Unlike the mainstream market where hybrid technology is used to maximize fuel efficiency, luxury carmakers have employed hybrid systems as a way to maintain or improve performance while making concessions to efficiency. The BMW X6 ActiveHybrid, due out for retail sale this fall, is a prime example.
Rated at a combined output of 480 horsepower and 575 pound-feet of torque, the big SUV uses a twin-turbo 4.4-liter V-8 engine and a nickel-metal hydride hybrid powerpack to claim the title of the world's most powerful gasoline-electric hybrid passenger vehicle. That's no mean feat, with contenders like Mercedes-Benz, Lexus and Cadillac in the space. The two electric synchronous motors contribute 91 horsepower/192 pound-feet and 86 horsepower/206 pound-feet, respectively.
Accordingly, it's no wimp at the stoplight strip, sprinting to 60 mph in just 5.4 seconds, and on to an electronically limited top speed of 130 mph. And it does it all while eeking out 22.8 mpg in the European combined cycle, about 20% better than the standard V-8's ratings. The improvement is due largely to the hybrid system's ability to run on electricity alone up to 37 mph, though the hybrid-specifc automatic stop-start function also helps reduce wasted fuel at idle.
Like its big, brawny brother the X6 M (read our first drive of the X6 M here), however, the X6 Hybrid's main problem is a very American one - weight. Racking up 400 pounds for the hybrid drivetrain in addition to the standard vehicle's 5,000-pound curb weight, it's impressive that the X6 Hybrid gets the fuel efficiency it does.
Prototypes of the vehicle were spotted frequently throughout its development sporting a huge domed hood where the electronics and diagnostics equipment lived. That's been mosltly solved for the retail version, with BMW packaging it all away tidily, though you'll still know the hybrid version from a distance.
The hybrid system employed by the X6 ActiveHybrid is a version of the Daimler-Chrysler-GM Two-Mode system that uses twin electric motors that can alternately provide extra power, charge the batteries at a 50kW regeneration rate, or trade power between each other as necessary. Tying the electrical side to the gasoline engine is a two-mode active transmission based on an electrical CVT and a standard seven-speed automatic transmission.
Accordingly, it's no wimp at the stoplight strip, sprinting to 60 mph in just 5.4 seconds, and on to an electronically limited top speed of 130 mph. And it does it all while eeking out 22.8 mpg in the European combined cycle, about 20% better than the standard V-8's ratings. The improvement is due largely to the hybrid system's ability to run on electricity alone up to 37 mph, though the hybrid-specifc automatic stop-start function also helps reduce wasted fuel at idle.
Like its big, brawny brother the X6 M (read our first drive of the X6 M here), however, the X6 Hybrid's main problem is a very American one - weight. Racking up 400 pounds for the hybrid drivetrain in addition to the standard vehicle's 5,000-pound curb weight, it's impressive that the X6 Hybrid gets the fuel efficiency it does.
Prototypes of the vehicle were spotted frequently throughout its development sporting a huge domed hood where the electronics and diagnostics equipment lived. That's been mosltly solved for the retail version, with BMW packaging it all away tidily, though you'll still know the hybrid version from a distance.
The hybrid system employed by the X6 ActiveHybrid is a version of the Daimler-Chrysler-GM Two-Mode system that uses twin electric motors that can alternately provide extra power, charge the batteries at a 50kW regeneration rate, or trade power between each other as necessary. Tying the electrical side to the gasoline engine is a two-mode active transmission based on an electrical CVT and a standard seven-speed automatic transmission.
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