Handbook of
`Air Pollution from
`Internal Combustion
`Engines
`
`PAICE 2032 B
`
`See hg
`ERAN SHER
`
`.
`IPR2020-01299
`
`1
`
`PAICE 2032
`BMW v. Paice
`IPR2020-01299
`
`

`

`Handbook of
`Air Pollution from
`Internal Combustion Engines
`Pollutant Formation and Control
`
`2
`
`

`

`This Page Intentionally Left Blank
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`3
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`

`Handbook of
`Air Pollution from
`Internal Combustion Engines
`Pollutant Formation and Control
`
`Edited by
`
`Eran Sher
`
`a
`
`ACADEMIC PRESS
`
`Boston
`London
`
`San Diego New York
`Sydney Tokyo Toronto
`
`4
`
`

`

`‘This bookis printed on acid-free paper.
`
`Copyright © 1998 by Academic Press.
`
`All rights reserved.
`Nopart of this publication may be reproduced or
`transmitted in any form or by any means, electronic
`or mechanical, including photocopy, recording, or
`any information storage and retrieval system, without
`permission in writing from the publisher,
`
`ACADEMIC PRESS
`525 B Street, Suite 1900, San Diego, CA 92101, USA
`1300 Boylston Street, Chestnut Hill, MA 02167, USA
`http://www.apnet.com
`
`United Kingdom Edition published by
`ACADEMICPRESS LIMITED
`24-28 Oval Road, London NW1 7DX
`http://www.hbuk/co.uk/ap/
`
`ISBN: 0-12-639855-0
`Library of Congress Cataloging-in-Publication Data
`Handbookofair pollution from internal combustion engines : pollutant
`formation and control / edited by Eran Sher.
`p.
`cm.
`Includes bibliographical references and index.
`ISBN 0-12-639855-0 (alk. paper)
`1. Motor vehicles—Motors—Exhaust gas—Environmental aspects,
`2. Internal combustion engines—Environmental aspects.
`3. Air-
`Pollution.
`I. Sher, Eran.
`TD886.5.H36
`1998
`629.25'28—dc21
`
`97-48256
`CIP
`
`Printed in the United States of America
`
`98 99 00 0102 IP98 7654321
`
`5
`
`

`

`Dedication
`
`I owe my roots to Professor Chaim Elata of the Ben-Gurion University,
`Beer-Sheva,Israel,
`whotaught me howto think,
`
`I owe mystem to the late Professor Rowland S. Benson of UMIST
`Manchester, England,
`who taught me how to observe.
`
`I owe myfoliage to Professor James C, Keck of MIT, Cambridge,
`Massachusetts, USA,
`who taught me howto analyze.
`
`6
`
`

`

`This Page Intentionally Left Blank
`
`7
`
`

`

`Contents
`
`List OF GOnEMDULOIS :2.6cca.cc5ac0saaarewer yeas aalaes
`
`Acknowledgments ........ 05000505 e ee ceeeeteeenes
`
`PART|
`
`COVERWIEW cc 2ccdccdtddiddcvacadiaiapnzetiowabad
`
`1. Motor Vehicle Emissions Control: Past
`Achievements, Future Prospects
`
`xiii
`
`xix
`
`|
`
`3
`
`John B. Heywood Sun Jae Professor of Mechanical Engineering,
`Director, Sloan Automotive Laboratory, Massachusetts Institute of
`Technology, Massachusetts, United States
`D0)|SprApsis cic ucaichanialetaels, de gre qaie haw hee aed opel w aw 4
`
`Ei)
`PRIPQEICHON 2. Soy Serge ceneiee reg sane creda wettest
`4
`
`5
`1.3. Motor Vehicles and Air Pollution ...................
`9
`1.4
`The Science of Pollutant Formation and Control ........
`15
`1.5
`Effectiveness of Current Emission Control Technology .. .
`17
`1.6 Direct-Injection Engines, Two-Strokes, and Diesels... ...
`
`at7Putte Prospects: 932 oo00 baa 2k itees pe eaieaec ons 20
`REIPPENCER %.4,5,554 5065 165 PS CDS SSS AAS SSS PRESET
`23
`
`PARTII
`
`SLOBAL ASPECTSATs Sil 0h ecco Shee KK CE COREE
`
`2. Environment Aspects of Air Pollution
`
`25
`
`27
`
`Eran Sher Department of Mechanical Engineering, The Pearlstone
`Centerfor Aeronautical Engineering Studies, Ben-Gurion University of
`the Negev, Beer Sheva, Israel
`
`
`id!©UBOUNCHON rin ies ene VAG Bes Rees CHen ew yw 28
`
`Vii
`
`8
`
`

