Audi is quattro and quattro is Audi – the famous all-wheel-drive system has been a defining feature of the Vorsprung durch Technik brand for over 35 years, and proof of that enduring appeal has been provided this week by the eight millionth quattro-equipped model to leave the production line. Fittingly, the worthy recipient of this particularly momentous example of the all-weather roadholding and driver appeal amplifier is an all-new Q5 SUV in Garnet Red fresh from a brand new plant in San José Chiapa, Mexico.
quattro technology made its debut in 1980, and today it is available in more than 100 model versions. The quattro all-wheel drive system is standard in the Audi Q7, the Audi A4 allroad quattro, the Audi A6 allroad quattro, the Audi A8, the Audi R8 and all S and RS models, and it is available as an option in all other model series. In 2015, 44 percent of all Audi customers worldwide chose models equipped with quattro drive. The Audi Q5 topped the list with about 262,000 units. The quattro models generated particularly strong sales in the United States, Canada, Russia and in the markets of the Middle East. In Germany quattro sales totaled 122,048 cars.
Audi offers quattro all-wheel-drive in different versions tailored to each model. For the compact model series with transverse-mounted engines, an electronically controlled hydraulic multi-plate clutch is mounted at the rear axle. On the R8 mid-engine sports car, the multi-plate clutch is mounted on the front axle. According to the driving situation encountered, these active systems distribute drive torque variably to both axles.
The self-locking centre differential used in many Audi models with a longitudinally installed, front-mounted engine, is a purely mechanical planetary gear. Normally it splits the drive torque sent to the front and rear wheels with a 40:60 distribution.
The sport differential is available on the rear axle with some of the top-of-the-range engines. It actively distributes the torque between the rear wheels by means of two superposition units, each with an electrohydraulic multi-plate clutch. In extreme cases, almost all of the torque is sent to one wheel – the system actually pushes the car into the curve, eliminating any chance of understeer.
Latest development: quattro with ultra technology
The latest phase of development from Audi is the quattro system featuring ultra technology. Designed for models with a longitudinally mounted engine, it uses an actively controlled multi-plate clutch at the end of the transmission which distributes the torque variably between the drive axles in all-wheel drive operation. A decoupler in the rear axle differential can additionally open the connection to the rear wheels. Both clutches are opened in driving situations where the all-wheel drive doesn’t offer any advantage. This way, the parts of the rear drivetrain responsible for drag are not engaged. The system’s control unit uses a multitude of data to produce a model of the vehicle’s status projecting about half a second into the future. If the system detects, for instance, that the inside wheel is about to lose grip, it switches predictively to all-wheel drive. As a result, the all-wheel drive is always ready when it is needed. The new concept considerably boosts efficiency without diminishing traction or driving dynamics.
Success story: the history of quattro
Audi achieved a milestone in automotive history with the quattro permanent all-wheel drive system – in 1980, no other manufacturer offered fast-running and light all-wheel drive technology for high-volume production. The technology premiered in 1980 in the Ur-quattro at the Geneva International Motor Show. In 1986 Audi replaced the first generation’s manually locking centre differential with a Torsen differential which could variably distribute drive torque. The planetary drive followed in 2005, with its asymmetrical, dynamic distribution of power and torque. The self-locking centre differential is the subject of continual development by Audi engineers and is considered the benchmark for traction and driving dynamics combined with very light weight.
Audi has also celebrated many triumphs in motorsport with quattro technology. The list so far includes four World Rally Championship titles, six victories in the famous Pikes Peak Hill Climb race in the United States, a title win in the TransAm series in the U.S., two DTM titles, 11 national Super Touring Car Championships, and a Touring Car World Cup. The latest victory for quattro technology: In late November, Mattias Ekström and his private rallycross team EKS captured the Driver World Champion and Team World Champion titles with the Audi S1 EKS RX quattro in the FIA World Rallycross Championship.