When the Audi A4 allroad quattro hits European dealerships this summer, it will boast an extra 1.3 inches of ground clearance, jagged new headlights, and a unique “offroad mode” that keeps the vehicle composed during tricky situations. That’s not the only new tech on the car though, because the allroad with also benefit from a trick all-wheel drive system called quattro ultra.
Instead of permanent AWD, Audi describes quattro ultra as “permanently available,” which means it uses a multi-plate clutch to disengage the rear axle when extra traction is not needed. When the computer deems it appropriate, another clutch in the rear differential can decouple as well, stopping the prop shaft from spinning and further reducing losses from friction. The result? Audi says quattro ultra is at least 5 percent more efficient than the standard quattro system, which will pay dividends for fuel economy as well as in reduced CO2 emissions.
Drive systems like this have been around for years now, however Audi’s technology is a bit different because of its proactive, predictive, and reactive capabilities. A bevy of sensors monitor variables like steering angle, throttle position, and lateral acceleration every ten milliseconds, activating the rear axle roughly 0.5 seconds before a loss of traction occurs. That’s the proactive level. On the predictive end, the car’s computer tailors itself to the driver’s habits, using data from the electronic stability system and drive mode select settings to accommodate a more dynamic motoring style. Finally, quattro ultra can act reactively as a last resort, channeling power to and from the rear wheels if the road conditions dramatically change, such as when the car hits a patch of ice, water, or dirt.
Quattro ultra is expected to show up in a variety of Audi vehicles riding on the brand’s modular longitudinal (MLB) platform, including the A4, A5, A6, A7, and Q5.