At the start of 2016, the new Audi A4 allroad quattro became the first Audi model to feature quattro with ultra technology. The system is now available on other models including the Audi A4, Audi A5 and Audi Q5.
Just to make things clear from the start: Also with new ultra technology, quattro drive remains permanent quattro drive. The term “permanent” is just interpreted in an intelligent new way. Permanently available doesn’t have to mean permanently active.
So how does that work? The revolution lies in the interplay of the newly developed all-wheel drive components, a comprehensive array of responsive sensors and a sophisticated operating strategy. The sensors continuously measure and assess data on driving dynamics, road condition and driver behavior. That on its own is not necessarily new. What is new is that the systemdecides proactively, depending on the data, whether all-wheel drive offers an advantage in a given situation. Then, quattro ultra technology can be activated predictively, i.e. before all-wheel drive is actually required. The system is constantly looking ahead. So all-wheel drive stays switched off when it’s not needed but remains permanently available in the background. The switch is imperceptible to the driver but makes a significant difference in terms of fuel consumption.
The electronic system is networked with a large number of other control units. Every ten milliseconds, it captures and evaluates a variety of data—steering angle, lateral and longitudinal acceleration, and engine torque, to name just a few. On the proactive level, the focus is on the data supplied by the networked system. During rapid cornering, for example, the control unit uses the data to compute the point at which the inside front wheel will reach its limit of grip. It calculates roughly 0.5 seconds in advance. If the wheel approaches the limit of grip to within a defined threshold, all-wheel drive kicks in. With predictive activation, the quattro control unit bases its decision on the driver’s style of driving, the status of the ESC stabilization system and the mode set on the Audi drive select system. It also takes the trailer detection system into account. With reactive activation—which occurs rarely in practice—the system reacts to sudden changes in the coefficient of friction. These occur, for instance, when the wheels go from dry asphalt to a sheet of ice. In such situations, the system benefits from a basic architecture that enables rapid activation in all driving situations. In general, quattro drive will kick in more frequently in winter than in summer. The need for it is also greater at moderate and low speeds with acceleration phases than when the vehicle is driven at constant high speeds. This is why the use of quattro is lower on freeways than on twisting mountain roads. However, if the car is driven dynamically on a winding road, all-wheel drive remains active for extended periods, even on dry, grippy asphalt.
quattro drive is linked with Audi drive select, enabling the driver to select the all-wheel drive characteristics that best meet individual preferences. “Auto” mode, for instance, provides best-possible traction and balanced driving dynamics, while “dynamic” mode directs more torque to the rear wheels sooner for sportier handling. Wheel-selective torque control, a software function of the ESC, supports sporty drivers as they enter a curve by minimally braking the inside wheels, ensuring precise handling. When quattro is active, the power split between the front and rear wheels is calculated continuously. The control strategy takes into account ESC data, ambient conditions, driving situation and driver wishes.
Mechanically, two clutches in the drivetrain make the difference. When the system switches to front-wheel drive, the front clutch—a multi-plate clutch at the transmission takeoff—disconnects the drive shaft. An integrated decoupler in the rear-axle differential also opens. When both are open, the primary cause of drag losses in the rear section of the drivetrain is shut down. Despite the new technical components, the quattro drivetrain is nearly four kilograms lighter. That, too, saves fuel and enhances handling.
Ultra technology marks the next evolutionary step in over 35 years of Audi quattro performance. It makes the drive system even smarter and more efficient than ever before—without any loss of driving dynamics or composure.
Audi A4 allroad quattro fuel consumption urban/extra-urban/combined (in l/100 km): 8.2–5.4/5.9–4.4/6.7–4.9. CO2 emissions combined (in g/km): 154–127. Where stated in ranges, fuel consumption, CO2 emissions and efficiency classes depend on tires/wheels used.