engine fundamentals v - educational resources & · pdf fileelectrical system 13 ......

CHAPTER 8 • ENGINE FUNDAMENTALS V

Part 1 • Introduction to motor vehicles 1 1 Motor vehicle components 3 2 Workshop safety 17 3 Workshop practices 29 4 Tools and their use 45 5 Measuring and checking 69 6 Friction and bearings 87 7 Seals, gaskets and sealants 103 8 The environment and the automotive service industry 117

Part 2 • Engines and engine systems 131 9 Engine fundamentals 13310 Engine construction and components 14911 Cooling system and service 16912 Engine-lubricating systems 19113 EFI fuel systems 20714 Carburettor fuel systems 22315 Gas fuel systems 25716 Intake and exhaust systems 279

Part 3 • Manual transmissions and drives 29517 Clutches 29718 Clutch service 31119 Manual transmission and transaxles 32520 Manual transmission and transaxle service 35121 Drive lines and shafts 37522 Rear axles and fi nal drives 39323 Rear-axles and fi nal-drive service 411

Part 4 • Running gear 43324 Tyres, wheels and balance 43525 Brakes 45526 Brake service 48527 Suspension systems 50728 Suspension service 52729 Steering systems 54930 Steering-system service 57331 Wheel alignment 593

Part 5 • Maintenance 61532 Fuels, fl uids and lubricants 61733 Service and maintenance 63134 Basic mechanics and diagnosis 645

Part 6 • Basics of the electrical system 65935 Basic electrics 66136 Effects and applications of electric currents 67737 Basic electronics 69538 The battery 711

Appendix: The SI system of measurement 727Common abbreviations 734Glossary 735Index 751

About the authors xiiiCompetency grid xivPreface xvi

Acknowledgments xvi

Supplemements for Instructors

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About the authors xiiiCompetency grid xiv

Preface and Acknowledgments xviSupplements for instructors xviii

Motor vehicle components 3Mechanical arrangements 4Sections of a motor vehicle 4Hybrid-drive vehicles 5The engine assembly 5Vehicle construction 5The drive train 6Transmissions 9Running gear 10Electrical system 13Body and associated parts 13Names of components and parts 15Technical terms 15Review questions 15

Workshop safety 97Personal safety 98Other personal safety issues 99Machine and equipment safetyMotor vehicle safety 99Safety with vehicle components 101Engine safety 101Battery safety 102Hazardous materials Emergency procedures Fire safety 103Fires 103Fire extinguishers 104First aid 105Technical terms 105Review questions 105

Workshop practices 17Automotive service procedures 18Workshop operations 20Production processes 21Fasteners 23Locking devices 25Screw threads 26V-threads 27Sources of information 28Vehicle identifi cation 30Technical terms 30Review questions 30

Tools and their use 33Tools for turning 34Tools for holding and gripping 38Tools for hammering and driving 39Tools for cutting and forming 41Tools for drilling and reaming 44Tools for threading 46Tools and materials for grinding and abrading 48Tools for pulling and pushing 51Portable power tools Special service tools 52Technical terms 52Review questions 52

Measuring and checking 53Measuring instruments 54Micrometers 55Reading micrometers 57Accuracy and care of micrometers 59

PART 1 • INTRODUCTION TO MOTOR VEHICLES

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Vernier calipers 59Dial gauge and its use 60Hole gauges Depth gauges 61Marking and checking 61Tools for marking and checking 62Other gauges and instruments 65Electrical test instruments 66Technical terms 67Review questions 67

Friction and bearings 69Friction 70Types of friction 70Making use of friction 71Bearings 71Plain bearings 73Antifriction bearings 74Special types of bearings 76Removing and installing bearings 77Cleaning and checking bearings 78Bearing adjustments 79Bearing failures 80Antifriction bearing defects 81Technical terms 83Review questions 83

Seals, gaskets and sealants 85Purpose of oil seals 86Types of oil seals 86Servicing oil seals 88Gaskets 91Gasket materials 92Handling and storing gaskets 93Sealants and sealing compounds 93Installing gaskets 93How to make a gasket 95Pipes, hoses and connections 95Technical terms 96Review questions 96

The environment and the automotiveindustry 00Introduction 00Legal responsibilities Water quality Liquid waste and chemical storage Solid waste Air quality 00Noise An environmental checklist Technical terms 96Review questions 96

