EST-42 gearbox

F544

C907

C906

B089

A100

HD-OBD

B088

E593

CANnetwork

CF75 IVCF85 IVXF105

System and component informationZF intarder EST 42

© 200634 DW

©200634 DAF Trucks N.V., Eindhoven, The Netherlands.

In the interest of continuing product development, DAF reserves the right to change specifications or products at any time without prior notice.

No part of this publication may be reproduced and/or published by printing, by photocopying, on microfilm or in any way whatsoever without the prior consent in writing of DAF Trucks N.V.

STRUCTURE

© 200634

ΧΦ75 Ις/85 Ις, ΞΦ105 series

0

1

Structure TECHNICAL DATA

ZF INTARDER EST 42

© 200634 1

ContentsTECHNICAL DATA


0Technical dataCONTENTS

Page Date

1. ZF INTARDER EST 42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . 2006341.1 Power supply and earth of electronic unit . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . 2006341.2 CAN connections electronic unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 . . . . . 2006341.3 K-line electronic unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . 2006341.4 Steering column switch / Steering wheel switches . . . . . . . . . . . . . . . . . . 1-4 . . . . . 2006341.5 Coolant temperature sensor, intarder . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6 . . . . . 2006341.6 Neutral position switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8 . . . . . 2006341.7 Intarder proportional valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9 . . . . . 2006341.8 Intarder air supply valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11 . . . . 200634

2 © 200634

TECHNICAL DATAContents ΧΦ75 Ις/85 Ις, ΞΦ105 series

0

© 200634 1-1

ZF intarder EST 42TECHNICAL DATA


01. ZF INTARDER EST 421.1 POWER SUPPLY AND EARTH OF ELECTRONIC UNIT

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414

A Electronic unit connection point

B Description of connection point

C Reading at connection point (Ubat = battery voltage)

D Measuring unit

E Explanatory notes (if applicable)

F 'X' mark indicates that additional information is available in 'Technical data'

A B C D E F

20 Earth(In combination with manual gearbox in-put signal neutral position switch E593)

< 0,5 V DC Voltage loss measurement with as many consumers as possible switched on.

27 Earth < 0,5 V DC Voltage loss measurement with as many consumers as possible switched on.

28 Earth < 0,5 V DC Voltage loss measurement with as many consumers as possible switched on.

31 Power supply after contact Ubat V DC Ignition on

53 Power supply after contact Ubat V DC Ignition on

54 Power supply before ignition Ubat V DC

55 Power supply before ignition Ubat V DC

1-2 © 200634

TECHNICAL DATAZF intarder EST 42 ΧΦ75 Ις/85 Ις, ΞΦ105 series

0 1.2 CAN CONNECTIONS ELECTRONIC UNIT

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414




D Measuring unit



A B C D E F

22 V-CAN2-H According to ISO 11898

49 V-CAN2-L According to ISO 11898

© 200634 1-3



01.3 K-LINE ELECTRONIC UNIT

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414




D Measuring unit



A B C D E F

14 HD-OBD diagnostic connector (A100)

1-4 © 200634


0 1.4 STEERING COLUMN SWITCH / STEERING WHEEL SWITCHES

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414




D Measuring unit



A B C D E F

15 Steering column switch position 1 input signal

0 VDC If switch not operated

Ubat VDC If switch is in position 1





0 VDC If switch is in position 1








© 200634 1-5



0

Downhill Speed Control function

V301054

100%

66%

33%

0%

Position - 0 intarder offPosition - 1 33% braking powerPosition - 2 66% braking powerPosition - 3 100% braking power

K102020

1 3 5

2 4 6

Downhill Speed Control 0% - 100% braking power

1-6 © 200634


0 1.5 COOLANT TEMPERATURE SENSOR, INTARDER

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414




D Measuring unit



A B C D E F

9 Input signal, coolant temperature (F544) 5 V DC Open voltage, with detached connec-tor

X

37 Earth, coolant temperature sensor (F544)

< 0,5 V DC

© 200634 1-7



0

Resistance in relation to measured temperature

V300589

Model NTC

Temperature ( C) Resistance ( )Minimum Maximum

20 - 25 33000 4700080 3300 370090 2400 2600100 1650 1750110 1250 1350120 950 1050130 700 800140 550 590

1-8 © 200634


0 1.6 NEUTRAL POSITION SWITCH

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414




D Measuring unit



A B C D E F

20 Input signal neutral position switch (E593)

Ubat V DC Gearbox in neutral

< 0,5 V DC Gear box in gear

Model Normally Open

© 200634 1-9



01.7 INTARDER PROPORTIONAL VALVE

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414




D Measuring unit



A B C D E F

3 Earth, proportional valve (B088) < 0,5 V DC X

4 Output signal, proportional valve (B088) - % (I) Duty cycle (control current) depends on the switch position selected

X

1-10 © 200634


0

Readings

V300603

Resistance of intard-er proportional valve at 20 to 25 C 23 - 27

The following table lists the proportional valve control currents and the accompanying pressures in the intarder.Control current with defective coolant tempera-ture sensor or with temperature > 120 C 250 ≥ 15 mA

