Competes with: Mercedes-Benz C-Class, Infiniti G37, Audi A4
Looks like: A little bit bigger outside, just a teensy bit bigger inside
Drivetrain: 240-hp, 2.0-liter twin-turbocharged inline-four cylinder; 300-hp, twin-turbo 3.0-liter inline-six cylinder; 335-hp, twin-turbo 3.0-liter inline-six cylinder hybrid powertrain; six-speed manual transmission and eight-speed automatic transmission; rear- or all-wheel drive
Hits dealerships: February 2012

BMW has worked judiciously over the past few years to improve its fleetwide gas mileage, and that mantra continues today with BMW’s best-seller: the 3 Series.

Besides an all-new design that makes the car slightly larger, the redesigned 2013 BMW 3 Series makes news with the addition of a four-cylinder powertrain and a hybrid system. Other fuel-efficiency measures include a lighter curb weight, smarter automatic transmission and auto start-stop and regenerative braking technology. Despite the new green emphasis, BMW promises that the new 3 Series will be faster and handle better than the outgoing model.

The new 240-horsepower inline-four comes standard on the 328i — the same engine has already shown up on the BMW 5 Series and Z4. BMW says the new engine will be powerful — it makes 10 more hp compared with the outgoing I-6 — and will propel the 328i from zero to 60 mph in 5.7 seconds with a top speed of 130 mph, and 155 mph with the Sport Line trim.

The 328i also features an auto start-stop system and regenerative braking with either a six-speed manual transmission or a new eight-speed automatic transmission. The eight-speed is the first of its kind for a compact luxury sedan, BMW says. The automaker will release fuel economy figures closer to the launch of the 3 Series early next year.

The 335i twin-turbocharged inline-six carries over, now producing 300 hp. Probably the most exciting news is the addition of the ActiveHybrid 3 model, which features the same hybrid powertrain found on the 2012 BMW ActiveHybrid 5. The automaker is quoting a near-37 mpg figure in combined European fuel consumption testing (adjusted to U.S. measurements). That would easily put the ActiveHybrid 3 among the top fuel misers here. Rear-wheel drive and all-wheel drive (335i xDrive and 328i xDrive) are available.

All powertrains come with new controls that modify powertrain management: Comfort, Sport, Sport + and Eco Pro. Eco Pro mode promises to reduce fuel consumption by as much as 20%.

No word if there will still be a diesel option or whether the hybrid model is meant to replace it.

The new exterior sheet metal gives the 3 Series a wider and meaner-looking stance. The wider look isn’t all smoke and mirrors, either: The new platform’s track is 1.45 inches wider, and the wheelbase is 1.85 inches longer than before.

The larger external dimensions make for a roomier cabin, but just slightly. There’s 0.71 inches of additional legroom and 0.31 inches more rear knee room, BMW says. The redesigned interior is more driver-focused; the center stack is tilted slightly toward the driver, leaving a large, clean expanse of wood- or matte silver-finished trim on the passenger side. The display unit is now free-standing, on top of the dash, when equipped. The car is equipped with either leatherette or real leather upholstery.

A new extensive list of tech features includes a color head-up display, surround view monitoring system that gives a compressive Infiniti-like bird’s-eye view, self-parking system, lane departure warning system, camera-based collision warning system ... the list goes on. The BMW will also feature an optional hands-free trunk opener, which opens the trunk by waving one foot underneath the rear of the car. (We saw something similar on the aborted Ford C-Max.)

The 3 Series sedan will go on sale in February. All-wheel-drive models will go on sale in the summer. The ActiveHybrid 3 will go on sale nearly a year from now, in fall 2012.