Audi has announced the availability of a new high-tech innovation for its A8 luxury sedan, and that is predictive active suspension. When specified, the fully active suspension system with electro-mechanical actuators continuously manages ride height at all times, and is able to lift or lower the car’s body by up to 85 mm from its central position.
There are compact electric motors located close to each of the A8’s wheels, drawing power from the car’s onboard 48-volt electrical system. A belt drive and harmonic drive step up the e-motor’s torque by 200-fold to 1,100 Nm and apply it to a steel rotary tube that’s attached to a preloaded titanium rod located within.
From the end of the rotary tube, the force is transmitted to the suspension via a lever and coupling rod – at the front suspension it acts on the spring strut, and at the rear suspension on the transverse link. Each electric motor can individually lift up or force down any given wheel, and operates within five-tenths of a second. Audi says its predictive active suspension operates highly efficiently, with power consumption averaging between 10 to 200 watts (actual threshold is much higher, up to six kW), which is much less than comparable hydraulic systems.
Together with air suspension and Audi drive select dynamic handling system (both standard on the A8), the new predictive active suspension enables unprecedented levels of comfort and sporty driving. For example, in Dynamic mode, the suspension stiffens up, allowing the car to roll just two degrees when cornering fast with 1G of lateral acceleration. That’s sports car level, just so you know.
When Comfort Plus mode is selected, the flagship sedan “glides with velvety smoothness” over any bumps in the road surface. Here, the suspension works with a front-facing camera that scans the road, identifying its surface and predictively regulates the suspension. Even before the car hits a bump, the predictive function (developed in-house by Audi) signals the correct positioning travel to the actuators and actively adjusts the suspension. We’ve also sampled this feature in the Maybach S-Class with Magic Body Control.
This reduces body movement and compensates almost entirely for long road undulation or similar unevenness. This seemingly complex process takes just a few milliseconds: the camera scans road surface properties 18 times a second, and the electronic chassis platform processes the data and precisely actuates all suspension components almost in real time.
In the same drive mode, there’s also a new transverse force reduction feature. When approaching a corner, the suspension raises the body on the outer side of the bend, while lowering it on the other side. The A8 leans into the bend by up to three degrees, and the concept is akin to riding a motorcycle. This angle reduces the transverse forces and is especially impressive when driving between 80 to 130 km/h (lateral acceleration up to 0.4G).
How effective is all this, you ask? Well, Audi claims that a full cup of coffee in the cup holder will not spill when Comfort Plus mode is engaged. For passengers, the suspension helps reduce forces acting on the human body under hard braking or acceleration, and eases entry and exit by raising the car’s height by 50 mm (elevated entry function).
Lastly, with pre sense 360 safety system, the system is able to raise the car’s body by up to 80 mm when a side impact is detected. This brings the sill into a better position to absorb the impact energy, sometimes as high as 50% compared with a lateral collision in which the suspension is not raised.
In Germany and other European markets, predictive active suspension costs an extra 5,450 euros (RM25k) and can be ordered for TFSI versions of the Audi A8. European customers can begin ordering from August 2019. Fancy yourself a suspension like this?
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Good luck when this high tech suspension break down