Switch position Control current Control pressure Intarder pressure Pump pressure0 0 - 15 mA 0 bar 1.5 bar 1.5 bar

Downhill Speed Control

0 - 425 ≥ 15 mA 0 - 5.5 ≥ 1 bar 1.5 - 10.25 ≥ 1 bar 10.5 ≥ 1 bar

1 255 ≥ 15 mA 2.0 ≥ 1 bar 3.0 ≥ 1 bar 10.5 ≥ 1 bar2 320 ≥ 15 mA 3.0 ≥ 1 bar 5.5 ≥ 1 bar 10.5 ≥ 1 bar3 430 ≥ 15 mA 5.0 ≥ 1 bar 10.0 ≥ 1 bar 10.5 ≥ 1 bar

© 200634 1-11



01.8 INTARDER AIR SUPPLY VALVE

55 54 53 49 44 42 37 34 31 30 2952

28 27 22 20 18 16 15 9 1V300601

23414




D Measuring unit



A B C D E F

1 Output signal air supply valve (B089) Ubat V DC Valve activated

34 Earth air supply valve (B089) < 0,5 V DC

1-12 © 200634


0

V300446

Resistance of intard-er air supply valve at 20 to 25 C 125 - 145 Required air pres-sure 6.3 - 10 bar

© 200634 1

ContentsZF INTARDER EST 42


1

ZF intarder EST 42CONTENTSPage Date

1. GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . 2006341.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 . . . . . 200634

2. SYSTEM DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . 2006342.1 Electrical system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 . . . . . 2006342.2 Hydraulic system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 . . . . . 2006342.3 Intarder switched off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6 . . . . . 2006342.4 Switching the intarder on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7 . . . . . 2006342.5 Intarder switched on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9 . . . . . 2006342.6 Switching the intarder off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11 . . . . 200634

3. DESCRIPTION OF COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 . . . . . 2006343.1 Control switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 . . . . . 2006343.2 Coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3 . . . . . 2006343.3 Neutral position switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4 . . . . . 2006343.4 Intarder proportional valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5 . . . . . 2006343.5 Intarder air supply valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7 . . . . . 2006343.6 Volume control valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8 . . . . . 2006343.7 Freewheeling torque reducing system. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9 . . . . . 200634

4. CONTROL FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 . . . . . 2006344.1 Limitation of power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 . . . . . 2006344.2 Downhill Speed Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3 . . . . . 2006344.3 Temperature adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7 . . . . . 2006344.4 Control with activated ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9 . . . . . 2006344.5 Control via CAN network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10 . . . . 200634

5. DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 . . . . . 2006345.1 Hydraulics diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 . . . . . 2006345.2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 . . . . . 200634

2 © 200634

ZF INTARDER EST 42Contents ΧΦ75 Ις/85 Ις, ΞΦ105 series

1

© 200634 1-1

GeneralZF INTARDER EST 42


1

1. GENERAL1.1 INTRODUCTION

This system manual describes the layout, operation and control of the ZF intarder EST42.

The intarder is a wear-resistant, hydraulic continuous brake. It is primarily intended for use in prolonged braking, for example when decelerating from high speed on a level road or when driving downhill. This reduces service brake wear. The intarder can be switched on with the right-hand steering column switch.

The main functions of the ZF intarder EST42 are:

1. Continuous operation of a wear-resistant vehicle brake. When driving on a level road or when driving downhill, the intarder can be used to slow down the vehicle without using the service brake, depending on the selected level for the (constant) braking moment. This will relieve the service brake.

2. Downhill Speed Control function The Downhill Speed Control function of the intarder can be used to achieve a constant vehicle speed (within the system limits) when driving downhill.

3. Communication with other vehicle systems to guarantee the optimum braking effect.

1-2 © 200634

ZF INTARDER EST 42General ΧΦ75 Ις/85 Ις, ΞΦ105 series

1

© 200634 2-1

System descriptionZF INTARDER EST 42


1

2. SYSTEM DESCRIPTION2.1 ELECTRICAL SYSTEM

The electrical section of the intarder consists of the electronic unit EST 42 and a number of components which provide input signals and a number of components which are controlled depending on the input signals.

A number of control functions have been programmed in the electronic unit. For example:

1. Limitation of power2. temperature control3. Control with activated ABS4. Downhill Speed Control5. Control via CAN

In order to be able to perform the control functions, the electronic unit EST 42 requires various input signals and the electronic unit will control various components.

