Engine 1 Training

TRAINING TIPS AND TACTICS

Engines - Mechanical

1

2

Contents Measuring

Dial Test Indicator Rocker dial gauge Micrometer Vernier callipers

Engine data

Designation Engine type/control system Emission levels Force, work, power Torque, horsepower Engine sub-groups - IMPACT

Camshaft & valve mechanism

Timing gears/cam markings Camshaft Rocker arms Camshaft wear

11 15 19 27

41 42 43 45 47 50

53 57 59 61

Lubrication Systems

D12C D7C D9A oil valves D12C & D12D oil valves D12C/D oil cooler & cover D12D500TC oil valves

Fuel Systems

System types D6A system D6A timing adjuster D6B VP44 FIP D7C system D7C Bosch RP43 FIP D7C Bosch EHAB D7C No. 1 injector Early D9A system D9A feed pump & valves

65 69 73 75 77 79

83 85 87 93 101 105 111 113 115 117

3

Fuel Systems - cont.

D9A/D12D overflow valve D10B Bosch P8000 FIP D12C system Early D12D/D16C system Later D9A/D12D/D16C system D12C feed pump Unit injectors Early D9A/D12D/D16C fuel filter Later D9A/D12D/D16C fuel filter

119 121 125 131 137 139 141 153 159

Exhaust Pressure Governor (EPG) EPG operation D9A EPG air control valve

163 171

Volvo Engine Brake (VEB) Volvo Compression Brake (VCB) VEB operation D16C rocker arm Checking VCB oil pressure

177 191 192

D12C turbocharger D9A turbocharger Turbocompound D9A air intake system D12C intercooler

195 197 203 207 209

Turbochargers

Cooling Systems

D9A/D16C drive belts D12C drive belts D12C cooling system D12C coolant pump & filter D16B cooling system D16C cooling system D16C fan drive

213 215 217 225 227 231 235

4

Introduction About this Pocket guide

This guide is intended as a memory jogger for the knowledge you have gained during your training course. The guide includes a summary of the material covered in:

Engines - Mechanical

5

Danger, Warning, Caution & Note

In this guide, risk of injury or damage is indicated by the following headings: DANGER - indicates a risk of serious personal injury or death. WARNING - indicates a risk of personal injury, or severe product damage. CAUTION - indicates risk of product damage. Note - draws attention to special methods or particular features. Read and implement all DANGER, WARNING and CAUTION instructions.

6

Replacement parts

When replacement parts are required, it is essential that only Volvo genuine parts are fitted. If Volvo genuine parts are not used: - safety features embodied in the vehicle or components may be impaired. - performance and/or operation of the vehicle or components may be adversely affected. - Volvo warranty terms may be invalidated.

7

Specification

Volvo are constantly seeking ways to improve their products, and alterations take place accordingly. Whilst every effort has been made to ensure the accuracy of this guide, it should not be regarded as an infallible guide to current specifications of any product. Neither Volvo, nor the supplier of this guide shall, in any circumstances, be held liable for inaccuracy or the consequences thereof.

Copyright

C

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, transmitted or copied without written permission from Volvo Truck & Bus Ltd. Volvo Truck & Bus Ltd. 2005

8

Measuring 9

Measuring 1 2 3 4 5 6 7 8

10

Measuring Dial Test Indicator (DTI)identification

1. Lock for the scale 2. Adjustable tolerance marks 3. Pointer 4. Turn pointer 5. Scale 6. Mounting tube 7. Measuring spindle 8. Probe

11

Measuring

1

2

12

Measuring DTI readings

1. The DTI is showing - 0.93 mm. 2. The DTI is showing - 0.34 mm.

13

Measuring 1

2

3

4 14

Measuring Rocker dial gauge - identification

1. Fixing device 2. Rotating scale 3. Change of measurement direction 4. Lever/probe

15

Measuring

1

2

3

16

Measuring Using the rocker gauge

Measurement error

The rocker gauge can be used to check: - gear wheel backlash If the gauge is used incorrectly, the measurement will be wrong: 1. Correct - error = 0% 2. 300 - error = 13% 450 - error = 30% (Not illustrated) 3. 600 - error = 50%

17

Measuring 1 2 3 4 5

1. Fixed measuring anvil 2. Clamp 3. Adjustable measuring spindle 4. Lock 5. Sleeve, with main scale 6. Counter, with rotating Vernier scale 7. Friction thimble

6

7 18

Measuring Micrometer usage Different types

A micrometer is used when greater accuracy is required - e.g. measuring shim thickness. Different types are available - e.g. for measuring inside dimensions, outside dimensions or depth. Different measurement ranges are available - e.g. 0 - 25 mm, 25 - 50 mm, 50 - 75 mm. All micrometers have a friction thimble, which should always be used to move in the spindle without applying too much force. The clamp is insulated to prevent heat from your hand influencing the measurement.

When using:

- avoid touching the measuring spindle. - zero the micrometer before use - before removing the micrometer from the object, lock the spindle. 19

Measuring 1

3

2 20

Measuring A micrometer has two scales: - a main scale on the sleeve. The sleeve top scale (1) is in increments of 0.5 mm - the bottom scale (2) is in increments of 1.0 mm. - a rotating Vernier scale (3) on the counter. Micrometer accuracy

On micrometers we normally use, the Vernier scale (3) is in increments of 0.01 mm - so this is the accuracy of this micrometer. One complete turn of the counter represents 0.50 mm, so two full turns are required to close the jaws by 1.00 mm.

21

Measuring 0.5

0.35

2.0 22

Measuring Taking a reading

1. Note the last graduation visible on the lower main scale, immediately to the left of the counter. 2. If a graduation is visible on the upper main scale, this represents 0.5 mm, and must be added to the total. 3. Note the reading from the Vernier scale. 4. Add all readings together. In the above example: The last graduation visible to the left of the counter on the shank lower scale is 2.00 mm A 0.50 mm graduation is visible to the left of the counter on the shank upper scale. The vernier scale is reading 0.35 mm. Added together, these = a total measurement of - 2.85 mm.

23

Measuring

3

1

2

24

Measuring Example measurements

The illustration examples above are showing the following readings: 1. 11.65 mm 2. 21.52 mm 3. 9.41 mm

25

Measuring 1

1. Measuring contacts (inner measurement)

2

2. Measuring contacts (outer measurement)

3

3. Sliding Vernier scale

4

4. Lock screw

5

5. Main scale 6. Depth rod - for depth measurement

6

26

Measuring Vernier callipers - using

Before measuring, close the measuring contacts and check that: - the contacts are parallel - the scale reading is zero

Vernier callipers - accuracy

The accuracy of vernier callipers is - 0.05 mm.

27

Measuring 15.00mm

8

15.80mm

mm

0.80mm

28

Measuring Vernier reading example 1

1. Note the last graduation on the main scale immediately to the left of the zero on the Vernier scale - 15.00 mm. 2. Note the graduation on the Vernier scale which exactly lines up with any graduation on the main scale - 0.80 mm. The dimension of an object between the jaws is 15.80 mm.

29

Measuring

37.00 mm

0.46 mm

30



31

Measuring

34.00 mm

0.60 mm

32



33

Measuring

34


1. Note that the zero on the Vernier scale lines up with 40.00 mm on the main scale. 2. Note also that the ten on the Vernier scale lines up with a graduation on the main scale. The dimension of an object between the jaws is 40.00 mm.

35

Measuring 1

4

7

External

2

5

8

Internal

Depth

3

6

9

36

Measuring Vernier measurement positions

The correct measurement positions for the Vernier callipers are: 1, 5, 9

37

38

Engine Data 39

Engine Data

D6*000888 D = Diesel 9 = 9 litre A = Generation

1

D12C

D12C Mk3

40

Engine Data Designations - 1

Older engine variants were prefixed ʻTDʼ which indicated ʻturbo-dieselʼ. All Volvo diesel engines have a turbocharger. The ʻTʼ has been dropped from the designations of later engines. All Volvo diesel engines have an intercooler. The ʻFʼ - used in early engine designations - e.g. TD 101F - has been dropped from the designations of later engines.

