Quattro is the trademark used by the automotive brand Audi to indicate that all-wheel drive (AWD) technologies or systems are used on specific models of its automobiles.
"quattro" logo badge on the grille of an Audi car
The original quattro centre differential (1980)
Audi quattro Torsen centre differential
Audi quattro Crown Gear centre differential
Four-wheel drive
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A four-wheel drive, also called 4×4 or 4WD, is a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case providing an additional output drive shaft and, in many instances, additional gear ranges.
The Jeep Wrangler (pictured is a TJ Wrangler) is a 4WD vehicle with a transfer case to select low-range or high-range four-wheel drive.
Center transfer case sending power from the transmission to the rear axle (right) and front axle (left)
The Lamborghini Murciélago is an AWD that powers the front via a viscous coupling unit if the rear slips
The HMMWV is a 4WD/AWD that powers all wheels evenly (continuously) via a manually lockable center differential, with Torsen differentials for both front and rear