torque than the previous LaCrosse eAssist, plus the system’s overall size is smaller and has been packaged more efficiently.

Even so, the battery impinges on trunk space. Although the rear seats fold down, the rectangular bump in the trunk floor stretches across the pass-through opening to the car’s cabin. The loss of cargo space is only one cubic foot (14 versus 15), but the disruption of the load floor makes it more of a detriment than those numbers suggest. Still, it’s less intrusive than the previous LaCrosse eAssist’s battery pack.

How Light is Light Electrification?

The 2018 LaCrosse eAssist is EPA-rated at 25 mpg city, 35 highway, and 29 combined, which is only slightly improved from the 2016 model’s 24/35/28 ratings. We averaged 27 mpg overall and managed an impressive 38 mpg on our 75-mph highway fuel-economy test. The higher-trim LaCrosse models come with a V-6 engine; when we tested a front-wheel-drive V-6 version—152 pounds heavier than this front-drive eAssist—it managed only 31 mpg on its highway run and returned 24 mpg overall.

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