All-new 3rd generation Audi A8 luxury sedan

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New 3rd generation Audi A8 deploys it technologies
From its own onboard network to received satellite data

1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - Dimensions

Continued... The new Audi A8 comes with standard adaptive air suspension, including controlled damping and the Audi drive select dynamics system. The dynamic steering system is optional.

The new Audi A8 comes with standard adaptive air suspension.

The integral subframe for the engine and the front axle, which is made of high-strength steel and is reinforced with X-shaped braces, forms the backbone of the front suspension which comprises five links per wheel – two transverse links on the upper plane, the support link and control arm in the lower plane and the track rod. All suspension control arms are forged aluminium parts for low unsprung masses. The anti-roll bar is made from a high-strength tube to reduce weight.

The five-link front axle was shifted forward by 145 millimetres (5.71 in) compared to the previous model, for a more balanced distribution of vehicle weight between the front and rear axles. The rear-axle differential in the quattro drivetrain and the battery located in the trunk contribute to this balance.

The struts are newly developed with increased air capacity.

Major elements of the rear suspension have also been redesigned. Unlike in the previous model, the struts no longer rest against the upper transverse links, but rather directly on the wheel carriers. This allows a 30 percent higher damping ratio so that the dampers react with greater sensitivity.

Adaptive air suspension

The air supply for the standard adaptive air suspension is located in the rear of the A8. A quiet compressor generates 18 bar of pressure and fills a 5.8-litre cylindrical pressure vessel of aluminium. Control from the pressure reservoir substantially accelerates the level regulation processes.

The struts have been newly developed; their increased air capacity now allows a soft characteristic even without an auxiliary accumulator and a fine response even to slight irregularities.

When integrated into the Audi drive select system, the standard adaptive air suspension combines a high-end air suspension with controlled damping.

The driver can choose between four modes with the Audi drive select system. “auto” offers balanced properties; damping is particularly soft in “comfort.” In both cases the body is initially set to the standard ride height when starting out.

Front axle with the suspension.

In “auto” mode, the body is lowered by 20 millimetres (0.79 in) when the A8 has driven for at least 30 seconds at a speed greater than 120 km/h (74.56 mph). This increases stability and reduces wind resistance. The body is not lowered in “comfort” mode.

In “dynamic” mode, on the other hand, the body is lowered 10 millimetres (0.39 in) from the outset, with the ride height lowered another 10 millimetres when the switchpoint is reached.

In the fourth mode, “lift,” ground clearance is increased 25 millimetres (0.98 in) from the standard ride height so that smaller obstacles can be overcome. This mode can be selected at speeds of up to 80 km/h (49.71 mph) and automatically switches back to the last mode selected at speeds above 100 km/h (62.14 mph).

Rear axle with the suspension.

The adaptive air suspension also serves as a level control to keep the body at the optimal ride height at all times, regardless of the load. Audi also offers the A8 with an optional setup that emphasizes dynamics. The adaptive air suspension sport lowers the ride height in standard mode by 10 millimetres (0.39 in).

The friction of the regulated dual-tube shock absorbers, inside which the air springs are located, was reduced by around 10 percent. The continuous damping control (CDC) has hydraulic shock absorbers with the dual-tube principle and controllable internal valves. Supplied with data from a complex system of sensors, the control unit adapts the function of the shock absorbers to the road conditions, the driver’s style, and the mode specified in the Audi drive select system.

Individual adjustments for each wheel are made by the millisecond via the control current for the damper valves. When driving quickly though a curve, for example, the computer reduces body roll by selectively increasing the damping force for certain wheels. During braking, it instantly hardens the shock absorbers to reduce dive and shorten the stopping distance. The dampers also support the work of the ESP program.

Audi select drive

Audi drive select: integration of the adaptive air suspension, engine, 8-speed tiptronic, servotronic and Audi pre sense basic.

With the Audi drive select system comes the integration of the adaptive air suspension, the engine, the eight-speed tiptronic, servotronic and Audi pre sense basic. The system modifies the characteristics of the air springs, dampers and the accelerator, and adapts the shift points, steering boost, and the trigger time for the reversible belt tensioners.

The MMI allows the driver to change the characteristics of these modules between the comfort, auto, and dynamic modes at any time via the “Vehicle settings” menu. He / she can also compose his / her own “individual” mode – within reasonable limits – by choosing settings from the portfolio.

Steering

The steering gear, which used to be installed on the bottom of the radiator tank, is now placed low and far to the front, below and in front of the centre of the wheel on the subframe.

The steering gear is a rack-and-pinion design with a casing of lightweight die-cast aluminium. The sporty and direct steering ratio of 16.1:1 is meant to communicate precise feedback from the road. Unlike conventional power-steering pumps, which circulate a large volume of oil internally, a controlled-output vane-type pump delivers only as much oil as is needed at any given operating point. This reduces the fuel consumption, according to Audi, by 0.1 litres/100 km.

All A8 versions have a standard servotronic power steering, which adapts its power assistance to the speed being driven.

Dynamic steering: steering ratio is varied by nearly 100%.

With the dynamic steering option (opposite photo), the steering ratio is varied by nearly 100 percent as a function of driving speed and the setting in Audi drive select.

The central component is a superposition gear integrated into the steering column and driven by an electric motor. The compact and light unit reacts precisely, with low friction.

While the steering is very direct at low speeds, such as in city traffic and when manoeuvring, the power assist is also high to keep it very easy to manoeuvre into a parking space. At moderate highway speeds, the system becomes less direct and provides less power assist. At fast highway speeds, an indirect steering ratio and low level of power assist facilitate steady tracking.

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The dynamic steering system cooperates closely with the ESP program. It even countersteers if necessary, since the system is designed to reduce understeer or oversteer as necessary. When the brakes are applied on surfaces with different coefficients of friction, the system actively intervenes with stabilizing steering manoeuvres so that track offset, stopping distance and the amount of countersteering required from the driver are minimized.

The dynamic steering needs less time for its corrections than the brake system needs to develop pressure at the wheels. Audi says that in many situations it does most of the work and there is no need for the braking manoeuvres or they serve only as damping to reduce speed. This is particularly pronounced when driving at higher speeds on a slippery surface such as snow.

Brakes

The front and rear brake discs are internally ventilated.

The front and rear brake discs are internally ventilated. The front axle of the new A8 features discs measuring 356 x 34, 380 x 36 and 400 x 38 millimetres (14.02 x 1.34, 14.96 x 1.42 and 15.75 x 1.50 in). Stainless steel pins connect the friction rings, which are made of a newly developed, high-strength cast iron material, to the lightweight aluminium brake caps. This reduces the weight and thus the unsprung masses by as much as 4.5 kilograms (9.92 lb) depending on the size of the disc.

The rear brake discs measure either 330 or 356 millimetres (12.99 or 14.02 in) depending on the engine. The electromechanical parking brake is integrated into the callipers.

3rd Gen. Audi A8	Body and exterior	Interior, network	Engines	Transmission
Steering, suspension...	Active safety	Passive safety	MMI & media	Dimensions

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