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BMW F12 2011 Technical Training Manual
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BMW F12 2011 Technical Training Manual

BMW F12 2011 Technical Training Manual

Chassis dynamics
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Technical￿training.
Product￿information.
F12￿Chassis￿Dynamics
BMW￿Service

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Summary of Contents for BMW F12 2011

  • Page 1 Technical￿training. Product￿information. F12￿Chassis￿Dynamics BMW￿Service...
  • Page 2 General￿information Symbols￿used The￿following￿symbol￿is￿used￿in￿this￿document￿to￿facilitate￿better￿comprehension￿or￿to￿draw￿attention to￿very￿important￿information: Contains￿important￿safety￿information￿and￿information￿that￿needs￿to￿be￿observed￿strictly￿in￿order￿to guarantee￿the￿smooth￿operation￿of￿the￿system. Information￿status￿and￿national-market￿versions BMW￿Group￿vehicles￿meet￿the￿requirements￿of￿the￿highest￿safety￿and￿quality￿standards.￿Changes￿in requirements￿for￿environmental￿protection,￿customer￿benefits￿and￿design￿render￿necessary￿continu- ous￿development￿of￿systems￿and￿components.￿Consequently,￿there￿may￿be￿discrepancies￿between the￿contents￿of￿this￿document￿and￿the￿vehicles￿available￿in￿the￿training￿course. This￿document￿basically￿relates￿to￿the￿European￿version￿of￿left￿hand￿drive￿vehicles.￿Some￿operating￿el- ements￿or￿components￿are￿arranged￿differently￿in￿right-hand￿drive￿vehicles￿than￿shown￿in￿the￿graphics in￿this￿document.￿Further￿differences￿may￿arise￿as￿the￿result￿of￿the￿equipment￿specification￿in￿specific markets￿or￿countries. Additional￿sources￿of￿information Further￿information￿on￿the￿individual￿topics￿can￿be￿found￿in￿the￿following: • Owner's￿Handbook • Integrated￿Service￿Technical￿Application. Contact:￿conceptinfo@bmw.de ©2010￿BMW￿AG,￿Munich Reprints￿of￿this￿publication￿or￿its￿parts￿require￿the￿written￿approval￿of￿BMW￿AG,￿München The￿information￿contained￿in￿this￿document￿forms￿an￿integral￿part￿of￿the￿technical￿training￿of￿the￿BMW Group￿and￿is￿intended￿for￿the￿trainer￿and￿participants￿in￿the￿seminar.￿Refer￿to￿the￿latest￿relevant￿infor- mation￿systems￿of￿the￿BMW￿Group￿for￿any￿changes/additions￿to￿the￿technical￿data. Status￿of￿the￿information:￿November￿2010 VH-23/International￿Technical￿Training...

  • Page 3: Table Of Contents

    F12￿Chassis￿Dynamics Contents Introduction ................................................1.1. Driving￿dynamics￿and￿comfort ................................1.2. Bus￿system￿overview ....................................... Models ....................................................2.1. Comparison ............................................. Chassis￿and￿suspension ......................................... 3.1. Front￿ axle ............................................3.1.1. Technical￿data .................................... 3.1.2. Service￿Information ................................3.2. Rear￿ axle ............................................... 3.2.1. Technical￿data ..................................3.2.2. Service￿Information ............................... 3.3. Suspension/dampers ....................................3.3.1.
  • Page 4 F12￿Chassis￿Dynamics Contents Driving￿stability￿control ........................................ 6.1. Directions￿of￿action ......................................6.2. Dynamic￿Stability￿Control￿DSC ..............................6.3. Electronic￿Damper￿Control￿(EDC) ............................6.4. Active￿Roll￿Stabilization￿ARS￿(Dynamic￿Drive) ....................6.5. Drive￿dynamic￿control￿switch ................................. 6.5.1. Handling￿dynamics￿programs ........................

  • Page 5: Introduction

    F12￿Chassis￿Dynamics 1.￿Introduction 1.1.￿Driving￿dynamics￿and￿comfort F12￿Chassis￿and￿suspension Index Explanation Suspension/dampers Electromechanical￿Power￿Steering￿(EPS) Integral￿V￿rear￿axle Electromechanical￿Parking￿Brake￿(EMF) Wheels Dynamic￿Stability￿Control￿(DSC) Brakes Double-wishbone￿front￿axle The￿chassis￿and￿suspension￿of￿the￿F12￿is￿based￿on￿the￿F10.￿It￿has￿been￿adapted￿to￿the￿specific￿re- quirements￿of￿the￿F12￿in￿order￿to￿achieve￿outstanding￿driving￿dynamics￿while￿maintaining￿extremely high￿standards￿of￿comfort. A￿double-wishbone￿front￿axle￿is￿used￿instead￿of￿the￿double￿pivot￿spring-strut￿axle￿of￿the￿E64.￿The￿inte- gral￿V￿rear￿axle￿replaces￿the￿integral￿IV￿rear￿axle￿that￿featured￿in￿the￿E64.
  • Page 6 F12￿Chassis￿Dynamics 1.￿Introduction The￿F12￿features￿innovations￿already￿familiar￿from￿other￿BMW￿models,￿such￿as￿Integral￿Active￿Steer- ing,￿Integrated￿Chassis￿Management￿(ICM),￿Dynamic￿Drive￿and￿Electronic￿Damper￿Control￿(EDC). 1.2.￿Bus￿system￿overview F12￿Bus￿System￿overview...
  • Page 7 F12￿Chassis￿Dynamics 1.￿Introduction Index Explanation Control￿units￿with￿wake-up￿authorization Start-up￿node￿control￿units￿for￿starting￿up￿and￿synchronizing￿the￿FlexRay￿bus system ACC-SEN Active￿Cruise￿Control￿Sensor ACSM Advanced￿Crash￿Safety￿Module Active￿steering AMPT Top￿HiFi￿amplifier Battery￿Charge￿Unit￿(for￿auxiliary￿battery￿only￿w/IAC) Car￿Access￿System Central￿information￿display COMBOX Combox￿(Combox￿multimedia,￿Combox￿multimedia￿with￿telematics) Controller Convertible￿top￿module Digital￿Motor￿Electronics Dynamic￿Stability￿Control DVDC DVD￿changer EDCSHL Electronic￿Damper￿Control￿satellite,￿rear￿left EDCSHR Electronic￿Damper￿Control￿satellite,￿rear￿right EDCSVL Electronic￿Damper￿Control￿satellite,￿front￿left EDCSVR Electronic￿Damper￿Control￿satellite,￿front￿right Electronic￿transmission￿control EKPS Electronic￿fuel￿pump￿control Electromechanical￿parking￿brake Electronic￿power￿steering￿(electromechanical￿power￿steering) Footwell￿module Gear￿selector￿switch HEADUNIT Headunit￿(car￿information￿computer￿or￿car￿information￿computer￿basic￿II) Rear￿axle￿slip￿angle￿control...
  • Page 8 F12￿Chassis￿Dynamics 1.￿Introduction Index Explanation Park￿Distance￿Control Parking￿maneuvering￿assistant TPMS Tire￿Pressure￿Monitor￿System SINE Siren￿with￿tilt￿alarm￿sensor SMBF Front￿passenger￿seat￿module SMFA Driver's￿seat￿module Blind￿Spot￿Detection￿(Lane￿change￿warning) Steering￿column￿switch￿cluster TRSVC Control￿unit￿for￿camera￿systems Vertical￿Dynamics￿Management Video￿switch Central￿gateway￿module...

