BMW G12 - Page 133

G12�Driver�Assistance�Systems
19.�Cruise�Control
127
equipment�(OE�5DF),�the�distance�is�adjusted�using�two�buttons;�one�to�reduce�and�one�to�increase
the�distance.�In�vehicles�with�the�DrivingAssistantPlusoptional�equipment�(OE�5AT),�the�distance�is
adjusted�using�the�rocker�button.
ACC�Stop&Go�calculates�the�reference�distance�for�the�control�from�this�preselection.�The�following
distance�most�recently�selected�is�saved�depending�on�the�key�being�used.
The�reference�distance�during�the�journey�is�proportional�to�the�driving�speed.�At�a�lower�driving�speed
and�at�standstill,�the�proportional�distance�to�the�driving�speed�is�no�longer�used�for�the�ACC�Stop�&
Go,�but�a�fixed�value�in�metres.
If�a�vehicle�moves�into�the�driver's�lane,�which�is�anticipated�due�to�the�current�driving�condition,�or
if�the�driver�is�approaching�a�vehicle�driving�ahead,�the�ACCStop&Go�function�discretely�adapts�the
speed�to�the�vehicle�pulling�in�or�vehicle�ahead.
The�distance�control�uses�the�prepared�object�data�with�the�highest�diagnostic�statistic�as�input
variables.�The�distance�control�takes�into�consideration�the�following�situations�in�particular:
• Maximum�values�for�acceleration�and�deceleration:
The�maximum�values�for�acceleration�and�deceleration�of�the�ACC�Stop&Go�system�below
about�50km/h�are�dynamic�values.�They�correspond�to�the�acceleration�and�deceleration
values�that�the�driver�would�use�himself�and�considers�comfortable.�In�situations�where
sharper�deceleration�is�required�than�the�system�offers�as�part�of�the�speed�adjustment
feature,�a�visual�and�acoustic�signal�is�issued�to�the�driver�to�inform�him�to�take�over�vehicle
handling.
Depending�on�the�situation,�the�ACC�Stop�&�Go�accelerates�by�a�maximum�of�about�2m/s²
and�decelerates�by�a�maximum�of�about�4m/s².
• Stop�and�start�stability:
In�the�case�of�very�heavy�traffic�and�very�low�driving�speed,�the�risk�of�rear-end�collisions
increases�through�heavy�acceleration�and�braking.�The�ACC�Stop&Go�distance�controller�is
therefore�designed�to�decelerate�as�early�as�possible,�but�not�more�than�the�vehicle�ahead.
The�system�can�decelerate�by�up�to�2.5m/s²�at�the�most�during�subsequent�operation,�and�by
up�to�4m/s²�at�the�most�when�stopping.
Request�to�take�over�vehicle�handling
When�ACC�Stop&Go�is�no�longer�able�to�maintain�a�safe�distance�or�a�critical�situation�is�detected,
e.g.�on�account�of�very�high�differential�speeds�or�an�insufficient�maximum�deceleration,�two�short
warning�signals�sound�and�the�orange�lit�up�vehicle�symbol�in�the�instrument�cluster�or�the�Head‐Up
Display�(optional�equipment�OE�610)�flashes.�The�system�continues�to�perform�its�control�function
and�prompts�the�driver�to�take�over�vehicle�handling�and�to�keep�their�distance�accordingly.
19.3.2.�Operation
Activation�and�deactivation
The�activation�and�deactivation�of�the�ACC�Stop�&�Go�and�the�Dynamic�Cruise�Control�are�almost�the
same.�ACCStop&Go�can�either�be�activated�while�driving�or�at�a�standstill.�For�safety�reasons,�when
the�vehicle�is�at�a�standstill�the�function�can�only�be�put�in�Standby�mode�or�deactivated�while�the
footbrake�is�applied.