Exit one BMW hybrid, enter another.

Next March will see the U.S. launch of the 2012 BMW ActiveHybrid 5, the second hybrid sedan in the Germany luxury-car maker's lineup.

And the ActiveHybrid 5 marks an important evolution: It's the first BMW that uses the single-motor hybrid system jointly developed with Daimler to offer full-hybrid capability, namely the ability to run solely on electric power (up to 37 mph, BMW says).

The company also says the system can run electrically for as much as 2.5 miles, and we give them credit for noting that the distance assumes an average speed of just 22 mph.

The production ActiveHybrid 5 echoes the BMW Concept 5-Series ActiveHybrid shown 18 months ago at the Geneva Motor Show.

Its 40-kilowatt (55-horsepower) electric motor sits between the 300-hp twin-scroll turbocharged 3.0-liter inline six-cylinder engine and an eight-speed automatic transmission that's been modified to work even with the engine switched off.

BMW quotes the combined power of the engine and electric motor at 335 horsepower, noting that the electric motor alone can produce 155 lb-ft of torque, more than half that of the engine.

The 40-kW electric motor is far more powerful than the 15-kw (20-hp) motor used in the mild-hybrid ActiveHyrid 7, which lets the new model travel on electricity alone where the earlier hybrid couldn't.

2012 BMW ActiveHybrid 5

2012 BMW ActiveHybrid 5

As with the earlier ActiveHybrid 7, the powertrain has been tuned for performance. BMW quotes a 0-to-60-mph time of 5.7 seconds, just a few fractions of a second behind the similarly-sized 2012 Infiniti M35h hybrid.

The 2012 ActiveHybrid 5 includes the usual suite of hybrid modifications, including regenerative braking to recharge the lithium-ion battery pack (located in the trunk) and engine shutoff on stops.

There's also a driver-selectable ECO PRO mode that sacrifices a bit of acceleration for greater efficiency. It also switches off fuel to the engine on coasting and braking even at speeds as high as 100 mph, a feature that will grow increasingly common on all cars--hybrid and otherwise--in the near future.

The EPA has not yet rated the gas mileage of the 2012 BMW ActiveHybrid 5, so we don't presently know how it compares to the gasoline-only 2012 BMW 535i model.


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