  • Page 9: Models

    F12￿Chassis￿Dynamics 2.￿Models 2.1.￿Comparison The￿following￿technical￿data￿allows￿a￿comparison￿to￿be￿made￿between￿the￿chassis￿and￿suspension￿of the￿F12￿and￿its￿predecessor￿the￿E64. Designation E64￿BMW￿650i F12￿BMW￿650i Wheelbase 2780￿mm 2855￿mm Front￿track￿width 1558￿mm 1600￿mm Rear￿track￿width 1596￿mm 1657￿mm Tires,￿basic￿wheels 245/45￿R18￿96W 245/45￿R18￿96Y Basic￿wheel￿rims 8J￿x￿18￿IS￿14 8J￿x￿18￿IS￿30 Front￿axle Double￿pivot￿spring- Double-wishbone￿front￿axle strut￿front￿axle Springs/dampers Steel￿spring/con- Steel￿spring/con- ventional￿or￿EDC ventional￿or￿EDC Anti-roll￿bar,￿front mechanical￿or￿hy- mechanical￿or￿hy- draulic￿(Dynamic￿Drive) draulic￿(Dynamic￿Drive) Front￿brake￿disc￿dia. 348 mm 374 mm Steering Hydraulic￿or￿active￿steering...
  • Page 10 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension 3.1.￿Front￿axle F12￿Double-wishbone￿front￿axle Index Explanation Spring￿strut Upper￿wishbone Swivel￿bearing Anti-roll￿bar￿link Lower￿wishbone Wheel￿hub Track￿rod Trailing￿link Front￿axle￿support Anti-roll￿bar￿with￿hydraulic￿actuator￿(Dynamic￿Drive) Steering￿box...
  • Page 11 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension The￿F12￿double-wishbone￿front￿axle￿was￿originally￿introduced￿with￿the￿E70/E71.￿The￿design￿was￿fur- ther￿developed￿and￿also￿used￿in￿the￿F01/F02,￿F07,￿and￿F10. Conventional￿shock￿absorbers￿or￿EDC￿can￿be￿installed￿in￿the￿double-wishbone￿front￿axle.￿In￿addition,￿It is￿can￿also￿be￿equipped￿for￿use￿in￿an￿all-wheel￿drive￿configuration. 3.1.1.￿Technical￿data Designation Castor￿angle 7°￿0' Camber -0°￿29'￿±￿30' Total￿toe-in 10'￿±￿12' Toe￿difference￿angle ≤￿12' Steering￿axis￿inclination 9°￿57' Rim￿offset￿IS 30￿mm Kingpin￿offset 2.89￿mm Track￿width 1600￿mm maximum￿outer￿steer￿angle 33°￿0' maximum￿inner￿steer￿angle 42°￿14' 3.1.2.￿Service￿Information The￿following￿tables￿show￿when￿wheel￿alignment￿of￿the￿double-wishbone￿front￿axle￿is￿necessary. Component￿replaced Wheel￿alignment￿required Front￿axle￿support Steering￿box Lower￿Wishbone Rubber￿mount￿for￿lower￿wishbone Trailing￿link Rubber￿mount￿for￿trailing￿link Upper￿wishbone Rubber￿mount￿for￿upper￿wishbone Track￿rod Swivel￿bearing Wheel￿bearing...
  • Page 12 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension Screw￿connection￿unfastened Wheel￿alignment￿required Front￿axle￿support￿to￿body￿(lowering) Steering￿box￿to￿front￿axle￿support Lower￿wishbone￿to￿front￿axle￿support Lower￿wishbone￿to￿swivel￿bearing Trailing￿link￿to￿front￿axle￿support Trailing￿link￿to￿swivel￿bearing Upper￿wishbone￿on￿body Upper￿wishbone￿to￿swivel￿bearing Track￿rod￿to￿steering￿box Track￿rod￿end￿to￿track￿rod Track￿rod￿end￿to￿swivel￿bearing Spring￿strut￿to￿Lower￿wishbone Support￿bearing￿to￿body Bottom￿steering￿shaft￿to￿steering￿box Steering￿column￿to￿bottom￿steering￿shaft 3.2.￿Rear￿axle The￿integral￿V￿rear￿axle￿installed￿in￿the￿F12￿is￿an￿innovative￿further￿development￿of￿the￿integral￿IV￿rear axle￿in￿the￿E60/65.￿The￿optimized￿lightweight￿rear￿axle￿made￿of￿solid￿aluminium￿has￿been￿specifically adapted￿to￿the￿new￿demands￿for￿more￿power￿and￿torque. The￿integral￿V￿rear￿axle￿of￿the￿F12￿is￿designed￿for￿the￿Integral￿Active￿Steering￿option￿code￿(SA￿2VH) chassis￿and￿suspension￿control￿system￿.
  • Page 13 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension F12￿Integral￿V￿rear￿axle Index Explanation Compression￿strut Spring￿strut Upper￿wishbone Integral￿link Wheel￿carrier Wheel￿bearing Trapezoidal-link￿suspension￿(swinging￿arm)
  • Page 14 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension Index Explanation Camber￿link Rubber￿mount￿for￿rear￿axle Rear￿axle￿support HSR￿actuator 3.2.1.￿Technical￿data 650i Rear￿tire 245/40￿R19 Rear￿wheel￿rim 19￿x￿8.5 Total￿toe-in 14'￿±￿12' Camber -1°50'￿±￿25' Track￿width 1629￿mm Rim￿offset￿IS 44￿mm 3.2.2.￿Service￿Information The￿following￿tables￿show￿when￿wheel￿alignment￿at￿the￿integral￿V￿rear￿axle￿is￿necessary. Component￿replaced Wheel￿alignment￿required Rear￿axle￿support Rubber￿mount￿for￿rear￿axle Swinging￿arm Integral￿link Ball￿joint￿in￿swinging￿arm Camber￿link Wishbone Wheel￿carrier Wheel￿bearing Spring￿strut Support￿bearing Screw￿connection￿unfastened Wheel￿alignment￿required Rear￿axle￿support￿to￿body Front￿compression￿strut￿to￿body Rear￿compression￿strut￿to￿body Front￿swinging￿arm￿to￿rear￿axle￿support...

