Xoutpost.com - BMW X6 Dual Mode Hybrid Coming for 2009

BMW says a hybrid version of its X6 "activity vehicle" will, indeed, hit the U.S. market in 2009, initially available only with the company's twin-turbo, 407-horsepower, 4.4-liter V8 coupled to the dual-mode electric drive system co-developed with General Motors and the former DaimlerChrysler.
It's the automotive equivalent of strapping a hydrogen bomb to a nuclear bomb for extra oomph.

In that configuration the hefty X6 won't be the poster child for fuel economy, but it will use less gas than the conventional model.

BMW hasn't disclosed mileage estimates for the hybrid, but says it should be about 20 percent better than the 19 mpg combined city/highway rating for the conventional version. That would put it close to 23 mpg for drivers who can keep the accelerator pedal off the floor.

The dual-mode system has resulted in 25 percent fuel economy hikes in the Chevrolet Tahoe and GMC Yukon SUVs that use GM's version.
The hybrid X6 will use a nickel metal hydride battery pack, recharged through regenerative braking, as do the GM, Daimler and Chrysler dual-mode systems. It won't use cylinder deactivation on the V8, as both GM and Chrysler do on their versions.

The dual mode system is now in use on GM's full-size SUVS and is soon to be introduced on '09 models of the Chevy Silverado and GMC Sierra full-size pickups and the Chrysler Aspen, Dodge Durango and Mercedes-Benz ML 450 SUVs.

It uses a sophisticated transmission outfitted with two electric motors and complex electronic programming that determines when the one or both of the motors should supplement power from the conventional gasoline engine and when electric power should replace the gas engine altogether.
For low-speed driving, the system acts like a conventional hybrid. It halts the gas engine when it can – at stop signs or under very light acceleration and cruising loads –and uses electric drive instead. During high-speed cruising, the electric motors supplement the gas engine.

During city driving, the electric motors operate about 75 percent of the time, while the gas engine provides power three-fourths of the time in highway driving.

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