Engine fundamentals 109Actions within a cylinder 110Reciprocating to rotary motion 110Cycles of engine operation 112Four-stroke cycle (petrol engine) 112Two-stroke cycle (petrol engine) 116Diesel engine operation 118Rotary engine 119Multicylinder engines 119Engine terms and defi nitions 121Engine systems 122Engine classifi cations 121Technical terms 122Review questions 123

Engine construction and components 125Engine construction 126Components of an engine assembly 129Engine features 130Working on engines — general 132Working on the underside of the engine 135Working on the front of the engine 136Working on the top of the engine 136Working on engine ancillaries 138Working on engine electrical systems 139Technical terms 141Review questions 141

VII

PART 2 • ENGINES AND ENGINE SYSTEMS

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Cooling system and service 143Basic cooling system 144Heat and temperature 145Heat transfer 146Liquid-cooling systems 146Cooling-system components 148Radiator assembly 152Radiator pressure cap and reservoir 153Coolant 154Cooling-system service 155Cooling-system repairs 158Water pump overhaul 160Cooling-system problems 161Trouble diagnosis guide 162Technical terms 162Review questions 162

Engine-lubricating systems 163Engine lubrication 164Oil circulation 165Oil pumps 167Oil pump service 169Oil fi lters 170Oil coolers 171Lubrication of engine bearings 173Crankcase ventilation 174Lubricating-system maintenance 175Lubricating-system problems 177Technical terms 178Review questions 178

EFI fuel systems 179Petrol as a fuel 180Air–fuel ratio 180Types of EFI systems 181Basic multipoint EFI system 181Multipoint fuel systems 181Fuel-supply system components 184Air intake system components 189Electronic control components 190Checks and precautions 191Service requirements 193Technical terms 193Review questions 193

Carburettor fuel systems 195Carburettor fuel system 196Carburettors 198Air and fuel fl ow in a carburettor 199Carburettor operation 199Carburettor systems 201Carburettor construction 201General carburettor design 203Carburettor external construction 204Single-barrel and multibarrel carburettors Throttle-valve operation Mixture correction Automatic chokes Manual chokes Other carburettor components Carburettor service and checks 205Basic carburettor problems 207Servicing fuel pumps 207Testing mechanical fuel pumps 208Checking electric pumps 210Fuel system problems 210Technical terms 211Review questions 211

Gas fuel systems 213Gas-fuelled vehicles 214LPG and NGV 214Location of LPG components 215LPG fuel container assembly 216Fuel container sub-compartment 217Fuel fi ller assembly 219Components of the supply subsystem 220Converter assembly 220Air–gas mixer 223LPG fuel system controls 224LPG fuel system components 224Converter with stepper motor 225LPG liquid and vapour injection NGV fuel systems 227Servicing LPG fuel systems 228Safety precautions with gas 229Technical terms 230Review questions 230

VIII

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Clutches 249Purpose of the clutch 250Types of clutches 250The clutch assembly 250Diaphragm clutch operation 251Diaphragm clutch components 252Clutch controls 255Other clutch features 258Pull-type clutches 259Clutch with central release 260Dual-mass fl ywheel 260Technical terms 261Review questions 262

Clutch service 263General checks and adjustments 264Adjusting mechanical controls 264Servicing mechanical controls 265Adjusting hydraulic controls 265Servicing hydraulic controls 266Bleeding the clutch system 269Major clutch service 269Repairs to pressure-plate assemblies 273Clutch housing alignment 273Analysing clutch problems 273Diagnosing clutch noise 274General clutch problems 275Technical terms 276Review questions 276

Manual transmissions and transaxles 277Purpose of a transmission 278Types of gears 278Gear ratio 279Basic transmission 280Basic transmission power fl ow 281

Sliding and synchromesh gears 281Basic synchromesh transmission 283Five-speed synchromesh transmission 285Power fl ow through a fi ve-speed transmission 286Six-speed transmission Transaxles 286Transaxle construction 286Transaxle operation 290Synchromesh operation 293Types of synchromesh 295Gearshift mechanisms 295Technical terms 300Review questions 300

Manual transmission and transaxle service 301Service operations 302Rear-wheel-drive transmissions 303Dismantling transmissions 307Dismantling and checking components 307Identifying internal components of a transmission 311Transaxles 312Identifying internal components of a transaxle 313Dismantling transaxles 316Reassembling transaxles 317Inspection of parts (all transmissions) 317Points relating to reassembly 319Removing transmissions and transaxles 321Transmission and transaxle fault diagnosis 321Road testing and diagnosis 321Transmission service summary 322Technical terms 324Review questions 324

