2.8.11
MODEL 963
Requirements f Vehicle speed f20 km/hf The Electronic Stability Program (ESP“) is switched on, and the ESP“ OFF indicator lamp (A1 h20) and the ESP“ indicator lamp (A1 h22) in the instrument cluster (ICUC) control unit (A1) are not lit.
Function
During driving, the Electronic Brake Control (EBS) control unit (A10b, A10c) uses the signals:
f from the steering wheel angle sensor (SAS) (B66) f from the left front axle rpm sensor (B13) f from the right front axle rpm sensor (B14) f from the left rear axle rpm sensor (B15) and f from the right rear axle rpm sensor (B16)
to continuously monitor the nominal course specified by the driver and compares this course with the actual course.
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The Electronic Brake Control (EBS) control unit (A10b, A10c) calculates the actual course from the signals supplied by the yaw rate and lateral acceleration sensors integrated in the Electronic Stability Program (ESP“) control unit (A25, A25a), taking the vehicle speed into consideration.
As soon as the Electronic Brake Control (EBS) control unit (A10b, A10c) detects a deviation between the nominal course and the actual course, it triggers brake intervention at the individual wheels in order to correct the course.
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i On vehicles with code (A4X) Load>relievable, steered trailing axle (7.5 t) or with code (A4Y) Liftable, load>relievable, steered trailing axle (7.5 t):
If the additional steering axle (ASA) control unit (A34) reports a fault, the control intervention procedure is deactivated by the Electronic Brake Control (EBS) control unit (A10b, A10c) and the ESP“ indicator lamp (A1 h22) in the instrument cluster (ICUC) control unit (A1) lights up.
W42.45>1004>11
Intervention by the brake system when understeering
If the tractor vehicle brakes away above the front axle, a yawing moment is built up by selective braking of the rear wheel on the inside of the curve, which turns the tractor vehicle into the curve so as stabilize it.
During automatic intervention by the brake system, the ESP“ indicator lamp (A1 h22) in the instrument cluster (ICUC) control unit (A1) lights up.
1 Nominal course 2 Actual course
W42.45>1005>11
Intervention by the brake system when oversteering
If the tractor vehicle brakes away above the rear axle, the oversteering handling is counteracted by specific braking of the front wheel on the outside of the curve. Simultaneously the semitrailer is braked via the trailer control valve and jackknifing of the semitrailer/tractor combination by straightening the
semitrailer/tractor combination.
During automatic intervention by the brake system, the ESP“ indicator lamp (A1 h22) in the instrument cluster (ICUC) control unit (A1) lights up.
1 Nominal course 2 Actual course
Arrow Brake system intervention
Instrument cluster (ICUC) control unit, component description
A1
Page 331
Electronic Brake Control (EBS) control unit, component description
A10b, A10c
Page 341
Electronic Stability Program (ESP) control unit, component description
A25, A25a
Page 357
Additional steering axle (ASA) control unit, component description
A34
Page 364
Rpm sensor, component description B13, B14, B15, B16
Page 405
Steering wheel angle sensor (SAS), component description
GF42.45>W>2004H
Electronic Stability Program intervention with risk of overturning, function
2.8.11
MODEL 963
W42.45>1028>79
Illustration shows Wabco version
A1 Instrument cluster (ICUC) control unit
A1 h20 ESP“ OFF indicator lamp A1 h22 ESP“ indicator lamp
A2 Central gateway (CGW) control unit
A3 Drive control (CPC) control unit
CAN 2 Interior CAN CAN 3 Frame CAN CAN 4 Drive train CAN CAN 6d ESP“ brakes CAN
S912 Antilock braking system (ABS) /Electronic Stability Program (ESP“) button
A4 Engine management (MCM) control unit
A10b Electronic Brake Control (EBS) control unit (Wabco)
A25 Electronic Stability Program (ESP“) control unit (Wabco)
A43 Modular switch panel (MSF) control unit
Requirements
f Vehicle speed f20 km/h
f The Electronic Stability Program (ESP“) is switched on, and the ESP“ OFF indicator lamp (A1 h20) and the ESP“ indicator lamp (A1 h22) in the instrument cluster (ICUC) control unit (A1) are not lit.
