Critical component wear in heavy duty engines

The critical parts of a heavy duty engine are theoretically designed for infinite life without mechanical fatigue failure. Yet the life of an engine is in reality determined by wear of the critical parts. Even if an engine is designed and built to have normal wear life, abnormal wear takes place either due to special working conditions or increased loading. Understanding abnormal and normal wear enables the engineer to control the external conditions leading to premature wear, or to design the critical parts that have longer wear life and hence lower costs. The literature on wear phenomenon related to engines is scattered in numerous periodicals and books. For the first time, the authors bring the tribological aspects of different critical engine components together in one volume, covering key components like the liner, piston, rings, valve, valve train and bearings, with methods to identify and quantify wear. The first book to combine solutions to critical component wear in one volume. Presents real world case studies with suitable mathematical models for earth movers, power generators, and sea going vessels. Includes material from researchers at Schaeffer Manufacturing (USA), Tekniker (Spain), Fuchs (Germany), BAM (Germany), Kirloskar Oil Engines Ltd (India) and Tarabusi (Spain). Wear simulations and calculations included in the appendices. Instructor presentations slides with book figures available from the companion site. Critical Component Wear in Heavy Duty Engines is aimed at postgraduates in automotive engineering, engine design, tribology, combustion and practitioners involved in engine R&D for applications such as commercial vehicles, cars, stationary engines (for generators, pumps, etc.), boats and ships. This book is also a key reference for senior undergraduates looking to move onto advanced study in the above topics, consultants and product mangers in industry, as well as engineers involved in design of furnaces, gas turbines, and rocket combustion.

List of Contributors xv

Preface xvii

Acknowledgements xxi

PART I OVERTURE 1

1 Wear in the Heavy Duty Engine 3

1.1 Introduction 3

1.2 Engine Life 3

1.3 Wear in Engines 4

1.3.1 Natural Aging 4

1.4 General Wear Model 5

1.5 Wear of Engine Bearings 5

1.6 Wear of Piston Rings and Liners 6

1.7 Wear of Valves and Valve Guides 6

1.8 Reduction in Wear Life of Critical Parts Due to Contaminants in Oil 6

1.8.1 Oil Analysis 7

1.9 Oils for New Generation Engines with Longer Drain Intervals 8

1.9.1 Engine Oil Developments and Trends 8

1.9.2 Shift in Engine Oil Technology 9

1.10 Filters 9

1.10.1 Air Filter 9

1.10.2 Oil Filter 10

1.10.3 Water Filter 10

1.10.4 Fuel Filter 10

1.11 Types of Wear of Critical Parts in a Highly Loaded Diesel Engine 10

1.11.1 Adhesive Wear 10

1.11.2 Abrasive Wear 11

1.11.3 Fretting Wear 11

1.11.4 Corrosive Wear 11

References 11

2 Engine Size and Life 13

2.1 Introduction 13

2.2 Engine Life 13

2.3 Factors on Which Life is Dependent 14

2.4 Friction Force and Power 14

2.4.1 Mechanical Efficiency 14

2.4.2 Friction 15

2.5 Similarity Studies 15

2.5.1 Characteristic Size of an Engine 15

2.5.2 Velocity 16

2.5.3 Oil Film Thickness 17

2.5.4 Velocity Gradient 18

2.5.5 Friction Force or Power 18

2.5.6 Indicated Power and Efficiency 18

2.6 Archard's Law of Wear 20

2.7 Wear Life of Engines 20

2.7.1 Wear Life 20

2.7.2 Nondimensional Wear Depth Achieved During Lifetime 21

2.8 Summary 23

Appendix 2.A Engine Parameters, Mechanical Efficiency and Life 25

Appendix 2.B Hardness and Fatigue Limits of Different Copper-Lead-Tin

(Cu-Pb-Sn) Bearings 26

Appendix 2.C Hardness and Fatigue Limits of Different Aluminium-Tin

(Al-Sn) Bearings 28

References 29

PART II VALVE TRAIN COMPONENTS 31

3 Inlet Valve Seat Wear in High bmep Diesel Engines 33

3.1 Introduction 33

3.2 Valve Seat Wear 34

3.2.1 Design Aspects to Reduce Valve Seat Wear Life 34

3.3 Shear Strain and Wear due to Relative Displacement 35

3.4 Wear Model 35

3.4.1 Wear Rate 36

3.5 Finite Element Analysis 37

3.6 Experiments, Results and Discussions 38

3.6.1 Valve and Seat Insert of Existing Design 39

3.6.2 Improved Valve and Seat Insert 39

3.7 Summary 45

3.8 Design Rule for Inlet Valve Seat Wear in High bmep Engines 45

References 45

4 Wear of the Cam Follower and Rocker Toe 47

4.1 Introduction 47

4.2 Wear of Cam Follower Surfaces 48

4.2.1 Wear Mechanism of the Cam Follower 48

4.3 Typical Modes of Wear 50

4.4 Experiments on Cam Follower Wear 51

4.4.1 Follower Measurement 51

4.5 Dynamics of the Valve Train System of the Pushrod Type 52

4.5.1 Elastohydrodynamic and Transition of Boundary Lubrication 52

4.5.2 Cam and Follower Dynamics 53

4.6 Wear Model 55

4.6.1 Wear Coefficient 55

4.6.2 Valve Train Dynamics and Stress on the Follower 55

4.6.3 Wear Depth 61

4.7 Parametric Study 64

4.7.1 Engine Speed 64

4.7.2 Oil Film Thickness 64

4.8 Wear of the Cast Iron Rocker Toe 64

4.9 Summary 66

References 66

PART III LINER, PISTON AND PISTON RINGS 69

5 Liner Wear: Wear of Roughness Peaks in Sparse Contact 71

5.1 Introduction 71

5.2 Surface Texture of Liners and Rings 72

5.2.1 Surface Finish 72

5.2.2 Honing of Liners 72

5.2.3...