Designations - example

Engine ID location

D = Diesel 9 = 9 litre A = Generation Engine ID and serial number is located on the cylinder block - usually on the N/S.

41

Engine Data Engine type/ control system

D6A - no electronic control. Mechanical throttle linkage. D10B - ʻElectronic Diesel Controlʼ (EDC). Electronic Control Unit (ECU) located on O/S cylinder block, below inlet manifold. D7C - EDC. ECU located on N/S cylinder block, next to injection pump. D16B - EDC. ECU located on O/S cylinder block, below injection pump. D12C Mk III - Marked C3*. Fitted with overhead camshaft and ʻUnit Injectorsʼ (UI). Control system designated ʻEngine Management Systemʼ EMS (UI) system. D9A, D12D and D16C engines are all based on the D12C design. ECU on cylinder block N/S. 42

Engine Data Emission levels

Euro 1

Euro 2

Euro 3

D6A D6B 180,220,250 D7C 250,290 D9A 260,300, 340, 380 D10B 320,360 D12A 340, 380, 420 D12C 340, 380, 420, 460 D12D 340, 380, 420, 460, 500 (turbo-compound) D16B 470, 520 D16C 550, 610

43

Engine Data MASS

MASS

FORCE

FORCE

DISTANCE LIFTED

DISTANCE SLID

Work = Force x Distance - ft lbs 44

Engine Data Mass

Mass is the measure of how much matter an object or body contains - i.e. the total number of electrons, protons and neutrons. Mass is important when calculating rate of acceleration.

Force

Force is a measure of pressure applied to an object. Force does not require the object to move. Force is measured in Newtons (N) or pounds (lb).

Work

Work is force in motion. For work to be performed, the object must move. The measure of work is the weight of the object and the distance moved - WORK = force x distance: footpound (ft-lb). E.g. Work done to raise a load of 600 lb to a height of 6 ft = 3600 ft-lb.

Power

Power is the rate or speed at which work is done. The more power that is generated, the more work is done in a given time. 45

1 N = 0.225 lb 1 lb = 4.448 N

Engine Data 1300

Torque Nm

1200 1100 1000

D7C 290

900

D7C 250

800 700

900 1000 1200 1400 1800 1900 2000 2200

Typical torque curves

rev/min

46

Engine Data Torque

1Nm = 0.737 lb-ft 1lb-ft = 0.113 Nm

Horsepower

Torque is one way to measure work. Torque is a measurement of rotational or twisting force expressed in units of force multiplied by the distance from the axis of rotation. E.g. a force of 10 lb applied to the end of a lever 1 foot long, results in a torque of 10 lb-ft. Torque is measured in Newton-metre (Nm), or pound feet lb-ft During early observations, James Watt found that one average horse could raise 33,000 lb by 1 foot in 1 minute: 1 horsepower is the amount of power needed to perform 33,000 ft-lb of work in 1 minute. Depending on where and how it is measured, several versions of horsepower can be found:

47

Engine Data Power kW 225

hp calculated from torque: D7C 290

200

D7C 250

175 150

hp =

Torque x rev/min 5252

1 kw = 1.341 hp 1 hp = 0.746 kW

125 100 75 900 1000 1200 1400 1800 1900 2000 2200

Typical power curves

rev/min

48

Engine Data Indicated horsepower - IHP

Brake horsepower - BHP

Road/effective horsepower

Indicated horsepower is the power resulting from pressures developed in the cylinders. IHP takes no account of ʻfrictionalʼ losses which occur inside the engine, and in engine driven components. Brake horsepower is the useable power available at the engine flywheel - IHP minus engine frictional losses. BHP is calculated from the torque measured by an engine dynamometer, in which a ʻbrakeʼ applies a load to a shaft connected to the flywheel. BHP is commonly used to specify and compare engine power outputs. In metric units, power is expressed in kiloWatt (kW). Road, or effective, horsepower is the useable power available at the driving road wheels - BHP minus transmission frictional losses.

49

Engine Data Engine subgroups IMPACT

20 = General 21 = Engine 22 = Lubricating and oil system 23 = Fuel system 25 = Intake and exhaust system 26 = Cooling system 27 = Engine controls 29 = Miscellaneous

50

Camshaft and Valve mechanism 51

Camshaft & valve mechanism 1

2

3

4

D9A

5

52

Camshaft & valve mechanism Timing gears

D9A

All engine timing gears are ʻhelicalʼ cut - i.e. the shape of each tooth is part of a helix or spiral. Helical cut gears are used primarily because they run more quietly than straight cut or ʻspurʼ gears. A disadvantage is that the teeth are always subject to an axial force. 1 - camshaft 2 - camshaft bearing 3 - inlet cam 4 - injector cam 5 - exhaust cam

53

Camshaft & valve mechanism 2 1

EPG

D12A/C/D, D16C

VCB

54


D12A/D/C, D16C

Exhaust Pressure Governor (EPG)

Markings on camshaft flange (1) are: - TDC - Digits 1 - 6 (cylinders) With a digit, 1 - 6, aligned with cap marking (2), set INLET valve, EXHAUST valve and INJECTOR, for the respective cylinder.

Volvo Compression Brake (VCB)

Markings on camshaft flange (1) are: - TDC - Digits 1 - 6 - V1 - V6 With a digit, 1 - 6, aligned with cap marking (2), set INLET valve, and INJECTOR, for the respective cylinder. With a V1 - V6, aligned with cap marking (2), set EXHAUST valve for the respective cylinder. 55


C A

B

Cam profile 56

Camshaft & valve mechanism Seven bearings

Volvo Compression Brake (VCB) camshaft Cam profile

The camshaft, which rotates at half engine speed, runs in seven bearings, with detachable caps (1). The shells for the front bearing have integral thrust washers. Note: the camshafts for VCB and non-VCB engines are different: the camshaft for VCB engines has additional, low profile, compression and decompression lobes.

A = Max. lift B = Base circle C = Cam lift, A minus B

57


A B

58

Camshaft & valve mechanism Bearing/roller clearance

A = bearing clearance B = rocker arm roller clearance It is important that these clearances are correct. Refer to IMPACT - Specifications - for correct dimensions.

59


C A

B

60

Camshaft & valve mechanism Camshaft wear Information

When assessing camshaft wear, refer to Service bulletin 215-19-03, and to Impact ref. 2154. In the above illustrations, wear patterns A and B are acceptable - scratching and uneven wear does not mean that the camshaft must be renewed. C wear pattern is not acceptable - the camshaft must be renewed.

61

62

Lubrication Systems 63

Lubrication systems 11

10

2

3

12

9

13

4

6 1

8 7

5

14 64

Lubrication systems D12C - valve functions

1. Regulator valve - controls the engine oil pressure; excess oil is fed back to the sump. 2. Overflow valve - opens if by-pass filter (8) becomes blocked. This ensures continued lubrication for the turbocharger. 3. Piston cooling valve - is pressure sensitive, and opens just above normal idling oil pressure. 4. Overflow valve - opens if full flow filter (7) becomes blocked. This ensures continued lubrication for the engine. 5. Over pressure valve - opens if the pressure becomes too high - e.g. cold weather start. 6. By-pass valve - opens to allow oil to by-pass the oil cooler during warm up. This ensures that oil is delivered as soon as possible, and warm up time is reduced. The valve is thermostatically controlled by sensing oil temperature.

65


10

2

3

12

9

13

4

6 1

8 7

5

14 66

Lubrication systems D12C - system operation

Gear driven pump (14) forces oil through full flow filter (7) and by-pass filter (8), via oil cooler (12).