IX

PART 3 • MANUAL TRANSMISSIONS AND DRIVES

Intake and exhaust systems 231Air cleaners 232Carburettor air cleaners 232EFI air cleaners 234Diesel air cleaners 236Air-cleaner service 236Engine manifolds 238

Intake-system problems 240Exhaust systems 240Exhaust-system service 243Exhaust-system problems 244Technical terms 246Review questions 246

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Drive lines and shafts 325Rear-wheel drive 326Universal joints 326Constant-velocity joints 328Alignment of universal joints (RWD) 329Removing and replacing propeller shafts 331Servicing cross-and-yoke joints 331Servicing a Löbro joint 334Front-wheel drive 335Constant-velocity joints (FWD) 337Servicing constant-velocity joints (FWD) 338Technical terms 340Review questions 340

Rear axles and fi nal drives 343Basic rear-axle assembly (RWD) 344Rigid rear axles 344Final drive and differential 346Axle shafts for rigid rear axles 349Rear-axle bearings 349Differential 350Limited-slip differentials 352Dynamic performance control

Rear axles for independent rear suspension 355Transaxle fi nal drive 357Four-wheel drive 359Technical terms 359Review questions 359

Rear-axle and fi nal-drive service 361General rear-axle service points 362Removing axle shafts and bearings 362Servicing differential assemblies 367Servicing a banjo-axle differential 367Servicing unitised rear-axle differentials 371Servicing IRS fi nal drives 372Crown wheel and pinion adjustments 374Checking gear tooth contact 376Bearing preload – pinion and side bearings 377Limited-slip differential service 379Transaxle fi nal-drive service 380Transaxle with crown wheel and pinion 380Summary of differential adjustments 381Diagnosis of rear-axle noises 381Technical terms 382Review questions 382

Tyres, wheels and balance 387Tyre construction 388Types of tyre construction 389Characteristics of tyres 390Tyre profi les 390Tyre sizes and identifi cation 391Tyre tread patterns 392Australian Design Rules 393Tyre wear 394Tyre rotation 396Wheels 397Removing and fi tting tyres 398Light-truck wheels and tyres 399Wheel balance 400Balancing wheels 402Technical terms 404Review questions 404

Brakes 407Basic brake system 408Hydraulic principles 408Brake hydraulic systems 410

Master cylinders 410Compensating-type master cylinder 413Centre-valve master cylinder 414Valves in the hydraulic system 416Wheel cylinders 418Hydraulic brake fl uid 420Brake booster 420Drum-brake assemblies 423Brake-shoe assemblies 424Disc-brake assemblies 426Parking brakes 430Technical terms 432Review questions 432

Brake service 435Maintenance and inspection 436Brake booster 438Hydraulic system – service points 439Bleeding brakes 441Master-cylinder service 442Drum-brake service 443Drum-brake adjustments 446Self-adjusting drum brakes 447

X

PART 4 • RUNNING GEAR

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Disc-brake service 448Parking brakes 451Brake tools 453Fault diagnosis 454Technical terms 455Review questions 455

Suspension systems 469General suspension designs 470Leaf springs 471Rear suspension with leaf springs 471Front suspension with leaf springs 473Types of coil springs 474Front suspension with coil springs 474Strut or McPherson suspension 476Rear suspension with coil springs 477Independent rear suspensions with struts 479Rear suspension with swing axles 480Torsion rear axle 480Torsion bar suspension 483Shock absorbers 483Height-control suspension 486Technical terms 486Review questions 487

Suspension service 489Maintenance 490Dismantling and reassembling procedures 490Ball joint front suspension 491Strut (McPherson) suspensions 492Rigid rear axle with coil springs 494Independent rear suspension (RWD vehicles) 495Rigid rear axle with leaf springs 496Dismantling and reassembling struts 498Servicing components 499Servicing hubs and bearings 502Hubs with tapered roller bearings 502Hubs with unitised bearings 504Other bearing arrangements 506Checking suspension parts 507Servicing shock absorbers 509Technical terms 510Review questions 510

Steering systems 511Steering systems 512Rack-and-pinion steering systems 512Steering systems with worm gearing 513Steering and suspension angles 514

