Quattro: How does all-wheel drive work?
Quattro is the designation of the all-wheel drive system used by the automobile company Audi. All Audi car models that are equipped with four-wheel drive carry this designation.
But how does Audi's all-wheel drive work, and why isn't Quattro like Quattro? We will shed some light on this in today's article.
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Audi Quattro history in brief:
The impetus for developing a car with all-wheel drive for the Audi car company was the Volkswagen Iltis, an all-terrain car developed on behalf of Audi. During the test drives, however, the idea of building an all-wheel drive into a passenger car was born.
In 1977, the Audi 80 was equipped with all-wheel drive from the Volkswagen Iltis for development. So a kind of prototype was created, which was designated A1. After various tests, this design was approved, and production of four-wheel drive vehicles could begin.
The first mass-produced Audi car equipped with all-wheel drive was the Audi Quattro model in 1980. This model was a huge success almost immediately after its introduction, so the Quattro designation is still used today on all Audi models equipped with this drive.
Other car companies of, Volkswagen concern use different designations for their 4WD cars. For example, the Volkswagen car company used several names indicating their vehicles equipped with all-wheel drives, such as Syncro or the still-used name 4Motion. However, Audi always uses only one designation for its 4WD cars: Quattro.
How does Quattro, that is, all-wheel drive, work?
The Quattro drive is permanent all-wheel drive with an inter-axle differential, with power split between the front and rear axles in a 50:50 ratio. Cars with this drive have very good driving characteristics, especially on slippery, wet, and unstable surfaces.
On the contrary, their disadvantage is higher fuel consumption and slightly worse dynamic characteristics than cars equipped with a drive of only one axle.
A compromise between all-wheel drive
The compromise between single-axle drive and all-wheel drive is single-primary axle drive, using a Haldex clutch that redistributes power between the front and rear axles when needed by engaging and disengaging the rear axle drive.
Some Audi cars are also equipped with such a system, for example, the TT model, but also the A3 model. These models also bear the same designation, but many call it fake quattro or false Quattro because, from a technical point of view, this designation belongs to full-fledged, permanent all-wheel drive.
Advantages of BMW xDrive compared to Audi Quattro
Compared to the Quattro system with a constant 50:50 power split, BMW with xDrive has a much lower tendency to understeer, mainly because the preferred driven axle is always the rear axle.
What is a fake Quattro?
So what is the difference between the mentioned Quattro and the fake Quattro? A car with the right Quattro system has the engine and transmission mounted longitudinally. The engine power is transmitted through the gearbox to the differential, which permanently redistributes the power in a ratio of 50:50 to the front and rear axles.
The engine and transmission are mounted transversely with the fake Quattro system. The engine power primarily drives only the front axle, and the rear axle is connected using a Haldex clutch only when needed or in an emergency.
In this case, it is not a true Quattro system, and the driving characteristics of the car do not correspond to those of a car equipped with Quattro permanent all-wheel drive.