en a ble t he H CU to per for m th e br a ke flu id m a n age-
men t con tr ol a s th e com bin a tion /pr opor tion in g
valve s .
Th e Bosch 5.7 system u ses th e CAB/H CU/P u m p
Mot or t o m a ke a n i n tegra l elect r onic/h ydr a u lic un it
wh ich sh a res da t a wit h ot h er elect r onic modu les on
th e veh icle via th e CAN C Bu s net wor k. To access
DTCs fr om t h e CAB, t he DRBIII" uses t h e K-ABS
lin e loca t ed in t h e Da t a Lin k Con n ector (DLC).
3.3 BRAKE ASSIST SYSTEM (HBA)
Th e Bra k e Assist Syst em (H BA) a n alyzes h ow
ha r d a nd fast th e dr iver wa nt s t o br a ke. It m on it or s
th e bra ke pr essu re via a pr essu r e sen sor. The
pa ssen ger ca r br a k e a ssist syst em u ses a va cu um
booster solen oid. Th e Spr in t er u ses t h e h ydr au lic
cont r ol un it t o develop t he br a ke pr essu re.
3.4 TCS (ASR)
Th e pr im a r y fun ction of t h e Tr act ion Con t r ol Syst em
is t o r educe wh eel slip a n d m ain t a in t r a ct ion at t h e
dr iven wheels when t h e roa d su rfa ces a r e slipper y. Th e
Tra ct ion Con t r ol Syst em r educes wh eel slip by a pplying
th e bra ke t h at ha s lost t ra ct ion . Th e syst em is design ed
to oper at e a t speeds below 50 km /h (30 m ph ). Th e
en gin e’s t or que ca n be r educed by th e ECM via the CAN
C Bu s, if n ecessar y. Th e TCS ca n be dea ctiva ted wit h
swit ch on t he da sh . Th e Tra ct ion Con t rol Syst em u ses
th e ABS t o in dica te spinn in g t ir es to en a ble th e t r a ction
cont r ol fun ct ion . Th e TCS soft wa r e is in t h e CAB.
Th e TCS (ASR) per for m s th e followin g fu nct ions:
1. En gin e power der a te
2. En gin e deceler a tion r egu la tion . If t he veh icle is
on a pa t ch of ice, th e sim ple act ion of r elea sing
th e t hr ot t le is en ou gh to cau se t h e rea r wh eels t o
slip. To a void t h is, th e t h rot t le in pu t is r egu la ted
so power dr ops slowly in st ead of a bru pt ly. The
en gin e power is r edu ced (deceler at ed) a s n eces-
sary.
3.5 ELECTRONIC BRAKE DISTRIBUTION
(EBD)
Th e syst em was en ha n ced a n d elim in a tes the
need for t h e ALB syst em (loa d sen sin g va lve). All
ESP equ ipped models will n ot h a ve ALB. Th e EBV
syst em self-a da pt s t o oper at in g condit ions. It de-
tect s t h e veh icle’s pa yloa d wh en t he veh icle st a r ts
an d pu lls a wa y. Ba sed on t he a cceler a tion r a te
wh en t he veh icle fir st pu lls awa y fr om a st a n dst ill,
th e syst em is a ble t o ca lcula te t he act u a l pa yloa d.
Th is is a r ou gh est im a te wh ich is u sed init ia lly.
La t er on, th e syst em ga th er s m or e pr ecise in form a -
tion by mon it or in g t h e br ake pr essu re a n d wh eel
speed a nd negat ive slip when t he driver a pplies th e
br a k es. Th e syst em will th en pr odu ce a m or e accu -
ra t e ca lcu la t ion of pa yloa d depen ding on br a ke
ret a rda t ion . Th e ada pt at ion is er ased wh en t he
ign it ion is swit ch ed off. A n ew a da pt at ion will occu r
on t h e n ext dr ivin g cycle. By defa u lt , t h e syst em
act s u pon t h e veh icle as if in an unloa ded con dition
(sa fe m ode).
On ce a n ew dr ivin g cycle begin s wit h t he vehicle
in a fu lly loa ded con dit ion (wit hou t ha vin g ga t h er ed
mor e pr ecise in form a tion ) t h e syst em will det ect
ABS a ctu a t ion in t he fr on t wh eels an d will a llow
en ou gh pr essu re t o be a pplied to th e r ear axle, t o a n
ext en t wh er e t h e wh eels a r e ju st about t o lock u p
(ma xim u m br a kin g possible).
Th e syst em ca lcu la t es t h e br a k in g for ce at th e
fron t an d rea r a xles. If th e dr iver a pplies t he br a kes
gently and then re alizes he nee d s to ap p ly the
br a k es fur t her, th e E BV a llows th e pr oper pr essu re
to be applied to t h e fr ont a n d rea r bra kes.
Th e E BV a lso con t a in s a fea t ur e ca lled “cor ner
br a k e syst em ” (CBS) wh ich opera t es wh en th e ve-
hicle is br aked wh ile corn er in g t o avoid a possible
over st eer ing condit ion . Th e E BV m on it or s t h e
wh eel speed of bot h rea r wh eels to det ect wh en t he
veh icle is cor n er in g an d a llows pr ecise bra k e pres-
su re a pplica t ion t o t h e fron t a n d r ea r br akes. Also
wh en t h e br akes a r e applied du rin g corner in g, t h e
out er wh eels get m or e of t he veh icle’s weigh t wh ile
th e in n er wh eels get less weigh t a n d cou ld lose
tr a ction (wh eel lock u p). Th e EBV syst em split s th e
pr essu re bet ween left a n d righ t sides in a ddit ion t o
fron t a nd r ea r br a k es.
3.6 VEHICLE CONTROLLING (FZR)
Ve h ic le co n tro llin g (F ZR) r equ ir es a ddition al
sensor s t o oper at e. Th e t er m E SP refer s t o t h e
soft wa r e of t h e syst em . Th e t er m FZR r efers to t h e
syst em cont r oller. Th e TCS (ASR) syst em r equir es
wh eel speed sensor s t o mon itor wh eel slip a nd CAN
bu s com m un ica tion s to r egu la t e en gin e power. In
addit ion to t h ese in pu ts, th e veh icle con tr ollin g
(FZR) r equ ir es a st eer ing a ngle sen sor, a n d a la ter a l
acceler a t ion /ya w rat e sen sor.
Th e E SP syst em does n ot t a ke t h e veh icle loa d
in t o a ccou n t. In st ead, t he coefficien t of fr ict ion is
calcu la t ed in a 20 millisecon d per iod, wh ere th e
cont r oller m ea su res th e r a te a t wh ich t h e wheel
speed is deceler a t ed, a s br ake pr essu re is a pplied t o
the wheel.
3.7 S Y S T EM COMP ON EN T S
• Con tr oller Ant ilock Br ake (CAB)
• Hydr a ulic Con t rol Unit (H CU)
• Pu m p Mot or
2
GEN ERAL I N FORM AT I ON
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