Offers Maximum Comfort, Outstanding Agility
Predictive active suspension is now one of Audi’s high-tech innovations. Fitted to the flagship Audi A8 L luxury sedan, intelligent predictive active suspension affords the full-size model to deliver — depending on the chosen settings — the supreme ride comfort of a chauffeur-driven limousine or the firm handling of a sports car.
The Audi A8 L’s predictive active suspension works together with a camera placed at the front of the car. With this, the system identifies uneven surfaces before these are reached and predictively regulates the active suspension system. So even before the car hits a bump, the predictive function — developed in-house at Audi — signals the correct positioning travel to the actuators and actively adjusts the suspension. This reduces body movement and compensates for undulations or similar unevenness on roads. Plus, the complex process takes just a few milliseconds as the camera generates information about road surface properties 18 times a second. The electronic chassis platform processes the road surface data and precisely actuates all suspension components almost in real time.
Completely dynamic, the Audi A8 L’s predictive active suspension uses electromechanical actuators to adjust its settings. These actuators can lift up or force down each of the vehicle’s wheels individually to actively manage ride height in every situation. The active suspension can raise or lower the car’s body by up to 85 millimeters from its central position at all four corners within five-tenths of a second.
Allowing for this are compact electric motors located close to each of the Audi A8 L’s wheels, all of which operated by the car’s 48-volt primary electrical system and governed by power electronics. A belt drive and a compact harmonic drive step up the electric motor’s torque almost 200 times, or to 1,100 Nm, and apply this to a steel rotary tube. The latter is permanently attached to a pre-loaded titanium rod located inside it and capable of turning through more than 20 degrees. From the end of the rotary tube, the force is transmitted to the suspension via a lever and coupling rod. At the front it acts on the spring strut while at the rear it works on a transverse link.
Included in the Audi A8 L’s predictive active suspension settings are “dynamic” and “comfort plus.” The feature works in conjunction with the car’s air suspension and the Audi drive select dynamic handling system. In “dynamic” the Audi A8 L becomes a sports car as it turns in firmly, its body leaning over by only two degrees, instead of more than five degrees in standard setting, when cornering fast. The car’s front end rises or dives minimally during acceleration or braking, respectively.
In contrast, “comfort plus” profile, as chosen in Audi drive select, lets the luxury sedan glide with velvety smoothness over any bumps any surface. The setting also offers transverse force reduction. Upon entering a bend, this raises the body on the outer side of the bend while lowering it on the other side. The result is that the driver and passengers barely notice the Audi A8 L is cornering — even drinks in the cup holder will not spill. Straight-line travel in “comfort plus” also reduces the car’s pitching motions.
Predictive active suspension even works when the car is at a standstill. When the Audi A8 L’s door handle is pulled, the body quickly raises by up to 50 millimeters to make entry and exit into the car even easier.
The predictive active suspension, when combined with Audi’s “pre sense 360°” system, also increases the Audi A8’s passive safety function. In an impending side impact at speeds exceeding 25 km/h, the active suspension raises the body by up to 80 millimeters on the side of the impact. This brings the car’s sill into a better position to absorb the impact energy. With predictive active suspension, the Audi A8 L boasts a multi-faceted personality.