`

`vill
`
`Contents
`
`ack,
`22
`
`AMORA EMTCCtE. OF a. cee cae Gacadas oeaaedaseweny bee
`Regional Effects: 2.3 hiedsecelolwisaaneniwdwate
`RoeferenGer
` c6s60ahs ohde ciate oio34 te yielaiaiess
`
`3. Health Aspects of Air Pollution
`
`Rafael S. Carel Division of Community Medicine, Faculty of Health
`Sciences, Soroka Medical Center, Beer-Sheva, Israel
`3.1
`Anatomy and Physiology of the Respiratory System .....
`3.2 Defense Mechanismsof the Lung ...,............--.
`3.3. Ventilatory Function Tests... 2.0.2.0... 20.02.00,
`3.4
`Principles of Inhalation Injuries..........-2.-........
`3.5 Airborne Pollutants Causing Cancer and other Diseases
`.
`,
`RGTEKGHOER i ult gh ven nev Ke bv Saw Far aevEeee Sve
`
`4. Economic and Planning Aspects of Transportation
`Emission
`
`Pnina O. Plaut Faculty of Architecture and Town Planning, Technion,
`Israel Institute of Technology, Haifa, Israel
`
`28
`35
`4]
`
`42
`
`43
`52
`56
`58
`63
`64
`
`65
`
`Steven E. Plaut Graduate School of Business Administration, University
`of Haifa, Haifa, Israel
`0 a en's ee ws 66
`49 ne Ah yay od os Bas
`1)
`‘Tntyoutecuiah,
`4.2.
`The Notion of Optimal Pollution Abatement and Control
`.
`68
`4.3. Alternative Sets of AbatementPolicies for Mobile-
`72
`SOOTCE EMisSiONS....0%sis5: afoieeis ta aw ls celgsie ca awaleraas
`
`4.4 Administrative Methods of Pollution Emissions Control.. 77
`4.5
`Indirect Pricing Mechanisms ...........-600e ee eeues
`82
`AS)
`(OOMGSHISIONG:
`Sy fa.a'a ala his Ao Alviels lula shy ha el ateule qajers
`86
`RROTRTEMGOS p04 keh do eae eh Oe OA TOROS RG
`87
`
`PARTIll
`
`
`
`SPARK-IGNITION ENGINES ............. 50-0000.
`
`5.
`
`Introductory Chapter. Overview and the Role
`of Engines with Optical Access
`
`Richard Stone Department ofEngineering Science, University of
`Oxford, Oxford, United Kingdom
`FT!) NAOT At
`ie) ots Gesell aleatansy are we aula rulatere aire ae
`5.2
`Engines with Optical Access .......--... 20202200 e es
`5.3.
`High-Speed Photography .............00200c0 ena
`5.4
`Flame Front Detection .............. 04002000 e cease
`5.5 Mixture Preparation and Combustion Diagnostics .......
`
`71
`
`93
`
`94
`97
`98
`102
`105
`
`9
`
`

