BMW F12 2011, Техническое учебное пособие, Страница: 34 / 68

F12�Chassis�Dynamics
4.�Brakes
30
• Brake�pedal�applied,�or
• Automatic�transmission�parking�lock�engaged,�or
• Clutch�pedal�depressed�(vehicles�with�manual�gearbox�only).
That�prevents�the�vehicle�starting�to�roll�when�not�intended,�e.g.�if�another�occupant�apart�from�the
driver�presses�the�parking�brake�button.�Once�the�parking�brake�is�released,�the�red�indicator�lamp�on
the�instrument�panel�(KOMBI)�and�the�red�LED�in�the�parking�brake�button�go�out.
Activation�of�the�EMF�actuator�sets�the�spindle�in�motion.�The�rotation�of�the�spindle�moves�the�spin-
dle�nut�a�small,�defined�distance�away�from�the�brake�piston.
Dynamic�emergency�braking
The�law�requires�that�there�are�two�operating�facilities�for�the�brakes.�The�second�operating�facility
in�the�F12�after�the�brake�pedal�is�the�parking�brake�button�in�the�center�console.�If�the�parking�brake
button�is�pulled�up�while�the�vehicle�is�moving,�the�DSC�system�performs�a�dynamic�emergency�brak-
ing�operation�in�a�defined�sequence.�This�function�is�intended�for�emergency�situations�in�which�the
driver�is�not�able�to�brake�the�vehicle�using�the�brake�pedal.�Other�occupants�can�also�bring�the�vehicle
to�a�standstill�in�this�way�if,�for�example,�the�driver�suddenly�falls�unconscious.
During�dynamic�emergency�braking,�brake�pressure�is�generated�hydraulically�at�all�four�wheel�brakes.
The�DSC�functions�are�fully�active�and�the�brake�lights�are�operated.�That�represents�a�fundamental
advantage�over�manual�parking�brakes.
Dynamic�emergency�braking�only�occurs�while�the�parking�brake�button�is�being�pulled.�The�level�of
deceleration�applied�by�the�DSC�is�steeply�increased.�During�dynamic�emergency�braking�the�EMF�in-
dicator�light�on�the�instrument�panel�(KOMBI)�is�activated.�In�addition,�a�Check�Control�message�is�dis-
played�along�with�an�acoustic�signal�in�order�to�draw�the�driver's�attention�to�this�special�situation.
If�the�driver�decelerates�by�pressing�the�brake�pedal�and�pulling�the�parking�brake�button�at�the�same
time,�the�DSC�control�unit�priorities�and�implements�the�higher�braking�demand.�If�dynamic�emergen-
cy�braking�continues�until�the�vehicle�is�at�a�standstill,�the�vehicle�remains�braked�even�after�the�park-
ing�brake�button�is�released.�The�EMF�indicator�light�in�the�instrument�panel�(KOMBI)�remains�on.�The
driver�can�then�release�the�parking�brake�(see�"Releasing�the�parking�brake").
Parking�brake�fault
If�the�parking�brake�develops�a�fault,�the�EMF�indicator�lamp�in�the�instrument�panel�(KOMBI)�shows
yellow.�A�Check�Control�message�is�displayed.
F12�Indicator�light�showing�parking�brake�fault
Emergency�release
No�provision�is�made�for�the�customer�to�release�the�parking�brake�in�emergencies.