From the filters, oil is fed to the main gallery in the cylinder block and from there via channels to all components needing lubrication. Oil reaches the camshaft and valve mechanism via vertical channels in the cylinder block and cylinder head. If the engine is fitted with a Volvo Compression Brake (VCB), oil passes through regulating valve (11). Compressor (9) is lubricated via an external hose connected to the filter housing. Turbocharger (10) is lubricated via an external hose connected to the by-pass filter.

67

Lubrication systems 10 11 3 2

13

1 9

4 6

8

12

7

14 5

68

Lubrication systems D7C - valve functions

1. Overflow valve - opens if full flow filter (8) becomes blocked. This ensures continued lubrication for the engine. 2. By-pass valve - opens at a pressure slightly above normal idling pressure, to allow oil to flow to the by-pass filter. 3. Regulator valve - controls the engine oil pressure; excess oil is fed back to the sump. 4. Piston cooling valve - is pressure sensitive, and opens just above normal idling oil pressure. 5. Over pressure valve - opens if pressure becomes excessive on the piston cooling side of the oil pump. 6. Over pressure valve - opens if pressure becomes excessive on the lubricating oil side of the oil pump.

69

Lubrication systems 10 11 3 2

13

1 9

4 6

8

12

7

14 5

70

Lubrication systems

D7C - system operation

Note: The D7C oil pump differs from other Volvo engine pumps: it has three gears and two outlets. One outlet is for the main lubrication system, and the other is for the piston cooling system. Oil from pump outlet (7) is fed to the bottom of the cylinder block, via a pipe, and then to full flow filter (8). From the filter, oil is fed to the main gallery in the cylinder block and from there via channels to all components needing lubrication. Oil from pump outlet (14) is fed to the oil cooler, via a pipe, and then to piston cooling channel (12). From valve (2) on the full flow filter bracket, oil is fed to bypass filter (9); excess oil returns to the sump. Oil for lubrication of the compressor, injection pump (11), and turbocharger (10) is supplied via external pipes. 71


4

7

2 5

6 1 72

Lubrication systems D9A - oil valves

1. Safety valve - oil pump. Marking - purple. 2. Overflow valve - by-pass filter. Spring free length 69 mm. Spring length with load of 13 - 15 N (1.3 - 1.5 kgf) 40 mm. 3. Control valve - oil cooler. Marking - 124. 4. Reduction valve - oil pressure. Marking - blue. 5. Overflow valve - full flow filter. Spring free length 69 mm. Spring length with load of 13 - 15 N (1.3 - 1.5 kgf) 40 mm. 6. Opening valve - piston cooling. Spring free length 112 mm. Spring length with load of 95 N (9.5 kgf) 63 mm. 7. Control valve - piston cooling. Spring free length 112 mm. Spring length with load of 60 N (6.0 kgf) 84 mm.

73


4

3

2

1

6

74

Lubrication systems D12C and D12D - oil valves 340/380/420/460 safety valve

1. Safety valve. Marking - yellow. 2. Control valve - oil cooler. Marking - 124.

3 &5. Overflow valves - oil filter. Spring free length 69 mm. Spring length with load of 13 - 15 N (1.3 - 1.5 kgf) 40 mm. 4. Piston cooling valve. Marking - orange. 6. Reduction valve - oil pressure. Marking - blue.

75

Lubrication systems 2 1

A 76

Lubrication systems Oil cooler and cover D12C/D

By increasing the number of discs (1) from six to seven, the oil cooling capacity has been increased. This results in increased depth (A). A new cover (2) has a smooth exterior because the reinforcement ribs are now on the inside. CAUTION Do not fit the new cover to the early type oil cooler: this will reduce coolant flow through the cooler. Note: The oil cooler is a common area where leaks can allow oil and water to mix.

77

Lubrication systems

2

1

3

4 78

Lubrication systems Oil valves D12D500TC (Turbocompound)

The main differences on D12 D500 TC are around the oil filter housing. The turbo-compound unit is lubricated with oil from the bypass filter via hose (1). The turbocharger is lubricated with oil from the full flow filter via hose (2). The piston cooling system is optimised and controlled by two slide valves. Valve (3) is a control valve that provides a constant piston cooling pressure, regardless of engine speed. D9A has the same feature. Valve (4) is a pressure sensing on-off valve.

79

80

Fuel Systems 81

82

Fuel systems System types

Conventional fuel system using full mechanical operation with timing adjuster. Used on D6A. Conventional fuel system using electronic control with timing adjuster. Used on D10B and D16B - designated EDC. In-line injection pump controlled by the engine management system. Used on D7C - designated EMS. Rotary injection pump controlled by the engine management system. Used on D6B - designated EMS. Unit injector system controlled by the engine management system. Used on D9A, D12A/C/D and D16C - designated UI system

83

7

5

2

1 6

4

3

84

Fuel systems D6A fuel system

This is a conventional fuel system using full mechanical operation. The fuel injection pump (FIP) is driven from the timing gear train, via a mechanical injection timing adjuster. Fuel lift pump (1) draws fuel from tank (2) through strainer (3). Pressurised fuel is fed through two fuel filters (4), and into FIP (5). FIP (5) delivers fuel at high pressure to each injector (6). Excess fuel from the injectors returns to pressure regulating valve (7) on the return side of the system. This fuel returns to the tank with excess fuel from the FIP.

85

Fuel systems

6 5

4

1

7

2 3

8 86

Fuel systems D6A timing adjuster

With the exception of D6A180, all D6A engines have an injection timing adjuster assembly (1), which is attached directly to the pump camshaft. (On D6A180, the adjuster assembly is replaced by an intermediate shaft). The fuel injection pump (FIP) mounting flange is attached to the adjuster assembly housing (2). The adjuster housing is attached to the engine timing gear housing (3). FIP drive gear (4) has oval holes for attachment screws (5), to allow adjustment of injection timing. Cover (6) is removed to gain access to screws (5). The instruments used for adjustment and testing of injection timing receive their signals from indicator (7). For final attachment adjustment the rear support bracket (8) is in two parts. CAUTION To prevent tension at the attachment points, the FIP must be refitted in accordance with service instructions in IMPACT. 87

Fuel systems 2 1

9 7

3 4

6 5

4

6

8

5 3

88

Fuel systems D6A timing adjuster assembly

Adjuster hub (1) is attached to the fuel injection pump (FIP) camshaft. The FIP drive gear is attached to outer connecting flange (2). Hub (1) and flange (2) can move angularly in relation to each other. This angular movement (timing adjustment) is regulated by eccentric bushes (3) and (5). Large bushes (3) are attached to stub shafts (4) which are part of centrifugal weights (7). Small bushes (5) are located in large bushes (3). Stub shafts (6), which are part of small bushes (5), locate in flange (2). Outward movement of weights (7) is regulated by springs (8). Indicator (9), for monitoring injection timing, is attached to hub (1).

89

Fuel systems

A

B

C 90

Fuel systems D6A timing adjuster operation

D6A FIP timing tool location

Diagram (A) shows the injection timing adjuster at low engine speed. The centrifugally operated weights are held inwards by the springs, and no movement takes place between the eccentric bushes. Diagram (B) shows the injection timing adjuster when engine speed is high enough to provide the centrifugal force needed to cause the weights to move out to their limit. The movement of the eccentric bushes results in an relative angular movement between the adjuster hub and connecting flange. The angular movement is 3°, which doubles to 6° between the engine and fuel injection pump (FIP). The arrow in illustration (C) shows where special tool 9987057 should be located when checking FIP timing.