V301052

F544

C907

C906

B089

A100

HD-OBD

B088

E593

CANnetwork

2-2 © 200634

ZF INTARDER EST 42System description ΧΦ75 Ις/85 Ις, ΞΦ105 series

1

Input signals- Intarder steering column switch positions

(C906/C907)- Gearbox neutral position (E593)- Downhill Speed Control (via V-CAN2)- Coolant temperature intarder (F544)

Output signals- Intarder air supply valve (B089):- Proportional valve (B088)

EST 42 communicates via V-CAN2 with various other vehicle systems.EST 42 is diagnosed using DAVIE XD via a K-line.

© 200634 2-3



1

2.2 HYDRAULIC SYSTEM

The hydraulic section of the intarder consists of a housing which is mounted behind the gearbox. The hydraulic system is controlled and regulated by the electrical system.

2-4 © 200634


1

8

2

V300602

1

4

3

5

7

6

9

10

1 Oil pump pressure control valve2 Selector valve spring sealing plug

© 200634 2-5



1

3 Accumulator4 Heat exchanger5 Control plunger for proportional solenoid

valve6 Stator and rotor7 Oil pump gear wheels8 Freewheeling torque reduction ring

segment9 Freewheeling torque reduction control

plunger10 Residual pressure valve

2-6 © 200634


1

2.3 INTARDER SWITCHED OFF

When the intarder is switched off, the steering column switch is in position 0 (zero position).The proportional valve (8) is not energised by the electronic unit; the pressure in the intarder circuit is 0 bar (there is no oil in the intarder circuit). This means that the pressure between the control plungers of the freewheeling torque reducing system (10) is also 0 bar. The ring segments of the freewheeling torque reducing system are now situated between the stator and rotor and thus reduce the friction in the drive line.

The intarder oil pump (3) pumps the oil via the selector valve (13) to the heat exchanger (16) and into the accumulator (11). The accumulator is filled with oil until a maximum pressure of 1.5 bar is reached, this pressure being limited by the residual pressure valve (14). The output of the oil pump (3) depends on the vehicle speed. After the intarder has been switched off, the accumulator (11) will be completely full when approximately 500 metres have been covered.

Any excess oil goes back to the gearbox oil reservoir. When the accumulator (11) is full, the gearbox oil is pumped through the heat exchanger (16). In this way the gearbox oil is continuously cooled.

1

2

3

4

56

7

8

9 11

12

13

10

14

15

1617

18

19

12Q

1

2

1 2

V300582

© 200634 2-7



1

2.4 SWITCHING THE INTARDER ON

The steering column switch can be used to switch the intarder on and to select the desired braking moment. The electronic unit then activates the following components:

- the proportional valve (8). The current supplied by the electronic unit depends on the desired braking moment. The control pressure is set by means of the proportional valve.

- the intarder air supply valve (12). The air pressure (max. 10 bar) pumps the oil out of the accumulator into the intarder circuit.

Further control is completely hydraulic.

The proportional valve (8) sets a control pressure that depends on the current supplied by the electronic unit. Two valves are actuated on the basis of this control pressure, viz.:

1

2

3

4

56

7

8

9 11

12

13

14

15

1617

18

19

12Q

1

2

1 2

V300596

10

2-8 © 200634


1

1. the selector valve (13). The control pressure switches the selector valve (13) directly. This valve being switched results in a so-called intarder circuit. Now the oil runs from the rotor/stator via the selector valve (13) to the heat exchanger and then back again to the rotor/stator via the selector valve (13).

2. the volume control valve (9). The control pressure determines the position of the valve. This position ensures that the oil pump can actually pump oil into the intarder circuit. In the intarder circuit a pressure is built up and this intarder pressure, the control pressure and a preset spring pressure determine the position of the valve.

© 200634 2-9



1

2.5 INTARDER SWITCHED ON

If the intarder is switched on, the electronic unit supplies a constant current to the proportional valve (8). As a result, this valve also supplies a constant control pressure to the selector valve (13). Owing to this control pressure, the pump pressure, the spring pressure and the pressure in the intarder circuit, the volume control valve (9) reaches a state of balance.

The pressure in the intarder circuit determines the braking power supplied by the intarder. This pressure depends on the degree of filling and the rpm, so that the volume control valve (9) will constantly search a state of balance via the speed range. If the intarder is switched on, only part of the total quantity of oil in the gearbox is pumped through the heat exchanger (16).

The pressure in the intarder circuit also exists in the freewheeling torque reducing system (10). The ring segments between the stator and rotor are now pushed out, so that they no longer affect the braking effect of the intarder.

