Alfa Romeo Alfa 147 GTA, Руководство пользователя, Страница: 137 / 290

GETTING TO KNOW YOUR CAR
136
VDC SYSTEM
(
Vehicle Dynamics Control
)
The VDC is an electronic system that con-
trols vehicle stability, intervening on the dri-
ving torque and braking the wheels in a dif-
ferentiated manner, in the lack of grip, it
helps to bring the car back to the correct
direction.
When travelling the car is subjected to lat-
eral and longitudinal forces which can be
controlled by the driver as long as the tyres
offer adequate roadholding; when this falls
below the minimum level, the car begins
to divert from the course required by the dri-
ver.
Especially when travelling on an uneven
surface (such as paving, or due to the pres-
ence of water, ice or soil), changes in speed
(acceleration or braking) and/or course
(bends or the need to avoid obstacles) may
cause the tyres to lose grip.
When the sensors detect the conditions
that would lead to skidding, the VDC system
intervenes on the engine and on the brakes
producing a stabilising torque.
HOW THE VDC
SYSTEM WORKS
The VDC system is engaged automatical-
ly when the car is started and cannot be
switched off.
The basic components of the VDC system
are:
– an electronic control unit that process-
es the signals received from the various sen-
sors and brings about the most appropriate
strategy;
– a sensor that detects the position of the
steering wheel;
– four sensors that detect the turning
speed of each wheel;
– a sensor that detects rotation of the car
around its vertical axis;
– a sensor that detects lateral acceleration
(centrifugal force).
The heart of the VDC system is the VDC
control unit, which with the data supplied
by the sensors installed on the car calculates
the centrifugal forces generated when the
car is cornering. The yawing sensor, which
originates from the aeronautical industry, de-
tects the rotations of the car around its own
vertical axis. The centrifugal forces gener-
ated when the car is cornering are detect-
ed by a highly sensitive lateral acceleration
sensor.
The VDC system helps the driver to keep
the car under control in the event of a loss
of tyre grip.
The forced induced by the VDC system to
control the loss of vehicle stability always
depend on the grip between the tyre and
the road surface.
The performance of the
system, in terms of active
safety should not induce the driver
to take pointless and unnecessary
risks. The style of driving must in
any case always be adapted to the
conditions of the road surface, vis-
ibility and traffic. The responsibil-
ity for road safety is always and
in any case the driver’s.
WARNING