Critical Component Wear in Heavy Duty Engines

P.A. Lakshminarayanan is the Head of R&D at Ashok Leyland in India. He has been the team leader or lead designer of about 10 diesel and CNG engines for different applications. He has guided 2 PhDs at IIT Delhi and 4 M.Techs at IIT Madras, and has published 40 papers in ASME, SAE, IMechE, and AVL journals and conferences. Previous appointments include 20 years from Manger to Senior General Manger of R&D at Kirloskar Oil Engines Ltd, over 15 years as a Visiting Lecturer at IIT Madras, and 5 years as a Research Associate to J.C. Dent at Loughborough University of Technology. He is a Fellow of SAE-International. Lakshminarayanan holds a B.Tech, and M.S. and a PhD from IIT Madras.Nagaaraj S. Nayak is a Professor of Mechanical Engineering based at Sahyadri College of Engg. & Management. Previously, he was a Senior Manager at the R&D department of Kirloskar Oil Engines Ltd for 9 years, and was a Postdoctoral Fellow at University of Wisconsin Madison for 2 years. He has been a team leader for emission upgrades on 3 engines platforms, and performance development of 2 new engine platforms.

• List of Contributors xv Preface xviiAcknowledgements xxiPART I OVERTURE 11 Wear in the Heavy Duty Engine 31.1 Introduction 31.2 Engine Life 31.3 Wear in Engines 41.3.1 Natural Aging 41.4 General Wear Model 51.5 Wear of Engine Bearings 51.6 Wear of Piston Rings and Liners 61.7 Wear of Valves and Valve Guides 61.8 Reduction in Wear Life of Critical Parts Due to Contaminants in Oil 61.8.1 Oil Analysis 71.9 Oils for New Generation Engines with Longer Drain Intervals 81.9.1 Engine Oil Developments and Trends 81.9.2 Shift in Engine Oil Technology 91.10 Filters 91.10.1 Air Filter 91.10.2 Oil Filter 101.10.3 Water Filter 101.10.4 Fuel Filter 101.11 Types of Wear of Critical Parts in a Highly Loaded Diesel Engine 101.11.1 Adhesive Wear 101.11.2 Abrasive Wear 111.11.3 Fretting Wear 111.11.4 Corrosive Wear 11References 112 Engine Size and Life 132.1 Introduction 132.2 Engine Life 132.3 Factors on Which Life is Dependent 142.4 Friction Force and Power 142.4.1 Mechanical Efficiency 142.4.2 Friction 152.5 Similarity Studies 152.5.1 Characteristic Size of an Engine 152.5.2 Velocity 162.5.3 Oil Film Thickness 172.5.4 Velocity Gradient 182.5.5 Friction Force or Power 182.5.6 Indicated Power and Efficiency 182.6 Archard’s Law of Wear 202.7 Wear Life of Engines 202.7.1 Wear Life 202.7.2 Nondimensional Wear Depth Achieved During Lifetime 212.8 Summary 23Appendix 2.A Engine Parameters, Mechanical Efficiency and Life 25Appendix 2.B Hardness and Fatigue Limits of Different Copper–Lead–Tin(Cu–Pb–Sn) Bearings 26Appendix 2.C Hardness and Fatigue Limits of Different Aluminium–Tin(Al–Sn) Bearings 28References 29PART II VALVE TRAIN COMPONENTS 313 Inlet Valve Seat Wear in High bmep Diesel Engines 333.1 Introduction 333.2 Valve Seat Wear 343.2.1 Design Aspects to Reduce Valve Seat Wear Life 343.3 Shear Strain and Wear due to Relative Displacement 353.4 Wear Model 353.4.1 Wear Rate 363.5 Finite Element Analysis 373.6 Experiments, Results and Discussions 383.6.1 Valve and Seat Insert of