1

2

3

4

56

7

8

9 11

12

13

14

15

161017

18

19

12Q

1

2

1 2

V300597

2-10 © 200634


1

Changing to another brake positionIf another braking moment is desired via the operating handle, the electronic unit will vary the current to the proportional valve (8). As a result, the proportional valve (8) supplies an altered control pressure, so that the volume control valve (9) takes on a new balanced position. This will change the oil pressure in the intarder circuit, resulting in the desired braking moment.While the intarder is in use, the intarder air supply valve (12) stays activated so that there is still air pressure on the accumulator (11).As long as there is oil pressure in the stator/rotor circuit, the ring segments of the freewheeling torque reducing system are not positioned between the stator and rotor.

© 200634 2-11



1

2.6 SWITCHING THE INTARDER OFF

When the intarder is switched off, the air supply valve (12) is no longer energised. As a result, the accumulator (11) is bled and once again completely filled with oil.

The proportional valve (8) is no longer controlled by the electronic unit, so that there is no control pressure on the selector valve (13). The selector valve (13) becomes pressureless and is pressed in such a position by the pre-tensioned spring that no more oil is pumped into the intarder circuit. The remaining oil leaves the intarder circuit via the volume control valve (9). The oil is then only pumped through the heat exchanger (16). Air is all that is left in the intarder circuit.

The oil pressure in the freewheeling torque reducing system (10) falls away as well.The spring tension causes the control plungers and therefore also the ring segments to move in between the stator and rotor. The air flow between the stator and rotor is blocked, which reduces the friction loss moment.

1

2

3

4

56

7

8

9 11

12

13

10

14

15

1617

18

19

12Q

1

2

1 2

V300582

2-12 © 200634


1

© 200634 3-1

Description of componentsZF INTARDER EST 42


1

3. DESCRIPTION OF COMPONENTS3.1 CONTROL SWITCHES

When the vehicle is equipped with an intarder, then the vehicle is always fitted with one of the two steering column switches illustrated in combination with steering wheel switches.

Switching the intarder onThe intarder is switched on by moving the right-hand steering column switch downwards from the rest position (OFF). The intarder has three positions (1, 2 and 3). The Downhill Speed Control must be activated via a steering wheel switch.

The division of the maximum braking effect of the intarder is as follows:

V301043

1

2

3

V301044

1

2

3

K102020

1 3 5

2 4 6

Rest position (OFF)

Intarder not active

Brake position 1:

approx. 33% of the maximum braking effect.

Brake position 2:

approx. 66% of the maximum braking effect.

Brake position 3:

the maximum braking effect (with the as-sistance of the engine brake).

Downhill Speed Control

0 to 100% braking effect.

3-2 © 200634

ZF INTARDER EST 42Description of components ΧΦ75 Ις/85 Ις, ΞΦ105 series

1

Note:If the warning indicator '"(( ® ))" on the instrument panel lights up, the intarder is activated.

Switching the intarder offThe intarder is switched off by moving the steering column switch upwards into its rest position (OFF).

Engaging Downhill speed controlThe Downhill Speed Control is activated by pressing the spring-operated switch (5) on the left-hand steering column switch. When the intarder is switched on in the Downhill Speed Control, the intarder will not allow the vehicle to go faster than the speed it was doing when it was switched on.

Disengaging Downhill speed controlPress steering wheel switch (6) to deactivate Downhill Speed Control.

V300611

R

K102020

1 3 5

2 4 6

© 200634 3-3



1

3.2 COOLANT TEMPERATURE SENSOR

The coolant temperature sensor is an NTC resistor. The resistance decreases as the temperature increases. The coolant temperature at the output side of the cooler is monitored with the aid of this sensor. If the coolant temperature is too high the maximum available intarder braking moment is adjusted. See "Technical data". A special control in the electronic unit of the intarder is put into operation before the maximum permissible temperature is reached so that the braking moment is adjusted.

V300589

3-4 © 200634


1

3.3 NEUTRAL POSITION SWITCH

The neutral position switch (E593) is fitted on the gearbox gearshift cover.If a gear is engaged, the selector shaft (5) is in such a position that pin 4, its contact surface against the pressure of spring 3, links connections 1 and 2. The neutral position switch is now closed and an earth signal is therefore sent. This signal can be used for various vehicle systems or functions (intarder, engine management, cruise control, engine speed control).

The table below lists the statuses of the neutral position switch.

V300612

2

4

3

1

5

Gearbox Neutral position switchNeutral Open

Gear engaged Closed

© 200634 3-5



1

3.4 INTARDER PROPORTIONAL VALVE

This valve converts the control current supplied by the electronic unit into a control pressure in the intarder housing. The proportional valve consists of two parts: a solenoid valve and a control plunger.The solenoid valve is located on the outside of the intarder housing.

The control plunger is located inside the intarder housing.The solenoid valve is a duty-cycle controlled valve. This means that the control current gets higher as the duty cycle increases.Inside the solenoid valve there is a core.The force with which the core is pressed out of the coil depends on the duty-cycle value (control current).The core pushes against the control plunger of the proportional valve.