Function
The Electronic Brake Control (EBS) control unit (A10b, A10c) monitors the course of the tractor vehicle and, to detect the vehicle's tendency to overturn, also monitors the lateral acceleration on corners. For this purpose, the Electronic Stability Program (ESP“) control unit (A25, A25a) supplies the signals from the integrated lateral acceleration sensor to the Electronic Brake Control (EBS) control unit (A10b, A10c).
The Electronic Brake Control (EBS) control unit (A10b, A10c) triggers a reduction in vehicle speed via the drive control (CPC) control unit (A3) or the engine management (MCM) control unit (A4) as soon as, due to inappropriate cornering speed, exceeding of the permissible lateral acceleration with increased risk of overturning is detected.
i If at the same time the tire pressure monitor (TPM) control unit (A35) detects a drop in pressure owing to a tire blowout, the Electronic Brake Control (EBS) control unit (A10b, A10c) lowers the control intervention threshold.
If despite reduced vehicle speed it is not possible to stabilize the vehicle during cornering, the Electronic Brake Control (EBS) control unit (A10b, A10c) initiates automatic braking of the vehicle.
The ESP“ indicator lamp (A1 h22) in the instrument cluster (ICUC) control unit (A1) flashes while the vehicle speed is being reduced or the vehicle is being braked.
Instrument cluster (ICUC) control unit, component description
A1
Page 331
Central gateway (CGW) control unit, component description
A2
Page 333
Drive control (CPC) control unit, component description
A3
Page 334
Engine management (MCM) control unit, component description
A4
Page 335
Electronic Brake Control (EBS) control unit, component description
A10b, A10c
Page 341
Electronic Stability Program (ESP) control unit, component description
A25, A25a
Page 357
Tire pressure monitor (TPM) control unit, component description
A35
Page 365
Modular switch panel (MSF) control unit, component description
GF42.60>W>0009H
Compressed air supply system, function
2.8.11
MODEL 963, 964
W42.60>1224>09
Illustration shows code (B1C) Electronic Air>Processing Unit (EAPU) (low) with dual compressor, switchable
1.10 Dual compressor, switchable 6.16 Electronic Air>Processing Unit
(EAPU) (low) 30.01 Safety valve
B26 Condensation sensor (only with code (B4A) Condensation sensor for compressed air system) B97 Temperature sensor (EAPU) 38.02 Test connection M16¥1.5
A18 Electronic Air Processing Unit (EAPU) control unit
Pneumatic connections
11 Compressed air supply (from compressor)
21 Compressed air release (rear axle brake circuit supply)
22 Compressed air release (front axle brake circuit supply)
23 Compressed air release (trailer control)
24 Compressed air release (ancillary consumers)
25 Compressed air release (parking brake)
26 Compressed air release (transmission control and clutch operation supply)
27 Compressed air release (air suspension)
Compressed air circuits
AS Trailer control FB Parking brake GS Transmission control RA Rear axle brake circuit KB Clutch operator NV Auxiliary consumers RB Pipe fracture protection VA Front axle brake circuit W Cab air suspension X Chassis air suspension
Compressed air reservoir
5.01 Compressed air reservoir (rear axle brake circuit supply) (V1)
5.01 Compressed air reservoir (front axle brake circuit supply) (V2)
5.01 Compressed air reservoir (trailer control brake circuit supply) (V3) 5.01 Compressed air reservoir
(transmission control and
automatic clutch operation supply) (V6)
W42.60>1225>09
Illustration shows code (B1D) Electronic Air>Processing Unit (EAPU) (mid) with dual compressor, switchable
1.10 Dual compressor, switchable 6.17 Electronic Air>Processing Unit
(EAPU) (mid) 30.01 Safety valve
B26 Condensation sensor (only with code (B4A) Condensation sensor for compressed air system) B97 Temperature sensor (EAPU) 38.02 Test connection M16¥1.5
A18 Electronic Air Processing Unit (EAPU) control unit
Pneumatic connections
11 Compressed air supply (from compressor)
