Page 2 - Objectives
2 Objectives At the end of this presentation, you should be able to: 1. Explain the function of and purpose for SBC 2. Describe the customer interface with SBC 3. List the hydraulic and electronic components used for SBC 4. Describe how the “normal” feel of the brake pedal is maintained 5. Explain e...
Page 3 - Contents
3 Contents Advantages of SBC 5 Driving with SBC 8 SBC components 13 Brake operating unit (BOU) 17 Traction system hydraulic unit 27 Three pressure stages 32 Temperature Compensation 38 Deactivation 39 System activation 42 Bleeding the system 49
Page 4 - SBC Incorporates these Functions:
4 SBC Incorporates these Functions: ABS (Anti lock Brakes 1984) + ASR (Automatic Slip Regulation 1991) + ETS (Electronic Traction System 1995) + ESP (Electronic Stability Program 1996) + BAS (Brake Assist System 1998)
Page 5 - Advantages of SBC
5 Advantages of SBC • Improves metering of required brake pressure – each wheel can be precisely controlled • Improved BAS function – monitors release of accelerator pedal and application of brake – maximum pressure available immediately – pre-filling of system (overcoming play) – when the BAS funct...
Page 10 - Driving with SBC – Delayed Off Function
10 Driving with SBC – Delayed Off Function Time that SBC remains operational after use: • with vehicle stationary and was locked = 20 seconds • with vehicle stationary and ignition in “0”, brake pedal not operated = 2 minutes • with vehicle stationary, ignition in “0”, brake pedal operated in delaye...
Page 11 - Warning Display; Complete ESP control module failure -
11 Warning Display Complete ESP control module failure - Instrument cluster will scroll through failure displays
Page 12 - SBC control module failure
12 Warning Display SBC control module failure Certain faults will trigger audible signal
Page 13 - SBC Components
13 SBC Components • Brake Operating Unit (BOU) • Wheel speed sensors • Traction System Hydraulic Unit (A7/3)
Page 16 - X11/4 Diagnosis Connection
16 X11/4 Diagnosis Connection X11/4 Pin 9 Z6/33 R230 W211 A7/3n1 SBC N47/5 ESP N15/5 ESM N51/2 ABC X11/4 Pin 9 A7/3n1 SBC N47/5 ESP Z70/4 N10/1 L.F.SAM
Page 18 - Brake Operating Unit
18 Brake Operating Unit The Brake Operating Unit (BOU) consists of the following: • Brake fluid reservoir (Do not overfill!) • SBC pedal value sensor • Tandem master cylinder • Brake pressure simulator (Note: no vacuum booster)
Page 19 - Master Cylinder; • Fluid return line
19 Master Cylinder • Fluid return line • Supply hose to SBC • Do not overfill • Fluid level sensor • Hydraulic lines to SBC
Page 20 - Fluid Reservoir Cover; • Ultraviolet protection
20 Fluid Reservoir Cover • Ultraviolet protection (211 only)
Page 22 - BOU Tandem Master Cylinder
22 BOU Tandem Master Cylinder Fluid reservoir Floating piston Primary piston Brake pressure simulator Fill valves GF42.46 -P- 4200-03SL A7/3 y1 y2 A7/3 - Traction system hydraulic unit with separation valves y1 and y2
Page 23 - Normal Braking - Light Pressure
23 Normal Braking - Light Pressure A7/3 y1 y2 GF42.46 -P- 4200-03SL • Driver applies pressure to the brake pedal • Pedal travel sensor sends a signal to A7/3 • Fill valves close • y1 and y2 energized, preventing fluid movement externally • Floating piston allows fluid to enter simulator, compressing...
Page 24 - Normal Braking - Increased Pressure
24 Normal Braking - Increased Pressure A7/3 y1 y2 • Increasing pedal travel causes thelarger spring tocompress, providing harder pedal feel
Page 25 - Normal Braking - Strongest Feedback
25 Normal Braking - Strongest Feedback A7/3 y1 y2 • Further pedal travel causes piston to compress rubber bumper, providing greatly increased pedal pressure
Page 26 - Emergency Operation
26 Emergency Operation A7/3 y1 y2 Left front Right front GF42.46 -P- 4200-03SLGF42.46 -P- 3000SL • All electrical functions canceled • Hydraulic pressure created with NOpower assist • Pressure directed through A7/3 y1 andy2 to .... Left Front andRight Front calipersonly !
Page 28 - Traction System Hydraulic Unit
28 Traction System Hydraulic Unit A7/3 GF42.50 -P- 4000-03S
Page 29 - Legend
29 Legend 1 Brake Operating Unit 2 Brake pressure simulator 3 Pressure reservoir 7 Left front media separator (dividing piston) 8 Right front media separators(dividing piston) A7/3 Traction system hydraulic unit A7/3b1 Front axle pre- pressure sensor A7/3b2 Reservoir pressure sensor A7/3b3 Left fron...
