2010 BMW ActiveHybrid X6, Bal Harbour, FloridaEnlarge Photo
"Our goal was to fundamentally change the view of hybrids," said Peter Tünnermann, project manager for the 2010 BMW ActiveHybrid X6. "We wanted to make a 'non-hybrid' hybrid."
In other words, a hybrid that didn't drive like a hybrid. And in that goal, BMW has succeeded admirably.
Drivers at the international launch of BMW's first hybrid-electric vehicle agreed that if the badges and instruments had been removed, they would have been hard-pressed to know that this latest X6 had electric motors and all sorts of software wizardry between its engine and the wheels.
Their only clue, in fact, would have been the fuel economy. No other X6 even comes close to achieving 20 miles per gallon in mixed use.
Engine and transmission
BMW's clear goal was "to build the BMW of hybrids," as Tünnermann said. There could be no compromise in power, performance, or driving experience.
The result turned out to be the most world's most powerful hybrid car. It has overall power of 485 horsepower and 575 foot-pounds of torque, from a combination of a 407-hp, 4.4-liter twin-turbocharged V8 engine and two electric motors of 67 and 63 kilowatts (91 and 86 hp).
2010 BMW ActiveHybrid X6 engineEnlarge Photo
That's the same engine used in the X6 xDrive 50i, minus belt-driven air-conditioning compressor and power steering pump, now both electrically operated so they work when the car runs on electricity alone. The engine's only remaining belt, in fact, operates the water pump.
The hybrid system uses similar components and much of the software of the Two-Mode Hybrid system developed jointly by General Motors, Chrysler, Daimler, and BMW.
But the Two-Mode in the BMW is light-years away in feel from the version found in such plebian transport as the full-size 2009 Chevrolet Silverado Hybrid and GMC Sierra Hybrid pickup trucks.
In fact, two families of Two-Mode development have arisen. And the version built by BMW and Mercedes-Benz differs quite a lot from the one used in GM and Chrysler sport utilities and pickups.
It uses a differently shaped housing, for one thing, since the tunnel for BMW's standard six-speed automatic in the X6 is longer and narrower than those in General Motors trucks. And it's built for both German partners in Stuttgart, by Mercedes-Benz, rather than in Cincinnati, Ohio.
More importantly, BMW has eliminated all "hybrid feel" by simulating seven fixed ratios. First, third, fifth, and seventh ratios are the four fixed gears of the Two-Mode transmission, while second, fourth, and sixth are simulated "gears" that programmed into the electronic continuously variable transmission, or eCVT.
It works. Under light, moderate, and full acceleration, the ActiveHybrid system's up- and down-shifts felt just like a standard automatic transmission. Engine speed was directly proportional to road speed in each "gear," rising and falling with throttle input.
Acceleration from 0 to 62 miles per hour is 5.6 seconds, equivalent to the xDrive 50i.
But the ActiveHybrid X6's liquid-cooled, 2.4-kilowatt-hour battery pack can also propel the car in electric-only mode up to 37 miles per hour and, under specific circumstances, for up to 1.6 miles.
2010 BMW ActiveHybrid X6Enlarge Photo
The gas mileage far exceeds any X6 with a V8 and BMW's standard six-speed automatic. During 120 miles of mixed driving, including freeway travel and a few brief speed runs, we averaged 20.4 miles per gallon.
The most economical mode was freeway travel using the cruise control, where we saw close to 21 mpg. Most hybrids typically get better fuel efficiency in the city than on the highway, but the 2010 BMW ActiveHybrid X6 can take advantage of electric assistance even at high speed.