  • Page 15: Suspension/Dampers

    F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension Screw￿connection￿unfastened Wheel￿alignment￿required Rear￿swinging￿arm￿to￿rear￿axle￿support Swinging￿arm￿to￿integral￿link/wheel￿carrier Integral￿link￿to￿wheel￿carrier Camber￿link￿to￿rear￿axle￿support Camber￿link￿to￿wheel￿carrier Wishbone￿to￿rear￿axle￿support Wishbone￿to￿wheel￿carrier Spring￿strut￿to￿wheel￿carrier/swinging￿arm 3.3.￿Suspension/dampers Both￿axles￿of￿the￿F12￿are￿equipped￿as￿standard￿with￿steel￿springs￿and￿EDC￿shock￿absorbers. 3.3.1.￿Electronic￿Damper￿Control￿(EDC) F12￿Components￿of￿EDC Dynamic￿Damper￿Control￿is￿standard￿and￿is￿a￿sub-function￿of￿the￿Vertical￿Dynamics￿Management VDM.￿With￿EDC,￿the￿actuator￿unit￿and￿the￿specified￿satellite￿sensors￿at￿the￿shock￿absorber￿are￿con- nected￿to￿the￿VDM￿control￿unit￿via￿FlexRay.￿The￿damper￿characteristics￿stored￿in￿the￿VDM￿control￿unit can￿be￿selected￿via￿the￿drive￿dynamic￿control￿switch￿in￿the￿center￿console.
  • Page 16 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension The￿primary￿objective￿of￿the￿EDC￿system￿is￿to￿increase￿ride￿comfort￿and￿maintain￿a￿high￿standard￿of driving￿safety￿without￿compromise.￿Greater￿ride￿comfort￿is￿achieved￿if￿the￿vertical￿movement￿of￿the vehicle￿body￿is￿virtually￿eliminated￿despite￿excitation￿of￿the￿vehicle￿due￿to￿the￿roadway￿(unevenness, joints)￿or￿cornering.￿This￿is￿why￿the￿adjustable￿dampers￿are￿operated￿using￿a￿soft,￿comfortable￿damp- ing￿characteristic￿in￿as￿many￿situations￿as￿possible. A￿high￿standard￿of￿driving￿safety￿is￿guaranteed￿if￿the￿wheels￿never￿lose￿contact￿with￿the￿roadway￿and deliver￿a￿high￿bearing￿force￿when￿necessary.￿This￿is￿why￿a￿harder￿damping￿action￿is￿set￿if￿the￿driving situation￿or￿driver￿intervention￿(e.g.￿steering,￿braking)￿is￿required. In￿addition,￿the￿EDC￿control￿takes￿steering￿operations￿(e.g.￿transition￿from￿straight-ahead￿driving to￿cornering)￿into￿account￿based￿on￿the￿steering￿angle￿characteristic.￿If￿the￿EDC￿detects￿a￿rapid￿in- crease￿in￿the￿steering￿angle,￿the￿controller￿deduces￿that￿cornering￿is￿starting￿and￿can￿now￿set￿a￿harder damper￿setting￿at￿the￿outer￿cornering￿wheels￿as￿a￿preventative￿measure.￿The￿EDC￿therefore￿supports the￿ARS￿control￿and￿thus￿assists￿in￿reducing￿the￿rolling￿movement￿of￿the￿vehicle. EDC￿can￿also￿detect￿when￿the￿driver￿is￿braking￿based￿on￿the￿information￿supplied￿by￿the￿DSC￿on￿brake pressure.￿A￿high￿brake￿pressure￿normally￿causes￿a￿pitching￿movement￿of￿the￿vehicle.￿EDC￿counteracts this￿by￿setting￿the￿front￿damper￿for￿higher￿damping￿forces.￿This￿also￿improves￿the￿braking￿force￿distri- bution￿at￿the￿front/rear￿which￿produces￿a￿small￿braking￿distance￿advantage￿(when￿compared￿to￿a￿vehi- cle￿without￿EDC). The￿basic￿damping￿force￿level￿is￿adapted￿by￿the￿EDC￿controller￿depending￿on￿which￿damping￿program is￿selected￿by￿the￿driver￿(comfort/sport).￿Irrespective￿of￿this,￿e.g.￿even￿if￿the￿Comfort￿program￿is￿se- lected,￿high￿damping￿forces￿act￿on￿individual￿wheels￿in￿critical￿driving￿situations.￿A￿reference￿damp- ing￿force￿is￿output￿via￿FlexRay￿for￿every￿wheel￿or￿damper￿according￿to￿the￿prioritization￿of￿the￿individu- al￿controller￿components.￿In￿addition,￿a￿default￿current￿value￿for￿the￿quiescent￿operating￿point￿is￿speci- fied￿for￿the￿dampers. 3.4.￿Wheels￿&￿Tires Run-flat￿tires￿are￿fitted￿in￿the￿F12￿as￿standard. 650i Front￿tire 245/40￿R19￿all￿season￿run￿flat￿(standard) 245/35￿R20￿performance￿tire￿(option) Rear￿tire 245/40￿R19￿all￿season￿run￿flat￿(standard) 275/30￿R20￿performance￿tire￿(option) Front￿wheel￿rim 19￿x￿8.5￿(standard) 20￿x￿8.5￿(option) Rear￿wheel￿rim 19￿x￿8.5￿(standard) 20￿x￿9.0￿(option)
  • Page 17 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension 3.5.￿Tire￿Pressure￿Monitor￿System 3.5.1.￿System￿function The￿Tire￿Pressure￿Monitor￿System￿is￿installed￿in￿the￿F12. The￿direct￿measuring￿TPM￿system￿(RDC)￿consists￿of￿the￿TPMS￿control￿unit￿with￿integrated￿reception aerial￿and￿four￿wheel￿electronics.￿It￿was￿possible￿to￿reduce￿the￿number￿of￿components￿and￿cost￿of￿the TPM￿system￿by￿integrating￿the￿reception￿antenna￿in￿the￿TPMS￿control￿unit. The￿four￿wheel￿electronics￿transmit￿the￿tire￿pressure￿and￿temperature￿to￿the￿TPMS￿control￿unit￿via radio￿communication￿(433￿MHz).￿Once￿the￿wheel￿electronics￿have￿been￿woken￿up,￿(vehicle￿speed￿> 20￿km/h),￿a￿total￿of￿25￿telegrams￿are￿transmitted￿once￿at￿two￿second￿intervals.￿Providing￿the￿pressure does￿not￿drop,￿individual￿telegrams￿are￿then￿sent￿every￿18￿seconds￿from￿the￿wheel￿electronics￿to￿the TPMS￿control￿unit.￿As￿a￿prerequisite￿for￿the￿wheel￿electronics￿to￿go￿to￿sleep,￿the￿wheel￿must￿be￿at￿a standstill￿for￿more￿than￿five￿minutes. Resetting￿the￿tire￿pressure￿values The￿tire￿pressure￿values￿are￿reset￿via￿the￿instrument￿panel￿(KOMBI)￿or￿Central￿Information￿Display (CID).￿The￿TPMS￿text￿message￿appears,￿or￿the￿permanent￿TPMS￿indicator￿light￿lights￿up,￿in￿the￿instru- ment￿panel￿(KOMBI)￿when￿the￿teach-in￿process￿starts. Teach-in￿process During￿the￿teach-in￿process,￿the￿wheel￿electronics￿identification￿numbers￿(IDs)￿are￿transmitted￿to￿the TPMS￿control￿unit.￿The￿TPMS￿control￿unit￿can￿identify￿the￿wheel￿position￿of￿the￿corresponding￿wheel electronics￿via￿the￿identification￿numbers￿once￿the￿teach-in￿process￿is￿complete. Two￿acceleration￿sensors￿are￿installed￿in￿each￿of￿the￿wheel￿electronics￿in￿order￿to￿be￿able￿to￿determine their￿positions.￿The￿acceleration￿sensors￿determine￿the￿wheel's￿direction￿of￿rotation.￿This￿means￿that it￿is￿possible￿to￿differentiate￿between￿the￿positions￿of￿the￿right/left￿wheel￿electronics￿at￿the￿vehicle. The￿high￿frequency￿signals￿received￿are￿evaluated￿in￿order￿to￿determine￿whether￿the￿wheel￿electronics are￿at￿the￿front￿or￿rear￿axle.￿The￿TPMS￿control￿unit￿with￿integrated￿receiver￿is￿installed￿in￿the￿luggage compartment.￿The￿level￿of￿the￿signals￿received￿by￿the￿TPMS￿control￿unit￿from￿the￿wheels￿on￿the￿rear axle￿is￿higher￿than￿the￿level￿of￿signals￿sent￿by￿the￿wheel￿electronics￿on￿the￿front￿axle.￿This￿means￿it￿is possible￿to￿determine￿whether￿the￿wheel￿electronics￿are￿at￿the￿front￿or￿rear￿of￿the￿vehicle. The￿entire￿teach-in￿process￿takes￿between￿roughly￿one￿and￿twelve￿minutes￿at￿the￿most.￿The￿following factors￿influence￿the￿time￿it￿takes￿to￿complete￿the￿process: • The￿condition￿of￿the￿road￿(smooth￿or￿rough￿surface) • The￿current￿mode￿of￿the￿wheel￿electronics￿(awake/gone￿to￿sleep) • The￿RDC￿control￿unit￿already￿knows￿what￿the￿IDs￿of￿the￿wheel￿electronics￿are.
  • Page 18 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension F12￿TPMS–￿teach-in￿process￿complete Once￿the￿teach-in￿process￿is￿complete,￿the￿RDC￿text￿message￿or￿solid￿TPMS￿indicator￿light￿is￿can- celled.￿Four￿green￿tire￿symbols￿subsequently￿appear￿in￿the￿CID. Pressure￿drop F12￿TPMS–￿pressure￿drop Once￿the￿teach-in￿process￿is￿complete,￿the￿wheel￿electronics￿send￿the￿pressure,￿temperature￿and￿also the￿identification￿numbers￿of￿the￿tires￿to￿the￿TPMS￿control￿unit￿at￿regular￿intervals￿when￿driving. If￿a￿pressure￿change￿of￿>￿20￿kPa￿(0.2￿bar,￿2.9￿psi)￿is￿identified￿within￿two￿successive￿pressure￿measure- ments,￿the￿wheel￿electronics￿for￿the￿relevant￿wheel￿immediately￿assumes￿a￿fast￿transmitting￿mode.￿It then￿sends￿information￿to￿the￿TPMS￿control￿unit￿at￿one-second￿intervals.￿If￿the￿tire￿pressure￿drops￿by more￿than￿25%,￿the￿RDC￿text￿message￿"Tire￿Low"￿appears.
  • Page 19 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension 3.5.2.￿System￿overview F12￿System￿overview￿of￿TPMS Index Explanation Wheel￿electronics￿(battery-operated￿sensor￿with￿transmitter￿unit￿433￿MHz) Instrument￿panel￿KOMBI TPMS￿control￿unit￿with￿integrated￿reception￿antenna...
  • Page 20 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension 3.5.3.￿System￿wiring￿diagram F12￿System￿wiring￿diagram￿RDC...
  • Page 21 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension Index Explanation Wheel￿electronics,￿front￿left Wheel￿electronics,￿front￿right Luggage￿compartment￿power￿distribution￿box Wheel￿electronics,￿rear￿right Wheel￿electronics,￿rear￿left Tire￿Pressure￿Monitor￿(TPMS) Central￿gateway￿module￿(ZGM) Instrument￿panel￿(KOMBI) Central￿information￿display￿(CID) Headunit Central￿operating￿element Terminal￿30B Terminal￿30,￿basic￿operation 3.5.4.￿Notes￿for￿Service Teach-in￿process The￿wheel￿electronics￿must￿be￿taught￿in￿under￿the￿following￿circumstances: • The￿tire￿pressure￿has￿been￿changed • A￿tire￿change￿has￿been￿carried￿out • Wheels￿have￿been￿replaced The￿driver￿can￿start￿the￿teach-in￿process￿via￿the￿Central￿Information￿Display￿(CID)￿and￿the￿controller. For￿more￿information,￿refer￿to￿the￿vehicle￿owner's￿manual. Service￿life￿of￿batteries￿for￿wheel￿electronics The￿service￿life￿of￿the￿batteries￿installed￿in￿the￿wheel￿electronics￿is￿roughly￿7.5￿years.￿The￿current￿val- ue￿of￿the￿service￿life￿counter￿in￿the￿batteries￿of￿the￿wheel￿electronics￿can￿be￿read￿out￿via￿the￿diagnosis system. If￿the￿battery￿is￿fully￿discharged￿or￿faulty,￿a￿fault￿message￿is￿displayed￿via￿the￿TPMS. Removing/installing￿the￿wheel￿electronics The￿following￿points￿must￿be￿observed￿when￿removing/installing￿the￿wheel￿electronics￿of￿the￿Tire Pressure￿Monitor￿System:...
  • Page 22 F12￿Chassis￿Dynamics 3.￿Chassis￿and￿suspension • Do￿not￿use￿high￿pressure￿cleaners￿to￿clean￿the￿wheel￿rim￿with￿integrated￿wheel￿electronics when￿the￿tire￿has￿been￿removed • Replace￿the￿wheel￿electronics￿if￿tire￿sealant￿has￿been￿used • Clean￿the￿valve￿and￿valve￿seat￿thoroughly￿before￿installing￿the￿wheel￿electronics • To￿clean￿the￿wheel￿electronics,￿simply￿wipe￿down￿with￿a￿clean￿cloth. • Do￿not￿apply￿solvents￿or￿cleaning￿agents￿to￿the￿wheel￿electronics,￿or￿clean￿them￿with￿com- pressed￿air F12￿Wheel￿electronics￿–￿TPMS Index Explanation Data￿Matrix￿Code BMW￿part￿number FCC￿ID￿=￿approval￿for￿wireless￿operation Wheel￿electronics￿ID Transmission￿frequency￿(433￿MHz) Pressure￿sensor Production￿date￿of￿wheel￿electronics Tightening￿torque Width￿across￿flats￿of￿union￿nut...

