Today the quattro all-wheel drive we see it as something usual in the full range of Audi models, but if we go back a bit in time warned that their existence is relatively recent. He debuted in 1980 at mythical Audi quattro, one precious square shapes coupe 200 hp, in its racing version would mark a before and after in the World Rally Championship.
But we step back a little more, namely the cold winter 1976/1977 in Sweden, where Audi engineers did a validation testing future systems and models. In addition, he accompanying them Volkswagen Itis They -a small military TT, a kind of Jeep Willys to the German- 75 hp, with which realized that, despite its low power, on slippery surfaces easily exceeded its much more powerful and large sedans front-wheel drive. From there came the germ of what three years later unveiled the Audi quattro at the Geneva Motor Show.
Technically, the first quattro all-wheel drive in its transmission had a secondary hollow shaft of 236 mm through which flowed force in two directions. At its rear end the central differential, which sent 50 percent of torque to the rear axle, which had a limited slip was connected. It was a system light, compact and efficient, able to function without a heavy box or a second transfer shaft as usual in the terrain.
Quattro all-wheel drive in competition
It was also in 1977 when Audi started programming their participation in rallies. In 1981, He debuted at World Rally Championship Finnish Hannu Mikkola. His start was impressive, marking the fastest in the first six sections of the first race of the championship, Rally Montecarlo time, but Victory escaped to an accident when he is leading the race with more than 6 minutes ahead. It was clear that the binomial Mikkola / Audi was not long in win, something that happened in the following quote, in Sweden. The championship went to the hands of Ari Vatanen (Ford Escort RS), for one year after finding no opposition between cars with single axle drive. So, In 1982 he had seven wins, alongside the constructors and drivers titles with Mikkola. Title getting back Mikkola in 1983 and 1984 with Stig Blomqvist.
But he quattro also had its moments of glory in the circuits, with Titles made in the American series TransAm in 1988 with the spectacular Audi 200 in IMSA GTO, the prestigious German Touring Car Championship DTM, the climb Pikes Peak (Colorado), the 24 Hours of Le Mans with the hybrid R18 e-tron ... With hits like the headline-grabbing Audi A4 quattro Super Touring, In 1996 he won seven national championships -in three continents in which he participated.
Different devices quattro all-wheel drive
Meanwhile, the AWD system also evolved for its road models. Thus, 1986 the manual lock was replaced central differential one type Torsen Meanwhile in 2005 a planetary gear allowed distribute torque asymmetrically and dynamically.
He first TDI in counting quattro all-wheel drive appeared in nineteen ninety five and today, almost independently of the engine, we can find the quattro logo on each of the bodies that market. Albeit with different systems.
The most famous is that of Central Torsen, which it is used in all models longitudinal front engine (A4, A6, A7, A8, Q5 and Q7) with a limited slip center differential Torsen which it is configured as a planetary gear mechanical immediate reaction. His initial allocation is 40 percent to the front and 60 for the rear, although it can send forward to 70 and back to 85 percent. In more powerful models can be supplemented with sport differential, what actively and independently distributes torque between the rear wheels to counter understeer.
Now, in the A4, A5 and Q5 future, so far only with the 2.0 TFSI, the so-called offers ultra quattro. This account with two clutches in the drive shaft, one at each end, so that when they are disconnected from the front axle both the tree and the rear differential stop moving to eliminate dragout. Thus, in certain circumstances it works only with front-wheel drive to save on average about 0.3 l / 100 km fuel versus quattro all-wheel drive with Torsen center differential.
For the transverse front engine (S1, A3, Q3, and TT) uses a multiplate clutch electronically controlled Haldex no center differential a hydraulic actuator on the rear axle to which pair is sent when it detects a loss of traction front.
At Audi R8 supercar Instead, center rear differential are integrated to through an electrohydraulic clutch in Front differential active control send torque to the front wheels; to which can reach 100 percent, compared with 35 up to the 1st generation.
These, in future, will join the AWD e-tron quattro, which as we saw in prototype form at the 2015 Frankfurt Motor Show offers three electric motors: one for the front axle and two for the rear, able to distribute the force between the two axes depending on many parameters extraordinarily quickly.
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