V300603

V300604

3-6 © 200634


1

Operation of control plungerThe control plunger (7) of the proportional valve is located inside the intarder housing.When the proportional valve is not in operation, the control plunger (7) is in its extreme right position.The pump pressure side (1) is cut off from the control pressure side (2) and the return side (3) is connected to the control pressure side (2).

When the solenoid valve (5) presses the core (6) to the left, the core in its turn will press the control plunger (7) to the left.The pump pressure side (1) is connected to the control pressure side (2) and the return side (3) is cut off. The control pressure increases.The pressure in the control pressure side (2) can reach the enclosed space (8) to the left of the control plunger (7) via a bore (4) in the control plunger (7).

The control pressure on the left-hand side of the control plunger (7) and the force exerted by the core (6) on the right-hand side of the control plunger (7) create a state of balance so that the control pressure is adjusted.

1 2 3

7

5

48

6

V300251

© 200634 3-7



1

3.5 INTARDER AIR SUPPLY VALVE

This valve is an electropneumatic 3/2-way valve. This valve is used to pass on the air pressure from the air supply system to the accumulator.As a result, the intarder responds more quickly so that braking power is available to the driver right away.

When the intarder is switched on, the electronic unit energises the air supply valve.The air pressure sets the piston in the accumulator in motion. The piston presses the oil out of the accumulator and forces it into the intarder circuit.

When the intarder is switched off the air supply valve is no longer energised.The oil pressure will cause the piston to move upward.The air above the piston can escape into the air supply valve via a bore.

V300446

3-8 © 200634


1

3.6 VOLUME CONTROL VALVE

The volume control valve consists of a plunger (8) and a control plunger (9).In rest position, the spring (7) presses the control plunger (9) in its extreme left position. The return side (1) is connected to the intarder pressure side (2).The pump pressure side (3) is cut off from the intarder pressure side (2). In this way the intarder pressure side (2) is pressureless.

When there is a control pressure on the left-hand side of the control plunger (9), the control plunger (9) is pushed to the right, against the spring pressure. The pump pressure side (3) is now connected to the intarder pressure side (2) and the return side (1) is cut off.This causes the pressure on the intarder pressure side (2) to increase. The intarder pressure (2) can get into the control plunger (9) via bore 6 in the control plunger (9). The pressure in the control plunger (9) and the force exerted by spring 7 cause the control plunger (9) to move to the left against the control pressure, until it reaches a state of balance.In this way it is possible to control the intarder pressure and the resulting braking moment.

1 2

74 9 86

3 1 5

V300252

© 200634 3-9



1

3.7 FREEWHEELING TORQUE REDUCING SYSTEM

The freewheeling torque reducing system consists of a double control plunger (4) with spring (1) and two ring segments (5) that hinge on pivot points (2). The pivot points (2) are located inside the intarder housing (12).

5

2

5

2

8

9

1 4 4 1 7

12

V300609

3-10 © 200634


1

Both ring segments (5) are located between the stator (9) and the rotor (8). When the intarder is switched on and off, the oil pressure moves the ring segments (5) parallel to the stator and the rotor. The ring segments (5) are mechanically connected to the control plungers (4).

V300608

10

8

11

2

3 6

5

4

9

© 200634 3-11



1

Intarder not switched onIf the intarder is not switched on, all the oil has disappeared from the intarder circuit and the intarder circuit is pressureless. The pressure exerted by the springs (1) causes the control plungers (4) of the freewheeling torque reducing system to move inwards.The ring segments (5) have a cam on the underside, which falls into a recess in the plunger (4). In this way the moving plunger carries the ring segment along.The ring segments move between the stator and rotor, impeding the air flow between the rotor and stator. The friction between the stator and rotor decreases, reducing the friction losses in the drive.

Intarder switched onWhen the intarder is switched on, oil pressure builds up in the intarder circuit.The oil pressure reaches the intarder housing via the rotor (11) outlet and bores 3 and 6 between the two control plungers. The oil pressure presses both control plungers outward against the pressure of both springs (1). The ring segments are mechanically connected to the control plungers and are consequently moved away from their position in between the stator and rotor. The ring segments do not hinder the oil flow between the rotor and stator, so that the intarder can use maximum braking force.

V300618

2 55

634 4 11 7

V300619

2 55

634 4 11 7

3-12 © 200634


1

© 200634 4-1

Control functionsZF INTARDER EST 42


1

4. CONTROL FUNCTIONS4.1 LIMITATION OF POWER

Limitation of powerThe electronic unit uses the braking moment (control current to proportional valve) and the speed of the output shaft to calculate the braking power that has been built up. When the calculated braking power has reached the maximum value, the electronic unit reduces the current to the proportional valve. This will decrease the control pressure in the intarder unit and the volume control valve reduces the intarder pressure. In this way the braking power is limited to a maximum.

