5_-_brakes.pdf

Brake System TATA Motors Limited 1

LPO 1623 GLOBUS Bus Body Builders Instruction Manual

Chapter Number 5 BRAKE SYSTEM Table of contents 1) Introduction. 2) Brake Schematic Circuit Layout. 3) List of components. 4) Position configuration & Nylon Pipe connection details 5) Precautions. 1) Introduction The Bus Body brake System Manual consists of Brake Schematic Circuit diagram and contains detail information about the brake aggregates used in brake system. The Brake schematic circuit also contains details about the auxiliary system, which uses compressed air. The Manual comprises of a list of components with information of the components in the Air - Brake system. The information covers the Part Numbers, description, make, type, technical details and function of each component. The information is explained by giving suitable figures of the component. The Manual also contains the position configuration. It shows where the components are positioned in a bus and details about the Nylon pipe connections from Front Module to Rear Module. It covers the precautions to be taken at the time of body building. Written by Checked by Date of Release

10-10-2005 Approved by

TATA MOTORS

LIMITED Revision No: 0

Revision Date:


2) Brake Schematic Circuit Layout The Brake Schematic Circuit layout consists of a skeleton diagram with description of all the valves used in the brake system. It also shows in detail about all the Auxiliary system operating on the compressed air. It shows how the various components are connected to one another, how the compressed air lines are routed in the chassis. Pipe connections and joints are displayed in the diagram. On the Brake aggregates the air connections are marked with a number describing what each connection is intended for. The designations are as follows Intake is normally 1, if there are two intakes, they are designated as 11 and 12. Outlet is normally designated 2; if there are several they receive the numbers 21, 22, 23 Number 3 is for Exhaust. There is an “END OF LINE CHECK” given in the Air Brake Schematic Sheet No. – 2. This End of the Line Check is required to be done after building the bus body. This End of the Line Check ensures correct functioning of the Brake System. Hence END OF THE LINE CHECK to be done mandatory after completion of bus body. The Brake Schematic Circuit is divided in Two Sheets. Sheet – 1/2 Shows the Nylon Pipe connections from Front Module to Rear Module. Sheet – 2/2 is divided into four tables

Table – I for Pneumatic Actuation System. Table – II for Characteristic of System Protection Valve. Table – III for Foundation Brake Details. Table – IV for End of the Line Check to be done after complete Brake assembly.

Please Refer Attached Drawing No. – 2892 4390 00 01 for Brake Schematic Circuit.


3) List of Components

Brake system o Aggregate Details

o Compressor

Function:

This compressor is used for building air pressure in reservoirs of air brake system in vehicles.

o Drying and Distribution Unit Integrated with Quadruple System

Protection Valve

Drying and distribution unit (DDU) combines the function of the Air dryer with unloader valve, purge tank (fitted with the air dryer) and the Quadruple System Protection Valve (QSPV)

Function:


Air Drying – Removes moisture completely from the compressed air Unloading – Regulates system pressure by exhausting the compressor delivery air to atmosphere when system pressure is reached and allows re-charging of the system when the system pressure reduces. Safety Valve – In case of any malfunctioning of the unloader, protects the compressor and system by blowing off the excess pressure. This device is integral with the unloader mechanism. Quadruple System Protection Valve (QSPV) – This function is integrated into the DDU, which protects the healthy circuits of the air brake system, in case of failure in one of the circuits. The non-return valves in this portion prevent back flow of stored compressed air upstream Tyre inflator – This device helps in tapping air from the DDU for inflation of vehicle tyres. Purge tank – This tank which is integral with the DDU stores dry air for regeneration of desiccant bed.

o Reservoir

o Dual treadle valve


Function: The unit gives a sensitive, graduated actuation during brake application and release of dual circuit brake systems on commercial vehicles.

o Relay Valve

Function: Relay valve is used to reduce the response time of brake

application when the driver applies the brake. The relay valve is connected in rear brake circuit.

o Quick Release Valve

o Brake Chamber

Function : The Brake chamber is used in the compressed air brake system to generate the braking force, by actuating the Slack adjuster to decelerate / stop the vehicle. It can also be used as a working cylinder for the operation of other equipment


o Spring Brake Actuator

Function:

The brake chamber applies the force of the compressed air to the service brake. The spring brake chamber has a compression spring for applying the parking brake. The brake is released by compressed air. The spring brake chambers are combined with a diaphragm section for the service brake section.

o Hand Brake Valve Delivery

Inlet Function:

This is an inverted, graduated ON-OFF valve and is used to control air pressure in the spring brake chambers to gradually apply and release the parking / hand brakes in proportion to the hand movement. This valve can also be used as an upright valve to deliver air pressure in a graduated manner to any auxiliary circuit. The valve can also be locked in brakes “OFF” or “ON” position by means of a sleeve to prevent accidental operation. This valve is generally mounted on the dash board on the driver’s cabin.

