March 03, 2008
2008 BMW Vision EfficientDynamics X5 Concept Revealed at Geneva Motor Show
GENEVA, SWITZERLAND – The Geneva Motor Show, taking place Mar. 4-16, will mark the world premiere of the BMW Vision EfficientDynamics, a concept car designed to showcase the future direction of BMW’s performance-enhancing and emissions-lowering innovations.
Mild ActiveHybrid technology is combined with a twin-turbocharged four-cylinder diesel engine, a new eight-speed automatic gearbox, and a roof-mounted solar panels.The BMW Vision EfficientDynamics delivers 43.5mpg on the combined cycle and just 172g/km of CO2 emissions.
With its twin-turbocharged 2.0L diesel engine delivering more than 100hp per liter, the BMW Vision EfficientDynamics concept completes the sprint from 0- 62 mph in just 8.9 seconds.The 2.0L, four-cylinder, diesel engine in the BMW Vision EfficientDynamics uses BMW’s Variable Twin Turbo concept, third-generation common-rail injection, and an all aluminium crankcase to deliver 204 hp and 400 Nm of torque between 2,000 and 2,250 rpm.
The engine is supplemented by a mild hybrid concept that delivers a further 20 hp and 210 Nm of torque under acceleration. As a consequence, even though the BMW Vision EfficientDynamics features a relatively small capacity engine, it delivers nearly the same levels of horsepower as the conventional X5, but offers improvements in its already class-leading consumption and emissions figures.
The mild hybrid solution in the BMW Vision EfficientDynamics uses a compact generator that, for the first time, is flange mounted directly onto the gearbox. This motor produces up to 20 hp of on-demand power. In addition, BMW’s Brake Energy Regeneration is used to capture energy that would previously have been lost when the engine is on overrun. The alternator is also integrated into the crankcase rather than conventionally driven from the front of the engine.
BMW’s concept uses lithium-ion batteries in the boot area to store the power generated. These high-storage-capacity batteries enable optimum use of Brake Energy Regeneration. In addition, they create possibilities to power the air conditioning, electric coolant pump, and the electric power steering system. For these functions, a 120-volt vehicle power system was designed and runs in parallel with the conventional 12-volt system.
The power harnessed by the batteries is also supplemented by roof mounted photovoltaic solar panels, measuring 1.0 meter square. The energy generated can either be used immediately or stored for later use. The power created in this zero-CO2 way can be used to pre-heat the diesel fuel. The less efficient warm-up phase is thus shortened considerably.
This engine is directly mated to a new eight-speed automatic transmission. Developed jointly between BMW and ZF, the new gearbox delivers fast and efficient gear changes. With such a spread of gears, the car will always be in exactly the right ratio for the prevailing driving conditions. It also improves fuel consumption and minimizes emissions.
The chassis and ride-height of the X5 have been adapted for the BMW Vision EfficientDynamics. This includes 19-inch light alloy wheels with reduced ventilation. The design of the spokes reduces wind resistance to the extent that, at 100 mph, the car has to produce one horsepower less than a conventionally-wheeled car.