Audi New "Ultra" Quattro
All-Wheel Drive
Audi has been at the forefront of
all-wheel drive on passenger cars, starting with its rally racers, and now it
has readied yet another evolution.
The German company has just unveiled its
new quattro system with "Ultra technology" that aims to improve fuel
efficiency of all-wheel drive models thanks to a trick new setup.
Typically, AWD cars use more fuel than
front- and rear-wheel drive ones because of increased friction (and, in most
cases, weight). Audi's new Ultra tech, though, makes the system operate in
front-wheel drive mode under normal condition and sends power to the rear
wheels only when necessary.
Not exactly a revolution, since
AWD-on-demand has been used for quite some time. Still, Audi's uses a number of
new sensors that monitor things like steering input, grip and throttle pedal
position, a processor located in the gearbox determines when the front wheels
are about to lose traction and then funnels some power to the rear. By working
in collaboration with the firm's stability control system, sensors can also
determine if the car is being driven hard and then engage the rear wheels if
required.
The system itself is also unique from
the previous normal quattro setup as it incorporates a clutch between the
gearbox and propshaft as well as one on the rear axle to allow for the seamless
shift in power.
All told, the new all-wheel drive system
is said to save about 0.3 L/100 km and will debut on the new A4 Allroad in the
coming months.
