Audi A6 allroad: quattro ultra, the all-wheel drive that engages before it is needed
The Audi A6 allroad combines versatility, comfort and roadholding thanks to an intelligently managed all-wheel drive system: quattro ultra. It is fitted to both powertrains in the range. The first is the 3.0-litre V6 TDI. The second is the e-hybrid, the first plug-in hybrid powertrain offered on the A6 allroad. The principle behind quattro ultra is to give the driver the benefits of all-wheel drive at all times, while reducing energy losses when it is not needed. Both versions are available to order.
quattro when it is needed, efficiency when it is possible
quattro ultra is based on two clutches:
- an electronically controlled multi-plate clutch at the gearbox output;
- a decoupling clutch integrated into the rear differential.
When all-wheel drive offers no benefit in the prevailing conditions, the system opens both clutches. The propshaft and rear components are then disconnected, significantly reducing friction. Under low load and with no risk of wheelspin, the A6 allroad therefore consumes like a front-wheel-drive car, with 100% of the torque sent to the front wheels.
The system’s strength lies in its ability to anticipate. It continuously analyses a wide range of parameters:
- steering angle;
- power demand;
- selected gear;
- lateral and longitudinal acceleration;
- body movements;
- road surface grip.
It also learns the driver’s style and takes into account the mode selected in Audi drive select. The smoother the driving, the less the all-wheel drive intervenes. The more dynamic the driving, the more quattro comes into play.
Using these calculations, the system predicts around 0.5 seconds in advance when four-wheel drive will be useful. It reactivates all-wheel drive within 200 milliseconds, the time needed to synchronise the components and re-engage the rear clutch. When pulling away, cornering at speed, accelerating hard or driving on a slippery surface, quattro is therefore already active before the wheels start to slip.
Electrified powertrains and intelligent torque distribution
quattro ultra works with two electrified powertrains. The 3.0-litre V6 TDI features MHEV plus mild hybrid technology and an electric compressor. The e-hybrid version brings plug-in hybrid technology to the A6 allroad for the first time. In both cases, Audi aims to combine performance with efficiency. quattro ultra contributes directly to this by limiting drivetrain friction whenever conditions allow.
As soon as the situation demands it, the multi-plate clutch sends torque to the rear axle. The distribution then adjusts according to three priorities: traction, dynamics and comfort. Under hard acceleration, the rear can receive a large share of the power: according to Audi’s internal measurements, more than 70% of the torque on a dry road. The A6 allroad’s handling becomes more agile, without losing any of the stability expected from all-wheel drive.
quattro ultra is part of a story that began in 1980. Since the Ur-quattro and its manually locking centre differential, the technology has gone through several generations of Torsen differentials, followed by today’s electronically managed systems. Audi has produced more than 15.6 million quattro vehicles, around a third of its output since 1980.
On the A6 allroad, this drivetrain ensures safe driving on motorways as well as on snow-covered roads or dirt tracks, while consuming less whenever all-wheel drive is not required. To discover the Audi A6 allroad and choose between the V6 TDI and the e-hybrid, the Segond Automobiles team will be pleased to welcome you for a test drive at its Audi dealership in Monaco.