Power limitation in constant brake positionOne of the constant brake positions can be selected using the steering column switch. If the vehicle speed varies somewhat while driving downhill while the brake is in a constant position, the electronic unit of the intarder automatically adjusts the current to the proportional valve.

Should the vehicle speed increase a little, the current through the proportional valve will slightly decrease. The braking moment will become lower, yet the braking power remains constant.

Power limitation during accelerationIf the accelerator pedal is operated while one of the constant brake positions has been selected, the current maximum available braking power is reduced by 100 kW. If the desired braking power is below the current maximum available braking power, the reduction will be less as well. A situation may occur in which there is no reduction at all.

If the Downhill Speed Control function is active then there is no reduction during acceleration but the Downhill Speed Control function is switched off.

3500

3000

2500

2000

1500

1000

500

0 100 300 700 1100 1500 1900 2300 [min-1]

[Nm] 420 kW

V300583

I [A]

V [km/h]

V300584

4-2 © 200634

ZF INTARDER EST 42Control functions ΧΦ75 Ις/85 Ις, ΞΦ105 series

1

Power limitation at low engine speedWhen the intarder is activated, the electronic unit of the intarder checks the engine speed.

If too low an engine speed is detected, the maximum braking power of the intarder is restricted.

When the engine speed is low and consequently the coolant pump output is low, the through-flow of the cooling system will be low as well. If the coolant flows slowly through the cooling system, the oil in the intarder cannot be sufficiently cooled and the coolant temperature becomes too high.

This situation may occur when the intarder is activated while driving downhill and a high gear (too high) has been chosen.

350

300

250

200

150

100

50

0 0 1000 2000 500 1500 2500 3000 3500

450[kW]

400

V300588

[min-1]

© 200634 4-3



1

4.2 DOWNHILL SPEED CONTROL

This control keeps the desired vehicle speed at a constant level during descents.

Downhill Speed Control can be activated with the steering wheel switch (5).The current vehicle speed is stored in the electronic unit.The intarder is switched on when the vehicle speed increases:

- the warning indicator on the instrument panel is activated.

- the proportional valve and the air supply valve are activated.

If the vehicle speed keeps increasing, the electronic unit generates a higher control current, so that the braking moment of the intarder increases. The intarder is switched off once the vehicle speed has been reduced to the stored value.

V300592

K102020

1 3 5

2 4 6

V300611

R

4-4 © 200634


1

When the intarder is switched off via the steering column switch (OFF) or the ignition lock or when it is switched to position 1, 2 or 3, the Downhill Speed Control value stored in the electronic unit is erased.

Note:During Downhill Speed Control, the maximum braking moment is also possible under certain conditions, for instance on long descents!

Selection of Downhill Speed Control during a constant brake positionDownhill Speed Control can still be activated during descents with a selected constant brake position (1, 2 or 3).This means that the electronic unit automatically activates the function that requires the highest braking moment.

Suppose brake position two has been selected and the vehicle speed during a descent keeps increasing, the Downhill Speed Control function can be selected as well to stop the speed from increasing further.The electronic unit automatically adjusts the control current through the proportional valve, so that the intarder supplies the desired braking moment to keep the vehicle speed at a constant level.The Downhill Speed Control function is switched off once the vehicle speed again equals the speed that was stored in the electronic unit when the Downhill Speed Control function was selected. Brake position two, which was selected as well, takes over again.

V301043

1

2

3

© 200634 4-5



1

Downhill Speed Control in combination with the cruise control functionDownhill Speed Control and cruise control can be selected at the same time. This means that both functions can be selected at the same vehicle speed.

However, in connection with unnecessary heating of drive line and cooling system and the extra consumption of fuel, it is not desirable that both functions are active at the same time.

This is why the electronic unit of the intarder automatically adjusts the currently stored vehicle speed of the Downhill Speed Control in relation to the stored cruise control speed by a minimum programmed value of 3 km/h.

Example:If both functions are selected at a vehicle speed of 60 km/h, the vehicle speed is maintained while driving on a level road or while driving on an incline at 60 km/h (cruise control) and during a descent at about 63 km/h (Downhill Speed Control).

Downhill Speed Control and neutral switchIf, during a descent, a lower gear is selected while the intarder is switched on, it may happen that the engine speed is synchronised with the lower engaged gear (double-declutching).If, however, the accelerator pedal is operated when the Downhill Speed Control is active, the electronic unit of the intarder deactivates the Downhill Speed Control function.

Example:In the situation below it is not desirable that the intarder of the rearmost vehicle, during Downhill Speed Control, is switched off during a descent.

