1、Laser Diagnostics and Optical Measurement Techniques in Internal Combustion Engines Zhao The increasing concern about CO 2emissions and energy prices has led to new CO 2emission and fuel economy legislation being introduced in world regions served by the automotive industry. In response, automotive
2、manufacturers and Tier-1 suppliers are developing a new generation of internal combustion (IC) engines with ultra-low emissions and high fuel ef ciency. To further this development, a better understanding is needed of the combustion and pollutant formation processes in IC engines. As ef ciency and e
3、mission abatement processes have reached points of diminishing returns, there is more of a need to make measurements inside the combustion chamber, where the combustion and pollutant formation processes take place. However, there is currently no good overview of how to make these measurements. Based
4、 on the authors previous SAE book, Engine Combustion Instrumentation and Diagnostics, this book focuses on laser-based optical techniques for combustion ows and in-cylinder measurements. Included are new chapters on optical engines and optical equipment, case studies, and an updated description of e
5、ach technique. The purpose of this book is to provide, in one publication, an introduction to experimental techniques that are best suited for in-cylinder engine combustion measurements. It provides suf cient details for readers to set up and apply these techniques to IC engines and combustion ows.
6、About the Author Hua Zhao has been involved in R Email: CustomerServicesae.org; Website: http:/books.sae.org Laser Diagnostics and Optical Measurement Techniques in Internal Combustion Engines Hua Zhao Warrendale, Pennsylvania USA Copyright 2012 SAE International eISBN: 978-0-7680-7766-7400 Commonwe
7、alth Drive Warrendale, PA 15096-0001 USA E-mail: CustomerServicesae.org Phone: 877-606-7323 (inside USA and Canada)724-776-4970 (outside USA) Fax: 724-776-0790 Copyright 2012 SAE International. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, distribu
8、ted, or transmitted, in any form or by any means without the prior written permission of SAE. For permission and licensing requests, contact SAE Permissions, 400 Commonwealth Drive, Warrendale, PA 15096-0001 USA; e-mail: copyrightsae.org; phone: 724-772-4028; fax: 724-772-9765. ISBN 978-0-7680-5782-
9、9 SAE Order No. R-406 DOI 10.4271/R-406 Library of Congress Cataloging-in-Publication Data Zhao, Hua, 1963- Laser diagnostics and optical measurement techniques in internal combustion engines / Hua Zhao.p. cm. Includes bibliographical references. ISBN 978-0-7680-5782-9 1. AutomobilesMotorsExhaust ga
10、sMeasurement. 2. AutomobilesMotors Combustion. 3. Internal combustion enginesCombustion. 4. Optical measurements. 5. LasersIndustrial applications. I. Title. TL214.P6Z43 2012629.2504dc23 2012013193 Information contained in this work has been obtained by SAE International from sources believed to be
11、reliable. However, neither SAE International nor its authors guarantee the accuracy or completeness of any information published herein and neither SAE International nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is publis
12、hed with the understanding that SAE International and its authors are supplying information, but are not attempting to render engineering or other professional services. If such services are required, the assistance of an appropriate professional should be sought. To purchase bulk quantities, please
13、 contact: SAE Customer Service E-mail: CustomerServicesae.org Phone: 877-606-7323 (inside USA and Canada)724-776-4970 (outside USA) Fax: 724-776-0790 Visit the SAE Bookstore at books.sae.orgv Contents Preface . xi Chapter 1. Optical Engines 1 1.1 Introduction .1 1.2 Optical Access .1 1.2.1 Optical A
14、ccess Through the Cylinder Head 2 1.2.2 Optical Access Through the Piston .4 1.2.3 Optical Access Through the Sides .6 1.3 Endoscopic Access 7 1.4 Optical Materials .8 1.5 Operation of Optical Engines 9 References 10 Chapter 2. Introduction to Laser-Based Optical Instruments . 13 2.1 Overview of Las
15、er-Based Optical Instruments 13 2.2 Lasers 16 2.2.1 High-Energy Pulsed Lasers 17 2.2.2 High-Repetition Pulsed Lasers 18 2.2.3 Continuous Wave Lasers 19 2.3 Laser Beam Delivery and Focusing21 2.3.1 Gaussian Laser Beam 21 2.3.2 Focusing of a Gaussian Laser Beam 22 2.3.3 Laser Sheet Optics .25 2.4 Opti
16、cs and Photodetection Systems .26 2.4.1 Optics 26 2.4.2 Photon Detectors and Charge-Coupled Device (CCD) Cameras 32 2.4.3 High-Speed Imaging .36 2.5 Image Processing and Calibration37 2.6 Summary 39 References 40 Further Reading 40 Websites .40vi Contents Chapter 3. Fundamentals of Laser Spectroscop