Existing Design 393.6.2 Improved Valve and Seat Insert 393.7 Summary 453.8 Design Rule for Inlet Valve Seat Wear in High bmep Engines 45References 454 Wear of the Cam Follower and Rocker Toe 474.1 Introduction 474.2 Wear of Cam Follower Surfaces 484.2.1 Wear Mechanism of the Cam Follower 484.3 Typical Modes of Wear 504.4 Experiments on Cam Follower Wear 514.4.1 Follower Measurement 514.5 Dynamics of the Valve Train System of the Pushrod Type 524.5.1 Elastohydrodynamic and Transition of Boundary Lubrication 524.5.2 Cam and Follower Dynamics 534.6 Wear Model 554.6.1 Wear Coefficient 554.6.2 Valve Train Dynamics and Stress on the Follower 554.6.3 Wear Depth 614.7 Parametric Study 644.7.1 Engine Speed 644.7.2 Oil Film Thickness 644.8 Wear of the Cast Iron Rocker Toe 644.9 Summary 66References 66PART III LINER, PISTON AND PISTON RINGS 695 Liner Wear: Wear of Roughness Peaks in Sparse Contact 715.1 Introduction 715.2 Surface Texture of Liners and Rings 725.2.1 Surface Finish 725.2.2 Honing of Liners 725.2.3 Surface Finish Parameters 725.2.4 Bearing Area Curve 745.2.5 Representation of Bearing Area Curve of Normally Honed Surface or Surfaces with Peaked Roughness 755.3 Wear of Liner Surfaces 765.3.1 Asperities 765.3.2 Radius of the Asperity in the Transverse Direction 765.3.3 Radius in the Longitudinal Direction 775.3.4 Sparse Contact 775.3.5 Contact Pressures 795.3.6 Friction 795.3.7 Approach 805.3.8 Detachment of Asperities 805.4 Wear Model 815.4.1 Normally Honed Liner with Peaked Roughness 815.4.2 Normal Surface Roughness 815.4.3 Fatigue Loading of Asperities 815.4.4 Wear Rate 825.4.5 Plateau Honed and Other Liners not Normally Honed 835.5 Liner Wear Model for Wear of Roughness Peaks in Sparse Contact 855.5.1 Parametric Studies 865.5.2 Comparison with Archard’s Model 885.6 Discussions on Wear of Liner Roughness Peaks due to Sparse Contact 895.7 Summary 92Appendix 5.A Sample Calculation of the Wear of a RoughPlateau Honed Liner 93References 936 Generalized Boundary Conditions for Designing Diesel Pistons 956.1 Introduction 956.2 Temperature Distribution and Form of the Piston 966.2.1 Top Land 966.2.2 Skirt 966.3 Experimental Mapping of Temperature Field in the Piston 976.4 Heat Transfer in Pistons 986.4.1 Metal Slab 986.5 Calculation of Piston Shape 986.5.1 Popular Methods Used Before Finite Element Analysis 996.5.2 Calculation by Finite Element Method 1016.5.3 Experimental Validation 1036.6 Summary 108References 1097 Bore Polishing Wear in Diesel Engine Cylinders 1117.1 Introduction 1117.2 Wear Phenomenon for Liner Surfaces 1127.2.1 Bore Polishing 1127.3 Bore Polishing Mechanism 1137.3.1 Carbon Deposit Build Up on the Piston Top Land 1137.3.2 Quality of Fuel and Oil 1137.3.3 Piston Growth by Finite Element Method 1137.3.4 Piston Secondary Movement 1147.3.5 Simulation Program 1157.4 Wear Model 1157.4.1 Contact Pressures 1157.4.2 Wear Rate 1167.5 Calculation Methodology and Study of Bore Polishing Wear 1167.5.1 Finite Element Analysis 1167.5.2 Simulation 1177.6 Case Study on Bore Polishing Wear in Diesel Engine Cylinders 1187.6.1 Visual Observations 1187.6.2 Liner Measurements 1197.6.3 