With its compelling handling, pioneering technology and exclusive design and equipment, the new Audi A8 redefines the notion of sports appeal in the luxury segment. The saloon combines technical properties that clearly separate it from the competition in its class. As the brand flagship the A8 embodies the characteristics of the future Audi generation through sporting dynamism and clear design, innovative technology and the highest level of quality.
The idea of ease unites the central development points on the new Audi A8: design and lightweight construction, dynamism and electronics. Ease in the sense of design harmony, ease of acceleration, ease in the sense of weight, the ease with which it can be handled – the driver of an A8 does not have the impression of handling a large saloon car – and, finally, ease of operation.
Its design gives visual expression to the unique character of the new A8. Expansive, strikingly arched surfaces are bordered by precisely plotted lines. The silhouette of flat front and short body overhangs, plus the highly contoured rear end, provide clear dynamic signals.
Engine and transmission: full power output
Two powerful V8 engines with 4.2 and 3.7 litres of displacement are available at first with 246 kW (335 bhp) and 206 kW (280 bhp) respectively. One new feature in the A8 is the 6-speed automatic transmission with tiptronic function, which constantly assures an optimum transition between the various speed stages.
As an option, it is also possible to change gear in addition to the selector lever via shift paddles mounted on the steering wheel; the ergonomic advantages of this concept have already been demonstrated on the Le Mans champion model, the Audi R8. The driver can also change gear when cornering, without having to take his hands off the steering wheel.
Quattro permanent four-wheel drive remains unequalled in the luxury segment. It translates engine performance into superbly effective propulsion and lateral support.
Aluminium body: with ease at the top
The innovative aluminium body, based on a further developed version of the Audi Space Frame ASF, provides the high-strength basis for low weight, excellent performance and handling of the new Audi A8. The number of components on the completely closed ASF could be considerably reduced compared to the first A8 generation through large functional castings and extruded sections. The static torsional rigidity has been increased by 60 percent and ensures a major enhancement in vibrational comfort, safety and dynamic handling potential. Compared to a steel body the weight of the body shell is 50 percent lower: minimal mass with maximum stability.
Running gear: more dynamism as the driver wishes
The new Audi A8 has a further developed aluminium chassis with four-link front axle and a self-stabilising trapezoidal-link rear axle. The brakes and steering system with variable ratio and servotronic are a new design.
Adaptive air suspension – 4-corner air springing with continuous damper control – solves the classic conflict of aims between good handling properties and suspension comfort commensurate with the luxury class. Adaptive air suspension has the right characteristic for every driving situation, reduces body movements with its continuously adjusting damping and thus optimises roadholding and comfort.
The data from four sensors on the axles and three acceleration sensors on the body is evaluated in the adaptive air suspension’s central control unit. This computer prompts the adjustment of the individual shock absorbers in a matter of milliseconds, based on the driving situation identified, thereby always assuring optimum driving dynamics and ride comfort.
The driver can choose between four predefined settings, for a suspension characteristic ranging from overtly sporty to ultra-comfortable.
- In the automatic mode, the body is at the standard height when stationary and at medium speed, with 120 millimetres of ground clearance. If the new A8 is driven at more than 120 km/h for over 30 seconds, the body is lowered by 25 millimetres. In the reverse order, the body is raised if the vehicle is driven more slowly than 70 km/h for more than two minutes or as soon as it drops below a speed of 35 km/h.
- The dynamic mode lowers the vehicle by 20 millimetres to a ground clearance of 100 millimetres even before it sets off; its centre of gravity is lower and the air suspension operates with firmer springs and a harder damping characteristic. The suspension tuning is particularly agile as a result. Once again the same threshold speeds apply for automatic changes in ride height: if the car is driven faster than 120 km/h for more than 30 seconds, the body is lowered by a further 5 millimetres. And the body is raised again if the vehicle is driven more slowly than 70 km/h for more than two minutes or as soon as it falls below a speed of 35 km/h.
- The comfort mode enables the car to glide extra-smoothly over all kinds of surface bumps because the system increases damping forces less frequently at lower speeds. The automatic lowering at motorway speeds is suppressed in order to obtain maximum compression travel.