21 Compressed air release (rear axle brake circuit supply)
22 Compressed air release (front axle brake circuit supply)
23 Compressed air release (trailer control)
24 Compressed air release (ancillary consumers)
25 Compressed air release (parking brake)
26 Compressed air release (transmission control and clutch operation supply)
27 Compressed air release (air suspension)
Compressed air circuits
AS Trailer control FB Parking brake GS Transmission control RA Rear axle brake circuit KB Clutch operator NV Auxiliary consumers RB Pipe fracture protection VA Front axle brake circuit W Cab air suspension X Chassis air suspension
Compressed air reservoir
5.01 Compressed air reservoir (rear axle brake circuit supply) (V1)
5.01 Compressed air reservoir (front axle brake circuit supply) (V2)
5.01 Compressed air reservoir (transmission control and
automatic clutch operation supply) (V6)
W42.60>1226>09
Illustration shows code (B1E) Electronic Air>Processing Unit (EAPU) (high) with dual compressor, switchable
1.10 Dual compressor, switchable 6.18 Electronic Air>Processing Unit
(EAPU) (high)
7.01 Overflow valve with return flow
B26 Condensation sensor (only with code (B4A) Condensation sensor for compressed air system) B97 Temperature sensor (EAPU) 30.01 Safety valve
38.02 Test connection M16¥1.5 A18 Electronic Air Processing Unit
(EAPU) control unit
Pneumatic connections
11 Compressed air supply (from compressor)
21 Compressed air release (rear axle brake circuit supply)
22 Compressed air release (front axle brake circuit supply)
23 Compressed air release (trailer control)
24 Compressed air release (ancillary consumers)
25 Compressed air release (parking brake)
26 Compressed air release (transmission control and clutch operation supply)
27 Compressed air release (air suspension)
Compressed air circuits
AS Trailer control FB Parking brake GS Transmission control RA Rear axle brake circuit KB Clutch operator NV Auxiliary consumers RB Pipe fracture protection VA Front axle brake circuit W Cab air suspension X Chassis air suspension
Compressed air reservoir
5.01 Compressed air reservoir (rear axle brake circuit supply) (V1)
5.01 Compressed air reservoir (front axle brake circuit supply) (V2)
5.01 Compressed air reservoir (transmission control and
automatic clutch operation supply) (V6)
5.01 Compressed air reservoir (air suspension supply) (V7)
General information
The compressed air supply system consists primarily of the Electronic Air>Processing Unit (EAPU) and the associated
compressed air reservoirs. The EAPU is a compact mechatronic unit containing the compressed air dehumidification unit, pressure regulation, protection of the compressed air circuits and the control electronics. Owing to its dynamic and energy>saving pressure regulation, the EAPU provides the following benefits: f Reduction in number of compressed air reservoirs f Intelligent regeneration management
f Increased compressed air availability for clutch and transmission control
f Improvement of air suspension lifting times f Improved compressed>air drying
f Deceleration phase control f Diagnosis capability
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Reduction in number of compressed air reservoirs
The pressure level of 12.5 bar in the compressed air reservoirs provides a high air volume, thereby reducing the number of compressed air reservoirs (depending on the vehicle variant). i Despite this, a pressure of max. 10.0 bar is applied at the brake cylinders. This pressure is limited by the Electronic Brake Control (EBS). The configuration and dimensioning of the brake are therefore unchanged.
Intelligent regeneration management
Owing to the intelligent regeneration management, no regeneration compressed air reservoirs are required. The compressed air required for regeneration is drawn from the compressed air reservoirs of the brake circuits.
i The pressure in the compressed air reservoirs of the brake circuits is reduced slightly by the regeneration process. This is not a malfunction or an indication of leakage.