Results of Finite Element Analysis 1197.6.4 Piston Motion 1217.6.5 Wear Profile 1237.6.6 Engine Oil Consumption 1257.6.7 Methods Used to Reduce Liner Wear 1257.7 Summary 127References 1278 Abrasive Wear of Piston Grooves in Highly Loaded Diesel Engines 1298.1 Introduction 1298.2 Wear Phenomenon in Piston Grooves 1308.2.1 Abrasive Wear 1308.2.2 Wear Mechanism 1308.3 Wear Model 1328.3.1 Real Contact Pressure 1328.3.2 Approach 1328.3.3 Wear Rate 1328.4 Experimental Validation 1348.4.1 Validation of the Model 1348.4.2 Wear Measurement 1358.5 Estimation of Wear Using Sarkar’s Model 1378.5.1 Parametric Study 1388.6 Summary 139References 1409 Abrasive Wear of Liners and Piston Rings 1419.1 Introduction 1419.2 Wear of Liner and Ring Surfaces 1419.3 Design Parameters 1439.3.1 Piston and Rings Assembly 1439.3.2 Abrasive Wear 1439.3.3 Sources of Abrasives 1449.4 Study of Abrasive Wear on Off-highway Engines 1449.4.1 Abrasive Wear of Rings 1449.4.2 Abrasive Wear of Piston Pin and Liners 1449.4.3 Accelerated Abrasive Wear Test on an Engine to Simulate Operation in the Field 1469.5 Winnowing Effect 1499.6 Scanning Electron Microscopy of Abrasive Wear 1509.7 Critical Dosage of Sand and Life of Piston–Ring–Liner Assembly 1509.7.1 Simulation of Engine Life 1519.8 Summary 152References 15310 Corrosive Wear 15510.1 Introduction 15510.2 Operating Parameters 15510.2.1 Corrosive Wear 15510.3 Corrosive Wear Study on Off-road Application Engines 15610.3.1 Accelerated Corrosive Wear Test 15610.4 Wear Related to Coolants in an Engine 16110.4.1 Under-cooling of Liners by Design 16110.4.2 Coolant Related Wear 16110.5 Summary 165References 16511 Tribological Tests to Simulate Wear on Piston Rings 16711.1 Introduction 16711.2 Friction and Wear Tests 16811.2.1 Testing Friction and Wear of the Tribo-System Piston Ring and Cylinder Liner Outside of Engines 16811.3 Test Procedures Assigned to the High Frequency, Linear Oscillating Test Machine 17011.4 Load, Friction and Wear Tests 17211.4.1 EP Test 17211.4.2 Scuffing Test 17211.4.3 Reagents and Materials 17211.5 Test Results 17511.5.1 Selection of Coatings for Piston Rings 17511.5.2 Scuffing Tribological Test 17811.5.3 Hot Endurance Test 17911.6 Selection of Lubricants 18411.7 High Performance Bio-lubricants and Tribo-reactive Materials for Clean Automotive Applications 18511.7.1 Synthetic Esters 18511.7.2 Polyalkyleneglycols 18511.8 Tribo-Active Materials 19011.8.1 Thematic ‘Piston Rings’ 19011.9 EP Tribological Tests 19211.9.1 Piston Ring Cylinder Liner Simulation 192Acknowledgements 194References 194PART IV ENGINE BEARINGS 19712 Friction and Wear in Engine Bearings 19912.1 Introduction 19912.2 Engine Bearing Materials 20212.2.1 Babbitt or White Metal 20212.2.2 Copper–Lead Alloys 20312.2.3 Aluminium-based Materials 20412.3 Functions of Engine Bearing Layers 20512.4 Types of Overlays/Coatings in Engine Bearings 20612.4.1 Lead-based Overlays 20812.4.2 Tin-based Overlays 20812.4.3 Sputter Bearing Overlays 20812.4.4 Polymer-based Overlays 20812.5 Coatings for Engine Bearings 20912.6 Relevance of Lubrication Regimes in the Study of Bearing Wear 21012.6.1 Boundary Lubrication 