- The lift mode can be activated in the speed range below 80 km/h as required. It raises ground clearance constantly by 25 millimetres and offers the balanced damping characteristics of the automatic mode. It is therefore particularly suitable for driving on uneven terrain. At speeds above 100 km/h adaptive air suspension returns to the previously set mode.
The steering
The A8 has rack-and-pinion steering with variable ratio and speed-dependent power assistance, servotronic, as standard equipment. The result is improved steering precision and clear feedback at high speeds without having to accept a loss in comfort at low speeds.
With high-performance brake system
The new Audi A8 is fitted with a newly developed high-performance brake system that is fully in keeping with the demands and the character of a sports saloon in the luxury segment. This applies both to deceleration potential as well as to stability and braking comfort.
The brake system on the eight-cylinder versions of the new A8 is much larger than on the predecessor model: aluminium floating-calliper brakes are fitted at the front and rear. With 360 millimetre brake discs at the front and 310 millimetre discs at the rear, the system now also achieves a braking performance in conjunction with 17-inch wheels that was previously reserved for 18-inch systems.
The brake system is supported by the Electronic Stabilisation Program ESP 5.7 with ABS, ASR traction control, Electronic Brake-force Distribution EBD, Electronic Differential Lock EDL and hydraulic brake assist.
Electromechanical parking brake
The electromechanical parking brake is also making its debut on the Audi A8. It brings clear functional benefits as well as performing all the tasks of a conventional handbrake.
The system, operated via a pull/push control on the centre console, automatically ensures the necessary parking brake application force. The operating concept is deliberately based on what most drivers would consider the usual operating principle for conventional systems: a quick pull of the switch applies the brake; if the driver pushes it down – while the brake pedal is depressed – the system is released.
An integrated starting assist function facilitates smooth driving off on hills without the driver having to manually disengage the brake. The system calculates the moment and rate at which the parking brake is to be released, on the basis of data such as the transmission speed selected, the accelerator pedal position, the engine speed and the angle of incline. As soon as there is sufficient torque to move the vehicle forwards, the electronics automatically release the parking brake.
It goes without saying that the electromechanical parking brake also has the emergency braking function stipulated by law: above a speed of 8 km/h the driver can stop the vehicle simply by pulling on the switch. Braking values of 8 m/s2 can be achieved at the same time – considerably more than with a conventional handbrake. A brake-pad monitoring system, which informs the driver in the cockpit of the current status, is combined with the electromechanical parking brake.
There is a further advantage to the electromagnetic parking brake: by eliminating the conventional handbrake lever, it enables the designers to give the centre console a new, neat layout.
Wheels and tyre pressure monitoring system
The 3.7-litre and 4.2-litre versions of the A8 have the elegantly sporty 10-hole 8Jx17″ alloy wheels as standard, with size 235/55 R17 tyres. This combination blends excellent handling and comfort properties, and sets new standards of wet adhesion and rolling resistance.
The wheels range includes other wheel versions of sizes up to 8.5Jx19″, with 255/50 R19 tyres. These produce even better dynamic stability, coupled with a quality of tyre comfort that befits the luxury class.
The new A8 is equipped with the tyre mobility system as standard, comprising an electric compressor and sealant. If the car suffers a puncture, this system enables the driver to reach the nearest service station without needing to change the wheel. The A8 can also be supplied with a full-size spare wheel as a no-cost option.
A permanent tyre pressure monitoring system is also available as an option for the new Audi A8. The system monitors the tyre pressure and temperature of each individual wheel. It informs the driver optically and acoustically via the display in the instrument cluster if there is a loss of pressure and indicates which wheel is affected.
A summary of all the momentary inflation pressures and temperatures of all four wheels can in addition be called up via the MMI terminal. Correct values appear in green lettering, red values indicate that the pressure should be corrected without delay.
As an option: PAX wheels
This is the first luxury-class vehicle to be available with cast aluminium wheels with run-flat properties, the so-called PAX system. Its design means that the driver can continue for up to 200 kilometres at a maximum speed of 80 km/h even if a tyre is fully deflated. At the same time the PAX wheel guarantees a perfect synthesis of agility and ride comfort and therefore rounds off the A8’s typical dynamic performance in perfect style.