  • Page 23: Brakes

    F12￿Chassis￿Dynamics 4.￿Brakes F12￿Brakes Index Explanation Brake￿fluid￿expansion￿tank Brake￿servo Brake￿pedal Actuator￿for￿Electromechanical￿Parking￿Brake￿(EMF) Brake￿disc Dynamic￿Stability￿Control￿(DSC) Brake￿caliper 4.1.￿Service￿brakes The￿F12￿has￿a￿dual-circuit￿hydraulic￿brake￿system￿with￿front/rear￿split.￿Lightweight￿construction￿brake discs￿with￿riveted￿aluminium￿disc￿centers￿sections￿are￿installed￿at￿the￿front￿and￿rear￿axle￿of￿the￿F12. Conventional￿bracket-type￿aluminium￿floating￿calipers￿are￿used￿on￿the￿front￿axle￿while￿cast￿iron￿floating caliper￿brakes￿with￿integrated￿EMF￿actuator￿(for￿the￿Electromechanical￿Parking￿Brake)￿are￿installed￿at the￿rear. The￿familiar￿brake￿pad￿wear￿monitoring￿function￿for￿the￿Condition￿Based￿Service￿display￿continues￿to be￿used. The￿brake￿discs￿at￿the￿front￿and￿rear￿axle￿are￿ventilated￿internally.
  • Page 24 F12￿Chassis￿Dynamics 4.￿Brakes Brake￿dimensions Front￿axle 650i Brake￿disc￿diameter 374￿mm Brake￿disk￿thickness 36￿mm Brake￿piston￿diameter 60￿mm Design Lightweight￿construction Rear￿axle 650i Brake￿disc￿diameter 345￿mm Brake￿disk￿thickness 24￿mm Brake￿piston￿diameter 44￿mm Design Lightweight￿construction 4.2.￿Electromechanical￿Parking￿Brake￿(EMF) An￿EMF￿is￿integrated￿in￿the￿rear￿brake￿calipers￿of￿the￿F12. The￿use￿of￿the￿electromechanical￿parking￿brake￿offers￿the￿following￿advantages: • Operated￿via￿an￿ergonomic￿button￿in￿the￿center￿console • Safe￿and￿reliable￿application￿and￿release￿of￿the￿parking￿brake￿under￿all￿preconditions • Automatic￿protection￿of￿the￿hydraulic￿holding￿functions￿(automatic￿hold￿function) • Dynamic￿emergency￿braking￿function￿ensured￿by￿way￿of￿the￿control￿systems￿(ABS)￿even￿on surfaces￿with￿a￿coefficient￿of￿friction • The￿discontinuation￿of￿the￿parking￿brake￿lever￿in￿the￿center￿console￿creates￿space￿for￿new equipment￿features.
  • Page 25 F12￿Chassis￿Dynamics 4.￿Brakes 4.2.1.￿System￿overview F12￿System￿overview￿–￿Electromechanical￿Parking￿Brake￿(EMF)
  • Page 26 F12￿Chassis￿Dynamics 4.￿Brakes Index Explanation DSC￿unit Brake￿caliper,￿front￿left Brake￿caliper,￿front￿right Brake￿caliper,￿rear￿right Brake￿caliper,￿rear￿left Parking￿brake￿button Wheel￿speed￿sensor,￿front￿left￿(not￿used￿for￿EMF) Wheel￿speed￿sensor,￿front￿right￿(not￿used￿for￿EMF) Wheel￿speed￿sensor,￿rear￿right Wheel￿speed￿sensor,￿rear￿left EMF￿actuator,￿rear￿left EMF￿actuator,￿rear￿right Electromechanical￿parking￿brake Dynamic￿Stability￿Control Junction￿box￿electronics KOMBI Instrument￿panel PT-CAN Powertrain￿controller￿area￿network...
  • Page 27 F12￿Chassis￿Dynamics 4.￿Brakes 4.2.2.￿System￿wiring￿diagram F12￿System￿wiring￿diagram￿–￿Electromechanical￿Parking￿Brake￿(EMF)
  • Page 28 F12￿Chassis￿Dynamics 4.￿Brakes Index Explanation Dynamic￿Stability￿Control￿(DSC) Central￿gateway￿module￿(ZGM) Footwell￿module￿(FRM) Car￿Access￿System￿(CAS) Instrument￿panel￿(KOMBI) Parking￿brake￿button Junction￿box￿for￿the￿power￿distribution￿box Luggage￿compartment￿power￿distribution￿box EMF￿control￿unit EMF￿actuator,￿rear￿left EMF￿actuator,￿rear￿right Wheel￿speed￿sensor,￿rear￿left Wheel￿speed￿sensor,￿rear￿right 4.2.3.￿System￿structure The￿EMF￿control￿unit￿receives￿the￿driver's￿command￿to￿engage￿the￿parking￿brake￿through￿the￿park- ing￿brake￿button.￿The￿vehicle￿condition￿is￿queried/detected￿via￿the￿electrical￿system￿connection￿and the￿bus￿systems.￿The￿control￿unit￿decides￿whether￿all￿conditions￿for￿engaging￿the￿parking￿brake￿are￿in place.￿If￿this￿is￿the￿case,￿the￿two￿EMF￿actuators￿on￿the￿rear￿brake￿calipers￿are￿activated. 4.2.4.￿System￿function Due￿to￿the￿spindle's￿self-locking￿facility,￿the￿clamping￿force￿remains￿securely￿applied￿even￿when￿no power￿supply￿is￿connected,￿and￿the￿vehicle￿is￿thus￿securely￿held.￿Once￿the￿required￿force￿is￿reached, the￿parking￿brake￿applied￿status￿is￿indicated￿by￿a￿red￿indicator￿lamp￿in￿the￿instrument￿panel￿(KOMBI) and￿an￿additional￿red￿LED￿in￿the￿parking￿brake￿button.
  • Page 29 F12￿Chassis￿Dynamics 4.￿Brakes F12￿Design￿of￿EMF￿actuator Index Explanation Plug￿connection Electric￿motor Drive￿belt Planetary￿gears Housing Connection￿to￿spindle The￿EMF￿actuator￿is￿fixed￿to￿the￿brake￿caliper￿and￿acts￿directly￿on￿the￿brake￿piston. The￿force￿is￿transmitted￿to￿a￿two-stage￿planetary￿gear￿system￿(4)￿by￿an￿electric￿motor￿(2)￿and￿a￿belt drive￿system￿(3).￿The￿spindle￿illustrated￿in￿the￿graphic￿below￿is￿driven￿via￿the￿connection￿to￿the￿spindle (6).
  • Page 30 F12￿Chassis￿Dynamics 4.￿Brakes F12￿Spindle￿and￿spindle￿nut￿in￿brake￿piston Index Explanation Groove Spindle￿nut￿with￿anti-twist￿lock Brake￿piston Spindle Spindle￿end￿stop Connection￿to￿planetary￿gearing F12￿Current￿and￿force￿progression￿of￿Electromechanical￿Parking￿Brake￿EMF Index Explanation Current￿flow Force￿flow Applying￿parking￿brake Parking￿brake￿applied Releasing￿parking￿brake...
  • Page 31 F12￿Chassis￿Dynamics 4.￿Brakes F12￿Overview￿of￿EMF￿actuator￿with￿brake￿caliper Index Explanation Plug￿connection Electric￿motor Drive￿belt Planetary￿gears Housing Brake￿piston Spindle￿and￿spindle￿nut Roller￿bearing...
  • Page 32 F12￿Chassis￿Dynamics 4.￿Brakes F12￿Electromechanical￿parking￿brake￿EMF￿applied￿with￿new￿brake￿pads Index Explanation Drive￿belt Planetary￿gears Brake￿piston Dust￿boot Sealing￿ring Spindle￿nut Electric￿motor Spindle Roller￿bearing Sealing￿ring Housing The￿driver￿applies￿the￿vehicle's￿parking￿brake￿by￿pulling￿out￿the￿parking￿brake￿button.￿The￿operating direction￿is￿the￿same￿as￿for￿a￿mechanical￿parking￿brake￿lever.￿The￿signal￿from￿the￿parking￿brake￿button is￿imported￿by￿the￿EMF￿control￿unit.￿The￿EMF￿actuators￿on￿the￿rear￿brake￿calipers￿are￿individually￿con- trolled￿by￿the￿EMF￿control￿unit. The￿parking￿brake￿can￿be￿applied￿in￿any￿logical￿terminal￿status.￿The￿connection￿from￿terminal￿30￿to the￿EMF￿control￿unit￿makes￿it￿possible￿to￿apply￿the￿parking￿brake￿at￿terminal￿0.￿The￿EMF￿control￿unit wakes￿up￿if￿the￿driver￿operates￿the￿parking￿brake￿button￿at￿terminal￿0.￿The￿EMF￿control￿unit￿then wakes￿up￿the￿other￿control￿units￿in￿the￿vehicle.￿Only￿then￿does￿the￿EMF￿control￿unit￿receive￿the￿essen- tial￿information￿about￿vehicle￿standstill.￿In￿addition,￿the￿change￿of￿parking￿brake￿status￿can￿also￿be￿indi- cated￿once￿the￿system￿has￿woken￿up.