4) POSITION CONFIGURATION


POSITION CONFIGURATION FOR REAR MODULE

1) Air Tank For Retarder – is placed on Air suspension below mounting bracket in rear module as shown in fig.

2) Quick release Valve – is provided in rear brake parking lining and

mounted on rear axle through a mounting bracket. 3) Relay Valve – Provided in rear brake service line and mounted on

cross member just before the rear axle through a mounting bracket.

1

2

3


POSITION CONFIGURATION FOR FRONT MODULE

1) The Air Tank for front Brake, Rear Brake, Air Suspension and Auxiliary Air Tank are placed in Front Module as shown in fig.

2) Dual Treadle Valve – Place on floor panel in driver cabin.

3) Hand Brake Valve – Placed on Dash Board through a mounting

Bracket.

4) Drying &Distribution Unit – Place on cross Member in front module.

NYLON PIPING CONNECTION DETAILS

4 3

2

1


Precautions

1) The Nylon pipe connections from front module to rear module should be done as per Brake Schematic circuit layout.

2) The area near the air tank should be accessible for draining the

moisture from the air tank, for this a flap type cover should be provided in that area.

3) Care should be taken for accessibility of all the valves after doing

body building or Paneling work on the vehicle. All the valves should be accessible for repair or ease in changing them.

4) Nylon pipe should be protected from welding spatters or any other

hot objects at the time of body building on the vehicle.

5) After completing all the nylon pipe connections as per Brake schematic circuit, do the “End of the Line Check” as mentioned in the brake schematic circuit.

6) The Nylon Pipe Routing should be done in such a way that, it

should be accessible for checking any leakages, cut or Kink in the Nylon pipe.

7) Ensure that all pipes & fittings are free of dust from inside &

outside.

8) Ensure that the routing of nylon pipes should be such that it should not touch to any hot objects.

9) Ensure that the nylon pipes do not rub against any sharp edges.

10) Ensure that there are no Kinks or Folds in the nylon pipes.

11) For the requirement of additional Auxiliary connections (i.e.

Pneumatic Horn, driver seat suspension and locking of luggage compartment hatch) connection should be taken from 24 Port of DDU from where all the auxiliary connections are given.


Connection to Pneumatic horn should not be given from Dual Brake valve connections. It affects the function of brake system.

12) The Bus Body builder should not tamper the setting of the valves.

In case of some brake problem or system not generating sufficient pressure. It should be informed to chassis manufacturer.

13) The Bus Body builder should not change the location of any brake

aggregates for ease in Body Building. If there is a requirement for changing the location of brake aggregates, it should be done after approval from Chassis Manufacturer.

14) The Air pipelines should be cleaned with a compressed air before

connecting.

15) Work on Brake system should be carried out by persons with sufficient earlier experience in doing brake-piping connections.

16) Ensure that the relief outlets and draining outlets are not plugged

or painted by Bus Body builder.

Retarder installation instructions

Precautions to be taken for Retarder while assembling the Body on Chassis system.

1. There should be enough clearance between Retarder cooling circuit pipes and body member to ensure

• That there should not be fouling with pipes in the extreme movement conditions of components on bump.

• There should be air column of 50 mm min. so that there will be sufficient heat transfer to air from pipes to atmosphere.

2. Pipes of the retarder should be maintained at a height which is well

above lowest part of the vehicle i.e. Engine Oil sump or Differential housing.

3. Retarder ECU Location should be easily accessible.


4. Retarder ECU should be located close to ABS ECU so that the wiring length can be minimized.

5. All the ECU’s should be nicely covered with a casing to protect it

from dust, stones, mud etc. 6. 3 stage air pressure control switch for retarder should have an easy

access.

7. If possible body panel should cover the accelerator sensor switch to protect it from dirt, mud, stone etc. Enclosure should not affect accelerator linkage movement.

8. Retarder Hand lever switch should be ergonomically positioned with

respect to Driver seat, so that it is easily operable in all the driving conditions.

9. There should be provision made on dashboard panel for audio &

visual signal while operating retarder.

10. No NVH pad should cover retarder; this is required for effective heat transfer to atmosphere.

11. While welding, brazing care should be taken that the any of the air

connections, electrical wiring, ECU and Proportionate valve should not get damaged.

12. Please ensure that the following before cranking the engine.

• Proper amount of specified oil grade is there in retarder before cranking the engine.

• Please ensure recommended amount of coolant is present in the Engine & retarder cooling circuit.


