Thursday, April 29, 2010

Brand-New Powertrain in 2011 BMW 5-Series ActiveHybrid



BMW continues to add to its EfficientDynamics lineup of hybrid vehicles, with the 2011 BMW 5-Series ActiveHybrid Concept debuting at the Geneva Auto Show as the latest addition. The auto show was a major milestone for the 5-Series, as both the all-new gas-powered version and the first-ever hybrid 5-Series both made their first public appearances.

Rumors of a 5-Series hybrid have been swirling for years, and most automotive experts expected BMW to simply transfer an existing hybrid powertrain from the EfficientDynamics lineup under the hood of a 5-Series. Of course, in traditional BMW style, the automaker has outdone itself and exceeded expectations by bestowing a brand-new hybrid powertrain on the dazzling 5-Series. Buyers can expect the powertrain in the 2011 BMW 5-Series ActiveHybrid to trickle down to other models soon, however.

Engine and Performance

What sets the 5-Series ActiveHybrid Concept apart is its internal combustion engine, which is the most compact yet in the EfficientDynamics family. Instead of the 7-Series’ ActiveHybrid’s V-12 engine or the twin-turbo V8 in the X6 ActiveHybrid, BMW went smaller and chose an inline six-cylinder engine instead. The engine, called the N55 single-turbo, is a direct-injected 3.0-liter I6 with 300 horsepower and 300 pound-feet of torque.

The hybrid 5-Series matches the inline-six with an eight-speed automatic transmission with a 40kW electric motor placed in between. Joined to the gas engine by an automated clutch, the electric motor has the power to move the vehicle by itself, improve the gas-powered engine’s performance, or serve as a generator to recoup braking energy. Although regenerative braking technology is not a first for BMW, the 5-Series ActiveHybrid’s system is much more powerful than that of any other vehicle in the automaker’s lineup.

Electronics

A battery mounted by the rear axle provides power to the electric motor. The placement of the battery optimizes weight distribution and keeps it safe in collisions. In addition to powering the electric motor, the battery juices all of the 5-Series’ onboard electronics and the climate-control system so the cabin temperature stays consistent when the gas-powered engine isn’t running. To keep battery drain minimal, the vehicle’s electric systems are connected so the car’s central computer can maximize power flow to all of the components.

But the powers of the BMW 5-Series ActiveHybrid Concept’s computer don’t stop there. The machine also has a stop/start feature that allows it to shut off the gas engine and run only on electric power to conserve fuel. Additionally, it receives constant feedback from all of the car’s sensors in addition to the navigation system and uses the information to try to predict imminent road conditions and prep the vehicle’s systems in advance. What’s more, the 5-Series will also track your route, and if the battery is completely charged, turn off the gas engine early and finish the final leg of your journey on only electric power, which lengthens the vehicle’s electric-power-only range by 30 percent.

The End Result

Visually, the BMW 5-Series ActiveHybrid Concept does not look all that different from the gas-powered 5-Series. The only differences from the ActiveHybrid and the 535i are the propeller-looking five-spoke wheels, LED foglights, and a new horizontal bar on the lower front fascia. Overall, the various tweaks and innovations on the 5-Series hybrid have resulted in a 10-percent reduction in both fuel consumption and emissions. BMW will release more details about the 5-Series ActiveHybrid as it nears production in 2011.

source: automobile