K102020

1 3 5

2 4 6

K102021

1 3 5

2 4 6

4-6 © 200634


1

The neutral switch sends a signal to the electronic unit, indicating that the gearbox is in neutral.This prevents the electronic unit from automatically switching off the Downhill Speed Control when the accelerator pedal is operated in the neutral position.The neutral switch is open in neutral, so that the electronic unit of the intarder stops receiving an earth signal.

Furthermore, the clutch is operated when shifting down. The clutch proximity switch is linked to the engine management system and will use a CAN message to indicate that the drive line is interrupted. This function also prevents the Downhill Speed Control function from being deactivated when shifting down.

Display of desired vehicle speed on DIP when Downhill Speed Control is switched onIf the Downhill Speed Control is switched on at a certain vehicle speed, this desired vehicle speed is stored in the EST 42 unit memory. The value of the desired vehicle speed is also displayed on the DIP dot matrix when driving downhill.

The symbol for the desired vehicle speed appears at position 6a of the indication bar (A). The driver thus has constant feedback regarding the speed at which the Downhill Speed Control can become active.

V300590

K101943

© 200634 4-7



1

4.3 TEMPERATURE ADJUSTMENT

Temperature-dependent limitation of braking momentWhen the coolant temperature is too high, the electronic unit reduces the control current through the proportional valve in accordance with a fixed control program.The temperature at which this reduction is started depends on the desired braking moment (position of the steering column switch).With a desired high braking moment, the reduction will be started earlier than with a desired low braking moment.

Electronically controlled fan clutchSwitching onWhen using the intarder, the electronically controlled viscous fan clutch can be activated to control the fan speed. In this way, a sufficiently cooling air flow is obtained to keep the temperature of the cooling system within limits.

If the desired braking power of the intarder is higher than 10 kW, the electronic unit of the intarder will actuate the engine management system via a V-can message, to activate the electronically-controlled viscous fan clutch.

Delayed activationActuation of the fan clutch also depends on the coolant temperature.If the temperature exceeds 95 C, the fan clutch is immediately activated with a delay of 0 seconds.If the temperature is below 95 C, the fan clutch is activated with a delay of some seconds, depending on the exact temperature.

0

350

300

250

200

150

100

50

0 85 90 95 100 120115110105 125

450

[kW]

400

V300837

90

0

5

95

T [S]

V300585

4-8 © 200634


1

Fan speed controlThe speed of the electronically controlled fan depends on the coolant temperature. At a coolant temperature of 78 C, the fan speed is at least 200 rpm.The pre-programmed temperature control in the electronic unit ensures that the speed of the fan increases or decreases by 160 rpm with each 1 C change in the coolant temperature.However, the maximum fan speed still depends on the engine speed.

Activating the exhaust brakeIf the intarder is switched on while the Downhill Speed Control function is activated, the exhaust brake is automatically activated if the following conditions are met.

The conditions for activation of the exhaust brake are:- intarder coolant temperature higher than

92 C- the desired braking power is higher than 250

kW

The electronic unit of the intarder activates the exhaust brake via a V-CAN message to the electronic unit of the engine management system.By activating the exhaust brake, the braking moment calculated by the intarder can be reduced. This reduces the thermal load on the cooling system.

Together, the activated exhaust brake and the intarder (with adapted braking moment) provide the constant braking moment that is necessary to maintain a constant vehicle speed during descents.

The exhaust brake is deactivated again if the desired braking power of the intarder is below 10 kW.

78

200

2825

83

N [RPM]

160 RPM /

V300839

© 200634 4-9



1

4.4 CONTROL WITH ACTIVATED ABS

The ABS system is activated when one or more wheels threaten to slip during braking with the intarder.The ABS switches the intarder off. At that moment the electronic unit of the intarder switches the proportional valve and the air supply valve off.

The intarder is activated again when the ABS is no longer active.With an activated Downhill Speed Control, the stored vehicle speed is retained after an intervention of the ABS.

4-10 © 200634


1

4.5 CONTROL VIA CAN NETWORK

The electronic unit of the ZF intarder EST 42 is incorporated in the V-CAN2 network of the vehicle. The electronic unit communicates with other electronic vehicle systems via the CAN connection on points 22 and 49. In this way data is exchanged, so that other electronic systems can influence the control functions of the intarder.

The electronic unit of the intarder also needs data from other systems to optimise the intarder function. The intarder can also be limited or switched on and off by other vehicle systems, such as the EBS-2, ABS-D, tachograph, DMCI and AS Tronic.

The vehicle speed signal, for instance, is offered via the tachograph and CAN messages to the electronic unit of the intarder, among others.

If the speed signal should be missing due to a failure, the Downhill Speed Control (if active) will be deactivated. With an activated Downhill Speed Control function the speed signal is an important signal for the electronic unit of the intarder.

