The race is on for every automaker to provide the latest technological advancements and features in their cars. It is an arms race, and Audi has been at the forefront with its innovative and tested Quattro System. Quattro has been synonymous with Audi since 1980. Audi believes that this will make driving experiences far more efficient and does not compromise on the car’s performance and handling characteristics. So, how does the Audi Quattro System work?
Let us look at how the Quattro system works.
For the Quattro system, Audi engineers wanted to build an all-wheel drive sports car without requiring a traditional transfer box. Traditional transfer boxes are bulky and add weight, hardly the best thing to use in a supercar, or any sports car for that matter. Audi’s system makes use of a central differential. The differential allows the engine torque to be divided between the wheels even when they are rotating at different speeds. In the Audi Quattro system, the central differential is mounted within the gearbox and it connects two axles when slip in any of the wheels is detected. This approach allows an infinitely variable split of torque depending on the road conditions. When you compare this system with a traditional transfer box, it is lighter and more efficient.
Audi Quattro System
To understand how the Quattro system works, let’s take a look at Audi’s flagship super car-the R8. The R8’s engine is mid mounted, so how does this central differential system work?
It is quite simple, really. Since the engine is behind the driver rather than in front, the whole system is flipped backwards. The engine sits at the back and the gearbox in front of it. A Torsen differential is used in this case. Check out this video below that explains how a Torsen differential works.
The Torsen differential sends torque from the engine towards each of the 4 wheels. This is decided by the electronics. The electronics differentials integrated into the traction and stability control systems decide the amount of torque that the system sends to each individual on each axle as required. Since the R8 is a high performance sports car, the rear wheel gets a greater percentage of torque. The torque split is approximately 15:85.
Depending on the torque requirements for each wheel under different conditions, the torque is split between each individual wheel on each axle. The electronics decide the amount of torque to be given to each wheel and the Torsen differential sends the required amount of torque via the linkage. It is all quite simple, isn’t it? Indeed!
So, this is how Audi’s Quattro system works. Of course, some Audi cars employ a different Quattro system due to the difference in their engine layout when compared to the R8. Cars such as the Audi A3 or the Audi TT feature a transversely (sideways) mounted engine. This means the Torsen system cannot be employed as it would not fit under the bonnet. In such models, a Haldex four wheel drive system is employed.
Check out this video that explains how a Haldex system works.
Let’s see how the Haldex system works. In contrast to the Torsen, the Haldex sends all the torque that the engine generates to the front wheels under a normal scenario. If a slip is detected in the rear axle, the Haldex clutch can lock up and divert nearly 100% of the engine torque to the rear wheel. Again, the electronics help to distribute the torque to each individual wheel on each axle as necessary.
The two systems will have different characteristics under extreme driving conditions, but I hope you have managed to get the fundamentals of how the Audi Quattro System works.
Disadvantages of Quattro system
Such a system cannot come without its disadvantages. Thankfully, there are not many.
The need to package components tightly in Quattro systems means that the gearbox is longer than usual. Because of the longer gearbox, the engine has to be positioned further. This can upset the balance of the car during hard cornering, which can result in loss of grip at the front.
The second disadvantage is that since the AWD system is always engaged, the fuel economy is reduced.
Audi has introduced its latest Quattro System with Ultra Technology, dubbed the ‘Quattro Ultra’. You can read more about how the Audi Quattro Ultra Technology System works.
If you have any questions or comments about how the Audi Quattro System works, let us know in the comments below! If this got you interested, check out our simplified explanation of how Variable Geometry Turbochargers (VGT) work!