17、ic Techniques . 41 3.1 Introduction .41 3.2 Fundamentals of Molecular Spectroscopy 41 3.2.1 Internal Energy of a Molecule .41 3.2.2 Population of Energy Levels 48 3.3 Raman and Rayleigh Scattering .49 3.3.1 Rayleigh Scattering and Its Measurement .49 3.3.2 Raman Scattering Spectrum .53 3.3.3 Measure
18、ment of Raman Scattering .58 3.4 Laser-Induced Fluorescence 61 3.5 Comparison of LRS, SRS, and LIF 67 3.6 Summary 69 References 70 Further Reading 70 Chapter 4. Principle and Application of LDA and PIV for In-Cylinder Flow Measurements 71 4.1 Introduction .71 4.2 Laser Doppler Anemometry .71 4.2.1 T
19、he Principle of Laser Doppler Anemometry .71 4.2.2 Laser and Transmitting Optics 73 4.2.3 Light Collection System 75 4.2.4 Signal Processing .77 4.2.5 Discrimination of Flow Direction by Frequency Shifting 78 4.2.6 Seeding and Particles 79 4.2.7 Accuracy .81 4.2.8 Advanced LDA Systems .82 4.2.9 Data
20、 Analysis of In-Cylinder Flows84 4.2.10 Applications of LDA to IC Engines.90 4.3 Particle Image Velocimetry (PIV) .92 4.3.1 Principle of Particle Image Velocimetry .92 4.3.2 Operation of the Digital PIV System 94 4.3.3 Lasers and Light Sheets 95 4.3.4 Imaging Optics and Perspective Errors97 4.3.5 Ev
21、aluation of Particle Image Displacement Vectors .99 4.3.6 Seeding Particles 103 4.3.7 Optimization of a PIV System .104 4.3.8 Postprocessing of PIV Data 107 4.3.9 Advanced PIV Systems .109 4.3.10 PIV Measurements in IC Engines111vii Contents 4.4 Summary 128 References 129 Chapter 5. In-Cylinder Fuel
22、 and Combustion Specie Measurement by Laser- Induced Fluorescence 133 5.1 Introduction .133 5.2 Fuel Vapor Concentration Measurement by PLIF .133 5.2.1 Principle of Operation 133 5.2.2 Selection of Fluorescence Tracers 135 5.2.3 Experimental Setup of PLIF .137 5.2.4 Calibration of PLIF Images 138 5.
23、2.5 In-Cylinder Fuel Distribution Measurements by PLIF 139 5.3 Visualization of Combustion Species by PLIF 144 5.3.1 Introduction 144 5.3.2 Experimental Considerations 145 5.3.3 PLIF Measurements of OH.148 5.3.4 PLIF Measurements of NO.150 5.3.5 Visualization of Formaldehyde by PLIF 153 5.4 Imaging
24、of Water Vapor and CO by the Two-Photon LIF Technique 156 5.5 Summary 160 References 160 Chapter 6. Fuel and Mixture Composition Measurement by Raman and Rayleigh Scattering Techniques .165 6.1 Introduction .165 6.2 Fuel Concentration Measurement by Laser Rayleigh Scattering 165 6.2.1 Principle of O
25、peration 166 6.2.2 Implementation of LRS .167 6.2.3 Minimization of Background Light in LRS 168 6.2.4 Filtered Rayleigh Scattering .169 6.2.5 Application of LRS to IC Engines .171 6.3 Measurement of Mixture Composition by Spontaneous Raman Scattering 173 6.3.1 Introduction 173 6.3.2 Principle of Ope
26、ration 174 6.3.3 Experimental Setup of SRS .176 6.3.4 Background Radiation and Signal-to-Noise Ratio 179 6.3.5 Data Analysis and Calibration .181 6.3.6 Applications of the SRS Scattering Technique to IC Engines 183viii Contents 6.3.7 Multispecies Measurements by SRS in a CAI Combustion Engine 185 6.
27、4 Summary 194 References 194 Chapter 7. Fuel Injection and Spray Characterization 199 7.1 Introduction .199 7.2 Direct Imaging of Spray and Droplets .199 7.3 Liquid Droplet Sizing by the Fraunhofer Diffraction Method .201 7.3.1 Fraunhofer Diffraction 201 7.3.2 Implementation of the Fraunhofer Diffra
28、ction Method 202 7.4 Droplet Sizing and Velocity Measurements by the Phase Doppler Particle Analyzer (PDPA) 206 7.4.1 The Principle of the PDPA 206 7.4.2 Implementation of the PDPA .210 7.4.3 Data Reduction and Presentation213 7.4.4 Optimization of a PDPA System216 7.4.5 Application of PDPA to IC En
29、gines 219 7.5 Two-Dimensional Visualization of Spray Atomization by Mie Scattering and Laser-Induced Fluorescence (LIF) 220 7.5.1 Two-Dimensional Spray Imaging Through Mie Scattering or PLIF 220 7.5.2 Laser Sheet Droplet Sizing (LSD) by Combined MieScattering and LIF .222 7.6 Simultaneous Visualizat
30、ion of Fuel Vapor and Liquid Fuel by the Laser-Induced Exciplex Fluorescence Technique .223 7.6.1 Principle of Laser-Induced Exciplex Flourescence Technique 223 7.6.2 Experimental Setup of LIEF .226 7.6.3 Quantitative Analysis of Fuel Vapor ConcentrationUsing PLIEF 228 7.6.4 Application of PLIEF for
31、 In-Cylinder Fuel Visualization 228 7.6.5 Application of LIEF to In-Cylinder Diesel Spray Measurement 231 7.7 Summary 234 References 235 Chapter 8. Combustion Spectroscopy and Visualization Techniques 241 8.1 Introduction .241 8.2 Combustion Spectroscopy .241 8.2.1 Light Emission of Combustion 241ix
32、 Contents 8.2.2 Light Absorption of Combustion Species 243 8.2.3 Detection of Emission and Absorption 243 8.2.4 Application of Light Emission and Absorption Techniques 246 8.3 Chemiluminescence Imaging 248 8.4 Schlieren and Shadowgraph Techniques for Nonluminous Flow and Combustion Visualization .25