Steering boxes 516Rack-and-pinion steering boxes 517Rack-and-pinion power steering 518Rack-and-pinion power steering components 519Speed-sensitive rack-and-pinion power steering 521Electro-hydraulic power steering 522Electric power steering 523Steering boxes with worm gearing 524Power steering for worm-type boxes 525Four-wheel steering 528Four-wheel-steering systems 529Four-wheel steering with rear power cylinder 530Other steering features 533Technical terms 534Review questions 534

Steering-system service 535Servicing steering linkage 536Steering-column service 538Power-steering maintenance 540Rack-and-pinion steering service 542Rack-and-pinion power-steering service 545Analysing power-steering problems 547Servicing a recirculating-ball steering box 547Worm-type steering box adjustments 550Recirculating-ball box with power steering 551Steering faults 551Technical terms 552Review questions 552

Wheel alignment 553 Steering and suspension angles 554Front-suspension and steering adjustments 556Caster and camber adjustments 556Toe adjustments 558Adjustments for toe-out-on-turns 560Rear-suspension adjustments 560Wheel-alignment equipment 561Types of wheel aligners 562Using wheel aligners 565Front-wheel alignment 568Rear-wheel alignment 569Function and effects of the various angles 569More about suspension angles 571Technical terms 573Review questions 573

XI

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XII

Fuels, fl uids and lubricants 577Crude oil and its products 578Petrol 578Ethanol Gas fuels 580Automotive diesel fuels 581Alternative fuels Lubricating oil 582Grease 585Transmission oils 586Hydraulic brake fl uids 587Technical terms 588Review questions 588

Service and maintenance 589Servicing new vehicles 590New vehicle services 590Scheduled maintenance services 590Maintenance items 592Service intervals 597

Special services 598General service and repairs 598Lifting and jacking 598Towing and recovering 600Technical terms 601Review questions 601

Basic mechanics and diagnosis 603Diagnosis 604Forces that produce stress 604Failure analysis 607Analysing shaft failures 607Analysing fastener failures 608Analysing excessive wear 609Noise vibration and harshness (NVH) 610Analysing gear problems 611Bearing problems 613Materials and their use 613Other means of diagnosis 614Technical terms 614Review questions 614

PART 6 • BASICS OF THE ELECTRICAL SYSTEM

Basic electrics 619Automotive electrical components 620Nature of electricity 621Electron fl ow 622Current fl ow 623Types of electrical materials 623Summary of basic electrics 624Practical conductors, resistors and insulators 625Factors affecting current fl ow 627The language of electricity 627Electrical circuits 630Parallel and series connections 630Voltage drop in a circuit 632Technical terms 633Review questions 633

Effects and applications of electriccurrents 000Effects of an electric current 636Heating effect of a current 636Chemical effect of a current 637Magnetic effect of a current 638

Theory of magnetism 638Electromagnetism 640Solenoids and electromagnets 641Electromagnetic switches (relays) 643Electrical measuring instruments 644Electromagnetic induction 645Electric motors 648Direct and alternating current 649Technical terms 649Review questions 649

Basic electronics 651Electronics 652Electronic semiconductors 653Electronic components – diodes and transistors 654Other electronic components 656Use of electronic components 658Electronic systems 660Micro-computer 662Body electronic module 663Technical terms 665Review questions 665

PART 5 • MAINTENANCE

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Aur Description Volume Chapter

AURC270103A Apply safe working practice 1 2

AURC270789A Communicate effectively in the workplace 1 2,3

AURE218664A Remove and replace electrical/electronic units/assemblies 2 24, 25, 26, 27

AURE218676A Test, service and repair batteries 1 38

AURE219331A Install, test and repair low-voltage wiring/lighting systems 1 35–38

2 26–27

AURE219531A Install ancillary electrical components 2 26–36

AURE224008A Carry out soldering of electrical wiring/circuits 2 27

AURE318966A Repair instruments and warning systems 2 28

AURE320871A Service and repair electronically controlled steering systems 1 29, 30

AURE320971A Service and repair electronically controlled suspension systems 1 27, 28

AURE321066A Repair electronic systems 1 37

AURE321271A Service and repair electronic drive management systems 2 27

AURE321371A Service and repair electronic body management systems 2 26, 27, 29

AURE321471A Service and repair electronically controlled antilock braking systems 1 26

2 30

AURE321571A Service and repair electronically operated traction control system 2 30