21212.6.2 Mixed Film Lubrication 21512.6.3 Fluid Film Lubrication 21612.7 Theoretical Friction and Wear in Bearings 21712.7.1 Friction 21712.8 Wear 21812.9 Mechanisms of Wear 21912.9.1 Adhesive Wear 22012.9.2 Abrasive Wear 22312.9.3 Erosive Wear 23012.10 Requirements of Engine Bearing Materials 23412.11 Characterization Tests for Wear Behaviour of Engine Bearings 23812.11.1 Fatigue Strength 23912.11.2 Pin-on-disk Test 23912.11.3 Scratch Test for Bond Strength 24112.12 Summary 251References 252PART V LUBRICATING OILS FOR MODERN ENGINES 25313 Heavy Duty Diesel Engine Oils, Emission Strategies and their Effect on Engine Oils 25513.1 Introduction 25513.2 What Drives the Changes in Diesel Engine Oil Specifications? 25613.2.1 Role of the Government 25613.2.2 OEMs’ Role 25713.2.3 The Consumer’s Role 25813.3 Engine Oil Requirements 25813.3.1 Overview and What an Engine Oil Must Do 25813.4 Components of Engine Oil Performance 26513.4.1 Viscosity 26513.4.2 Protection against Wear, Deposits and Oil Deterioration 26813.5 How Engine Oil Performance Standards are Developed 26813.5.1 Phase 1: Category Request and Evaluation (API, 2011a, pp. 36, 37) 26913.5.2 Phase 2: Category Development (API, 2011a, pp. 41, 42) 27113.5.3 Phase 3: Category Implementation (API, 2011a, p. 45) 27313.5.4 API Licensing Process 27513.6 API Service Classifications 27613.7 ACEA Specifications 27613.7.1 Current E Sequences 27813.8 OEM Specifications 27913.9 Why Some API Service Classifications Become Obsolete 27913.10 Engine Oil Composition 28013.10.1 Base Oils 28013.10.2 Refining Processes Used to Produce Lubricating Oil Base Stocks 28113.10.3 Synthetic Base Oils 28513.10.4 Synthetic Blends 28613.10.5 API Base Oil Categories 28613.11 Specific Engine Oil Additive Chemistry 29013.11.1 Detergent–Dispersant Additives 29013.11.2 Anti-Wear Additives 29413.11.3 Friction Modifiers 29513.11.4 Rust and Corrosion Inhibitors 29613.11.5 Oxidation Inhibitors (Antioxidants) 29613.11.6 Viscosity Index Improvers 29813.11.7 Pour Point Depressants 30013.11.8 Foam Inhibitors 30113.12 Maintaining and Changing Engine Oils 30213.12.1 Oil Change Intervals 30313.12.2 Used Engine Oil Analysis 30313.13 Diesel Engine Oil Trends 30613.14 Engine Design Technologies and Strategies Used to Control Emissions 30613.14.1 High Pressure Common Rail (HPCR) Fuel System 30913.14.2 Combustion Optimization 31013.14.3 Advanced Turbocharging 31213.14.4 Exhaust Gas Recirculation (EGR) 31313.14.5 Advanced Combustion Emissions Reduction Technology 31413.14.6 Crankcase Ventilation 31513.14.7 Exhaust After-Treatment 31513.14.8 On-Board Diagnostics (OBD) 32413.15 Impact of Emission Strategies on Engine Oils 32413.15.1 Impact of Cooled EGR on Engine Oil 32513.15.2 Effects of Post-Injection on Engine Oils 32713.16 How Have Engine Oils Changed to Cope with the Demands of Low Emissions? 