Also special functions, such as the limitation of the maximum braking power of the intarder and actuation of the exhaust brake or the electronically controlled fan clutch (limitation of the coolant temperature), go via CAN messages.

Data received by the EST 42 unit includes:

Data sent by the EST 42 unit include:

Signal FromRpm of gearbox output shaft to calculate the (maximum) braking power TachographVehicle speed TachographVehicle speed backup DMCICruise control active signal: when the Downhill Speed Control function is activat-ed, the stored vehicle speed is automatically 3 km/h higher than the stored cruise control speed

DMCI

Stored cruise control speed DMCIEngine speed DMCIClutch proximity switch, prevents deactivation of Downhill Speed Control func-tion when accelerating during descent when drive line is broken

DMCI

Brake pedal switch, extra delay of vehicle by 'freezing' the intarder braking power in Downhill Speed Control function and use of service brake

DMCI

Accelerator pedal idling switch, to deactivate the Downhill Speed Control func-tion when accelerating and gearbox is engaged and clutch pedal is not operated

DMCI

Request to deactivate intarder owing to ABS intervention ABS/EBS-2Desired braking moment for service brake, request for percentage of intarder braking power, to assist service brake

EBS -2

Downhill Speed Control function active VIC-2

© 200634 4-11



1

Signal ToIntarder braking moment reference in Nm ABS/EBS-2/DMCI/AS

TronicCurrent intarder braking moment expressed as a percentage of Nm EBS-2/AS TronicDesired intarder braking moment in percent, to activate the electronically control-led fan clutch

DMCI

Desired intarder braking moment in percent, depending on the brake position or Downhill Speed Control function selected via the steering column switch or the steering wheel switch

EBS-2/VIC-2/AS Tronic

Selected constant intarder braking moment in percent, to deactivate the cruise control function when brake position 1, 2 or 3 is selected via the steering column switch

DMCI/AS Tronic

Maximum available intarder braking moment in percent, for combined action of EBS/intarder

EBS-2/AS Tronic

Request for activation of exhaust brake DMCI/AS TronicDisplay of desired vehicle speed on DIP when Downhill Speed Control function is switched on

VIC-2/AS Tronic

4-12 © 200634


1

© 200634 5-1

DiagramsZF INTARDER EST 42


1

5. DIAGRAMS5.1 HYDRAULICS DIAGRAM

Explanatory notes to hydraulics diagram

1. Gearbox oil pump2. Gearbox oil filter3. Intarder oil pump4. Intarder oil filter5. Rotor6. Stator7. Pressure-limiting valve8. Intarder proportional valve9. Volume control valve10. Freewheeling torque reducing system11. Accumulator12. Intarder air supply valve13. Intarder circuit selector valve14. Residual pressure valve15. Coolant temperature sensor16. Heat exchanger17. Engine18. Radiator19. Air supply

1

2

3

4

56

7

8

9 11

12

13

10

14

15

1617

18

19

12Q

1

2

1 2

V300582

5-2 © 200634

ZF INTARDER EST 42Diagrams ΧΦ75 Ις/85 Ις, ΞΦ105 series

1

5.2 BLOCK DIAGRAM

Block diagram V301042 applies to:- XF105- CF85 IV- CF75 IV

Block diagram legend

Explanation of block diagram

Basic code NameA100 Connector, HD-OBD diagnosisB088 Valve, proportional B089 Valve, supplyC906 Selector switch, Man/AutoC907 Switch, man. gear up/downD902 ECU, intarder EST-42E035 Fuse, steering columnE199 Fuse, ZF intarderE351 Fuse, electrical systemsE593 Switch, neutral positionF544 Sensor, coolant temp. intarder

A Version with manual gearboxB Version with AS Tronic

© 200634 5-3

DiagramsZF INTARDER EST 42


1

341

12

1

4T

R

379

2827

B0

89

Sup

ply

valv

e

F5

44

Coo

lant

tem

pera

ture

sens

or

EC

U, Z

F In

tard

er E

ST

42

D9

02

V30

1042

12ne

utra

lsw

itch

Veh

icle

CA

N2-

high

Veh

icle

CA

N2-

low

54

E1

99

kl. 3

0kl

. 15

kl. 1

5

3155

5316

4215

20

1012

98

Pos. 3

Pos. 2

Pos. 1

E3

51

G4

26

E5

93

Dia

gnos

is c

onne

ctor

A1

00

Ste

erin

g co

lom

n sw

itch

C9

06

/ C

90

7

E0

35

43

3 2

B0

88

Pro

port

iona

lva

lve

1411

CAN2-H 22

CAN2-L 4920

AB

87

5-4 © 200634

ZF INTARDER EST 42Diagrams ΧΦ75 Ις/85 Ις, ΞΦ105 series

1

Printed in the Netherlands DWEnglish

Documents

EST-42 gearbox