AURE321671A Service and repair electronically operated stability control 2 30

AURE321171A Service and repair electronic spare ignition engine management systems. 2 11

AURE218676A Test, service and charge batteries 1 38

AURE218708A Carry out repairs to single electrical circuits 1 35

2 26, 27

AURE320666A Repair ignition systems 2 11

AURE319266A Repair starting systems 2 24

AURE319166A Repair charging systems 2 25

AURE318866A Repair electrical systems 2 27

AURT200108A Carry out servicing operations 1 33

AURT205166A Repair exhaust system components 1 15

AURT201170A Inspect and service engines 1 9, 10

AURT202170A Inspect and service cooling systems 1 11

AURT203170A Service petrol fuel systems 2 14

AURT206670A Inspect and service transmissions (manual) 1 19, 20

AURT207170A Inspect and service transmissions (automatic) 2 19–22

AURT210170A Inspect and service braking systems 1 25–26

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XV


AURT212670A Service fi nal drive assemblies 1 22, 23

AURT213170A Service fi nal drive (drive line) 1 21

AURT215170A Inspect and service steering systems 1 29, 30

AURT216170A Inspect an service suspension systems 1 27, 28

AURT217606A Balance wheels and tyres 1 24

AURT270278A Use and maintain workplace tools and equipment 1 2–5

AURT200368A Select and use bearings, seals, gaskets, sealants and adhesives 1 6, 7

AURT201164A Remove and install engine assemblies 2 1

AURT202166A Repair cooling systems 1 11

AURT203670A Service diesel fuel injection systems 2 15, 16, 17

AURT204670A Inspect and service emission control systems 2 12

AURT205166A Repair exhaust system components 1 16

AURT213165A Remove and refi t drive-line components 1 21, 22, 23

AURT217108A Carry out wheel alignment operations 1 31

AURT217665A Remove, fi t and inspect wheel assemblies 1 24

AURT217668A Select tyres and rims for specifi c applications (light) 1 24

AURT217766A Remove, inspect, repair and fi t tyres and tubes (light) 1 24

AURT217865A Remove and refi t wheel hubs and associated brake components 1 25

AURT225667A Use and maintain measuring equipment 1 5, 8

AURT216170A Inspect and service suspension systems 1 27, 28

AURT209170A Service hydraulic systems 2 21

AURT301383A Dismantle, assemble and repair engine block and sub-assemblies 2 4, 5, 6, 7

AURT301483A Recondition cylinder heads 2 2, 3

AURT303666A Repair diesel fuel systems 2 15, 16, 17

AURT304270A Service LPG Fuel systems 1 15, 32

AURT305671A Inspect and repair engine forced induction systems 2 13

AURT307166A Repair transmissions (automatic) 2 19–22

AURT318054A Provide advice on the effects of wheel and tyre combinations 1 24

AURT401145A Overhaul engines and associated engine components 2 1–8

AURT403145A Overhaul petrol fuel system components 1 10, 14

AURT406145A Overhaul clutch assemblies 1 17–18

AURT406645A Overhaul transmissions (manual) 1 19–20

AURT407145A Overhaul transmissions (automatic) 2 19–22

AURT410145A Overhaul braking system components (light) 1 25–26

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XVI PART 3 • INTRODUCTION TO THE ENGINE


AURT412645A Overhaul fi nal-drive assemblies 1 21, 22, 23

AURT415145A Overhaul steering system components 1 29–30

AURT466208A Carry out diagnosis of complex system faults 1 34

AURT202166A Repair cooling systems 1 11

AURT271781A Implement and monitor environmental regulations in the automotive 1 8 mechanical industry

AURT301166A Repair engines and associated engine components 2 1–8

AURT303166A Repair petrol fuel systems 1 10, 14

AURT304666A Repair and replace emission control systems 2 12

AURT306170A Inspect, service and/or repair clutch assemblies and associated operating system components 1 17–18

AURT306666A Repair transmissions (manual) 1 19–20

AURT310166A Repair hydraulic braking systems 1 25, 26

AURT312666A Repair fi nal-drive assemblies 1 22, 23

AURT313166A Repair fi nal drive (drive line) 1 21

AURT315166A Repair steering systems 1 29–30

AURT316166A Repair suspension systems 1 27–28

AURT366108A Carry out diagnostic procedures 1 34

AURV327164A Remove and replace supplementary restraint systems (SRS) 2 33

XVI

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CHAPTER 1 • MOTOR VEHICLE COMPONENTS 3

• Mechanical arrangements

• Sections of a motor vehicle

• Hybrid-drive vehicles

• The engine assembly

• Vehicle construction

• The drive train

• Transmissions

• Running gear

• Electrical system

• Body and associated parts

• Names of components and parts

• Technical terms

• Review questions

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4 PART 1 • INTRODUCTION TO MOTOR VEHICLES

A motor vehicle is made up of a large number of parts which are assembled together during manufacture.

