Audi Q7 2017 Manual page 28

Function A
When the vehicles approaches another vehicle which is
moving much more slowly or is stationary, Instrument
Cluster Control Module J285 issues visual and audible
warnings to the driver if pre-defined limits are exceeded.
These warnings are given within a time frame ahead of the
last braking opportunity for braking or collision avoidance
before the actual collision occurs.
The timing of warnings depends on the driver's degree of
activity. Depending on steering, pedal and turn signal
inputs, the system classifies the driver as active or inactive
and, consequently, as attentive or inattentive. If the driver
is classed as attentive, the warning will be issued later than
a warning for a driver classed as inattentive. At the same
time, ABS Control Module J104 prefills the brake system
and changes the deployment algorithms for hydraulic brake
assist. This means that hydraulic brake assist starts to build
up brake pressure even at low brake pedal actuation
speeds.
If the driver does not respond to the warnings or, for
example, eases off the accelerator, ABS Control Module
J104 produces a warning jolt. The warning jolt is a very
brief but easily noticeable braking impulse and does not
serve to reduce speed. It alerts the driver to the traffic
situation and indicates to the driver that he must react
immediately in order to prevent an impending collision.
Depending on how attentive the driver is considered to be,
the warning jolt will be produced within a time window
ahead of the last opportunity to brake or take evasive
action to avoid a collision. If the driver still fails to react or
only eases his foot off the accelerator, the system will
initiate partial braking operation I
ing up to 35% of maximum brake force. If Driver Assistance
Systems Front Camera R242 has also detected the obsta-
cle, partial braking operation II
to 60% of maximum brake force.
Flowchart
Precharging of the braking system, hydraulic
brake assist reacts more sensitively
Audible and visual driver warnings
(rear collision warning)
Not available in all countries.
1)
24
, which involves apply-
1)
is initiated by applying up
1)
If the driver applies the brakes, a target braking maneuver
may be performed in all of the phases described above
(pre-charging of the brake system, reconfiguration of
hydraulic brake assist, driver warning, warning jolt, partial
braking operations I and II)
During the target braking maneuver, Audi pre sense front
computes whether the driver is applying enough brake
force to be able to avoid a collision. If this is not the case,
the required brake pressure is increased depending on the
situation.
If Audi pre sense front detects that an accident is likely to
be unavoidable, ABS Control Module J104 can initiate
automatic emergency braking
Emergency braking can be performed immediately up to a
defined maximum speed or after partial braking operation
II. If the vehicle has automatically brought the vehicle to a
halt without driver input, further audible signals will
sound. These signals alert the driver to the fact that he
must actively take control of the vehicle (for example, by
braking).
Warning Partial braking
jolt operation I or
partial braking
operation II
(if the front camera
has confirmed pres-
ence of a vehicle)
Target braking
Audi pre sense
.
1)
.
1)
Emergency braking Collision
(if collision is prob-
ably unavoidable).
637_041
637_001