91

Fuel systems 1

2 3

6

11 4

10 7

8

5

9

92

Fuel systems D6B VP44 Fuel Injection Pump (FIP) - main components

Radial pump with PCU

1. Fuel Pump Control Unit (PCU) 2. Pump speed and angle sensor 3. Drive shaft 4. Fuel supply vane pump 5. Cam ring 6. Supply pumping plungers 7. Plunger rollers 8. Timing device 9. Timing pulse solenoid valve 10. Snubber valve 11. High pressure solenoid valve - fuel metering This fuel injection pump (FIP) is an electronically controlled radial plunger pump. The pump has an inbuilt Fuel Pump Control Unit (PCU) which contains fuelling, timing and diagnostic data. The PCU communicates with the engine ECU, which supplies e.g. throttle position data.

93

Fuel systems 1

2 3

6

11 4

10 7

8

5

9

94

Fuel systems

D6B VP44 FIP - operation

An external, electrically driven, pump feeds fuel from the tank to the FIP at a max. pressure of 80 kPa (0.8 bar). The FIP also has an internal vane type supply pump (4). The rotating shaft (3) carries six equally spaced and radially opposed pumping plungers (6). The stationary cam-ring (5), has six equally spaced lobes on the inside diameter. At the outer end of each piston is a roller (7) which follows the inner diameter of the camring. When a roller passes over a cam lobe, the plunger is pushed inwards, and pressurises fuel in the fuel delivery chamber and distribution port . The distribution port is formed in the fuel distributor, which is part of the rotating assembly. As the assembly rotates, the distribution port aligns with one of six delivery ports, to deliver fuel to the injectors at exactly the right time and in the right sequence.

95

Fuel systems 1

2 3

6

11 4

10 7

8

5

9

96

Fuel systems D6B VP44 FIP operation, cont.

The rotational position of the cam-ring can be altered, so that the plunger rollers meet the cam lobes earlier or later, thereby advancing or retarding injection timing. Fuel pressure acting on timing piston (8) moves the camring. Fuel pressure is supplied by vane pump (4), and controlled by solenoid valve (9). A pulsed signal from the PCU controls the valve. Increasing pressure moves the piston further, and injection timing is advanced. Solenoid valve (11) controls a fuel metering valve, which controls fuel supply to the pumping chamber. When the chamber is charged with fuel, the valve closes and pressurisation begins. When the programmed amount of fuel has been injected, the valve opens, and injection stops instantaneously. The cycle then repeats for the next cylinder. This pump is able to generate pressures at the injector of 1500 - 1850 bar. 97

Fuel systems

A 1

2 3

6

11 4

10 7

8

5

9

98

Fuel systems D6B VP44 Fuel Injection Pump - service note

A fault in cable (A), which connects sensor (2) to fuel pump control unit (1) is a common cause of pump failure.

99

Fuel systems 3 2

2

3

4

4 9

1

5

6

7

8

100

Fuel systems

D7C fuel system

1. Fuel filter 2. Valve housing - hand pump 3. Hand pump 4. Bleed nipple 5. Feeder pump 6. Hand pump - behind ECU 7. Fuel shut-off valve 8. Overflow valve 9. Tank strainer

101

Fuel systems 3 2

2

3

4

4 9

1

5

6

7

8

102

Fuel systems D7C fuel system

The fuel injection pump FIP is flange mounted and bolted to the timing gear backplate on the LH of the engine. Fuel filter (1) is attached to a bracket at the front of the engine. A hand pump (3) and bleed nipple (4) are located on filter housing (2). (There is also a hand pump (6), behind the ECU, on the FIP). Feed pump (5) draws fuel from the tank via strainer (9) and electro-hydraulic fuel shut-off valve (7). From the feed pump, fuel is fed through filter (1), and into the FIP via shut-off valve (7). Return fuel from the FIP passes through the shut-off valve and overflow valve (8), and back to the tank. The leak-off line from the injectors is connected to the FIP via the suction line connection.

103

Fuel systems

5 1

3

2

8

4 6

7 9 10

104

Fuel systems D7C Bosch RP43 injection pump

1. Pump plunger 2. Control-sleeve 3. Control-sleeve actuator 4. Control-sleeve shaft 5. Pump barrel 6. Control rack - fuel quantity 7. Control rack actuator 8. Control rack position/movement sensor 9. Camshaft 10. Camshaft speed sensor

105

Fuel systems

5 1

3

2

8

4 6

7 9 10

106

Fuel systems D7C Bosch RP43 injection pump

Injected fuel quantity

This pump is a development of conventional electronically controlled in-line pumps, designed to further reduce exhaust emissions and improve fuel economy. These pumps are known as ʻcontrol-sleeveʼ pumps. In addition to electronic control of injected fuel quantity, control sleeve pumps have electronic control of injection timing. As in basic in-line pumps, injected fuel quantity is altered by rotating pump plungers (1). The plungers are rotated by control rack (6), which is moved by actuator (7), in response to signals from the engine ECU.

107

Fuel systems

5 1

3

2

8

4 6

7 9 10

108

Fuel systems

D7C Bosch RP43 injection pump

Injection timing

A control sleeve (2), which has a conventional spill port, is located around each pump plunger. Injection timing is advanced or retarded - relative to the position of the cam - by altering the vertical position of the control sleeve. The vertical position of the sleeves is altered by sleeve control shaft (4), which is rotated by actuator (3) in response to signals from the engine ECU.

109

Fuel systems

Volts = 24

Volts = 0 110

Fuel systems

D7C Bosch RP43 injection pump - electrohydraulic shut-off valve (EHAB)

Modern fuel pumps operate at very high injection pressures. Conventional shut-off devices cannot provide the instantaneous collapse of pressure required to ensure rapid engine stop. When energised with 24 V, the EHAB valve is set for normal fuel flow. When de-energised - start key off - fuel flow through the valve is reversed, and the fuel supply pump draws fuel back out from the injection pump. Fuel gallery pressure rapidly drops, and the engine stops within 2 seconds. Note: When bleeding the fuel system the valve must be energised - start key at ʻdriveʼ position.

111

Fuel systems

112

Fuel systems D7C Injector No. 1 - needle movement

As previously explained, control-sleeve injection pumps can electronically control injection timing by altering the position of control sleeves. The control signal is fed from the engine ECU to the control shaft actuator. This signal is calculated by the ECU according to engine load and speed. An important reference for the calculation is a signal fed to the ECU representing the instant injection starts. This signal is provided by a needle movement sensor in No. 1 injector. At the instant the needle starts to move upwards, a signal is induced in the sensor coil and fed to the ECU, indicating the start of injection.

113

Fuel systems 7

10

Early D9A

8 6 3

11

4 9

5

1 12

2

114

Fuel systems

Early D9A fuel system - fuel flow

Feed pump (1) draws fuel through strainer (2) in the combined tank unit, past electric fuel pump (3) into filter housing (9). If a pre-filter (4) and water separator (5) are fitted, fuel flows through these components, through ECU cooling loop (6) up to the fuel manifold. In the manifold, fuel from the tank is mixed with fuel returning from cylinder head passage (8) - via overflow valve (7) to the suction side of feed pump (1). The feed pump forces fuel through main filter (9) up to cylinder head passage (8). This passage supplies fuel to each injector via an annular groove around the injector body. Overflow valve (7) regulates fuel feed pressure to the injectors. Non-return valve (11) in electric pump (3) ensures that fuel does not return to the tank when the engine is stopped.

115

Fuel systems 1

13

12

12 2 116

Fuel systems

D9A fuel system - feed pump and valves

Feed pump (1) is a gear type pump attached to the rear of the power steering pump, and driven by the power steering pump shaft. Safety valve (12) allows fuel to flow back to the suction side if delivery pressure is too high - e.g. if the filter is blocked. Non-return valve (13) opens when electric pump (3) is in use.

117

Fuel systems

1

2

4

3 118

Fuel systems Overflow valve - D9A /D12D

Overflow valve (1), attached to the front of the cylinder head, regulates the fuel pressure to the injectors. Fuel flows from the valve to distributor housing (2), where it mixes with fuel being drawn from the suction side (3) on the way to the feed pump.