Page 30 - Emergency Operation Circuit
30 Emergency Operation Circuit GF42.46 -P3000SL • Pressure applied directly to front calipers • y1 and y2 not energized • b1, b3, and b4 pressure sensors may provide information to SBC control module • Media separator/Dividing piston 7 and 8 isolateemergency circuit fromnormal circuit
Page 31 - Brake Pressure Supply
31 Brake Pressure Supply GF 42.50 -P-4000 -04S GF42.46 -P- 0001SL • pressure reservoir charged to 160 bar • the high pressure charge pump runs as needed • pressure blocked by y6, y8, y10, y12
Page 32 - Three Pressure Stages; Same pressure stages as used with ABS functions:
32 Three Pressure Stages Same pressure stages as used with ABS functions: • Pressure apply • Pressure hold • Pressure release
Page 33 - Pressure Apply - Rear Wheels
33 Pressure Apply - Rear Wheels GF42.50 -P- 4000-04SGF42.46 -P- 1000SLGF42.46 -P- 4500-02SL Reservoir pressure Brake pedal pressure • Brake pedal depressed• B37/1 and b1 report brake application to control module • y1 and y2 energized• y10 and y12 intake control valves energized • Pressure at each r...
Page 34 - Pressure Apply - Front Wheels
34 Pressure Apply - Front Wheels GF42.50 -P- 4000-04S GF42.46 -P- 1000SL Reservoir pressure Brake pedal pressure • y6 and y8 energized• pressure applied to left and right dividing pistons 7 and 8 • 7 and 8 apply pressure to caliper• pressure at each wheel monitored by b3 and b4 • Balance valve y3 no...
Page 35 - Pressure Apply - All Wheels
35 Pressure Apply - All Wheels GF42.50 -P- 4000-04S GF42.46 -P- 1000SL • Outlet control valves y7, y9, y11, y13 energized
Page 36 - Pressure Hold - All Wheels
36 Pressure Hold - All Wheels GF42.50 -P- 4000-04S GF42.46 -P- 1000SL • y6, y8, y10, y12 de-energized
Page 37 - Pressure Reduction - All Wheels
37 Pressure Reduction - All Wheels GF42.50 -P- 4000-04S GF42.46 -P- 1000SL • y7, y9, y11, y13 de-energized
Page 38 - Temperature Compensation
38 Temperature Compensation During continuous brake use the fluid in the calipers expand, this:• creates high pressure • prevents valves 7 & 8 from moving To reduce this pressure, y1 and y2 are pulsed
Page 39 - Deactivation
39 Deactivation Deactivating the system will: • empty the pressure reservoir (a lower pressure with no volume may be retained) • prevent the charge pump from operating •Note: the warning buzzer is deactivated when accessing SBC with the SDS. SBC must be deactivated with SDS before any work is perfor...
Page 42 - System Activation
42 System Activation Activation must be performed anytime the system has been deactivated, BEFORE the engine is started! Failure to activate will prevent proper operation and create fault codes! Activating SBC with SDS will: • charge the accumulator• perform a Predrive Check• move the pads towards t...
Page 44 - Activation - Left Front; Caliper held with ~60 bar
44 Activation - Left Front Caliper held with ~60 bar
Page 45 - Activation - Right Front
45 Activation - Right Front Caliper held with ~60 bar
Page 46 - Activation - Right Rear
46 Activation - Right Rear Caliper held with ~60 bar
Page 47 - Activation - Left Rear
47 Activation - Left Rear Caliper held with ~60 bar
Page 48 - Activation - Recharge
Page 49 - Bleeding the Brake System; Proper system bleeding is critical!
49 Bleeding the Brake System Proper system bleeding is critical! Follow directions in SDS • Bleeding must be performed using the SDS • Pressure at bleeder valves will exceed 100 bar (Hold the bleeder hose securely) • Bleeding may require ~1.5 hours • Bleeding may use ~ 1.5 liters of brake fluid AR42...
Page 50 - Equipment Required
50 Equipment Required • Pressure bleeder• Adapters• Fluid receptacle • SDS - follow instructions carefully CAUTION:Extremely high pressure at bleeder! 211 589 01 91 00 AR42.10 -P- 0010-02RAR42.10 -P- 0012RWS42.00-P- 0048B
Page 51 - Connect equipment and follow steps in SDS
51 Bleeding the Brake System AR42.10 -P- 0012R Connect equipment and follow steps in SDS
Page 52 - Acronym List
52 Acronym List (Used in This Handout.) ABS - Anti-lock Brake SystemASR - Anti Slip RegulationBAS - Brake Assist SystemBOU - Brake Operating UnitCAN - Controller Area NetworkEBP - Electronic Brake ProportioningEBR - Electronic Brake RegulationE-Gas - Electronic AcceleratorESP - Electronic Stability ...
Page 53 - Appendix
53 Appendix AR42.10-P-0010I Carrying out bleeding operation AR42.10-P-0012R Bleeding system with Star Diagnosis GF42.45-P-0001-04SL ESP driver information GF42.45-P-0001SL ESP function GF42.45-P-2000SL ESP brake moment control GF42.45-P-3500SL ASR control mode function GF42.46-P-0001SL SBC function ...
