The BMW ActiveHybrid 5 is the first car in the company's mid-size 5 Series line with gasoline-electric hybrid capability, and it could improve fuel economy substantially over other 5 Series models.
The 2012 BMW ActiveHybrid 5 sedan (AH5 for short) is due in U.S. dealerships sometime after March 1, 2012. BMW revealed its ActiveHybrid 5 at the January 2012 North American International Auto Show in Detroit.
The 2012 ActiveHybrid5 is based on BMW's popular 535i sedan and powered by the same 3.0-liter turbocharged inline six-cylinder gas engine, but the addition of an electric motor actually raises peak horsepower. With a new 8-speed automatic transmission, the AH5 will accelerate from zero to 60 mph in an impressive 5.7 seconds, according to BMW. The company promises "the sportiest performance in its market segment'' with "a double-digit percentage improvement in fuel economy" compared to the conventional 535i. Government fuel economy ratings for the ActiveHybrid 5 are still pending.
The twin-turbo six in the AH5 is identical that in the 535i, delivering 300 horsepower and 300 pound-feet of torque. But in the hybrid, the gasoline engine is augmented by a synchronous electric motor that generates 55 horsepower and 155 pound-feet of torque. Together, the engine and motor can provide a maximum 335 horsepower and 315 pound-feet of torque at any given instant, or about 10 percent more than the 535i.
The AH5's motor is integrated into the transmission case, where it's coupled with and decoupled from the power path by an automatic clutch. The motor gets energy from a high-voltage, 675 watt/hour battery positioned between the rear wheel arches in the trunk. It works as a generator to charge the battery when the car is coasting or braking.
The ActiveHybrid 5 drives like the typical hybrid. Its engine shuts itself off whenever the car is stationary, and the electric motor can propel the car exclusively in town or through the traffic creep, as long as there's enough juice in the battery. The AH5 can operate in electric-only mode up to 37 mph. Its battery stores enough energy for about 2.5 miles of electric-only travel at 22 mph. Yet the AH5 raises the hybrid bar with a new coasting mode, which also shuts the engine down whenever the car is coasting at speeds below 100 mph. That further reduces gasoline consumption and helps keep the battery charged. Down a mountain grade, for example, the engine can switch off to save fuel, charging the battery to maximize the energy available for electric power in the process.
With standard 18-inch wheels, the AH5 looks pretty much like any 5 Series sedan from the outside, distinguished mostly by subtle badges. Inside, a special instrument package graphically illustrates energy flow, battery status, energy recovery and electric motor function.
In the ActiveHybrid 5, BMW adds an Eco Pro mode to its standard Driving Dynamics Control system, which usually includes sport, comfort and economy programs. Eco Pro helps wring maximum distance from every gallon of gasoline by maximizing electric-only travel and engine shut-off. It also syncs the standard navigation system with the power-control electronics, using location, speed limit and topographic data to plan electric/gasoline power strategies and maximize mileage.
The AH5 comes with all of the standard 5 Series safety features, including front and side airbags, head-protection curtains for front and rear passengers, belt force limiters and latch tensioners and automatic collision notification. The hybrid also adds a cooling system and extra structural protection for the power electronics and battery.
The ActiveHybrid 5's retail price of $61,845 includes the $895 destination charge. It should be widely available by late March 2012. The base price includes features not standard on all 5 Series models, like navigation and four-zone climate control. Yet an extensive array of options will be available, from electronically variable suspension to Surround View cameras to Head-Up Display to Blind Sport Warning, and those options could lift the AH5's price as much as $20,000.
BMW loyalists who prefer the compact 3 Series sedan need wait only about six months for a hybrid of their own. The company has announced that the ActiveHybrid 3, with a powertrain and technology identical to the AH5's, will go on sale in the fall of 2012 as a 2013 model.