119

1 2

3

4

7

6

5

120

Fuel systems

D10B fuel system - Injection pump

This pump is a Bosch P8000 unit, with electronic positioning of the control rack- EDC. A significant feature of this pump is the fuel supply path to the pump elements. With the usual supply path, fuel enters the pump at one end, and feeds each element one after the other in sequence, then leaves the pump at the opposite end after feeding the last element. With the high pressures used in this pump, this supply method can lead to significant differences in the temperature of fuel supplied to the first and last cylinder. Individual element pressures can also be affected by adjacent elements. These adverse factors are overcome by using ʻcross-flowʼ element supply (2), where each element has an isolated supply from a common supply channel.

121

1 2

3

4

7

6

5

122

Fuel systems

D10B fuel system - Injection pump

3. Overflow valve 4. Electronic control rack actuator. In place of the mechanical governor, the control rack position - and, therefore injected fuel quantity - is controlled by an electronic actuator. The actuator positions the rack in response to a PWM signal from the engine ECU. 5a. Location for special tool 9998190 - A & B lights for injection timing check. 5b. Camshaft speed sensor ring, which has 7 teeth - one for each cylinder, plus an extra tooth identifying No. 1 cylinder. 6. Manual feed pump used for bleeding the system. 7. Mechanical feed pump - actuated by a push-rod from the pump camshaft. The pump has two non-return valves and a spring return piston.

123

10

7

9

5

1

15

4

13 11

8

12

D12C 2

14

16

6

3

124

Fuel systems Fuel system - D12C

This system has unit injectors (1), and gear type feed pump (2) replacing the in-line pump and conventional injectors. Injection pressure - which is much higher than that in conventional systems (c. 1500 bar) - is developed mechanically by cams on the engine camshaft acting, via rocker arms, on the injector pumping units. The injectors are electronically controlled by signals from the engine ECU, which control injected fuel quantity and injection timing.

Fuel flow

Gear driven feed pump (2) draws fuel through tank strainer (3), via non-return valve (4). All fuel is drawn through ECU cooling loop (5) before reaching the pump.

125

10

7

9

5

1

15

4

13 11

8

12

D12C 2

14

16

6

3

126

Fuel systems Fuel flow - D12C -cont.

From the pump, fuel is fed through filter (6), and up to the injector gallery (7) in the cylinder head. Fuel enters the injectors via annular spaces around each injector.

Priming pump

A manual priming pump (8) is located on the filter head.

Overflow valve

An overflow valve (9), in the outlet from the fuel gallery, regulates the feed pressure in the system.

127

10

7

9

5

1

15

4

13 11

8

12

D12C 2

14

16

6

3

128

Fuel systems Bleed/drain nipples - D12C

Feed pump valves

Bleed nipples (10) and (11) are fitted to the cylinder head and filter head. A drain nipple (12) is fitted to the filter head. This can be used for draining fuel from the cylinder head injector gallery. Non-return valve (13) opens when the priming pump is being used, to allow fuel to by-pass the feed pump gears. Safety valve (14) opens to allow fuel back to the suction side of the pump when pressure beyond the feed pump is too high - e.g. if the filter is restricted. Air vent (15) allows continual ventilation back to the tank when the engine is running.

Non-return valves

Non-return valves (16) allow the priming pump to operate. Non-return valve (4) prevents fuel flow back to the tank when the engine is stopped. 129

Early D12D, D16C

10 8

6

7 11 3 9

13

4

16 5 17 15

1

12

14 2

18 130

Fuel systems

Fuel system early D12D, D16C

Drain nipple

Gear driven feed pump (1) draws fuel through tank strainer (2), through electric priming pump (3) and non-return valve (4). Fuel then passes through pre-filter/water separator (5), and through ECU cooling loop (6). At junction (7), fuel from the tank mixes with return fuel from cylinder head gallery (8), and is drawn into pump (1). From the pressure side of pump (1), fuel is fed through filter (9), and up to gallery (8) via the filter head. Overflow valve (10) controls the pressure in the injector gallery. Drain nipple (11), on the filter head, can be used for draining fuel from the cylinder head injector gallery.

131

Early D12D, D16C

10 8

6

7 11 3 9

13

4

16 5 17 15

1

12

14 2

18 132

Fuel systems

Fuel system early D12D, D16C

Electric fuel pump

Electric pump (3) is used for: - bleeding the system via the permanent vent pipe. - draining water from the water separator. The pump is activated by dashboard switch (12). Bleed and drain operations are described later.

Pressure sensor

A fuel feed pressure sensor (13) is fitted to the filter head, and measures the fuel pressure after the filter - i.e. a restricted filter will give a low pressure reading. Safety valve (14) opens to allow fuel back to the suction side when pressure beyond the feed pump is too high - i.e. if the filter is restricted.

133

Early D12D, D16C

10 8

6

7 11 3 9

13

4

16 5 17 15

1

12

14 2

18 134

Fuel systems

Non-return valve (15) opens when the electric priming pump is being used, to allow fuel to by-pass the feed pump gears. Non-return valve (4) prevents fuel flow back to the tank when the engine is stopped. Air vent valve (16) allows continual ventilation back to the tank when the engine is running, and allows fuel return to the tank during bleeding.

Level sensor

Drain valve

Level sensor (17) senses the level of water in the water separator. If the water level is too high, the yellow info. lamp is lit and a message is displayed. Water is drained via electrically controlled drain valve (18).

135

6 3

Later D9A, D12D, D16C

1 5

4

2

136

Fuel systems

Fuel system - later D9A, D12D, D16C Fuel flow

Gear driven feed pump (1) draws fuel through tank strainer (2). Fuel then passes through ECU cooling loop (3), and on to feed pump (1), via water separator (4). From the pump, fuel is fed through filter (5), and up to the injector gallery in the cylinder head. Fuel enters the injectors via annular spaces around each injector.

137

1 2

3

138

Fuel systems D12C fuel feed pump Shaft seals

The gear type pump is driven from the engine timing gears.

The drive shaft has two seals - one for fuel and one for oil. If the fuel seal leaks, fuel will drain back into the timing case and contaminate the oil. If the oil seal leaks, oil will contaminate the fuel.

Pump valves

1. Non-return valve 2. Return valve 3. Pressure regulating valve

139

Fuel systems 1

1

1

2 2

2

3

3

A

B

C

140

Fuel systems Unit injectors

The above illustration shows the three types of unit injector in use in Volvo truck engines: A - Lucas B - Bosch C - Delphi Although different in construction, the principle features and operation are the same. Each injector is a ʻunitʼ made up of a: 1. Pump assembly 2. Fuel control valve 3. Injector

141

Fuel systems 1

Delphi E1

A 142

Fuel systems Unit injectors cont.

Delphi E1 injectors

The centre part of the unit is housed within the cylinder head. An annular groove around the injector body aligns with the fuel supply gallery (1) which runs the length of the cylinder head. Delphi type E1 unit injectors are fitted to D9A and D12D engines, and differ significantly from Lucas and Bosch injectors. The main difference is that the fuel control valve is located within the injector body. This results in a more compact and lighter unit, with shorter internal channels providing faster response. Each Delphi injector has a manufacturing tolerance, the code for which is marked on the electrical connector (A). Whenever an injector is renewed, the tolerance code must be programmed into the engine ECU using VCADSPro.