Some parts are large and others are quite small. Many parts are fi tted together to form larger com-ponents. Some parts are bolted together while others, such as the body panels and subframes, are welded together.

Motor vehicles vary greatly in design and body style, and the term motor vehicle can be used to include passenger cars, station wagons, vans, utilities, trucks, buses and coaches. In fact, any wheeled vehicle that operates on roads can be included.

In this book, most of the information will relate to passenger vehicles and light commercial vehicles. However, the basic principles involved apply to all motor vehicles and, in many instances, to vehicles that do not usually operate on roads, such as agricultural tractors and industrial and construction equipment.

Mechanical arrangementsThere are two basic arrangements of the major mechanical components of passenger and light com mercial vehicles: front-wheel drive and rear-

wheel drive. These are shown in simplifi ed form in Figures 1.1 and 1.2 with their parts identifi ed. While the main difference is whether the front wheels or the rear wheels drive the vehicle, this can affect a

number of other components, such as the mounting of the engine, the transmission, the drive line and the suspension.

In addition to these two basic arrangements, there are also four-wheel-drive vehicles. These have additional transmission and drive-line compon ents that carry the drive to all four wheels of the vehicle.

In many four-wheel-drive vehicles, front-wheel drive is selected by the driver only when it is needed, but other vehicles, referred to as all-wheel drives, operate in four-wheel drive at all times.

Sections of a motor vehicleA motor vehicle consists of a number of sections which, for convenience, can be considered as follows:1 The engine assembly, which is the source of

power.2 The frame or chassis, which forms the basic

structure to support the engine and the various mechanical components.

3 The drive train, which has gears and shafts to connect the engine to the driving wheels.

4 The running gear, consisting of the wheels, tyres, suspension, steering and brakes, which enables the vehicle to operate on the road.

2 3 4 5 6 7 8 9 10 11 12 13

14

15

16171819201

Figure 1.1 Skeletal arrangement of a rear-wheel-drive vehicle

1 engine assembly, 2 radiator, 3 alternator, 4 front suspension, 5 front disc brake, 6 steering assembly, 7 torque converter, 8 automatic

transmission, 9 handbrake, 10 propeller shaft, 11 rear suspension, 12 rear brake, 13 shock absorber, 14 rear-axle assembly, 15 fuel tank,

16 fi nal drive, 17 exhaust system, 18 catalytic converter, 19 wheel hub, 20 battery


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5 The electrical system, which includes the battery, wiring, lights, starter, alternator and other electrical components.

6 The body of the vehicle, which provides seating for the driver and passengers and, in commercial vehicles, carries loads.

To service these various parts of a motor vehicle, it is necessary to know the names of the various components, their location on the vehicle, and their purpose or function.

It is also necessary to understand how com ponents operate and to be familiar with their construction and design. A knowledge of adjustments and servic-ing requirements is also important, together with accepted methods of carrying out repairs.

Hybrid-drive vehiclesHybrid vehicles have an internal combustion engine combined with an electric motor to provide the power to drive the vehicle. The reason for this is to improve fuel economy and to reduce exhaust emissions. The engine can be designed so that it is smaller than normal and as a result is more fuel effi cient. The electric motor produces no emissions.

The basic hybrid arrangement is shown in Figure 1.3 on the following page with its main parts identifi ed. Depending on driving conditions, power to drive the vehicle is delivered by the engine, by the electric motor, or by a combination of the engine and the electric motor.

It has a fuel tank to supply petrol to the engine and high-voltage batteries to provide power to the electric motor. The battery is recharged by a generator when the electric motor is not in use. More information on hybrid vehicles can be found in Volume 2.

