An old adage says that a good horse jumps only as high as it needs to. Audis new Quattro closely followed this principle, because it occurs only in action when needs the driver. To be precise, a bit earlier. The result of this Tort minimalism is 0.3 liters per 100 kilometers reduced fuel consumption compared to a conventional four-wheel drive. “These are real values,” emphasizes drive developers Dieter Weidemann. Thus, the Quattro-consumption disadvantage compared to a front-wheel drive vehicle of about half a liter per 100 kilometers is almost eliminated.
The principle of this four-wheel-drive, the Ingolstadt marketing experts with the striking phrase ” Quattro have considered with Ultra technology “, is always interesting: on the transmission a multi-plate clutch is flanged and at the rear there is a so-called claw coupling which is closed only when additional traction is needed. So a variable control you get with a conventional four-wheel drive with self-locking differential out also. But the gimmick behind this arrangement is that over the separating clutch on the rear axle rotating elements, such as the propeller shaft or the ring gear, the panscht like a paddle steamer in oil, are completely shut down. Thus, there is less friction and no drag losses that inevitably occur when the engine must extend these components. This leads to a reduction in fuel consumption.
Such “Disconnect drives” are known. Audi reinvents the wheel because by no means new. The trick is in the details: The separating clutch on the rear axle is always ready, as she waits with tensioned springs to its use, even if it does not depend on the drivetrain. “Within 250 milliseconds, the system is ready for use,” says Weidemann. In order for these fast response time is achieved, the central multi-plate clutch is electro-mechanically activated, as a hydraulic system would be too slow. At rest, the claw clutch to the rear axle is in fact always closed. This ensures that the Quattro drive also is available when one has demolished an important cable in the field. At temperatures below four degrees and speeds below 30 km / pm – on the technique also to permanent four-wheel drive to
In order for the new drive concept reacts without self-locking central differential as it wishes of motorists. the engineers have invested a lot of brainpower in the software during the five-year development period. The result is a very challenging construct that is able even to learn. 100 times per second, the system collects data from various sensors, such as ESP, steering angle, accelerator pedal position, longitudinal and lateral acceleration as well as engine torque and performance. Using this data, the car looks even half a second in the future, so the four-wheel drive already is available when it is needed. Decisive for this is the inside front wheel, which provides information, what about liability. The traction is determined by the tire and the asphalt or the subsoil. The system is initially based on a mean value, determined the two actual parameters, ie learns to and arises as independently on the grip of the tires and the ground a. Will it smooth, the Quattro intervenes earlier. The whole thing works the way without the data from the navigation system
If an unforeseen event -. Such as the famous slab of ice – a, helping the short reaction time of the Quattro in order to respond appropriately. The software also detects whether the driver fires like faster around the curves and then switches to dynamic mode. This means that the Quattro drive engages a little earlier than in the normal mode and longer gun is in walking distance. The result is impressive: Even with twisty mountain roads 40 percent could be completed without all-wheel drive. The dynamic developments were not neglected. Is it even fast around the corners, can the A4 with a lot of oomph by the Tyrolean Alps pepper. Which is what the brake interventions at the individual wheels. The typical front torque steer in the steering wheel is also part of the past. However, the system does not does not quite reach the dynamics of R8 Quattro with sport differential.
Should there. The compromise of saving fuel and momentum is in the foreground. “For pure highway driving we even reach a value 95-98 percent with pure front-wheel drive.” In the next few years, Audi plans to sell 600,000 to 700,000 of these Quattro. The new all-wheel drive is only for the Modular Longitudinal Platform (MLB) and special motors, such as provided, for example, the 2.0 TFSI. More than a maximum torque of 500 Newton meters not cope with the powertrain at the moment and the use of a conventional torque converter transmission efficiency does not come to fruition. Therefore, there is the saving Quattro only with dual-clutch transmission and manual transmission. First, the Audi A4 Allroad will be equipped with it, followed by the Q5. The Q7 has a different architecture and will not get the Quattro Ultra.