2012 Buick LaCrosse with eAssist mates 4-cylinder with electric motor

The new, 2012 Buick LaCrosse lineup has a base model with four-cylinder engine mated to an electric motor, with regenerative braking, wind-smoothing, aerodynamic touches and automatic engine stop at traffic lights, to deliver improved gasoline mileage. It’s called the LaCrosse with eAssist.

The 2012 LaCrosse with eAssist delivers 6 more miles per gallon in both city and highway driving than a solitary four cylinder did in the 2011 LaCrosse, according to federal government estimates.

Specifically, the 2012 LaCrosse with eAssist is rated by the federal government at 25 miles per gallon in the city and 36 mpg on the highway.

This compares with 19/30 mpg for the 2011 LaCrosse with four cylinders and no eAssist.

Better yet, real-world, combined city and highway driving, as opposed to government laboratory testing that provides those government fuel rankings, can net between 31 mpg and 33 mpg in the LaCrosse with eAssist, based on the test car and federal government posting of real driver data.

Plus, the 2012 LaCrosse earned five out of five stars for driver and front-passenger protection in government front crash testing and five out of five stars for front-seat occupant protection in a side crash. Rear-seat occupant protection in a side crash garnered four out of five stars.

Introduced in the 2005 model year, the LaCrosse has come into its own as a second generation model with refined exterior and interior styling. The car is attractive, with a sloping roofline that, while pinching a few inches of headroom, gives the LaCrosse a graceful silhouette.

Categorized as a mid-size car, the 16.4-foot-long LaCrosse is at the larger end of mid-size. It’s 3 inches longer than a 2012 Acura TL sedan and 7.2 inches longer than an MKZ Hybrid.

The inside of the LaCrosse feels comfortably roomy for four, with back-seat legroom measuring a surprising 40.5 inches compared with 36.7 inches in the MKZ and 36.2 inches in the back of the TL. Still, at 6.1 feet wide, the LaCrosse is narrower than the TL and three adults sit closely in the back seat.

The most memorable part of the test LaCrosse drive experience, though, was the smoothness of the automatic engine shutoff and automatic restart at stoplights, stop signs and sometimes, backed-up traffic.

Plenty of hybrid vehicles have auto-stop, but often there’s a noticeable roughness — almost an uncomfortable feeling the car is about to stall — as the engine restarts.

There was none of this in the LaCrosse, where auto-stop is handled by a belt/alternator/starter system that quickly restarts the engine at 500 rpm, not a lower rpm that’s typical of an ignition-keyed starter.

The 2.4-liter, double overhead cam engine also doesn’t have the performance-snipping Atkinson cycle. Instead, it has performance-boosting direct gasoline injection.

Likewise, the transmission isn’t a continuously variable type that’s typical in hybrids and that sometimes draws criticism for engine drone sounds.

Instead, the LaCrosse has a regular six-speed that’s specially tuned for responsive power, and the test car readily moved with verve and pep, especially in city traffic.

Courtesy: Associated Press