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Increased compressed air availability for clutch and transmission control
The compressed air supply is protected and monitored separately from other auxiliary consumers. A separate compressed air reservoir provided for clutch and transmission control and integrated as a tubular crossmember in the frame ensures high compressed air availability for shift operations.
Improvement of air suspension lifting times
The pressure level of 12.5 bar in the compressed air reservoirs provides a large air volume. EAPU high, which has a separate compressed air reservoir with a pressure level of 15.0 bar in the air suspension circuit, is installed on vehicles with high air
consumption.
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Improved compressed>air drying
The intelligent regeneration management system optimizes air dehumidification. Depending on the operating state,
regeneration is possible even with the ignition switched off. Furthermore, the new cartridge technology with replaceable insert used for the "high" variant improves oil separation.
Deceleration phase control
In engine deceleration mode (downhill driving), the EAPU switches to the delivery phase, even if the cut>in pressure has not yet been reached.
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Diagnosis capability
The EAPU is integrated in the vehicle network via the Controller Area Network (CAN) and has diagnosis capability. The part number, measurement values, binary values and fault memory can be read out. The compressor version is also stored so that the delivery characteristics of the compressor can also be assessed. To be able to display safety>critical messages in the event of faults in the CAN, the EAPU is directly connected to the instrument cluster (ICUC) control unit (A1) via the EAPU>LIN (LIN 10) functioning as a redundant communication interface.
i The EAPU>LIN (LIN 10) does not have diagnosis capability. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
The EAPU is connected to the following components in the overall network:
f Engine management (MCM) control unit (A4) f Transmission (TCM) control unit (A5) f Drive control (CPC) control unit (A3)
f Electronic Brake Control (EBS) control unit (A10b, A10c) f Level control (CLCS) control unit (A26)
f Instrument cluster (ICUC) control unit (A1) f Central gateway (CGW) (A2)
Equipment variants
The EAPU is installed in three variants depending on the vehicle model and equipment.
f Code (B1C) Electronic Air>Processing Unit (EAPU) low f Code (B1D) Electronic Air>Processing Unit (EAPU) mid f Code (B1E) Electronic Air>Processing Unit (EAPU) high
Functional distinguishing features
EAPU low is intended for vehicles which have normal air consumption, which are not intended for operation with a trailer or which, owing to their brake configuration, require a separate compressed air reservoir in the trailer control circuit. Apart from the absence of an internal control unit for the trailer control circuit, this variant is essentially the same as the EAPU previously installed in the Actros (model 934), i.e. the "mid" variant. If, however, a trailer control unit is installed, a separate compressed air reservoir in the trailer control circuit is always required for this variant.
i EAPU low is only available from Haldex.
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EAPU mid is intended for vehicles with normal air consumption and is the same as the EAPU previously installed in the Actros (model 934). Owing to the presence of an internal control unit, a separate compressed air reservoir is not required for the trailer control circuit.
i EAPU mid is available from Haldex and Knorr and can be installed in the case of repair.
EAPU high is intended for vehicles with high air consumption and, unlike the "mid" variant, has an additional internal control unit for the air suspension circuit. A separate compressed air reservoir with a pressure level of 15.0 bar in the air suspension circuit provides a large air volume. An additional solenoid valve regulates filling of this compressed air reservoir and the circuit is monitored by an additional pressure sensor.
i EAPU high is only available from Haldex.
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Function
The compressor driven by the engine generates the compressed air. The compressed air first flows through the compressor line where it is cooled and then enters the EAPU. The compressed air is filtered and dehumidified by the compressed air desiccant cartridge. It is then distributed between the brake circuits and auxiliary consumer circuits and, if necessary, the air suspension circuit. The pressures in the compressed air circuits are monitored by pressure sensors and faults are signaled to the driver via the instrument cluster (ICUC) control unit (A1). In the case of a defective compressed air circuit, the EAPU protects the intact compressed air circuits against the defective circuit. The EAPU controls and regulates all functions on the basis of their preset