BMW unveils super high-tech hybrid 5-Series at Geneva show

BMW's ActiveHybrid X6 and 7 Series models have already caused much scratching of heads and raising of eyebrows for their use of hybrid technologies with a clear skew towards performance over fuel economy. Any plaudits they've attracted for performance gain have been muted by criticism on the matter of weight gain and paltry economy benefits.

Now comes an ActiveHybrid version of the new 5 Series. Unveiled at the Geneva show as a concept model, it's a variation on the Active 7's mild hybrid theme, combining a smaller petrol engine -- a version of the twin-turbo inline six from the 135i/335i models -- with a 40 kW electric motor, substantially more powerful than the 7's 15 kilowatt one.

Details are scarce at the moment, but if the car hitches up the 225 kW of that petrol six with those 40 extra electric kilowatts and full electric torque served up instantly, drivers can expect a very powerful take-off experience. With legs to match, given the likely ratio breadth of the car's eight-speed transmission.

Details like engine specs and electric range are thin on the ground, but BMW is claiming a 10 percent benefit in fuel efficiency over the car's petrol counterparts.

The new, compact electric motor sits between the burner and the transmission, with an automatic clutch separating electric and petrol motors to allow electric-only driving. The battery pack, described by BMW as "high voltage", sits over the rear axle to optimise weight distribution.

Regenerative braking and overrun systems keep the battery pack topped up and feed electrical components. The battery packs enough power to combine periods of all-electric driving with auto stop/start and numerous auxiliary functions such as audio, climate control and navigation, all available even when the combustion engine is off. There's even an auxiliary climate control system the driver can activate remotely to keep the interior cool while the car is parked in the sun.

The car incorporates some of the most powerful driver assistance technologies ever devised, including anticipatory systems taking into account exterior road, topographical and weather conditions, engine and chassis sensor data, driver behaviour and satnav information, allowing it to forecast conditions on the road some way ahead and set itself up to optimise performance, safety and fuel efficiency.

Some examples of how it might work, according to BMW's press release: it can recalibrate battery charge level to make the most of a downhill stretch in the road ahead. Or when the driver sets a destination, the car uses wider satnav data to ensure the car can charge its battery in time for a stretch of inner-city electric-only driving. The company claims this gives the vehicle the potential to extend its own zero-emission range by up to 30 percent.

Expect the ActiveHybrid 5 to arrive in showrooms in 2011.

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