The engine assemblyThe engine is the source of power that provides the torque or turning force which is used to drive the vehicle. Engines in motor vehicles can be internal com-bustion, electric or a combination of the two (known as ‘hybrid’). Internal combustion engines burn the fuel inside the engine using petrol, distillate or gas. Electric motors use electricity supplied from storage batteries fi tted to the vehicle. The batteries can be charged using an internal combustion engine, fuel cell, solar cell, power regeneration and external charging.

Figure 1.4 on the following page is a drawing of a basic engine with its main parts identifi ed. This is a

4 5 6 7 8 9 10 11 12 13

141516171821319

Figure 1.2 Skeletal arrangement of a front-wheel-drive vehicle

1 manual transaxle, 2 fi nal drive, 3 clutch, 4 radiator, 5 alternator, 6 engine assembly, 7 front disc brake, 8 hub, 9 wheel, 10 steering assembly,

11 exhaust system, 12 rear suspension, 13 rear brake, 14 fuel tank, 15 rear-wheel hub, 16 handbrake, 17 drive shafts, 18 suspension, 19 battery


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3

2 1 1 12 11 10

4 5 6 7 8 9

Figure 1.3 Skeletal arrangement of a hybrid-powered vehicle

1 hybrid transaxle, 2 electric-motor assembly, 3 radiator, 4 engine, 5 front brake, 6 front hub, 7 wheel, 8 steering assembly, 9 fuel line,

10 high-voltage battery, 11 fuel tank, 12 power cable

camshaft

timing belt

camshaftpulley

cylinder head

piston rings

piston

cylinder

connectingrod

timingpulley

crankshaftpulley

connecting-rodbearing

oil pan

crankshaftmain

bearing

crankshaft

exhaust valve

intake valve

flywheel

Figure 1.4 Basic construction of a four-cylinder engine


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four-cylinder petrol engine of the type fi tted to pas-senger cars and light commercial vehicles. More details of an engine of this type can be seen in Figure 1.5.

In operation, burning fuel inside the cylinders of the engine produces a high pressure which forces the pistons to move down their cylinders. Piston movement is transferred to the crankshaft by the connecting rods, causing the crankshaft to rotate. This rotary motion is then carried by the drive train to the driving wheels and used to propel the vehicle along the road.

The engine assembly includes the engine itself as well as all the components and systems needed to make it start and run. These include the starting, charging, cooling, ignition, lubrication, fuel and the exhaust systems.

Vehicle constructionPassenger cars have a body of unitised construction. Reinforced panels and subframes are built into the body to provide the necessary strength and stiffness. A body of this type is shown in Figure 1.6 on the next page.

Subframes for supporting the engine and trans-mission, the front and rear suspensions and other mechanical parts are built into the reinforced under-body panels. Strengthened sections of panels are used for mounting other components.

The subframes provide mountings for the engine, the transmission, the suspension and the steering. The engine has rubber mountings to prevent noise and

Figure 1.5 Four-cylinder engine, sectional view

1 timing belt, 2 camshaft drive pulley, 3 camshaft, 4 intake valve, 5 exhaust valve, 6 oil fi ller cap, 7 valve rocker gear, 8 cylinder head,

9 piston in section, 10 cylinder block, 11 cylinder, 12 connecting rod, 13 fl ywheel, 14 connecting-rod big end and crankshaft, 15 oil pan or

sump, 16 oil pump intake, 17 fan belt, 18 pulley on crankshaft, 19 oil pump, 20 water pump, 21 fan MITSUBISHI


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vibration being transmitted to the vehicle body. Rubber bushes between the various parts of the suspension and the subframe also insulate against the noise and vibration that originates at the road and tyres.

Some light commercial vehicles are designed with a cab and chassis. They have a driver’s cab of unitised construction and a frame, or rear chassis, on which a tray-type body, or a commercial body of some other design can be built.

Larger commercial vehicles have a full frame or chassis to which the body, engine, suspension, steering and other mechanical components are fi tted. The chassis is made of steel channel or box section for strength, with the parts being welded or riveted together. Cross-bracing is provided to make the frame rigid enough to withstand the shocks, twists and vibrations that it will be subjected to during operation.

The drive trainThe drive train, also called the power train, includes all the components that carry drive from the engine to the driving wheels of the vehicle. Different arrangements are used for rear-wheel drive and front-wheel drive (refer to Figures 1.1 and 1.2).

With rear-wheel drive, the drive reaches the rear wheels through the clutch, transmission, propeller shaft, fi nal drive, differential and rear axle.

