Tuesday, January 25, 2011

BMW X6 Wallpapers

BMW X6 Wallpapers
BMW X6 Wallpapers
The BMW X6 is a mid-size luxury crossover SUV released for sale in the second quarter of 2008 by German automaker BMW. The X6 combines the attributes of an SUV (high ground clearance, all wheel drive and all-weather ability, large wheels and tires) with the stance of a coupé (bold head-turning style, dramatic sloping roof).

It is built in BMW's North American plant in Spartanburg, South Carolina alongside the BMW X5 whose platform it shares. It is dubbed "Sports Activity Coupé" by BMW, and while slightly longer and wider than the X5 is significantly lower and seats only four people. The concept model debuted at the 2007 Frankfurt Auto Show. The production X6 officially debuted at the 2008 Detroit International Auto Show. A hybrid version, which will be the first such vehicle from BMW, was also announced.

The X6 marks BMW's first use of its new Dynamic Performance Control system, which works in unison with xDrive all-wheel drive (both are standard on the X6). DPC is a drivetrain and chassis control system that works to regulate traction and especially correct over- and understeer by actively spreading out drive forces across the rear axle. Torque is split not only between the front and rear wheels (xDrive) but also from side to side at the rear for improved agility and added stability (through the DPC rear axle).

The DPC differential features clutch packs on both output sides that are actuated by an electric motor. The clutch pack activates a planetary gearset which causes one wheel to be overdriven. A conventional control system will use the brakes to reduce the speed of the faster moving wheel (which is the one with less traction)and reduce engine power. This leads to increased brake wear and slower than optimal progress. The DPC system speeds up the slower moving wheel (the one with the most traction) in order to maintain stability when needed. For example; while turning, the outer wheel is overdriven to provide greater acceleration using the traction advantage through the dynamic loading of the outboard wheel in cornering. In an oversteer situation, the inner wheel is overdriven to regain traction balance.

Dynamic Performance Control is currently unique in that it is effective when the X6 is both accelerating and decelerating, so at any speed and under any road condition. (Simpler active differential systems that react under power have been available in various -generally sporting- Japanese models for some time, for example Subaru Impreza WRX and the USA Honda Legend).


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