143

Fuel systems 1

3

4

2

5 6

144

Fuel systems Unit injectors operation - timing and fuelling

Operation fill phase

The stroke of plunger (5) is constant, so the amount of fuel entering chamber (6) is also constant. However, the amount of fuel injected into the combustion chamber is determined by control valve (2), which opens and closes the path from the fuel gallery to the chamber. The valve is normally open, and is closed by solenoid (2) in response to a pulsed signal from the engine ECU. The start of the signal controls the start of injection. The duration of the signal controls the amount of injected fuel. Signal start and duration are calculated by the ECU in response to incoming signals from - e.g. throttle position, other sensors, other ECUʼs. The engine ECU is not sending a signal to fuel control valve solenoid (1), so valve (2) is open. The position of cam lobe (3) allows return spring (4) to draw back plunger (5). Fuel flows in from the gallery via the annular grooves, past fuel control valve (2), and into plunger chamber (6).

145

Fuel systems 1

4 3

2

5 6

146

Fuel systems

Unit injectors operation spill phase

The engine ECU is not sending a signal to fuel control valve solenoid (1), so valve (2) is still open. The position of cam lobe (3) forces down plunger (5), and injection pressure starts to build. Fuel now flows from plunger chamber (6), past control valve (2), and back to the gallery.

147

Fuel systems 1

4 3

2

5 6

148

Fuel systems

Unit injectors operation injection phase

The engine ECU is now sending a signal to fuel control valve solenoid (1), so valve (2) is closed. The position of cam lobe (3) is still forcing down plunger (5), and injection pressure continues to build Because control valve (2) is now closed, fuel in plunger chamber (6) is now trapped. Injection pressure now increases rapidly, and lifts the injector needle from itʼs seat. Fuel is sprayed into the combustion chamber at high pressure via the injector spray holes. Injection continues until the solenoid signal is switched off, and control valve (2) opens.

149

Fuel systems 1

4 5

2

5 6

150

Fuel systems

Unit injectors operation pressure reduction phase

The signal from the engine ECU is now switched off, so control valve (2) is open. The path from chamber (6) to the fuel gallery, via control valve (2) is now open. There is a rapid pressure drop in chamber (6). The needle return spring snaps the needle onto itʼs seat, and injection stops instantaneously. The position of cam lobe (3) is still forcing down plunger (5), so fuel remaining in chamber (6) is eventually returned to the fuel gallery.

151

3 A

4

B

1

2

5 152

Fuel systems Fuel filter/head assembly - early D9A, D12D, D16C

Filter/head assembly (A) includes: 1. Pre-filter, with water separator and - in the base of the separator - water level sensor and drain valve 2. Main filter 3. Fuel pressure sensor - under the cover with the electrical connector 4. Electric fuel pump for bleeding and water draining Filter/head assembly (B) includes: 2. Main filter 3. Fuel pressure sensor - under the cover with the electrical connector 4. Electric fuel pump for bleeding

153

3 A

4

B

1

2

5 154

Fuel systems Bleeding the fuel system - early D9A, D12D, D16C

Vehicle messages

If the water level sensor is not sensing high water level, when switch (5) is pressed, electric pump (4) pumps fuel and air around the engine and back to the tank. Air escapes through the tank breather. Bleeding takes 4/5 min. Bleeding will not take place unless: - vehicle is stopped - engine is stopped - park brake is applied - start key at ʻdriveʼ position

Display when bleeding or draining

155

3 A

4

B

1

2

5 156

Fuel systems Water draining early D9A, D12D, D16C

If the water level sensor is sensing high water level, when switch (5) is pressed, the water drain valve is opened, electric pump (4) starts, and water is pumped out of the fuel system. Water draining takes approx. 18 sec. Draining will not take place unless: - vehicle is stopped - engine is stopped - park brake is applied - start key at ʻdriveʼ position - water level sensor is sensing high water level

157

Fuel systems 2

3

6

F

1

E D

5

4 A B

C

158

Fuel systems Fuel filter assembly - later D9A, D12D, D16

1. Pressure side 2. Suction side - D12D 3. Ventilation - main filter 4. Return to fuel tank 5. Suction side - D9A, D16C 6. Supply to cylinder head gallery A. Valve - main filter B. Ventilating valve - main filter C. Air vent valve - primary filter D. Valve - suction side from fuel tank E. Manual hand pump F. Fuel pressure sensor

Features

No bleeding required after renewing filter. Bleeding is automatic when engine is started. When a filter is removed, valve peg (B or C), in the housing, closes and prevents fuel from draining. This assembly is fitted from early 2004.

159

Fuel systems Fuel bleed/water drain

Note: With early fuel systems, the cab switch operates both fuel bleeding and water drain. With later systems - without electric fuel bleeding - the switch operates only water drain.

160

Exhaust Pressure Governor (EPG) 161

EPG

1

2 162

EPG Exhaust pressure governor (EPG) - operation

Engine warm-up

Supplementary braking

The purpose of the EPG (1) is to create extra pressure in the engine cylinders, thereby increasing the load on the engine. Extra pressure is created when shutter (2) is closed or partially closed. Engine load is used to: - reduce engine warm-up time by making the pistons work against extra pressure in the cylinders. In this mode the EPG is activated automatically, provided that - coolant temperature is < 70oC, and parking brake is on. - provide supplementary braking to assist slowing the down the vehicle. In this mode, the EPG is activated by a 2 or 3 position switch.

163

EPG

2.0 bar 4

2 3

2.0

1

+

7.5–

12.0 bar

164

EPG EPG operation engine warm-up

With the park brake applied, and coolant temperature < 70oC, solenoid (1) is energised, allowing air at 12.0 bar to reach reduction valve (2). Valve (2) reduces the air pressure to 2.0 bar, and this is fed to EPG cylinder (3). This pressure closes shutter (4) to leave a gap of approx. 1.0mm. This creates a back-pressure, during the exhaust stroke, but allows a restricted gas flow. Note: If a PTO is fitted, and it is engaged when the engine is cold, the EPG is switched off to reduce black smoke emission.

165

EPG

7.5 bar 4 3

5

12.0 bar

6

+

166

EPG

EPG operation - engine braking

If a Volvo Compression Brake (VCB) is fitted, the control switch has 3 positions: - OFF = EPG and VCB not activated - 1 = EPG only - 2 = EPG + VCB = Volvo Exhaust Brake (VEB) With no VCB, the switch has 2 positions OFF > 1. With the control switch at position (1), solenoid (5) is energised. Reduction valve (6) reduces air pressure to 7.5 bar, and this is fed to EPG cylinder (3). This pressure closes shutter (4), which is balanced against exhaust gas pulses, allowing a small amount of gas to pass. The best braking power is produced when engine speed is kept in the blue sector of the tachometer - max. 160 kW braking power.

167

EPG Chassis No. Engine serial No. and bar codes Engine model: EC 96 = Euro 2 Injector type: 1 = Lucas 2 = Bosch

D12C engine labels

Exhaust brake: EPG = exhaust pressure governor VEB = Volvo Engine Brake

168

169

EPG W

1 170

EPG

EPG air control valve - D9A

Operation of the EPG on D9A is as described for D12C, but D9A has a different air control valve (1). The valve is called and Air Valve Unit (AVU), and it is controlled by a Pulse Width Modulated (PWM) signal from the engine ECU The PWM signal has a variable pulse width (W), which results in a stepless variable voltage applied to the valve solenoid. This voltage can vary the air pressure steplessly between 2.0 bar and 7.5 bar. This form of pressure control has advantages when used with - e.g. cruise control and Brake Blending (BBF).

171

EPG 0 1

2.3 bar

7.5 bar

= PWM 30%

=

PWM 90%

172

EPG

EPG air control valve - D9A Engine warm-up

When the coolant temperature is below 70o C, and the park brake is on, the PWM signal has a pulse width of 30%, which results in an air pressure of 2.3 bar fed to the AVU. As for the D12C EPG, this gives a shutter opening of approx. 1.0 mm.

Engine braking

When EPG engine braking is activated by the control switch, the PWM signal has a pulse width of 90%, which results in an air pressure of 7.5 bar fed to the AVU. This pressure closes the shutter, which is balanced against exhaust gas pulses, allowing a small amount of gas to pass.