  • Page 33 F12￿Chassis￿Dynamics 4.￿Brakes The￿"applied"￿status￿is￿indicated￿by￿a￿red￿indicator￿light￿in￿the￿instrument￿panel￿(KOMBI)￿and￿an￿addi- tional￿red￿LED￿in￿the￿parking￿brake￿button.￿Once￿the￿parking￿brake￿is￿on,￿pulling￿the￿parking￿brake￿but- ton￿again￿has￿no￿effect. F12￿Indicator￿lamp￿for￿parking￿brake￿applied Roll-away￿detection￿while￿parking￿brake￿applied The￿roll-away￿detection￿function￿is￿designed￿to￿prevent￿the￿vehicle￿rolling￿away￿while￿the￿parking￿brake is￿applied.￿The￿roll-away￿detection￿function￿is￿always￿activated￿whenever￿the￿parking￿brake￿status changes￿from￿"released"￿to￿"applied"￿and￿terminates￿after￿a￿defined￿period￿of￿time￿from￿that￿change￿of status. A￿signal￿from￿the￿DSC￿is￿used￿as￿the￿input￿variable￿for￿roll-away￿detection.￿As￿soon￿as￿that￿signal￿in- dicates￿that￿the￿vehicle￿is￿starting￿to￿roll￿during￿the￿detection￿window,￿the￿EMF￿actuators￿are￿immedi- ately￿further￿tightened.￿That￿is￿achieved￿by￿applying￿maximum￿current￿to￿the￿EMF￿actuators￿for￿100 ms￿in￿order￿to￿increase￿the￿clamping￿force.￿The￿system￿then￿waits￿for￿400￿ms.￿If￿the￿vehicle￿starts￿to roll￿again,￿the￿retightening￿process￿is￿repeated￿(up￿to￿three￿times).￿If￿rolling￿of￿the￿vehicle￿is￿still￿detect- ed￿after￿retightening￿the￿parking￿brake￿three￿times,￿the￿function￿terminates￿and￿a￿fault￿is￿entered￿in￿the fault￿memory. Temperature￿monitoring The￿temperature￿monitoring￿function￿ensures￿that￿the￿loss￿of￿parking-brake￿force￿that￿occurs￿when hot￿brake￿discs￿cool￿down￿is￿compensated￿for.￿The￿temperature￿monitoring￿function￿is￿activated￿if￿the temperature￿is￿above￿a￿defined￿value￿on￿a￿change￿of￿parking￿brake￿status￿from￿"released"￿to￿"applied". The￿temperature￿of￿the￿brake￿discs￿is￿calculated￿individually￿for￿each￿wheel￿by￿the￿DSC￿control￿unit and￿communicated￿to￿the￿EMF￿control￿unit.￿When￿the￿status￿changes,￿the￿higher￿of￿the￿two￿brake￿disc temperatures￿is￿used￿for￿temperature￿monitoring￿purposes.￿The￿temperature￿ranges￿and￿correspond- ing￿retightening￿periods￿are￿stored￿in￿a￿characteristic￿map. The￿appropriate￿retightening￿periods￿from￿the￿characteristic￿map￿are￿applied￿according￿to￿the￿temper- ature￿on￿change￿of￿status.￿Once￿the￿first￿retightening￿period￿has￿elapsed,￿the￿parking￿brake￿is￿retight- ened￿for￿the￿first￿time.￿After￿expiry￿of￿the￿second￿retightening￿period,￿the￿parking￿brake￿is￿retightened again,￿and￿again￿after￿the￿third￿period￿has￿elapsed.￿The￿characteristic￿map￿may￿also￿contain￿the￿value 0￿for￿one￿or￿more￿retightening￿periods.￿In￿that￿case,￿the￿corresponding￿retightening￿sequences￿do￿not take￿place.￿The￿function￿terminates￿when￿the￿last￿retightening￿sequence￿has￿been￿completed. Releasing￿the￿parking￿brake The￿parking￿brake￿is￿released￿by￿pressing￿the￿parking￿brake￿button￿down.￿However,￿for￿the￿parking brake￿to￿actually￿be￿released,￿Terminal￿15￿must￿be￿ON￿and￿at￿least￿one￿of￿the￿following￿preconditions satisfied:...
  • Page 34 F12￿Chassis￿Dynamics 4.￿Brakes • 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.
  • Page 35 F12￿Chassis￿Dynamics 4.￿Brakes The￿parking￿brake￿can￿be￿released￿by￿unscrewing￿the￿EMF￿actuators￿and￿manually￿screwing￿back￿the spindle. Replacing￿brake￿pads To￿replace￿the￿brake￿pads￿the￿EMF￿actuator￿must￿be￿in￿the￿fully￿released￿position￿so￿that￿the￿brake piston￿can￿be￿pressed￿back.￿The￿EMF￿actuators￿can￿be￿operated￿by￿means￿of￿the￿BMW￿diagnosis￿sys- tem￿and￿moved￿to￿the￿fully￿released￿position.￿That￿position￿is￿required￿in￿order￿to￿be￿able￿to￿replace￿the brake￿pads.￿Once￿the￿installation￿position￿is￿reached,￿installation￿mode￿is￿automatically￿activated. F12￿Electromechanical￿Parking￿Brake￿EMF,￿showing￿spindle￿nut￿in￿working￿position￿for￿brake￿pad￿replacement The￿parking￿brake￿cannot￿be￿applied￿while￿the￿EMF￿control￿unit￿is￿in￿installation￿mode￿for￿safety￿rea- sons.￿If￿the￿parking￿brake￿button￿is￿operated￿with￿the￿EMF￿control￿unit￿in￿this￿mode,￿the￿EMF￿indicator lamp￿on￿the￿instrument￿panel￿(KOMBI)￿flashes￿yellow. Installation￿mode￿can￿be￿cancelled￿in￿two￿ways: • By￿executing￿the￿service￿function￿"Reset￿installation￿mode"￿with￿the￿aid￿of￿ISTA • By￿driving￿the￿vehicle￿and￿exceeding￿a￿programmed￿minimum￿speed. The￿precise￿procedure￿for￿bedding-in￿the￿service￿brakes￿is￿described￿in￿the￿repair￿instructions.￿The￿in- structions￿here￿must￿be￿precisely￿followed.
  • Page 36 F12￿Chassis￿Dynamics 4.￿Brakes Brake￿test￿stand￿detection The￿EMF￿control￿unit￿determines￿via￿a￿plausibility￿check￿(comparison￿of￿wheel￿speeds)￿that￿the￿vehi- cle￿is￿on￿a￿brake￿test￿stand￿and￿switches￿to￿brake￿test￿stand￿mode.￿This￿process￿takes￿roughly￿six￿sec- onds. Pull￿the￿parking￿brake￿button￿several￿times￿in￿a￿row￿to￿approach￿the￿following￿target￿positions: • Brake￿pads￿in￿contact • Force￿level￿1￿for￿brake￿test￿stand • Force￿level￿2￿for￿brake￿test￿stand • Target￿force. Alternatively,￿the￿parking￿brake￿button￿can￿be￿continuously￿held￿in￿the￿pulled-out￿position￿while￿brake test￿stand￿mode￿is￿active.￿The￿target￿positions￿are￿then￿approached￿one-by-one￿at￿three￿second￿inter- vals. When￿brake￿test￿stand￿mode￿is￿active￿and￿the￿EMF￿actuators￿are￿released,￿the￿parking￿brake￿indicator light￿flashes￿slowly. When￿brake￿test￿stand￿mode￿is￿active￿and￿the￿EMF￿actuators￿are￿partially￿applied,￿the￿parking￿brake￿in- dicator￿light￿starts￿to￿flash￿more￿quickly. When￿brake￿test￿stand￿mode￿is￿active￿and￿the￿EMF￿actuators￿are￿fully￿applied,￿the￿parking￿brake￿indi- cator￿light￿remains￿permanently￿lit. When￿the￿vehicle￿is￿on￿a￿brake￿test￿stand,￿the￿parking￿brake￿can￿be￿released￿without￿having￿to￿press the￿brake￿or￿clutch￿pedal.￿Brake￿test￿stand￿mode￿is￿automatically￿cancelled￿when￿the￿vehicle￿is￿driv- en￿off￿the￿brake￿test￿stand.￿It￿is￿also￿deactivated￿if￿the￿parking￿brake￿button￿is￿pressed￿in￿or￿if￿a￿fault￿is present.

