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quattro®
quattro® is a permanent all-wheel drive system.
If the wheels on one axle of the vehicle lose grip
on the road and threaten to spin, then the power
is transferred to the other axle – automatically
and permanently distributed through the centre
differential. The basic distribution is 40 : 60 –
40% of the power goes to the front axle,
60% from the rear. The benefit is better traction
during acceleration and improved safety due to
exceptional grip. So much for the technology. But
what makes quattro unique is really the driving
feel. “As if you are stuck to the road,” some
customers say. We put it like this: quattro gives
you a better feel for the road and thus more
safety.
The optional quattro® with sports differential
further reinforces this unmistakeable quattro
feeling. Vehicles tend to experience understeer
when steering or driving into corners. This is a
normal physical process: a moving object opposes
a change in direction. The elastic tyres and the
suspension mounts tense up until the new
direction has been adopted.
When accelerating into a corner, the load on the
front axle is reduced and it therefore transfers less
lateral force to the tyres – the vehicle understeers.
With the sports differential on the rear axle, the
tendency to understeer is largely counteracted.
This is because the quattro rear axle differential
has been extended left and right by a clutch
system with two gear levels. They ensure that the
individual wheels on the rear axle receive different
levels of torque. The clutches are activated by an
electro-hydraulic actuator. Depending, for
example, on the steering angle, lateral
acceleration, yaw angle and driving speed, the
system calculates the right distribution of wheel
torque for any driving situation. In this way the
power is specifically channelled to the outer rear
wheel, when steering or accelerating into a corner.
The effect: the vehicle is virtually pressed into the
corner and follows the angle of the front wheels.
The variable left and right driving forces also help
stabilise the steering and the usual steering
corrections are hardly necessary.
With quattro® we created one of the
best all-wheel drive systems in the world.
Of course, that was not enough for us.
The fuel consumption and CO₂ emission figures can be found from page 120 onwards.
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quattro® with sports differential
continuously varies the amounts of
driving force distributed to each rear
wheel and ensures high cornering
agility and impressive driving
dynamics.
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