173

Volvo Engine Brake (VEB) Volvo Compression Brake (VCB) 174

175

VEB

A

B

C 176

VEB

Volvo Engine Brake (VEB) Exhaust brake

Compression brake

The VEB provides engine braking from a combination of: - Exhaust Pressure Governor (EPG), where the exhaust gas outlet is restricted by a shutter, causing pressure build up in the cylinders during the exhaust stroke (A) - as previously described. - Volvo Compression Brake (VCB), where exhaust gas pressure, created in the manifold by operation of the EPG, is allowed to enter the cylinders at the end of the induction stroke. This means that the cylinder is already pressurised at the start of the compression stroke. This results in a much higher pressure towards the end of the compression stroke (B), giving a powerful braking effect. Pressure is released from the cylinder just before TDC, by briefly opening the exhaust valves once more (C).

177

VEB

B A

C 178

VEB Low profile lobes

A. Exhaust cam lobe for normal valve opening B. Charging cam lobe C. Decompression cam lobe Gas entry for pressurisation is controlled by the exhaust valves which are opened by two extra, low profile, lobes on the exhaust cams - (B) and (C). Because the lift height of these lobes - 0.8 mm - is much less than normal valve clearance, these lobes do not normally cause valve opening. The lobes cause valve opening - brief and slight - only when the normal valve clearance is reduced to zero, by oil pressure acting on a plunger in the rocker arm. Valve opening through these lobes is approx. 1.1 mm.

179

VEB 6

3

2 4

5

A 6

1

B

5

180

VEB VCB control valve

The control valve - attached to the cylinder head under the valve cover - controls the pressure of oil behind the valve clearance control plunger in the rocker arm. Oil reaches the valve inlet (1) via a drilling in the cylinder block and head, and is always at full system pressure. Oil outlet (2) is connected to the rocker arm shaft by a connecting pipe.

Compression braking not selected

When compression braking is not selected (A), solenoid (3) is not energised, and oil pressure behind the rocker arm plunger is reduced from approx. 2 bar to 1 bar, by control valve (4). Held in position by oil pressure acting on one end, and the force of spring (5) acting on the other end, plunger (6) partially covers the outlet port.

181

VEB 6

3

2 4

5

A

7

6

1

B

5

182

VEB

VCB control valve Compression braking selected

When compression braking is selected (B), solenoid (3) is energised, and oil pressure behind the rocker arm plunger increases to approx. 2 bar. Held in position by oil pressure acting on one end, and the force of spring (5) acting on the other end, plunger (6) partially covers the outlet port. When energised, solenoid (3) opens a spill port (7), allowing the force of spring (5) to push over plunger (6) and fully open the outlet port.

183

VEB

1

9

3 7

2

4

5

6

8 184

VEB

VCB rocker arm assembly

Rocker arm (1) houses: - a non-return valve assembly - plunger (2), plunger spring (3), ball (4) and ball spring (5). - clearance reduction plunger (6), with pressure limiting ball valve (7), and ball spring (8).

Normal operation

During normal operation, the 1.0 bar oil pressure is sufficient for lubrication of the rocker arms and camshaft bearings. Oil enters the non-return valve from the rocker shaft via channel (9), and acts against plunger (2). However, 1.0 bar is not enough to compress spring (3). Plunger (2) holds ball (4) off itʼs seat, so no pressure is built up behind plunger (6).

185

VEB

1

9

3

10 2

4

7 11

5

6

8 186

VEB Compression braking selected

When compression braking is selected, by operating the control switch, oil pressure to the rocker arm increases to approx. 2.0 bar. A pressure of 2.0 bar is enough to compress spring (3), so plunger (2) is pushed away from ball (4). Ball spring (5) now pushes ball (4) towards itʼs seat, allowing oil pressure to build-up behind plunger (6). When plunger follower (10) is in tight contact with valve yoke (11), pressure behind plunger (6) rapidly increases, and ball (4) is forced tight onto itʼs seat. Normal valve clearance is reduced to zero, and the low profile cam lobes are able to open the valves as required - as shown on the following page.

187

A 0.3 mm

B

4

C 0.8 mm

5 6 1

2 3

1.1 mm

188

VEB

Compression brake - cam and valve operation Compression brake not selected - A

Flat spring (1) keeps rocker arm plunger follower (2) in contact with valve yoke (3). The normal valve clearance of 1.6 mm, between plunger follower (2) and yoke (3), results in a clearance of 0.3 mm between rocker arm roller (4) and charging lobe (5). The same clearance exists between the roller and decompression lobe (6).

Compression brake selected -B

Valve clearance is reduced to zero, so roller (4) closely follows the cam profile.

Compression brake selected -C

Charging lobe (5) is directly in line with roller (4), the lobe lift of 0.8 mm, magnified by the rocker arm, opens the exhaust valves by approx. 1.1 mm. The same valve opening occurs when decompression lobe (6) aligns with roller (4).

189

VEB

1

2

3 190

VEB Rocker arm - D16C

On later D16C engines, valve clearance is adjusted by a tappet screw (1), acting on plunger (2). Valve yoke (3) has no adjustment , and no shims are used. This arrangement will be introduced on D9 and D12 engines.

191

VEB Checking VCB oil pressure D12

To check oil pressure on D12 engines, the rocker cover must be removed to enable connection of an oil pressure test gauge.

D9A

On D9A, the rocker cover does not need to be removed. There is a coupling pipe on the right hand side of the engine at No. 6 cylinder position. An oil pressure test gauge can be connected to the pipe using a quick coupling.

192

Turbochargers 193

Turbochargers

A

B

194

Turbochargers Turbochargers - D12C

D12C engines have either a Garrett or Holset turbocharger: A. Garrett fitted to D12C 42 and 460 B. Holset fitted to D12C 340 and 380 In both cases, lubrication is direct from the bypass filter.

195

Turbochargers A

1

2 B

196

Turbochargers

Turbocharger - D9A - MWE

D9A turbochargers have an integral wastegate, and a feature called Map Width Enhancement (MWE). MWE has been introduced to improve and widen the turbo/engine working range, and to optimise the torque characteristics of the engine. MWE is achieved by dividing the compressor air inlet into a main central intake (1), surrounded by an annular intake (2). Air can pass from one to the other via an annular port. At low speed and high engine load (A), the full volume of air entering the intake cannot be consumed by the engine, so some of the air is recirculated between the ports. At high speed, and high boost pressure (B), the engine needs the full volume of air, so all the air is drawn into the engine.

197

Turbochargers

5

3 A

2

1 4

B

198

Turbochargers

Turbocharger - wastegate

Low speed - low boost

The wastegate is a pressure relief or bypass valve which allows some of the exhaust gases to bypass the turbine at higher engine speeds. This allows the turbocharger to be more effectively matched to the engine at lower engine speeds. The assembly comprises - an actuating cylinder (1), actuation linkage (2), and valve flap (3) located in the turbine housing. Inside the actuating cylinder is a diaphragm and spring. The chamber behind the diaphragm is connected to the compressor wheel chamber by a flexible pipe (4), so the diaphragm is subject to boost pressure at all times. At low speed (A), the boost pressure is not enough to overcome the force of the spring. Therefore, the wastegate valve is closed, so all exhaust gas passes the turbine (5).

199

Turbochargers

5

3 A

2

1 4

B

200

Turbochargers

Turbocharger - wastegate

Low speed - low boost

As the turbo speed and, therefore, boost pressure, increases, pressure on the diaphragm increases, and the valve starts to open (B). This allows some of the exhaust gas to bypass the turbine, so further boost pressure is limited.