  • Page 37: Steering

    F12￿Chassis￿Dynamics 5.￿Steering Electric￿Power￿Steering￿(EPS)￿is￿fitted￿to￿the￿F12￿as￿standard.￿The￿steering￿is￿now￿entirely￿electrically operated￿and￿replaces￿the￿conventional￿hydraulic￿steering.￿The￿Electromechanical￿power￿steering￿with parallel-axis￿arrangement￿(EPS-APA)￿familiar￿from￿the￿F10￿is￿used. Active￿steering￿and￿rear￿axle￿slip￿angle￿control￿are￿available￿in￿the￿Integral￿Active￿Steering￿optional equipment￿package￿(2VH). F12￿Steering￿components￿with￿Integral￿Active￿Steering Index Explanation Active￿Steering￿lock HSR￿actuator Steering￿wheel Steering￿column Active￿steering￿servomotor￿with￿motor￿angular￿position￿sensor Electric￿Power￿Steering￿(EPS)
  • Page 38 F12￿Chassis￿Dynamics 5.￿Steering 5.1.￿Basic￿steering 5.1.1.￿System￿overview F12￿Electric￿Power￿Steering Index Explanation Reduction￿gear Steering-torque￿sensor Track￿rod EPS￿control￿unit Electric￿motor￿with￿motor￿position￿sensor EPS￿steering￿reduces￿fuel￿consumption￿by￿roughly￿0.3l￿per￿100￿km￿when￿compared￿to￿conventional hydraulic￿power￿steering.￿This￿helps￿reduce￿carbon￿dioxide￿emissions. As￿there￿is￿no￿oil￿in￿an￿EPS,￿it￿is￿environmentally￿cleaner￿than￿conventional￿hydraulic￿power￿steering. For￿reasons￿inherent￿in￿the￿system,￿EPS￿is￿always￿equipped￿with￿the￿Servotronic￿function.￿Two￿differ- ent￿settings￿(“Normal”￿and￿“Sporty”)￿can￿be￿accessed￿via￿the￿driving￿dynamic￿control￿switch. The￿EPS￿is￿less￿sensitive￿to￿external￿disturbance￿variables￿such￿as￿shudder￿and￿steering￿wheel￿vibra- tion.￿It￿also￿features￿active￿roll￿damping￿which￿enhances￿the￿driving￿safety￿of￿the￿F12. The￿return￿characteristics￿of￿the￿EPS￿are￿fully￿configurable.￿That￿means￿that￿optimum￿drivability￿can be￿guaranteed.￿In￿addition,￿the￿EPS￿allows￿implementation￿of￿the￿parking￿assistance￿feature.
  • Page 39 F12￿Chassis￿Dynamics 5.￿Steering The￿operating￿principle￿and￿design￿of￿the￿EPS￿are￿identical￿with￿those￿of￿the￿F10￿and￿are￿described￿in detail￿in￿the￿F10￿Chassis￿Dynamics￿training￿material. For￿more￿information￿regarding￿the￿parking￿assistant￿feature￿refer￿to￿the￿"F12￿Driver￿Assistance￿Sys- tems"￿section￿of￿this￿training￿material.
  • Page 40 F12￿Chassis￿Dynamics 5.￿Steering 5.1.2.￿System￿wiring￿diagram F12￿System￿wiring￿diagram￿for￿basic￿steering...
  • Page 41 F12￿Chassis￿Dynamics 5.￿Steering Index Explanation Electromechanical￿power￿steering￿(EPS) Digital￿Motor￿Electronics￿(DME) Junction￿box￿for￿the￿power￿distribution￿box Junction￿box￿electronics￿(JBE) Integrated￿Chassis￿Management￿(ICM) Intelligent￿battery￿sensor￿(IBS) Battery Battery￿power￿distribution￿box Steering￿column￿switch￿cluster￿(SZL) Instrument￿panel￿(KOMBI) Central￿gateway￿module￿(ZGM) Terminal￿15N Ignition￿(after-run) Terminal￿30 Terminal￿30 5.2.￿Integral￿Active￿Steering F12￿Integral￿Active￿Steering...
  • Page 42 F12￿Chassis￿Dynamics 5.￿Steering Index Explanation Active￿Steering￿lock HSR￿actuator Active￿steering￿servomotor￿with￿motor￿angular￿position￿sensor 5.2.1.￿Functional￿ranges The￿Integral￿Active￿Steering￿further￿improves￿driving￿dynamics￿through￿additional￿control￿interventions at￿the￿front￿and￿rear￿axle.￿The￿vehicle￿speed,￿lateral￿acceleration￿and￿yaw￿rate￿calculated￿from￿mea- sured￿variables￿are￿compared￿with￿a￿set-point￿value.￿The￿difference￿between￿the￿set-point￿and￿actual value￿is￿converted￿into￿a￿reference￿yaw￿moment.￿The￿resulting￿control￿interventions￿are￿distributed￿in an￿optimum￿ratio￿between￿the￿active￿steering￿AL￿or￿rear￿axle￿slip￿angle￿control￿(HSR). The￿EPS￿is￿supplemented￿by￿a￿planetary￿gearbox￿with￿override￿function￿in￿the￿steering￿gear￿input￿and an￿active￿steering￿servomotor.￿The￿active￿steering￿servomotor￿can￿modify￿the￿steering￿angle￿specified by￿the￿driver￿with￿reference￿to￿default￿values￿from￿the￿active￿steering￿control￿unit. To￿do￿this,￿the￿active￿steering￿control￿unit￿evaluates￿the￿sensor￿signals,￿which￿include: • Steering￿angle • Wheel￿speed • Yaw￿rate • Lateral￿acceleration. In￿the￿event￿that￿the￿system￿fails,￿the￿active￿steering￿servomotor￿is￿braked￿and￿disabled￿by￿a￿lock.￿The full￿range￿of￿vehicle￿maneuverability￿is￿retained￿as￿a￿permanent￿mechanical￿connection￿between￿the steering￿wheel￿and￿the￿front￿wheels￿exists. Low￿speed￿range The￿variable￿steering￿ratio￿of￿the￿active￿steering￿component￿reduces￿the￿steering￿effort￿required￿to move￿the￿front￿wheels￿from￿lock￿to￿lock￿to￿roughly￿two￿steering￿wheel￿turns. At￿low￿speed￿ranges￿of￿up￿to￿roughly￿60￿km/h,￿the￿variable￿steering￿ratio￿of￿the￿front￿axle￿is￿coupled with￿an￿opposing￿steering￿angle￿at￿the￿rear￿axle.￿This￿increases￿the￿maneuverability￿of￿the￿vehicle. High￿speed￿range As￿the￿driving￿speed￿increases,￿the￿degree￿of￿steering￿angle￿amplification￿by￿the￿Active￿Steering￿com- ponent￿is￿reduced￿and￿the￿steering-gear￿ratio￿becomes￿less￿direct. At￿the￿same￿time,￿the￿steering￿strategy￿adopted￿by￿the￿Integrated￿Active￿Steering￿changes.￿While￿at low￿speeds￿the￿rear￿wheels￿are￿steered￿in￿an￿opposing￿direction￿to￿the￿front￿axle,￿at￿higher￿speeds￿the steering￿angle￿is￿in￿the￿same￿direction. As￿a￿result￿the￿instantaneous￿center￿of￿rotation￿shifts￿backwards.￿This￿corresponds￿to￿a￿vehicle￿with￿a longer￿wheelbase￿which￿enhances￿its￿directional￿stability.￿The￿radius￿of￿the￿curve￿becomes￿longer.
  • Page 43 F12￿Chassis￿Dynamics 5.￿Steering Overall,￿lane￿changes￿and￿steering￿maneuvers￿can￿be￿mastered￿with￿a￿greater￿degree￿of￿stability￿by coordinating￿steering￿interventions￿at￿the￿front￿and￿rear￿axle￿-￿without￿compromising￿agility￿and￿con- trol. The￿combination￿of￿the￿active￿steering￿with￿the￿rear￿wheel￿steering￿gives￿the￿driver￿advantages￿in￿all speed￿ranges. Stabilization￿when￿understeering When￿changing￿lanes￿quickly,￿all￿vehicles￿have￿a￿tendency￿to￿produce￿a￿significant￿yaw￿response￿and can￿sometimes￿start￿to￿oversteer. If￿the￿ICM￿dynamic￿handling￿controller￿detects￿a￿difference￿between￿the￿response￿desired￿by￿the￿driv- er￿and￿the￿reaction￿of￿the￿vehicle,￿it￿initiates￿coordinated￿steering￿interventions￿on￿the￿front￿and￿rear wheels.￿The￿speed￿of￿the￿stabilizing￿intervention￿is￿such￿that￿it￿is￿hardly￿perceptible￿by￿the￿driver. Decelerating￿DSC￿brake￿interventions￿can￿largely￿be￿dispensed￿with￿which￿improves￿the￿stability￿and damping￿of￿the￿vehicle. F12￿Possible￿driving￿dynamics￿interventions￿during￿understeering Index Explanation Prevention￿of￿understeer￿by￿individual￿brake￿modulation￿(DSC) Prevention￿of￿understeer￿by￿rear￿axle￿steering￿intervention￿(IAL) Individual￿brake￿modulation￿(DSC) Rear-wheel￿steering￿intervention￿(IAL) Course￿of￿an￿understeering￿vehicle Course￿of￿a￿vehicle￿with￿neutral￿drivability Yaw￿moment￿acting￿on￿the￿vehicle￿due￿to￿an￿intervention￿by￿the￿driving dynamics￿control If￿the￿driver￿misjudges￿a￿bend￿when￿driving￿fast￿on￿a￿country￿road,￿the￿vehicle￿may￿understeer.
  • Page 44 F12￿Chassis￿Dynamics 5.￿Steering Owing￿to￿the￿principle￿of￿active￿steering,￿up￿till￿now￿it￿was￿only￿possible￿to￿respond￿to￿oversteering￿ve- hicle￿behavior￿with￿individual￿brake￿modulation￿of￿the￿outside￿rear￿wheel￿by￿the￿DSC. With￿the￿introduction￿of￿active￿rear￿axle￿steering,￿corrective￿action￿is￿now￿possible￿in￿understeering￿sit- uations￿through￿intervention￿of￿the￿Integral￿Active￿Steering￿which￿further￿increases￿active￿safety. The￿components￿of￿Integral￿Active￿Steering￿"active￿steering￿AL"￿and￿"rear￿axle￿slip￿angle￿control￿HSR" cannot￿be￿ordered￿separately￿and￿are￿only￿available￿with￿the￿Integral￿Active￿Steering￿package￿(SA 2VH).
  • Page 45 F12￿Chassis￿Dynamics 5.￿Steering 5.2.2.￿System￿wiring￿diagram F12￿System￿wiring￿diagram￿of￿Integral￿Active￿Steering...
