What is it?
BMW X5 Vision

What's special about it?
Downsizing? Forget it!

This is BMW's message as it whips the wraps off its latest concept, the BMW X5 Vision Efficient Dynamics. This is a seven-passenger SUV that boasts the performance, fuel consumption and emissions rating of your average compact car.

The BMW X5 Vision is the latest in a growing number of vehicles produced under BMW's banner of Efficient Dynamics, and if comments from high-ranking corporate execs are to be believed, there is every chance the new concept will reach production in the next two to three years.

Featuring a combination of technology already found in selected BMW production models as well as developments the German carmaker is preparing for the future, the X5 Vision provides a look at how BMW sees the market for luxury SUVs evolving as ever-tighter emissions regulations compromise the appeal of such vehicles, especially in Europe. For example, the city of London has announced it will slap a surcharge on downtown visits by vehicles that exceed a standard of CO2 emissions.

At the heart of the new concept is a hybrid drivetrain that our source at BMW indicates will begin appearing in selected BMW models within the next three years, including the German carmaker's upcoming PAS (progressive activity sedan) and second-generation X3 — both due out next year.

Not to be confused with the full hybrid system revealed on the X6 ActiveHybrid at the 2007 Frankfurt Auto Show, the X5 Vision's new technology is a mild hybrid drivetrain. A small-displacement diesel is supplemented by an electric motor to make stop/start operation in traffic a practical enterprise.

Sitting up front underneath the reworked X5's expansive hood is BMW's new twin-turbocharged common-rail injection, 2.0-liter inline-4 diesel engine. Equipped with the latest Bosch piezo injectors, the diesel produces 204 horsepower along with an impressive 295 pound-feet of torque at 2,000 rpm. The small electric motor provides 20 hp and 155 pound-feet of torque and is powered by electricity stored in two separate lithium-ion batteries sited in the space usually reserved for the spare wheel underneath the floor of the cargo bay.

As in the usual mild hybrid, the X5 Vision's electric motor is only used to start the engine from a stop and provide a small amount of supplemental power. When stopped at a junction or when sitting idle in a traffic jam, the diesel engine automatically switches off to conserve fuel and reduce emissions. As soon as the driver releases the brake pedal and depresses the accelerator, the engine springs back to life. The existence of the lithium-ion battery pack means the operation of the air-conditioning and other systems reliant on electricity is maintained during short periods.

Drive is transferred via BMW's xDrive four-wheel-drive system to each wheel by a newly developed eight-speed automatic gearbox. Produced by German transmission specialist ZF, it is planned to replace the existing six-speed automatic across the BMW lineup from the end of 2008, starting with the fifth-generation 7 Series due out at the Paris auto show this coming September. For the X5 Vision, the new gearbox has been modified slightly to house the electric motor and its associated electronics package.

BMW claims the new package will achieve 36.2 mpg for its latest concept. This is dramatically better than the 29 mpg expected from an X5 with BMW's 225-hp 3.0-liter inline-6 diesel. The trade-off is in straight-line performance, although the difference is not as marked as one might expect, given that the emphasis here is very much on fuel-efficiency. While the X5 3.0d will crack 100 km/h (62 mph) in 8.3 seconds, the X5 Vision runs close, at 8.9 seconds to the same speed.

Other developments include the incorporation of a solar panel within the roof that acts as an additional electrical source. It enables pre-heating of the oil while providing a source of power for the air-conditioning, entertainment and other systems when the car is stationary.

The standard U.S.-built SUV's wheels have also been swapped for futuristic-looking alloys developed in BMW's wind tunnel. Their aerodynamic shape is claimed to play an important part in reducing fuel consumption by requiring one kilowatt less propulsion power at a speed of 100 mph. Further measures taken to reduce drag include a lower ride height, unique door mirrors, roof bars partly integrated into the body shell and an extended spoiler element over the split tailgate at the rear.

What's Edmunds' take?
Though the European car manufacturers have long disdained hybrid power, they've finally changed their tune. Suddenly affordable, GM-style mild hybrids seem like a practical solution, don't they?
— Andreas Stahl, Contributor