32813.17 Most Prevalent API Specifications Found In Use 32913.17.1 API CH-4 32913.17.2 API CI-4 33013.17.3 API CI-4 Plus 33113.17.4 API CJ-4 33313.18 Paradigm Shift in Engine Oil Technology 33613.18.1 Backward Compatibility and Engine Tests 33713.18.2 New Engine Sequence Tests 33813.18.3 Previous Engine Oil Sequence Tests 34313.18.4 Differences Between CJ-4 and Previous Categories and Benefits of Using CJ-4 Engine Oils 34713.19 Future Engine Oil Developments 34813.20 Summary 352References 353PART VI FUEL INJECTION EQUIPMENT 35514 Wear of Fuel Injection Equipment 35714.1 Introduction 35714.2 Wear due to Diesel Fuel Quality 35714.2.1 Lubricity of Mineral Diesel Fuel 35714.2.2 Oxygen Content of Biodiesel 36114.3 Wear due to Abrasive Dust in Fuel 36114.3.1 Wear of Injector Nozzle due to Heat and Dust 36114.3.2 Fuel Filters 36414.4 Wear due to Water in Fuel 36514.4.1 Corrosive Wear due to Water Ingress 36514.4.2 Use of Emulsified Water for Reducing Nitric Oxides in Large Engines 36514.4.3 Microbiological Contamination of Fuel Systems 36614.4.4 Water Separators 36714.5 Summary 367References 367PART VII HEAVY FUEL ENGINES 36915 Wear with Heavy Fuel Oil Operation 37115.1 Introduction 37115.2 Fuel Treatment: Filtration and Homogenization 37315.3 Water and Chlorine 37415.3.1 Fuel Injection Equipment 37415.4 Viscosity, Carbon Residue and Dust 37415.4.1 Fuel Injection Equipment 37415.5 Deposit Build Up on Top Land and Anti-polishing Ring for Reducing the Wear of Liner, Rings and Piston 37515.6 High Sulfur in Fuel 37715.6.1 Formation of Sulfuric Acid 37715.6.2 Mechanism of Corrosive Attack by Sulfuric Acid 37715.6.3 Control of Corrosion by Basicity and Oil Consumption 37815.6.4 Control of Sulfur Corrosion by Maintaining Cooling Water Temperature High 37915.7 Low Sulfur in Fuel 38015.7.1 Lubricity 38015.7.2 Lack of Formation of Oil Pockets on the Liner Bore 38115.7.3 Sudden Severe Wear of Liner and Rings 38215.8 Catalyst Fines 38315.9 High Temperature Corrosion 38315.9.1 Turbocharger 38515.9.2 Exhaust Valves 38515.10 Wear Specific to Four-stroke HFO Engines 38815.10.1 Wear of Bearings 38815.10.2 Inlet Valve 39115.10.3 Corrosive Wear of Valve Tips 39115.11 New Engines Compliant to Maritime Emission Standards 39115.11.1 Steps to Satisfy Emission Standards 39115.12 Wear Life of an HFO Engine 39315.13 Summary 393References 394PART VIII FILTERS 39716 Air and Oil Filtration and Its Impact on Oil Life and Engine Wear Life 39916.1 Introduction 39916.2 Mechanisms of Filtration 40016.3 Classification of Filtration 40016.3.1 Classification by Filter Media 40116.3.2 Classification by Direction of Flow 40216.3.3 Classification by Filter Size 40216.4 Filter Rating 40316.4.1 Absolute Rating 40316.4.2 Nominal Rating 40316.4.3 Mean Filter Rating 40316.4.4 b Ratio 40316.4.5 Efficiency 40416.5 Filter Selection 40416.6 Introduction to Different Filters in the Engine 40516.6.1 Air Filters 40516.6.2 Cleaning Air Filters and Impact on Wear Life 40916.7 Oil Filters and Impact on Oil and Engine Life 40916.7.1 Oil Performance and Life 41016.7.2 Oil Stress 41116.7.3 Application of the Concept of Oil Stress 41316.7.4 Advances in Oil Filter Technology 41316.8 Engine Wear 41316.8.1 Method to Predict Wear of Critical Engine Components 41516.9 Full Flow Oil Filters 41516.9.1 Bypass Filters 41716.9.2 Centrifugal Filters 41816.10 Summary 419Appendix 16.A Filter Tests and Test Standards 419References 419Index 421