BMW has already scooped CAR’s green award for its Efficient Dynamics eco package being rolled out onto its current range. But at the 2008 Geneva Motor Show, the Bavarians will unveil their vision for the next generation.
Dubbed Vision Efficient Dynamics, it’s an X5 equipped with the latest gizmos to reduce the amount of fuel you put into the tank and the gases pumped out of the exhaust. It’s powered by a twin-turbocharged four-cylinder diesel with a mild hybrid pack and sporting an array of fuel-saving technology.
BMW X5 Vision Efficient Dynamics: an eco angel
The X5 concept showcases BMW’s new eight-speed gearbox and even has roof-mounted solar panels to top up the battery. The company claims it’s enough to make the X5 (only a show idea at this stage, remember) the cleanest large 4×4 in the world, averaging 43.5mpg combined and emitting 172g/km of CO2
It’s not all dull, however. Thanks to the twin-turbo diesel, the X5 develops more than 100bhp per litre and sprints to 62mph in a scant 8.9 seconds. Quoting such performance figures on an eco car does make you wonder how much longer we’ll all trot out acceleration sprint times, though…
Click ‘Next’ to read about the BMW’s hybrid drivetrain
BMW Vision Efficient Dynamics: the tech
The familiar 2.0-litre four-cylinder diesel is a classic illustration of downsizing. Usually, full-size SUVs like the X5 use six or eight-cylinder power, but twin-turbocharging allows the engineers to use a much smaller capacity engine without losing the performance expected of a sporty 4×4.
It delivers 201bhp and 295lb ft of twist from just 2000rpm. Here’s where it gets interesting. Under acceleration, the mild hybrid system chips in with a further 155lb ft of torque; the Vision Efficient Dynamcis uses a compact generator mounted directly onto the gearbox.
Don’t waste the brakes!
As on today’s Efficient Dynamics models, the alternator only charges when coasting, meaning it’s not drawing power from the engine under load. Lithium-ion batteries in the boot store the power for the electric motor, and they’re trickle charged by 1.0sq m of solar panels built into the roof. This power is also used to pre-heat the diesel fuel, helping to warm the engine from start-up when it produces the most noxious emissions.
ZF’s new eight-speed gearbox is a production cert for BMW, and is designed to deliver more economical gearchanges, while the new 19-inch wheels on this concept car are designed to be aero friendly. BMW claims the spokes are so efficient at carving the air, it’s said to be worth one horsepower at 100mph. A baffling claim, but one that Munich reckons will do its own small bit to cut emissions.
CAR will be reporting live from the Geneva show on Tuesday 4 March 2008. Come back to CAR Online to read all the previews, news and gossip from Europe’s most important motor show