  • Page 46 F12￿Chassis￿Dynamics 5.￿Steering Index Explanation Speed￿sensor,￿front￿left Dynamic￿Stability￿Control￿(DSC) Ride￿height￿sensor,￿front￿left Active￿steering￿lock Active￿steering￿servomotor Active￿steering￿motor￿angular￿position￿sensor Digital￿Motor￿Electronics￿DME Speed￿sensor,￿front￿right Junction￿box￿for￿the￿power￿distribution￿box Junction￿box￿electronics￿JBE Speed￿sensor,￿rear￿right Control￿unit,￿rear￿axle￿slip￿angle￿control￿HSR Luggage￿compartment￿power￿distribution￿box Battery￿power￿distribution￿box HSR￿actuator Hall￿effect￿sensor Steering￿tie￿rod￿position￿sensor Ride￿height￿sensor,￿rear￿left Speed￿sensor,￿rear￿left Central￿gateway￿module￿(ZGM) Active￿steering￿control￿unit Car￿Access￿System￿(CAS) Instrument￿panel￿(KOMBI) Steering￿column￿switch￿cluster￿(SZL) Brake￿light￿switch￿(BLS) Integrated￿Chassis￿Management￿(ICM) Terminal￿15N Ignition￿(after-run) Terminal￿15WUP Wake-up￿with￿terminal￿15￿ON Terminal￿30 Terminal￿30 Terminal￿30B Terminal￿30,￿basic￿operation Terminal￿31 Ground￿connection...
  • Page 47 F12￿Chassis￿Dynamics 5.￿Steering 5.2.3.￿EPS￿with￿24￿V F12￿Electric￿Power￿Steering￿(EPS)￿with￿active￿steering Index Explanation Reduction￿gear Active￿Steering￿lock Steering-torque￿sensor Active￿Steering￿servomotor￿with￿motor￿angular￿position￿sensor Track￿rod EPS￿control￿unit Electric￿motor￿with￿motor￿position￿sensor As￿with￿the￿F10￿higher￿steering￿forces￿are￿required￿due￿to￿the￿active￿steering￿at￿the￿front￿axle,￿12￿V power￿steering￿would￿no￿longer￿be￿sufficient.￿An￿EPS￿with￿24￿V￿power￿supply￿is￿therefore￿used￿in￿the F12￿in￿conjunction￿with￿the￿optional￿equipment￿Integral￿Active￿Steering￿(2VH). The￿necessary￿components,￿an￿auxiliary￿battery￿with￿charger￿and￿a￿separator,￿are￿installed￿in￿the￿lug- gage￿compartment￿of￿the￿F12.
  • Page 48 F12￿Chassis￿Dynamics 5.￿Steering F12￿24￿V￿components Index Explanation Battery Separator Auxiliary￿battery Charging￿controller￿for￿auxiliary￿battery￿(Battery￿Charge￿Unit￿BCU) The￿following￿system￿wiring￿diagram￿shows￿how￿the￿24￿V￿components￿are￿incorporated￿into￿the￿vehi- cle￿electrical￿system.
  • Page 49 F12￿Chassis￿Dynamics 5.￿Steering F12￿System￿wiring￿diagram￿of￿EPS￿with￿24￿V￿and￿active￿steering...
  • Page 50 F12￿Chassis￿Dynamics 5.￿Steering Index Explanation Electric￿Power￿Steering￿(EPS) Digital￿Motor￿Electronics￿(DME) Junction￿box￿for￿the￿power￿distribution￿box Junction￿box￿electronics￿(JBE) Integrated￿Chassis￿Management￿(ICM) Separator Charging￿controller￿for￿auxiliary￿battery￿(Battery￿Charge￿Unit￿[BCU]) Luggage￿compartment￿power￿distribution￿box Auxiliary￿battery Intelligent￿battery￿sensor￿(IBS) Battery Battery￿power￿distribution￿box Steering￿column￿switch￿cluster￿(SZL) Instrument￿panel￿(KOMBI) Central￿gateway￿module￿(ZGM) Terminal￿15N Ignition￿(after-run) Terminal￿30 Terminal￿30 Terminal￿30F Terminal￿30,￿fault-dependent LIN-Bus Local￿interconnect￿network￿bus The￿BCU￿charges￿the￿auxiliary￿battery￿with￿the￿assistance￿of￿a￿DC/DC￿converter.￿It￿monitors￿the￿state of￿charge￿in￿the￿auxiliary￿battery￿and￿the￿cable￿shield￿that￿encloses￿the￿24￿V￿cable￿which￿is￿installed￿in the￿vehicle￿floor. It￿switches￿the￿relay￿in￿the￿separator￿that￿integrates￿the￿auxiliary￿battery￿into￿the￿circuit.￿The￿EPS￿is￿on- ly￿supplied￿with￿24￿V￿once￿this￿relay￿has￿been￿switched.￿If￿a￿fault￿develops,￿the￿EPS￿can￿also￿be￿oper- ated￿using￿12￿V.￿If￿no￿fault￿develops,￿the￿relay￿in￿the￿separator￿is￿switched￿from￿terminal￿15N. The￿following￿excerpts￿from￿the￿system￿wiring￿diagram￿show￿the￿various￿switching￿situations￿and￿the auxiliary￿battery￿charging￿operation.
  • Page 51 F12￿Chassis￿Dynamics 5.￿Steering F12￿24￿V￿operation￿of￿EPS Index Explanation Battery￿power￿distribution￿box Battery Intelligent￿battery￿sensor￿IBS Auxiliary￿battery Separator Charging￿controller￿for￿auxiliary￿battery￿(Battery￿Charge￿Unit￿[BCU]) Luggage￿compartment￿power￿distribution￿box Terminal￿30 Terminal￿30 Terminal￿30F Terminal￿30,￿fault-dependent LIN-Bus Local￿interconnect￿network￿bus The￿relay￿in￿the￿separator￿connects￿the￿battery￿and￿auxiliary￿battery￿in￿series￿in￿order￿to￿operate￿the EPS￿with￿24￿V.
  • Page 52 F12￿Chassis￿Dynamics 5.￿Steering F12￿12￿V￿operation￿of￿EPS￿in￿event￿of￿a￿fault Index Explanation Battery￿power￿distribution￿box Battery Intelligent￿battery￿sensor￿(IBS) Auxiliary￿battery Separator Charging￿controller￿for￿auxiliary￿battery￿(Battery￿Charge￿Unit￿[BCU]) Luggage￿compartment￿power￿distribution￿box LIN-Bus Local￿interconnect￿network￿bus The￿separator￿assumes￿the￿12￿V￿position￿before￿terminal￿15￿or￿if￿a￿fault￿develops.￿The￿auxiliary￿battery is￿no￿longer￿connected￿in￿series￿and￿is￿disconnected￿from￿the￿circuit.
  • Page 53 F12￿Chassis￿Dynamics 5.￿Steering F12￿Charging￿the￿auxiliary￿battery￿in￿24￿V￿mode Index Explanation Battery￿power￿distribution￿box Battery Intelligent￿battery￿sensor￿(IBS) Auxiliary￿battery Separator Charging￿controller￿for￿auxiliary￿battery￿(Battery￿Charge￿Unit￿[BCU]) Luggage￿compartment￿power￿distribution￿box LIN-Bus Local￿interconnect￿network￿bus The￿auxiliary￿battery￿can￿be￿charged￿in￿24￿V￿mode￿using￿the￿battery￿charging￿unit.￿The￿charger￿draws the￿power￿required￿for￿this￿from￿the￿vehicle￿electrical￿system￿via￿the￿Luggage￿compartment￿power￿dis- tribution￿box. When￿the￿Electric￿Power￿Steering￿is￿in￿24 V￿mode,￿the￿auxiliary￿battery￿is￿charged￿via￿the￿charging controller￿for￿auxiliary￿battery￿(BCU).￿As￿a￿voltage￿of￿24￿V￿is￿present￿in￿the￿EPS￿circuit￿due￿to￿the￿series connection￿of￿the￿main￿and￿auxiliary￿battery,￿the￿auxiliary￿battery￿can￿only￿be￿charged￿using￿a￿special measure. This￿involves￿using￿a￿DC/DC￿converter￿in￿the￿charging￿controller￿for￿auxiliary￿battery￿(BCU)￿that￿pro- duces￿different￿voltages￿at￿the￿input￿and￿output￿that￿are￿isolated￿from￿one￿another. Energy￿is￿drawn￿from￿the￿vehicle￿electrical￿system￿and￿fed￿to￿the￿auxiliary￿battery.
  • Page 54 F12￿Chassis￿Dynamics 5.￿Steering 5.2.4.￿Rear￿axle￿slip￿angle￿control￿HSR F12￿Installation￿location￿of￿HSR￿actuator￿at￿integral￿V￿rear￿axle Index Explanation Mounting￿plate Left￿camber￿link HSR￿actuator Right￿camber￿link HSR￿control￿unit The￿use￿of￿Integral￿Active￿Steering￿increases￿the￿overall￿ride￿comfort￿and￿dynamics￿of￿the￿vehicle￿by actively￿steering￿the￿rear￿wheels￿in￿certain￿conditions. The￿special￿HSR￿actuator￿on￿the￿rear￿axle￿is￿fastened￿underneath￿a￿support￿plate￿on￿the￿rear￿axle￿sup- port.￿This￿electromechanical￿actuator￿is￿located￿between￿the￿two￿camber￿links￿of￿the￿integral￿V￿rear axle.￿The￿rear￿wheel￿steering￿system￿includes￿a￿dedicated￿HSR￿control￿unit￿that￿controls￿and￿monitors the￿HSR￿actuator. Control￿systems￿were￿designed￿independently￿of￿one￿another￿using￿the￿state-of-the-art￿technology. In￿the￿F12￿these￿systems￿are￿networked￿by￿the￿ICM.￿In￿the￿ICM￿architecture￿a￿central￿control￿unit￿has superseded￿the￿driving￿dynamics￿sensors￿previously￿used￿and￿constitutes￿a￿central￿driving￿dynamics controller.
  • Page 55 F12￿Chassis￿Dynamics 5.￿Steering F12￿HSR￿actuator Index Explanation Left￿track￿rod￿joint Left￿shaft￿gaiter Worm￿shaft Spindle￿nut Electric￿motor Electrical￿connection Right￿shaft￿gaiter Right￿track￿rod￿joint Iron￿casing Armature￿winding Rotor￿winding￿with￿iron￿core Support/armature￿winding￿iron￿core The￿electromechanical￿actuator￿essentially￿consists￿of￿an￿electric￿motor￿which￿moves￿the￿two￿track rods￿by￿means￿of￿a￿worm-and-nut￿steering￿gear.
  • Page 56 F12￿Chassis￿Dynamics 5.￿Steering The￿HSR￿actuator￿is￿designed￿for￿a￿maximum￿stroke￿of￿±￿8￿mm￿which￿produces￿a￿maximum￿steering lock￿of￿±￿3°￿at￿the￿wheel. The￿worm-and-nut￿rear-wheel￿steering￿gear￿is￿self-inhibiting.￿This￿means￿that￿if￿the￿system￿fails,￿the vehicle￿has￿the￿same￿drivability￿is￿a￿vehicle￿without￿rear￿wheel￿steering. The￿components￿of￿Integral￿Active￿Steering￿"active￿steering￿AL"￿and￿"rear￿axle￿slip￿angle￿control"￿can- not￿be￿ordered￿separately￿and￿are￿only￿available￿with￿the￿Integral￿Active￿Steering￿package￿(SA￿2VH).