201

Turbochargers

202

Turbochargers Turbocompound

Conventional turbocharger

Power turbine

The essential component of the turbocompound unit is a second exhaust driven turbine wheel - the ʻpower turbineʼ - located downstream of the turbocharger. The power turbine extracts more heat energy from the exhaust gases, which would otherwise be wasted. Exhaust gases leaving the manifold are at approx. 6500 C. The gases drive a conventional turbocharger (1), where energy is use to boost power and torque in the combustion process. Gases leaving the turbocharger are at approx. 5500C. Instead of being lost to atmosphere via the exhaust system, these gases are directed to the power turbine (3). The energy is used to drive the power turbine at up to 55,000 rev/min. At this point, the gases are at approx. 4500C, and are discharged via the exhaust system.

203

Turbochargers

204

Turbochargers Speed reduction

Increased momentum

The high speed of the power turbine is stepped down via gears (4) and (6/7). A hydraulic coupling (5) balances out speed variations between the power turbine and the flywheel. At the crankshaft gear (2), speed is down to approx. 1,900 rev/min. The momentum of the flywheel is increased, and rotation is more even and stable.

205

Turbochargers

206

Turbochargers Intake system - D9A

Renew the element

The filter element is made of impregnated folded paper. The inner seal is part of the filter. The outer seal is located on the filter flange, and compressed when the cover is fitted. A combined air pressure drop and air temperature sensor is located on the pipe connecting the filter housing to the turbocharger. When the sensor senses increased pressure drop, indicating start of filter blocking, an indicator lamp on the instrument panel is lit. The filter element must be renewed when the lamp lights, or at least every 24th month.

207

Turbochargers 500 C

1500 C

208

Turbochargers Intercooler D12C

Turbocharging raises the temperature of the intake air, so it is less dense and able to burn less fuel efficiently. An intercooler, located in the intake system between the turbocharger and intake manifold, lowers intake air temperature, so that more fuel can be burned efficiently.

Air to air intercooler

The D12C intercooler is an ʻair to airʼ type, meaning that, heat is rejected from intake air to ambient air.

More power, less stress

The intercooler lowers intake air temperature by approx. 1000 C. allowing greater engine power output, and less thermal stress on engine components.

209

210

Cooling Systems 211

Cooling Systems 5

8

3

6

4 2

7

1 CAUTION

212

Cooling Systems Drive belts - D9A / D16C

These engines have two multi-groove drive belts. Inner belt (1) drives A/C compressor (2), and alternator (3). Belt tension is set by automatic tension adjuster (8). Belt to pulley contact is increased by spring loaded roller (9). Outer belt (4) drives fan pulley (5), and coolant pump (6). CAUTION It is essential that the belt is correctly fitted as shown in the illustration. The belt must run under the coolant pump pulley (6) - arrowed. If the belt runs over the pulley, the pump will rotate in the wrong direction, and may cause severe engine damage. Belt tension is set by automatic tension adjuster (7).

213

Cooling Systems

4

6

3

9

1

2 5

7

8

214

Cooling Systems Drive belts D12C

This engine has two multi-groove drive belts. Inner belt (1) drives A/C compressor (2), and alternator (3). Belt tension is set by manual tension adjuster (4) at the alternator bracket. Outer belt (5) drives fan pulley (6), which is available in three different sizes, according to engine capacity. Belt tension is set by automatic tension adjuster (7). Drive pulley (8) is driven from the engine timing gears. The gear housing is attached to the timing gear cover. The speed of fan (9) is thermostatically controlled. The fan bearing housing is attached to the timing gear cover in ʻhighʼ or ʻlowʼ position according to the truck model. The housing has sealed lubrication. It cannot be repaired, so must be renewed if faulty

215

Cooling Systems

4 2

1

5

3

216

Cooling Systems Cooling system - D12C

Depending on cooling requirements, two system types are available - COOLC-4- and COOLC-48. Radiator size and fan diameter vary according to engine power output. Radiator (1) has plastic top (2), and bottom (3) tanks. The transparent plastic header tank (4) has a level sensor connected to the engine ECU. The tank for FM12 has one filler cap with a pressure relief valve. The tank for FH12 has two filler caps, with a pressure relief valve in the upper cap.

217

Cooling Systems

4 2

1

5

3

218

Cooling Systems

Cooling system - D12C

Coolant is pumped into the cylinder block distribution jacket via hose (5). Most of the coolant flows through the oil cooler, but a small amount of coolant is fed into the cylinder lining lower cooling jackets. From the oil cooler, coolant is distributed to the cylinder liner upper jackets, and cylinder head. The cylinder head also receives coolant returning from the liner jackets, which is directed via nozzles to the exhaust ports and injector sleeves. All coolant returns to the pump or radiator via the thermostat at the front of the cylinder head.

219

Cooling Systems

220

Cooling Systems Coolant flow - D12C - engine cold

When the engine is cold the thermostat is closed. Coolant flows from the cylinder head, through the outer section of the thermostat housing back to the coolant pump.

221

Cooling Systems

222

Cooling Systems Coolant flow - D12C engine at normal temperature

When the engine is at normal operating temperature the thermostat is open, and the outlet to the pump is gradually closed. Coolant flows from the cylinder head, through the inner section of the thermostat housing to the radiator.

223

Cooling Systems 1

CAUTION

2

Remove seal

224

Cooling Systems Coolant pump and filter - D12C

Filter identification

Filter renewal

The pump is driven from the engine timing gears. The shaft is carried on a double row ball bearing (1), which is lubricated from the timing gears. There is a ventilated space between the oil seal and coolant seal.

Attached to the pump is a coolant filter (2). Early filters have P/N with a 1.0 mm line above. Later filters have P/N with a 10.0 mm line above. Also, there is a red protection seal inside the threads. CAUTION It is essential that this seal is removed before the filter is fitted. The filter must be renewed: - every six months or every second engine oil change. - every time coolant is renewed. Note: SB 175-09 does not apply to later filters.

225

Cooling Systems 11

10 9 8 7

6 5

4

12

1

2

3 226

Cooling Systems Cooling system - D16B

The radiator has plastic top and bottom tanks. The transparent plastic header tank (7) has a level sensor connected to the engine ECU. 1. Coolant pump 2. Coolant filter 3. Oil cooler 4. Return pipe from engine 5. Thermostat housing 6. Temperature sender 7. Expansion tank 8. Upper filler cap (used when cab raised) 9. Coolant level indicator 10. Front filler cap ( used when cab down) 11. Heat cell for cab 12. Air compressor

227

Cooling Systems A

A

B

228

Cooling Systems Coolant flow - D16B

A. Engine cold - thermostats closed B. Engine warm - thermostats open Coolant is pumped into the longitudinal gallery in the LH side of the cylinder block. From this gallery, coolant is fed around the cylinder liners and into the thermostat housing, via the cylinder head and oil cooler.

229

Cooling Systems 2 1

3

230

Cooling Systems

Coolant flow - D16C - engine cold

Thermostat (1) is closed, so no coolant flows to the radiator via outlet (2). Coolant is circulated around the engine by pump (3), via the coolant filter and oil cooler.

231

Cooling Systems 2 1

3

232

Cooling Systems Coolant flow - D16C - engine warm

Thermostat (1) is open, so coolant flows to the radiator via outlet (2). Coolant is circulated around the engine by pump (3), via the coolant filter and oil cooler.

233

Cooling Systems

1

234

Cooling Systems Fan drive - D16C

Via a viscous coupling, the fan is belt driven by a multigroove belt from the crankshaft pulley. Belt tension is set by an automatic tension adjuster, and a spring loaded idler pulley improves belt to pulley contact. Fan speed is controlled by a Pulse Width Modulated (PWM) signal - stepless variable voltage - from the engine ECU. Fluid flow in the viscous coupling is controlled by a fluid flow valve, which is progressively opened and closed by the varying field strength of electromagnet (1). Field strength is controlled by the PWM signal. Note: Other ECUʼs can influence fan speed. As a fail safe feature, with no PWM signal applied, the fan runs at full speed.

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236

237

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Engine 1 Training

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