33、1 8.5 Summary 255 References 255 Chapter 9. Gas Temperature Measurement .259 9.1 Introduction .259 9.2 Radiation Thermometry 259 9.2.1 Principles of Radiation Thermometry 259 9.2.2 Implementation of Radiation Thermometry .263 9.3 Laser Rayleigh Scattering (LRS) Thermometry 270 9.3.1 Principle of Las
34、er Rayleigh Thermometry .270 9.3.2 Implementation and Application of Rayleigh Thermometry 270 9.4 Temperature Measurement by Spontaneous Raman Scattering (SRS) .272 9.4.1 Principle of Raman Thermometry 272 9.4.2 Implementation and Application of Raman Thermometry .278 9.5 Temperature Measurement by
35、Coherent Anti-Stokes Raman Scattering (CARS) .280 9.5.1 Principle of CARS Thermometry 280 9.5.2 Implementation of CARS Nitrogen Thermometry .282 9.5.3 CARS Measurements in IC Engines .285 9.6 Two-Dimensional Temperature Measurement by PLIF 287 9.6.1 Introduction to Fluorescence Thermometry 287 9.6.2
36、 Monochromatic Fluorescence Thermometry.287 9.6.3 Two-Line Fluorescence Thermometry 290 9.7 Summary 299 References 300 Chapter 10. In-Cylinder Soot Concentration and Particle Size Measurement .305 10.1 Introduction .305 10.2 The Two-Color Method 306 10.2.1 Principle of the Two-Color Method 306x Cont
37、ents 10.2.2 Implementation of the Two-Color Method 309 10.2.3 Accuracy .316 10.2.4 Full-Field Two-Color Measurement317 10.3 Soot Concentration Measurement by the Light-Extinction Method .322 10.3.1 Principle of the Light-Extinction Method 322 10.3.2 Implementation of the Light-Extinction Method 326
38、10.4 Laser-Induced Incandescence .330 10.4.1 Introduction 330 10.4.2 Soot Volume Fraction Measurement by LII .331 10.4.3 Soot Particle Sizing Using LII and Laser Scattering (LS) .338 10.4.4 Particle Sizing by Time-Resolved LII (TiRe-LII)340 10.4.5 Further Considerations of LII Techniques .343 Refere
39、nces 344 Index 349 About the Author .359xi Preface The increasing concern with CO 2emissions and energy prices has led to a raft of new CO 2emission and fuel economy legislation being introduced in major automotive markets. It is therefore imperative for automotive manufacturers and Tier 1 suppliers
40、 to develop a new generation of internal combustion (IC) engines with both ultra-low emissions and high fuel efficiency. Better understanding of the combustion and pollutant formation processes in IC engines is clearly necessary to increase their efficiency and cleanliness and to develop new engines
41、 with increased efficiency and lower emissions. As improvements in efficiency and emission abatement have reached points of diminishing returns, there is an increasing need for measurements directly inside the combustion chamber, where the combustion and pollutant- formation processes actually take
42、place. Owing to the wide range of in-cylinder measurement techniques and the cross-disciplinary nature of laser-based optical techniques, it is difficult for postgraduates and research engineers to get an adequate overview on suitable measurement techniques in this field without extensive search and
43、 study of numerous publications. The purpose of this book is to provide, between one set of covers, an introduction to the experimental techniques that are suitable for in-cylinder measurements. In addition, it includes sufficient details for the reader to set up and apply these techniques to IC eng
44、ines and combustion flows. The spectrum of in-cylinder measurement techniques included in this book primarily covers advanced laser-based optical techniques and, where appropriate, other suitable techniques. The techniques described here are tied to the characterization of the flow and thermodynamic
45、 properties before, during, and after the combustion process, in the sequence of the processes taking place inside the cylinder, including flows, fuel injection, mixture formation, combustion, and pollutant formation. This approach ensures that the development and application of measurement techniqu
46、es are linked to an identified need, as it is the end that justifies the means but not vice versa. This approach is particularly useful for researchers or engineers who are interested in measurement tools to solve a specific research problem. At the same time, by presenting different techniques for
47、the same diagnostic purpose, the merits and limitations of each technique can be understood better. Based on Engine Combustion Instrumentation and Diagnostics, this book focuses on laser-based optical techniques for combustion flows and in-cylinder measurements and includes new chapters on optical engines and equipment, case studies, and updated descriptions of each technique. Chapter 1 is an introduction to optical engines, including optical engine design, optical access,
