Development of an Ultrasonic Sensing Technique to Measure Lubricant Viscosity in Engine Journal Bearing In-Situ (eBook)

Michele Schirru (Autor)

eBook Download: PDF

2017 | 1st ed. 2017
XVI, 167 Seiten
Springer International Publishing (Verlag)
978-3-319-53408-4 (ISBN)

Infos

This thesis presents a novel ultrasonic instrument for non-invasive and in-situ characterization of journal bearing lubricant viscosity. In particular, the application to journal bearings is described by non-invasively measuring the viscosity and localized power losses throughout operation. 

This ultrasonic viscometer is based on the reflection of polarized shear waves from a thin resonating coating layer to increase the measurement sensitivity, in comparison to conventional ultrasonic methods. This instrument allows for a full engine oil viscoelastic characterization in-situ. 

The book investigates the effects of temperature, pressure and shear rate, and describes in detail the ultrasonic setup and method. Further, it demonstrates that the same technique can be applied similarly to monitor the lubrication of other engine components. As such, it offers a unique instrument that can drive the research of oil formulations to improve engine performance and fulfill the requirements of international fuel economy regulations. 

Michele Schirru graduated as Mechanical Engineer at the University of Cagliari (Italy) in 2012. The same year, he joined the Leonardo Center for Tribology at the University of Sheffield for a PhD course in Tribology and graduated in 2016. His research focuses on the development of novel ultrasonic viscometer techniques and instrumentations for in-situ monitoring of lubricant performances in engines. He obtained the first circumferential viscosity measurement in an operating journal bearing using a novel matching layer viscometer. This technique is now employed by different lubricant manufacturers to design novel fully formulated engine oils. He won the 23^rd Mission for Tribology IMechE Prize for the novelty of his research  and also he won the 'Innovation in Tribology Prize' 2016 of the Institute of Physics Tribology Group.

