Car Design News: New BMW X5 in Depth

Page 1: Short Version (I)
Page 2: Short Version (II)
Page 3: The Concept
Page 4: Driving Dynamics
Page 5: All Wheel Drive
Page 6: Power Units
Page 7: Automatic Transmission
Page 8: Exterior
Page 9: Interior
Page 10: Body & Safety
Page 11: The iDrive Control System
Page 12: Features and Equipment (I)
Page 13: Features and Equipment (II)
Page 14: Production
Page 15: Specifications

Body and Safety

High body stiffness for extra safety and driving dynamics.
Stable passenger cell for first-class protection.
First SAV with runflat safety tyres.

First-class safety ensured by superior torsional stiffness and even more interior space � these are the particular advantages of the bodyshell and body design of the new BMW X5.

To obtain additional space also for a third row of seats and give the entire body even greater solidity, BMW�s engineers have focused consistently on intelligent lightweight construction and consistent geometry of the vehicle�s support bars, reinforcements and pillars. The result is truly outstanding torsional stiffness exceeding that of the former model by approximately 15 per cent, raising the benchmark in absolute terms from 23, 500 to 27, 000 Newton-metres/degree. And this greater stiffness not only ensures an even higher level of safety, but also helps to provide first-class driving dynamics. BMW�s engineers have also succeeded in optimising the standard of lightweight quality, a criterion defining torsional stiffness as a function of the vehicle�s dimensions on the road and its weight. Again, this proves the particular qualities of the new BMW X5 as a vehicle offering the highest level of solidity and agility currently possible in consideration of its body dimensions. Even installation of the optional, extra-large panorama glass roof does not have any noticeable effects on the stiffness of the bodyshell as a whole.

Compared with the former model, the body of the new BMW X5 is larger in every respect � up in length by 18.7, in width by 6.1 centimetres (or, respectively, 7.36 and 2.40�� ). By comparison, however, unladen weight of the new BMW X5 3.0si is up by only 30 kilos or 66 lb, now amounting to 2,125 kg or 4,686 lb according to the EU standard. And the new BMW X5 3.0d even remains just as light as before, weighing in once again at 2,180 kg or 4,807 lb.Intelligent lightweight technology and superior body stiffness.

The excellent standard of body stiffness results, inter alia, from the installation of low-lying support arms in the wheel arches. Swinging in towards the middle of the vehicle, these arms from a torsionally rigid connection to the engine support arms.

Torsional stiffness is then further increased by additionally linking these support arms to the bumper crossbar by way of diagonal thrust rods.
Both of these improvements optimise body stiffness at the front without requiring a larger number of components.

A good example of intelligent lightweight engineering is the cast-aluminium spring support featured for the first time in the front section of the new BMW X5 and reducing weight by approximately 50 per cent versus a conventional steel plate structure. Holding the spring strut and track control arm, the cast-aluminium spring support takes up forces from the suspension and transmits them to the body of the vehicle. The advantage of this construction is not only greater stability of the bodyshell as a whole, but also optimised driving dynamics. Around the C-pillar a fully enclosed torsion ring made up of the roof support bracket, the C-pillar, the longitudinal arms at the side, and the crossbars in the floor panel again helps to enhance body stiffness. Positive engagement of the tailgate between the two D-pillars helps to further enhance torsional stiffness, direct contact between the wedge elements and the surrounds at medium height being ensured by a soft-close function automatically drawing the tailgate firmly into the lock.

Supreme aerodynamics for enhanced driving dynamics.

Developing the bodyshell of the new BMW X5, BMW�s engineers and designers focused in particular on good aerodynamics. Despite the larger exterior mirrors now offering even better visibility to the rear, the new BMW X5 3.0si sets a new standard also in terms of streamlining with its drag coefficient of 0.33. Indeed, the former model was already best-in-class in this respect right up to the end of its production life � and now low downforces make a significant contribution to enhanced driving dynamics and safety on the road.

This superiority results inter alia from the underfloor almost consistently smooth from front to end, ram lips upfront of the wheels, and specific aerodynamic improvements at the rear. In addition, the underfloor covers improve the level of noise control and protect pipes and other components from stone-throw and dirt.

The new BMW X5 is the first production car in the world to feature a roof spoiler with air flow contours integrated at the side to reduce both air drag and lift forces. Again, these components blend harmoniously into the sporting and elegant roofline of the vehicle, the rear clusters with their air flow contours also serving, together with the roof spoiler, to provide an aerodynamically optimised flow of air cut off at exactly the right point.

Perfect protection in the stable passenger cell.

Optimum protection of the vehicle�s occupants � this was the brief given to the development engineers in designing and configuring the passenger cell of the new BMW X5. And so, through its body structure and wide range of safety features, the new model offers all the requirements for achieving best marks in all crash tests relevant the world over.

The passenger cell thus offers the occupants passive safety of the highest standard, the engine support bars and the chassis itself diverting the forces encountered in an accident along several load paths in order to prevent extreme impacts on individual load-bearing structures.

