BMW X5 Vision Diesel Hybrid Concept - Auto Shows

BMW X5 Vision Diesel Hybrid Concept - Auto Shows

BMW X5 Vision Diesel Hybrid Concept - Auto Shows
Rethinking the cylinder count.
BY JENS MEINERS February 2008

Let’s be honest: A four-cylinder engine is not something you want in a large SUV or off-roader. You need at least a six-cylinder to move with any authority. Better yet, a V-8.
The motor works of Munich in Bavaria are out to change that perception, showing us that even in a crossover such as the X5 a four-cylinder oil burner is sufficient when mated to an electric motor tiny enough to fit into the transmission case. The X5 Vision concept is part of BMW’s “Efficient Dynamics” strategy designed to offer performance while reducing fuel consumption and carbon-dioxide emissions.
The X5 Vision at the 2008 Geneva auto show uses the automaker’s newest turbo-diesel engine—the twin-turbocharged 2.0-liter four that has impressed us in smaller BMWs and that makes 201 horsepower on its own. The small electric motor is rated for an additional 20 horsepower.
In the torque department, the X5 Vision is ahead of the 260-hp X5 3.0si, which makes 225 pound-feet at 2750 rpm. The turbo-diesel four delivers 295 pound-feet at 2000 rpm. The electric motor produces another 155 pound-feet. You can’t add them up, as the electric motor reaches its torque peak at a different rpm than the diesel. But this hybrid should definitely launch with zeal.
As a mild hybrid, the X5 Vision doesn't run on just electric power. But the extra boost takes you north of 130 mph, and the SUV can do 0-to-60 mph in a claimed 8.9 seconds while delivering an impressive 36 mpg. Yes, it is a four, but in a diesel, the number of cylinders is not as relevant as are torque and efficiency.
Mated to an Eight-Speed Automatic
The mild-hybrid powertrain was co-developed with the former DaimlerChrysler. Mercedes is using the system with its seven-speed automatic transmission; BMW has decided to mate the hybrid technology to a ZF eight-speed automatic.
BMW is betting on mild and two-mode full hybrids simultaneously. BMW partnered with DaimlerChrysler and General Motors on the two-mode system. Next year, BMW will launch the X6 hybrid with a two-mode system that will have an electric motor that makes about 65 horsepower. The mild-hybrid package is set for production as well—but not in an X5. We hear it will first come in a gasoline-powered sedan, likely the all-new PAS (for "progressive activity sedan"), which will be based on the next-generation 5-series.
A side note: The European version of the full-hybrid Lexus RX400h gets just 29 mpg in Europe. Granted, at 272 horsepower it is more powerful than BMW’s X5 concept. But BMW proves that a mild hybrid can top a full hybrid’s mileage if the package is right. This sufficiently powerful and advanced concept is a compromise that many drivers would be able to live with—although we’d selfishly prefer the concept wheels on a crossover with a V-8.