Thanks to the run-flat properties of the PAX wheel, the driver can, in the event of a puncture, reach an Audi workshop of his choice instead of having to change the wheel himself or call a breakdown recovery service: a new dimension to mobility that befits the luxury segment.
The flat tyre still offers a high level of residual ride comfort – the driver does not perceive a loss of pressure as a permanent deterioration of running characteristics. However, to make the driver aware of an impending flat tyre or a gradual loss of pressure, the PAX system is only offered in combination with the automatic tyre pressure monitoring system. This means that the driver is kept informed of the condition of all wheels and is in addition reminded of the maximum permitted speed of 80 km/h if one of the tyres suffers a puncture.
The PAX system consists of a special wheel rim, a suitable modified tyre design and the actual emergency-run element, a support ring that sits almost in the middle of the rim and encloses it. On a conventional wheel/tyre system, the tyre bead is clamped behind the rim flange. On the PAX system the tyre is inserted into the seat of the rim flange. To make sure that the tyre remains safely in position, a lever action presses the tyre more firmly into its seat if subjected to loads – when cornering for example.
The size designation differs from conventional wheels: the wheel used on the A8 has the metric designation “500″ which, in purely mathematical terms, is equivalent to a size 18.3 inch wheel. The tyre designation is 245/690 R 500 Y.
MMI operating concept: maintaining diversity, reducing complexity
With the integrated user interface MMI, Audi is providing an infotainment platform and a user concept for the new A8 that keeps operation simple through stringent logic. MMI in the first instance comprises the control panel (MMI terminal) in the centre console with a control button that can be turned and pressed and four control keys grouped around it.
On either side of the terminal – apart from the Return key for exiting the menu level – there are a total of eight function keys with which the user can call up the principal main menus directly. The second central component of the MMI, a 7?inch colour monitor, is positioned above the centre console in the dashboard and therefore at an optimum angle of view for the driver.
The highlight: the basic geometry of the monitor display corresponds in detail to the layout of the control keys and button in the MMI terminal. In other words, the driver uses the top left control key to select the function displayed in the top left corner of the screen. There is thus an intuitive link between visual perception and hand movements.
Easy learning process
The driver only needs to remember four basic rules for operating the MMI:
1. The main functions of the system – entertainment, communication, information and control of vehicle systems – are accessed by the eight permanently assigned function keys.
2. Within these function menus, the driver activates the required functions by turning/pressing the control button.
3. The control keys, to which different functions are assigned for each menu, provide access to further functions in the menu. These can be read off in the corners of the display which also vary depending on the menu selected.
4. The user simply presses the Return key to skip back to the next-higher menu level.
The more frequently a function is used in the car, the higher up the menu structure it is placed, thus making it quicker and easier to access.
The electronics architecture
The field of electronics has long since advanced into automotive technology. This applies in particular to the luxury segment where driver expectations regarding communication, comfort and convenience systems naturally play a very important role.
The new A8 therefore offers numerous innovative technologies in this area, some of which are available for the very first time in an Audi. These include, to name just a few examples, the advanced key access and authorisation system, one-touch memory personalisation and the radar-assisted distance control system known as adaptive cruise control.
However, the Audi development engineers have by no means integrated innovations into the vehicle at a functional level only. Numerous new elements have also been introduced behind the scenes, in the vehicle’s electrical system. In view of a dramatic increase in the range of functions available, it was also important to guarantee operational reliability and efficient energy management.
Networking played a decisive role here. Five main bus systems connect all electronic components on board the new A8. The entire driveline – including engine, transmission and brake control units – is networked via a high-speed CAN bus. The infotainment components such as MMI, sound and navigation systems communicate via a further high-speed bus based on MOST technology. The comfort and convenience components, from door controls to air conditioning, are also networked with each other.
An independent “gateway” control unit acts as an interface between the bus systems. This connects the drive, comfort/convenience and infotainment networks hence making a control centre like the MMI possible in the first place.
The Audi development engineers also relied on new technologies for the vehicle’s wiring systems. New bus systems – such as the optical MOST technology – have been used; these include plastic-based optical fibres and foil wiring which is particularly space-efficient.
[source: audi-mediaservices.com]
Pictures of thew new Audi A8 from Paris Motor Show:
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