A particular feature in this context is the innovative steering column crash safety concept made up of a crash adapter and a crash tube: In an accident impact energy is progressively absorbed in a defined process, the lower and middle steering column following a predetermined fracture pattern at the same time to prevent intrusion into the passenger compartment.

To protect pedestrians, the body structure is lowered at the front, the intermediate space provided in this way being filled up by a plastic load-bearing structure for the side wall also made of a special synthetic material.
As a result, the new BMW X5 meets all requirements in terms of resilience crucial to pedestrian safety and body stiffness through an ideal combination of components and materials.

Rollover sensor for extra safety when rolling over.

The most advanced safety technology inside the new BMW X5 ensures effective safety and protection of all occupants. Apart from front and side airbags, these safety systems also include curtain head airbags at the side inflating out of the panels on the A-pillar and roof lining to protect the occupants in the first two rows from injury. The new BMW X5 is fitted with three-point inertia-reel belts on all seats including the third row, as well as headrests adjustable for height.

Further safety features also to be mentioned in this context are belt force limiters and belt tensioners on the driver�s and front passenger�s seats.
And a final highlight is the ISOFIX child seat fastenings in the second row of seats.

In the event of an imminent rollover, the rollover sensors again enhance safety to an even higher level, automatically detecting critical driving situations which might lead to a rollover and then automatically activating the curtain airbags and belt latch tensioners.

Being networked to Dynamic Stability Control (DSC), the rollover sensors guarantee quick activation whenever required.

The rollover sensors determine the angle of the vehicle around its longitudinal axis as well as angle speed and acceleration. Applying this data and various other figures obtained from DSC stability control, the rollover sensor system determines whether the vehicle is in a critical situation and activates both the curtain airbags and belt latch tensioners whenever this is the case.

To avoid a collision from behind, the new BMW X5 features two-stage brake lights: Whenever the driver applies the brakes particularly hard or when ABS is activated, the area covered by the brake lights becomes larger, generating a clear optical signal inducing motorists following from behind to brake harder, too.

Runflat safety tyres premiering in the SAV segment.

The new BMW X5 is the first vehicle in its class fitted as standard with runflat tyres. Benefiting from their reinforced flanks, these tyres are particularly robust and prevent the risk of a puncture particularly off the beaten track.

Even when completely empty, that is under zero pressure, runflat tyres allow the driver to go on safely, avoiding the risk of an accident or the need to change the tyre under dangerous conditions in the dark next to the road. The maximum range still remaining after a complete loss of pressure is between 50 (with full load) and 250 (with minor load) kilometres, or 30 and 155 miles, respectively, with the vehicle not exceeding a speed of 80 or 50 mph.

With a gradual loss of pressure, as is the case in 80 per cent of all punctures, the remaining range the driver is still able to cover is an even more significant 2,000 kilometres or 1,200 miles, ABS and DSC remaining fully functional also under these circumstances.

A further important feature is that in such a case optional AdaptiveDrive automatically shifts the weight of the vehicle to the wheels still maintaining optimum tyre pressure, thus taking maximum load off the flat tyre and again allowing extra mileage.

The runflat system is made up of the tyre itself, the extended-hump rim, and a tyre defect indicator. The runflat qualities of the tyres are ensured by reinforced side walls and heat-resistant rubber compounds, the special shape and contours of the wheel rims preventing the tyres from jumping off the rim even under sudden loss of pressure.

Clearly, all this means extra safety particularly at high speeds or on winding roads.

The tyre pressure indicator monitors tyre pressure at all times by consistently comparing the speed of wheel rotation. Then, as soon as wheel speed deviates from the ideal figure by more than 30 per cent, the driver is informed accordingly by a warning light.

In addition to extra safety, the runflat safety system also helps to save weight and space, since there is no longer any need for a spare wheel.

The new BMW X5 comes as standard on 18-inch light-alloy rims running on 255/55 tyres. Larger 19- and 20-inch light-alloy rims as well as tyres measuring up to 275/40 at the front and 315/35 at the rear are also available as an option.

Intensive test programme preparing the vehicle for all eventualities.

The entire bodyshell of the new BMW X5 has been subjected to the toughest tests on dynamometers, test rigs and endurance trials on road and track. Particular significance was given in all cases also to corrosion tests as well as insulation from water and dust. The dynamic corrosion test simulates the loads typically encountered in practice by spraying salt mist on to the body and subjecting the body structure to high air humidity in a climate chamber.
And then the entire body must also resist gravel, sand and stones as well as salt sludge and salt water under real-life driving conditions.

The dust test determines how well the ventilation system is protected from dust and how thoroughly the seals on moving parts resist dirt and contamination from outside.

The water drive-through test up to a depth of 50 centimetres or almost 20��, finally, ensures that there is no damage to the underfloor of the vehicle even under such conditions and that no water is able to enter the passenger and luggage compartments.

Conducted over thousands of kilometres, these tests create conditions and challenges within a few weeks far greater than the demands facing the vehicle under normal conditions throughout its entire service life.

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