babypuppi: [12] Bmw Hood Making Today Highlight

BMW's 5 Series Gran Turismo is the second vehicle off the new architecture that underpins the 7 Series and will form the basis for next year's 5 Series sedan and wagon and the next-generation 6 Series. Here are some of the highlight technologies:

3.0-LITER, DIRECT-INJECTION TURBO SIX
The new 5 Series Gran Turismo marks the first application of BMW's new single turbo, direct-injection, 3.0-liter straight six with Valvetronic variable valve timing. The engine has 3.53-inch bore and a 3.31-inch stroke and a 10.2:1 compression ratio. It develops 300 horsepower at 5800 to 6250 rpm, and 300 pound-feet of torque between 1200 and 6000 rpm. The decision to go to a single, twin-scroll turbocharger was driven by the need to meet forthcoming Euro6 and American SULEV emissions while retaining the responsiveness of a twin-turbo setup. The single-turbo layout allows closer placement of the catalytic converter for faster light-off. (The tough new Euro6 test means the catalytic converter has to be hot enough to be scrubbing exhaust emissions just seven seconds after the engine is started; BMW also utilizes a dual-wall exhaust manifold for maximum heat retention.) The twin-scroll layout funnels the exhaust gases from cylinders one through three and four through six to two separate turbines, ensuring an exhaust pulse hits each every 120 degrees of crankshaft rotation, as in a twin turbo setup, minimizing pulse interference and maximizing the energy transfer.

EIGHT-SPEED AUTOMATIC TRANSMISSION
First seen on the just launched V-12 powered 760i, BMW claims this new transmission's unique layout provides two additional ratios with no increase in bulk or weight. Four planetary gearsets and five clutch packs are controlled in a way that no more than two of the clutch packs are freewheeling at any given time.

Faster shifts are a further benefit because only one clutch pack is disengaged, and downshifting more than two gears is accomplished as a direct shift. For example, a downshift from eighth to second is made with only one clutch pack disengagement, and therefore occurs without stepping down through the intermediate gears. That means the 5GT can maximize time in eighth gear with the engine turning minimal revs - the 535i GT's 3.0-liter six is turning at just 1600 rpm at 60 mph - but still deliver fast kickdown response.

BRAKE-ENERGY REGENERATION
A car's alternator normally continuously charges the battery. In the Gran Turismo, it charges only when the vehicle is decelerating or braking; otherwise, it freewheels, drawing virtually no power from the engine, helping improve fuel consumption. An electronically controlled clutch, somewhat similar to that used with the air-conditioning compressor, is used to engage and disengage the alternator. The system also requires a special, more powerful battery that can satisfy high electrical demands without access to continuous charging. The battery's internal plates are separated with saturated absorbent glass-boron silicate rather than the usual liquid electrolyte, which reduces the battery's conversion of charging energy to heat.

INTEGRAL ACTIVE STEERING
BMW's Integral Active Steering system, optional on the 5GT, electronically varies the steering ratio on the basis of vehicle speed and other driving conditions, reducing the steering-wheel movements required for parking maneuvers, U-turns, and sharp corners. But the system also steers the rear wheels up to a maximum of three degrees via a servo motor acting on track rods. At low speeds, the rear wheels are countersteered to the fronts, reducing the 5GT's turning circle by more than two feet. At higher speeds, the rear wheels steer in the same direction as the fronts, enhancing stability. BMW claims rear-seat-passenger comfort is improved thanks to reduced lateral forces in highway lane-change conditions.

LED LIGHTING
With the 5GT, BMW's signature corona rings have taken on several functions -- as parking lights, as an identifying element when the headlights are on, and as daytime running lamps -- this last with 100 percent of their lighting power, the other functions with just 10 percent. For the first time, on the Gran Turismo they employ LED technology.