Inhalt

Supervisor’s Foreword 6
Contents 7
Nomenclature 11
Introduction 13
Thesis Layout 14
Summary 15
1 Introduction 17
1.1 Statement of the Problem 17
1.2 Project Aims 20
1.3 Thesis Layout 21
References 22
2 Background on Viscosity and Lubrication 23
2.1 Definition of Viscosity 23
2.1.1 Viscosity Relation with Temperature 24
2.1.2 Viscosity Index 25
2.1.3 Viscosity and Pressure 25
2.1.4 Viscosity and Shear Rate 26
2.2 Viscosity Measurement 29
2.2.1 Capillary Viscometers 30
2.2.2 Rotational Viscometers 30
2.2.3 Falling Body Viscometers 32
2.2.4 Vibrational Viscometers 33
2.2.5 High Pressure Viscometers 34
2.2.6 High Shear Viscometers 36
2.3 Engine Lubricating Oil Composition 38
2.3.1 Base Oils 39
2.3.2 Viscosity Modifiers 40
2.3.3 Detergents 41
2.4 Oil Classification by Viscosity 42
2.5 Lubrication Principles in Mechanical Components 43
2.5.1 The Stribeck Curve 43
2.5.2 Journal Bearing Lubrication 45
2.5.3 Considerations for Journal Bearing Design 48
2.6 Conclusions 50
References 50
3 Background on Ultrasound 52
3.1 Introduction to Ultrasound 52
3.2 Ultrasound and Material Properties 54
3.3 Ultrasonic Transducers 56
3.3.1 The Piezoelectric Effect 56
3.3.2 Ultrasonic Transducer Type 56
3.3.3 Other Type of Ultrasonic Transducers 59
3.4 Characteristics of Ultrasonic Signals 60
3.5 Transducers Arrangements 61
3.6 Reflection of Ultrasound Waves at Interface 63
3.6.1 Reflection and Transmission in a Three-Layered System 66
3.6.2 Reflection of Shear Waves at Solid-Liquid Boundary 68
3.7 Conclusions 72
References 72
4 Literature Review 74
4.1 The Crystal Resonator 74
4.2 The Resonating Plate/Rod 75
4.3 Reflectance Methodologies 77
4.3.1 The Newtonian Reflection Model 77
4.3.2 The Greenwood Model 80
4.4 The Attenuation Method 81
4.4.1 Ultrasonic Spectroscopy Methods 82
4.5 Ultrasonic Resonator to Analyse Lubricating Oils 84
4.6 Comparison of Ultrasonic Viscometers and Conventional Viscometers 87
4.7 Conclusions 89
References 90
5 A Novel Ultrasonic Model for Non-Newtonian Fluids 92
5.1 Introduction 92
5.2 The Maxwell Fluid Model 93
5.3 The Ultrasonic Model for Non-Newtonian Fluids 94
5.4 Comparison of Models 96
5.5 Non-Newtonian Ultrasonic Model Sensitivity Analysis 97
5.5.1 Reflection Coefficient 98
5.5.2 Fluid Density 101
5.5.3 Solid Density 101
5.6 Conclusions 102
References 102
6 Viscosity Measurements at an Aluminium-Oil Boundary 104
6.1 Ultrasonic Apparatus 104
6.1.1 The Transducers 105
6.1.2 The Cables 106
6.1.3 Thermocouple Calibration 106
6.1.4 Test Lubricants 108
6.1.5 Experimental Protocol 108
6.2 Signal Processing 109
6.3 Conventional Reflectance Technique: Results 111
6.4 Conventional Reflectance Technique: Acoustic Mismatch 113
6.5 Conclusions 114
References 115
7 The Matching Layer Method 116
7.1 Origins of the Matching Layer Methodology 116
7.2 Matching Layer Theory 118
7.3 Measurement Apparatus 122
7.3.1 Instrumentation 122
7.3.2 Test Cell and Matching Layer 123
7.3.3 Samples Tested 123
7.4 Signal Processing and Data Analysis 124
7.5 Results 126
7.5.1 Measurement Sensitivity Increment 126
7.5.2 Viscosity Results for Newtonian Oils 128
7.5.3 The Empirical Correlation Between Viscosity and Reflection Coefficient 129
7.5.4 Viscosity Results for Fully Formulated Engine Oils 131
7.6 Effect of Polymer Concentration and Excitation Frequency 133
7.7 Effect of Temperature on Ultrasonic Matching Layer Viscometry 137
7.7.1 Samples Tested 137
7.7.2 Experimental Protocol 137
7.7.3 Results 138
7.8 Effect of Pressure on Ultrasonic Matching Layer Viscometry 140
7.8.1 Materials 140
7.8.2 Signal Processing 142
7.8.3 Experimental Protocol 143
7.8.4 Results 143
7.9 Conclusions 147
References 148
8 Viscosity Measurements in a Journal Bearing 149
8.1 Apparatus 149
8.1.1 The Journal Bearing Test Rig 150
8.1.2 Ultrasonic Viscometer Probe 152
8.1.3 The Slip Ring 152
8.1.4 Triggering and Data Acquisition 153
8.1.5 Reflection Coefficient Acquisition in Journal Bearings 155
8.2 Experimental Protocol 157
8.3 Results 157
8.3.1 Effect of Seizure 162
8.4 Analytical Simulation of Journal Bearing Viscosity Field 164
8.4.1 Power Losses 170
8.5 Preliminary Application to a Real Bearing 174
8.6 Conclusions 176
References 176
9 Conclusions 177
9.1 The Ultrasonic Model for Non-Newtonian Fluids 177
9.2 The Quarter Wavelength Matching Layer Sensing Technique 178
9.3 Application of the Matching Layer Method in a Journal Bearing 178
9.4 Future Directions 179
References 180
Uncited References 180

Produkt-Details

• Erscheint lt. Verlag: 21.2.2017
• Reihe/Serie: Springer Theses
• Reihe/Serie: Springer Theses
• Zusatzinfo: XVI, 167 p. 155 illus., 80 illus. in color.
• Verlagsort: Cham
• Sprache: englisch
• Themenwelt: Technik ► Fahrzeugbau / Schiffbau
• Themenwelt: Technik ► Maschinenbau
• Schlagworte: automotive engineering • Characterization and Evaluation of Materials • Engineering Acoustics • Surfaces and Interfaces, Thin Films • Tribology, Corrosion and Coatings
• ISBN-10: 3-319-53408-4 / 3319534084
• ISBN-13: 978-3-319-53408-4 / 9783319534084