BMW to offer world's most powerful hybrid automobile

             The ActiveHybrid X6 is being built at BMW's Spartanburg, S.C., plant.

German manufacturer BMW will introduce the world’s most powerful hybrid automobile at the Frankfurt Motor Show next month and begin selling it in the United States later this year.

The BMW ActiveHybrid X6 will be powered by a 4.4-liter, 400-horsepower, twin turbo V-8 engine and two electric motors for a total output of 480 horsepower and 575 pound-feet of torque.

According to BMW, the hybrid powerplant can run exclusively on electric power up to 37 mph under light acceleration. It can also propel the vehicle from a stop to 60 mph in 5.4 seconds, and on to a governor-limited top speed of 130 mph.

In addition, the company said the ActveHybrid X6 achieves fuel economy that is approximately 20 percent better than a comparably powerful conventional gasoline engine and reduces carbon dioxide emissions. Official EPA fuel mileage estimates have not yet been released, but the hybrid X6 reportedly has achieved 22.8 miles per gallon of fuel on a European driving cycle.

The key to the system is a two-mode transmission in which the electrical motors are housed. One mode is for stop-and-go driving and low speeds. The second is for driving at higher speeds.

From a stop and at low speeds, only one of the electric motors is activated.
When more power is required, the second motor starts the gasoline engine and then serves as a generator to replenish the nickel metal-hydride battery pack located beneath the floor of the luggage compartment.

In steady, highway-speed driving most of the power is supplied by the gasoline engine, while one of the electric motors acts as a generator to supply electricity.

The transmission is set up to provide seven specific gear ratios, which the driver can access manually.

As with other hybrid systems, the ActiveHybrid X6 will have automatic stop/start, which shuts the gasoline engine down at stop signs and traffic lights; and regenerative braking, which boosts the supply of electricity to the battery pack when the car is being slowed or stopped.

Other than its new powerplant, the ActiveHybrid X6 is a near twin to the X6 Sport Activity Coupe that was introduced in 2008. A five-door vehicle with a coupe-like profile, it is powered by the 400-horsepower V-8, has all-wheel drive, greater ground clearance than a standard automobile, and a flexible cargo area.

Like the standard X6, the hybrid model will be built in BMW’s Spartanburg, S.C., plant