  • Page 57 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control 6.1.￿Directions￿of￿action Driving￿stability￿control￿systems￿can￿be￿differentiated￿in￿terms￿of￿their￿basic￿effective￿directions.￿They can￿act￿along￿as￿well￿as￿around￿an￿axis￿of￿the￿vehicle's￿fixed￿X,￿Y￿or￿Z￿coordinate￿system. Direction￿of Longi- Pitch Lateral Vertical Roll action tudinal   Integral￿Ac-   tive￿Steering     6.2.￿Dynamic￿Stability￿Control￿DSC The￿DSC￿prevents￿the￿driving￿wheels￿spinning￿when￿pulling￿away￿and￿accelerating. In￿addition,￿the￿DSC￿detects￿unstable￿driving￿conditions￿such￿as￿oversteer￿or￿understeer.￿The￿DSC helps￿to￿keep￿the￿vehicle￿on￿a￿safe￿course￿within￿the￿physical￿limits￿by￿reducing￿engine￿power￿output and￿individually￿modulating￿the￿brake￿intervention￿at￿each￿wheel. Driving￿style￿and￿safety￿always￿remains￿the￿responsibility￿of￿the￿driver,￿do￿Not￿rely￿solely￿on DSC￿to￿maintain￿stability￿of￿the￿vehicle. The￿additional￿safety￿features￿afforded￿by￿the￿system￿should￿not￿be￿diminished￿by￿risky￿driv- ing. The￿DSC￿system￿and￿its￿hydraulic￿block￿mounted￿control￿unit￿incorporate￿a￿large￿number￿of￿individual functions￿which￿are￿listed￿in￿the￿table￿below. Function Sub-function Designation Antilock￿Brake￿System Electronic￿brake￿force￿distribution Cornering￿Brake￿Control Dynamic￿Brake￿Control...
  • Page 58 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control Function Sub-function Designation Automatic￿Stability￿Control Engine￿torque￿control Engine￿drag￿control Braking￿torque￿control Dynamic￿Stability￿Control Yaw￿force￿control Overrun￿differential￿control Dynamic￿Traction￿Control The￿DSC￿can￿be￿operated￿in￿three￿modes: • Normal￿mode • Dynamic￿traction￿control￿(DTC) • DSC￿OFF. 6.3.￿Electronic￿Damper￿Control￿(EDC) F12￿Components￿of￿VDM...
  • Page 59 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control Index Explanation VDM￿control￿unit Drive￿dynamic￿control￿switch ICM￿control￿unit EDC￿satellite,￿front￿left EDC￿control￿valve￿for￿compression￿stage EDC￿control￿valve￿for￿rebound The￿F12￿features￿the￿Vertical￿Dynamics￿Management￿(VDM)￿with￿integrated￿Electronic￿Damper Control￿(EDC)￿function.￿The￿EDC￿was￿also￿referred￿to￿as￿Vertical￿Dynamics￿Control￿(VDC)￿in￿the￿large series￿from￿the￿F01/F02￿onwards.￿The￿VDC￿introduced￿with￿the￿E70/E71￿was￿systematically￿devel- oped￿further￿for￿the￿F01/F02,￿F10￿and￿now￿the￿F12￿uses￿the￿latest￿version. The￿EDC￿reduces￿undesirable￿vehicle￿movements￿that￿arise￿as￿a￿result￿of￿a￿dynamic￿driving￿style￿or uneven￿roadway.￿This￿achieves￿noticeable￿improvements￿in￿the￿following￿areas,￿even￿with￿a￿com- fort-oriented￿sports￿suspension: • Vehicle￿body￿comfort • Tire￿comfort • Driving￿dynamics. With￿EDC,￿the￿actuator￿unit￿and￿the￿specified￿satellite￿sensors￿at￿the￿shock￿absorber￿are￿connected￿to the￿VDM￿control￿unit￿via￿FlexRay. The￿vertical￿acceleration￿of￿the￿wheel￿is￿recorded￿by￿the￿acceleration￿sensors￿integrated￿in￿the￿satel- lite. The￿movement￿of￿the￿vehicle￿body￿is￿determined￿based￿on￿the￿wheel￿acceleration￿and￿ride￿height￿sig- nals.￿In￿addition,￿signals￿such￿as￿the￿vehicle￿speed￿are￿acquired￿via￿FlexRay￿and￿used￿to￿determine￿the reference￿forces￿for￿the￿damping￿action. The￿current￿supply￿required￿for￿the￿rebound￿and￿compression￿stage￿valves￿at￿the￿dampers￿is￿switched based￿on￿the￿calculated￿reference￿force￿and￿the￿damper￿characteristic￿map. In￿the￿F12,￿the￿Dynamic￿Damper￿control￿is￿standard￿and￿the￿optional￿Active￿Roll￿Stabilization￿(ARS,￿SA 229),￿is￿available￿as￿an￿option. 6.4.￿Active￿Roll￿Stabilization￿ARS￿(Dynamic￿Drive) The￿Active￿Roll￿Stabilization￿ARS￿was￿introduced￿for￿the￿first￿time￿in￿the￿E65/E66.￿With￿the￿F12,￿this￿is available￿as￿option.￿(SA￿229) ARS￿can￿bring￿about￿a￿noticeable￿reduction￿in￿the￿lateral￿tilt￿of￿the￿body￿that￿occurs￿during￿fast￿corner- ing￿or￿avoidance￿maneuvers.￿During￿this￿process,￿the￿ARS￿reduces￿the￿required￿steering￿angle￿and￿al- so￿minimizes￿the￿unwanted￿interference￿created￿by￿the￿wheels￿on￿the￿axle. The￿ARS￿significantly￿improves￿the￿bump￿steer￿as￿well￿as￿the￿load￿change￿response￿of￿the￿vehicle.
  • Page 60 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control With￿ARS￿the￿following￿variables￿are￿permanently￿measured￿or￿calculated: • Vehicle￿speed • Current￿lateral￿and￿longitudinal￿acceleration • Body￿and￿wheel￿acceleration • Steering￿wheel￿position • Ride￿heights. Control￿commands￿are￿sent￿to￿the￿hydraulic￿swivel￿motors￿of￿the￿anti-roll￿bars￿based￿on￿the￿data￿ac- quired￿in￿order￿to￿counteract￿the￿lateral￿tilting￿forces￿that￿occur.
  • Page 61 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control F12￿Dynamic￿Drive￿system￿wiring￿diagram...
  • Page 62 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control Index Explanation Dynamic￿stability￿control￿(DSC) Hydraulic￿oil￿level￿sensor Suction￿throttle￿valve Digital￿Motor￿Electronics￿(DME) Valve￿block,￿Dynamic￿Drive Front￿suspension￿pressure￿sensor/rear￿suspension￿pressure￿sensor Shift-position￿sensor Failsafe￿valve,￿direction￿valve￿and￿pressure￿valves Vertical￿Dynamics￿Management Junction￿box￿for￿the￿power￿distribution￿box Integrated￿Chassis￿Management￿(ICM) Steering￿column￿switch￿cluster￿(SZL) Instrument￿panel￿(KOMBI) Central￿gateway￿module￿(ZGM) Terminal￿15N Ignition￿(after-run) Terminal￿30 Terminal￿30...
  • Page 63 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control F12￿EDC￿system￿wiring￿diagram...
  • Page 64 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control Index Explanation Ride￿height￿sensor,￿front￿left Electronic￿Damper￿Control￿satellite,￿front￿left Dynamic￿Stability￿Control Ride￿height￿sensor,￿front￿right Electronic￿Damper￿Control￿satellite,￿front￿right Junction￿box￿for￿the￿power￿distribution￿box Vertical￿Dynamics￿Management Drive￿dynamic￿control￿switch Integrated￿Chassis￿Management￿(ICM) Electronic￿Damper￿Control￿satellite,￿rear￿right Ride￿height￿sensor,￿rear￿right Ride-height￿sensor,￿rear￿left Electronic￿Damper￿Control￿satellite,￿rear￿left Footwell￿module￿(FRM) Central￿gateway￿module￿(ZGM) 6.5.￿Drive￿dynamic￿control￿switch F12￿Center￿console...
  • Page 65 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control Index Explanation Driving￿dynamic￿control￿switch Controller F12￿Drive￿dynamic￿control￿switch Index Explanation Drive￿dynamic￿control￿switch￿for￿equipment￿without￿Adaptive￿Drive￿(not￿US) Drive￿dynamic￿control￿switch￿for￿equipment￿with￿Adaptive￿Drive In￿the￿F12,￿the￿combined￿effect￿of￿all￿drivetrain￿and￿driving￿stability￿control￿systems￿can￿also￿be￿influ- enced￿via￿the￿driving￿dynamic￿control￿switch.￿The￿operating￿principle￿is￿the￿same￿as￿the￿F01.￿In￿addi- tion￿to￿the￿three￿different￿modes￿of￿the￿DSC￿available￿through￿the￿DSC￿button,￿four￿different￿modes are￿available￿through￿the￿driving￿dynamics￿switch. The￿Sports￿mode￿can￿be￿configured￿with￿through￿the￿iDrive￿Controller. Sports￿mode￿configuration The￿“Sport”￿mode￿allows￿the￿driver￿to￿personalize￿the￿individual￿settings￿with￿regard￿to￿drivetrain, chassis￿and￿suspension￿or￿both.
  • Page 66 F12￿Chassis￿Dynamics 6.￿Driving￿stability￿control 6.5.1.￿Handling￿dynamics￿programs Dynamic￿Damper￿Control Comfort Normal Sport Sport+ Drivetrain￿systems Accelerator￿character- Normal Normal Sports Sports istic Shift￿program Normal Normal Sports Sports Shift￿speed Normal Normal Sports Sports Chassis￿and￿sus- pension￿systems Steering￿servo Normal Normal Sports Sports Integral￿Active￿Steer- Normal Normal Sports Sports Dynamic￿Stability DSC￿on DSC￿on DSC￿on Control Electronic￿Damper...
  • Page 68 Bayerische￿Motorenwerke￿Aktiengesellschaft Händlerqualifizierung￿und￿Training Röntgenstraße￿7 85716￿Unterschleißheim,￿Germany...