ABS installation instructions

Procedure for installing Modulator valve / Sensor extension cable assemblies (Rear frame harness) Following aspects to be taken into consideration while installing Rear frame harness comprising of Modulator valve and sensor extension cable assemblies 1. Refer the following table for Modulator valve cable assemblies as well as

the sensor extension cable assembly’s fitment on 18 pin female housing Description Where to connect the crimped

end of the Modulator valve cable assemblies in 18 pin connector female housing

Where to connect the crimped end of the Sensor Extension cable assemblies cable assemblies in 18 pin connector female housing

Rear left (RL) Rear left (RR) Rear left (RL) Rear left (RR) EV – inlet solenoid

2 8 --- ---

AV – outlet solenoid

5 9 --- ---

IG- sensor input

--- --- 14 18

IGM- sensor input

--- --- 11 17

2. The crimped wires of Modulator valve cable assembly (EV – inlet

solenoid and AV - outlet solenoid) and sensor extension cable assemblies (IG and IGM – Sensor inputs) to be inserted fully in the respective slots as detailed above.

3. After fully inserting the crimped wires ensure that the Junior Power

Terminal (JPT) is crimped to the Modulator valve and sensor extension cable assemblies are properly locked. This can be ensured by gently pulling the inserted crimped wires by hand.


4. Plug the crimped connector to the 18 pin female housing in the Electronic control unit (ECU) and ensure that the female 18-pin connector is fully locked with the ECU male connector

5. Modulator valves and Sensor extension cable assemblies to be covered

with corrugated tubes wherever it is routed through sharp edges. ECU Installation 1. ECU housing must be secured in such a way that the permissible

acceleration of 5g is not exceeded. 2. ECU must be protected from water entry and the installation has to avoid

proximity of heating devices so that hot air is diverted away from ECU. 3. Fixation of the ECU is through screws End of Line checking procedure using compact tester

Connecting the tester 1. Connect nine pole plug of the WABCO diagnostic cable into the

appropriate socket on the compact tester and connect other end of the cable to the diagnostic socket located in the cab

2. Switch on the ignition. Now the tester displays “888” 3. After approximately 12 seconds the tester tries to establish the diagnostic

connection with the ECU. The display begins to flash. After establishing connection with ECU successfully the type of system identified will be displayed

Ex- Time Display Comments 0-1 Sec ABS Only ABS system is

installed After 1 Sec or after 2 Sec

D Signifies D- Version


1. Error search

Push « ERROR » button located in the front panel of compact tester to read errors. The display of error is explained below digit wise

1st Digit 2nd Digit 3rd Digit Error path Error type Frequency Note: Refer attached file on compact tester for front panel description

2. Error Delete (< CLEAR BUTTON>)

Push the < CLEAR > button located in the compact tester front panel for more than 0.5 Sec. The whole error memory in ECU is deleted. Note: a) This is done only provided there is no currently existing error

b) To delete the whole of the error memory the ignition needs to be switched OFF and then ON again. After this the display once again shows the type of ECU identified (“ABS”)

If an ABS –D ECU is connected the system used will be shown as follows

3. Display system (< system>) button By pushing the < SYSTEM> button the system identified by the ECU can be displayed For a 4S4M system the display will be as follows

System Display For a 4S / 4M system 4 ----- 4

4. Functional Testing

After initial installation of ABS system the proper pneumatic and electrical allocation of the components must be checked. The functional test is activated by pushing the following buttons:

a) Push < SYSTEM> button and release b) System used (e.g. 4-2) is displayed


c) Push < CLEAR> button for more than 2 seconds. After 2 seconds “SYS” appears on the display.

d) If the warning lamp was ON it will go OFF before the < CLEAR> button is released

e) Pushing the < CLEAR> button for longer than 0.5Sec causes the next test step to be addressed.

f) If any other button is pushed for longer than 0.5Sec the functional test is aborted and the type of ECU identified appears on the display (ABS)

5. Testing Retarder control

When <CLEAR> button is pushed again for longer than 0.5 Sec the retarder is in active for 5 Sec (Display: “005” …. “000”). Depending on the type of retarder used the effect of this will vary Note: a) For more information please refer to the test instructions for the appropriate retarder b) If no retarder is identified the first digit of the display shows a dash in place of a zero

6. Allocation testing – without control pressure

a) After testing retarder control one wheel can be turned without the < CLEAR> button is being pushed again. The display shows the current speed of the wheel being turned in Kilometer per hour (K.P.H).

(Example: Wheel speed measured for wheel A = 5.6 k.p.h = display “A05”) b) Continue the same procedure as outlined in point (a) for other 3

wheels c) If ECU detects a speed more than one wheel the display will

show “--- --- --- “. d) The sensor / Modulator valve allocation is checked by

determining that the correct sensor / Modulator valve have been paired by way of listening or feeling.

e) The functional test is aborted by pushing any of the buttons.

5_-_brakes.pdf

Documents

air brake system

brake aggregates

reservoirs of air brake

brake system table of

bus body brake system

air brake schematic

brake schematic circuit

foundation brake details