With front-wheel drive, the drive is carried by the clutch, transaxle and drive shafts to the front wheels of the vehicle. There are similar components, but they are arranged differently and are more compact.

Vehicles with automatic transmissions have similar drive trains to those with manual transmissions, but they have a torque converter instead of a clutch.

Auto matic transmissions for front-wheel drive are known as automatic transaxles.

Handy hint: The term drive is one that is commonly used, although what is actually being transmitted is torque, or twisting force.

ClutchThe clutch is a friction-type coupling that enables the engine to be connected or disconnected from the trans mission. It consists basically of a large disc held against the engine’s fl ywheel by spring force. The disc is released by the driver pressing down the clutch pedal. This allows the gears to be engaged and gearshifts to be made. The clutch also enables the load to be applied gradually when starting the vehicle from rest.

A simplifi ed clutch arrangement is shown in Figure 1.7. The clutch disc is normally held against the face of the fl ywheel by the diaphragm spring, but is released by the movement of the pedal being transferred through the cable to the release fork.

A mechanically operated clutch is shown. Its operation depends on the action of levers. Other clutches are operated hydraulically.

Rear-wheel driveIn rear-wheel-drive vehicles, a drive shaft, called the propeller shaft, carries the drive from the transmission to the rear-axle assembly. It has universal joints and a sliding spline which allows the shaft to change its length and ‘angle’ so that it can adjust to rear-axle and suspension movement.

Figure 1.6 Body structure with different metals used. These provide light weight and strength COPYRIGHT HOLDEN 2008. USED WITH PERMISSION.

Body structuresteel usage

Materials

Low carbon

Medium strength

High strength

Advanced high strength

Ultra strength

Aluminium


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Names of components and partsFor identifi cation purposes, all the parts of motor vehicles have names, and replacement parts also have part numbers.

The names are given for various reasons. Some names relate to the location of the part, and the word upper or lower is often used in conjunction with the part name. Other part names include the words left or right, or front or rear. Examples of this are upper radiator hose and right front wheel.

Some parts are obviously named according to their function, such as fi lter, spring or shock

absorber.The connection of some other parts with

their names is a little harder to fi nd, as they can relate to the name of a person. For example, the

diesel engine takes its name from Dr Diesel, who developed the engine.

Names of components and parts can vary from country to country, as can the spelling. For example, clutch disc can be spelt disc or disk. However, with a little thought, the reason for the names which have been given to various parts can be understood. This will also assist in remembering their names.

Larger componentsLarger components consist of a number of small parts: for example, the gearbox can be considered as a component and the gears which are fi tted inside the gearbox as parts. Many components that contain other parts are referred to as housings or boxes, such as the clutch housing and gearbox.

In other cases, parts can be considered to form a system, which consists of a number of components or parts; for example, the fuel system includes the fuel tank, fuel pump, fuel lines and fuel injection components.

The diagrams in Figures 1.1 and 1.2 show the components in simple form and enable various components which make up the mechanical section of a motor vehicle to be identifi ed.

Handy hint: The terms components, parts, units and items are all used in relation to motor vehicle parts.

Technical termsMotor vehicle, front-wheel drive, rear-wheel drive, four-wheel drive, all-wheel drive, internal combustion, diesel, unitised, subframe, chassis, cross bracing, suspension, drive, drive train, power train, clutch, hydraulic, transmission, gear, gear ratio, manual transmission, housing, automatic transmission, torque converter, disc brake, drum brake, rack, pinion, worm, starter, alternator, electronic, electronic control unit, component, safety glass, body panels, body hardware, laminated, trim, mouldings, anticorrosive.

Review questions 1. Name the main sections of a motor vehicle. 2. Why is the engine referred to as an

internal-combustion engine? 3. What types of fuel are used in automotive engines? 4. What is the purpose of the shock absorbers? 5. Why are tyres necessary? 6. What are the parts of the power train? 7. Why is a clutch necessary? 8. Why is a transmission fi tted to a vehicle? 9. What is a transaxle?10. What is the function of the universal joints?11. What does the differential do?12. What are the two designs of brakes?13. What is the purpose of the suspension?14. Name some of the parts in a rear-axle assembly.15. Name some of the electrical parts of a vehicle.16. How is the alternator driven?17. What are the main differences between a front-

wheel-drive and a rear-wheel-drive vehicle?18. Name the main body parts of a passenger car. Refer

to the appropriate illustration.


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