The new Audi A8 will, for the first time, be equipped with an electrified drivetrain as standard. In line with this, all engines will be equipped with mild-hybrid technology which provides for superior, smooth running as well as improved performance, coupled with enhanced efficiency. The basis of this technology is the 48-volt electrical system which, for the first time ever, is being used in the new A8 as the primary on-board electrical system.
(1) Mild-hybrid technology: new level of efficiency and comfort
The mild-hybrid drive system is made up of two central components: the water-cooled 48-volt belt alternator starter (BAS) and the lithium-ion battery with the same voltage level and 10 Ah electrical capacity. The latter is located under the floor of the load compartment of the A8. The functions of the MHEV (mild-hybrid electric vehicle) are made possible by means of the 48-volt electrical system, as part of which a DC/DC voltage converter is responsible for creating the energy required by the 12-volt electrical system.
The new drive combines efficiency with comfort in a very special way: in its fourth generation, the A8 can switch off the engine and make use of the coasting function in the speed range between 55 and 160 km/h (34.2 and 99.4 mph). The vehicle can then travel with zero emissions for up to 40 seconds. As soon as the driver steps on the gas again, the BAS prompts a swift, very smooth restart. The new 48-volt system also allows for start/stop operation from a speed of 22 km/h (13.7 mph).
To achieve such a high standard of efficiency, the A8 comes equipped with an intelligent powertrain management system: it processes both route data and information from its comprehensive range of sensors, which also includes the front camera. Based on this, the powertrain management decides whether the A8 should use coasting mode or recover up to 12 kW of energy. It doesn’t just recover energy during braking or coasting.
The A8 also recovers energy if the efficiency assistant detects a vehicle traveling in front; it does this by decelerating the car using the BAS. These measures reduce the mild-hybrid drive system’s consumption in customer operation by as much as 0.7 liters per 100 km (0.2 US gal per 62.1 mi).
Extensively re-engineered: two six-cylinders at market launch
The new A8 will be launched on the German market with two extensively re-engineered V6 turbo engines. Further engines, including a plug-in hybrid variant will follow as of 2018. All engines work in harmony with a rapid and smooth-shifting eight-speed tiptronic transmission. A torsion damper which adapts to the engine speed is integrated in this and allows low engine speeds and thus efficient driving. On some engines and the plug-in hybrid model, active engine bearings connect the assemblies to the auxiliary frame. They create phase-shifted counter impulses which, to a great extent, eliminate the transfer of vibrations to the vehicle body. The plug-in hybrid also features active noise cancellation. As part of this, counter-noise is emitted by the speakers of the sound system in order to suppress undesirable noise in the vehicle interior.
The permanent quattro all-wheel drive system with self-locking central differential comes as standard in the new A8 and, in the case of all MHEV model variants, it can be supplemented by the optional sport differential. When cornering at high speeds, it actively distributes the drive torque between the rear wheels depending on where it is needed and thus makes for even sportier driving and more stable handling.
New model designations making their debut in the A8
Audi is standardizing the model designations for its worldwide vehicle range. In future, within the model families, globally applicable two-digit number combinations which designate the output spectrum of the powertrain will replace the previous range of market-specific model designations. As the first Audi model, the new Audi A8 will already bear the new output designations at market launch in a few weeks. The starting price for the A8 on the German market is 90,600 euros, with the A8 L starting at 94,100 euros.
The chassis: sporty and superior
Highly precise control arms, powerful brakes, large wheels, progressive steering, adaptive air suspension – the standard chassis of the new A8 combines its sporty character with a supreme level of comfort. The large sedan glides calmly over any type of road surface. Extensive acoustic optimizations to the body are also partly responsible for the incredible peace and calm on-board. Developed in accordance with the ASF principle (Audi Space Frame), it is comprised of as much as 58 percent aluminum components. The passenger compartment is made of ultra-high-strength steel components and supplemented by a rear wall made of carbon-fiber reinforced polymers (CFRP). A magnesium strut-tower bar rounds out the lightweight construction concept and sees a combination of four different materials being used for the first time ever.
(2) Limits re-defined: dynamic all-wheel steering
The new A8 will see Audi introduce dynamic all-wheel steering for the first time. It combines a sporty, direct steering response with the greatest possible level of stability, and varies the steering assistance depending on the vehicle’s speed. As part of this system, the rear wheels are also steered: at low speeds, they turn as many as five degrees in the opposite direction to the front wheels which not only facilitates maneuvering and driving around tight curves but also reduces the turning circle by around one meter (3.3 ft) to 11.4 meters (37.4 ft) on the A8 and 11.8 meters (38.7 ft) on the A8 L. At medium and high speeds, the wheels are turned by as many as two degrees in the same direction as the front wheels. Thus, the new A8 offers more stable road-holding and carries out rapid lane changes and evasive maneuvers both masterfully and serenely.
(3) Maximum levels of comfort and dynamism: the Audi AI active suspension
The second new item of technology – the Audi AI active suspension – is a fully active electro-mechanical suspension system which works in conjunction with the adaptive air suspension system. Depending on the driver’s wishes and the driving situation, each wheel can be separately loaded or relieved by means of electric actuators and thus the vehicle body can be both actively and optimally controlled. The signals for this are delivered by the electronic chassis platform which is the central control unit for the chassis and which also manages the dynamic all-wheel steering, the sport differential and the air suspension system. Drive energy for the Audi AI active suspension is drawn from the new 48-volt main electrical system. The conventional 12-volt electrical system is connected to this via a DC/DC converter.
The Audi AI active suspension delivers a completely new type of driving experience. In the Audi drive select system, if the driver selects the dynamic setting, the new A8 turns into a sports car: it steers tightly into corners, the roll angles are roughly a mere half of what they are with the normal suspension system and during braking, the body exhibits hardly any forward pitching. By contrast, in comfort mode, the vehicle floats smoothly over rough bumps in the road surface. If driving physics attempt to push the body into the wheel, the active suspension counteracts this.
On A8 vehicles equipped with the pre sense 360° system with central sensor data fusion in the central driver assistance controller, the Audi AI active suspension also increases passive safety. In an impending side impact at more than 25 km/h (15.5 mph), the body is raised within half a second by up to 80 millimeters (3.1 in) on the side of the impact. As a result, the other party of the accident collides with a more resistant zone of the sedan. The side sills and floor structure accommodate a large portion of the impact forces. Deformation of the cabin and the loads acting on the occupants, above all in the chest and abdomen areas, can thus be reduced by up to 50 percent compared with a lateral collision in which the suspension is not raised.
The equipment, data and prices specified in this document refer to the model range offered in Germany. Subject to change without notice; errors and omissions excepted.