`

`Contents
`
`5.6
`Sf
`
`Some Applications of Engines with Optical Access .....-
`“COMCMIONS:. seks a Oh didad is $4 oa tei i gee BES
`TREICTENEES Ge sen ewe gerdere ene KY 08 eo eR sea Eee
`
`6. Combustion-Related Emissions in SI Engines
`
`Simone Hochgreb Department ofMechanical Engineering,
`Massachusetts Institute of Technology, Massachusetts, United States
`6.1
`Tntodychon 2.4i44556 teees eins teek oes addie eae oC
`6:2
`NOY Bormiation. a6 cekane een wba wea mee caw ewwen
`Gd. Caro MONGRTE sea lids elas ale alaalealegecenlaeha Wialdlatace
`Gib)
`UBC! Be SSIGNS 225 nia cde ade edn Bo ha ave tied ew Sakon os
`Ga! Suan as 9.205624 7 Ae ASE ee oO RAe ce oF
`Meferchces: <-hi ode Ss oe Rae ERS ean
`
`7. Pollution from Rotary Internal Combustion Engines
`
`Mark Dulger Deparment of Mechanical Engineering, Ben-Gurion
`University, Beer-Sheva, Israel
`Tad!
`\intodittiony 2.0545 Sadan dhs, tape ste ta Sen yebe ts Bae
`7.2
`Sources of Hydrocarbon Emissions ...............-..
`WEIORONCES: lt cuttaa ie hp cca Ma es dergecv ates mp ly
`
`8. Control Technologies in Spark-lgnition Engines
`
`Brian E. Milton Nuffield Professor of Mechanical Engineering, Head of
`School, School ofMechanical and Manufacturing Engineering, The
`University of New South Wales, Sydney, Australia
`8.1 Global and Local Emissions: A Brief Overview ofthe
`PEO CE we deh oe aes Cees CPUS AWE Fe decags Kis
`8.2. Global Emissions from Sl Engines ..............2004
`8.3
`Engine Control Factors for Local Emissions .....-..,..
`8.4
`Transient Operation of Engines and the Effect on
`EXNISSIONS asa itehg yds gla arlake els trae Tis deaisere
`Some Details of Control Systems ...................
`8.5
`8.6 Developments for the Future ...........56 0000 cues
`ROTSCOHCES:
`2 at a aig + ie vie sllMy ava Dae eme ear
`
`112
`
`15
`
`115
`
`118
`
`119
`
`124
`
`135
`137
`
`163
`164
`
`171
`
`171
`
`175
`
`188
`
`189
`
`190
`
`205
`
`209
`
`210
`
`222
`246
`255
`
`PARTIV
`
`COMPRESSION-IGNITION ENGINES ...............
`
`259
`
`9.
`
`Introduction
`
`261
`
`Franz F. Pischinger FEV Motorentechnik GmbH and Co KG, Aachen,
`Germany
`9.1
`
`The Diesel Engine for Cars—ts There a Future? ........
`
`10
`
`

`

`X
`
`Contents
`
`G2.
`9.3
`9.4
`
`EME OF TECHNOER a. Saha he oiled a cteprinds pattanda eaters):
`Technology for the Future .... 2.0.0... .0202.000044-
`Summary and Conclusions ..............02.0000085
`
`10. Combustion-Related Emissions in Cl Engines
`
`J. Gary Hawley, Chris J. Brace, and Frank J. Wallace Department of
`Mechanical Engineering, University of Bath, Bath, United Kingdom
`
`Roy W. Horrocks Diesel Engine Powertrain, Ford Motor Coa.Ltd.
`Laindon, United Kingdom
`LO.1) POMC HOM,
`pote ha gags Sa eri ele ete dls iS s alee ele By
`10.2 Review of Current and Projected Emissions Concerns—
`General Considerations ...... 0000.60 b eee eee eee
`10.3. High-Speed DI Diesel Developments ........-..-....
`10.4 Overview of Emissions from CI Engines ,.............
`10.5 Current and Projected Global Emissions Legislative
`a
`REGUITEINENS Sc cadieg ve waited eee ae we wage die Digi
`10.6 Advanced Emission Reduction Strategies for the Year 2000
`and Bevin) 63.2635 i43% 5 oh ode se EAN aah babs a8
`10.7 Steady-State and Transient Emissions ................
`10.8 Application of Computational Tools Toward Predicting and
`Reducing Emissions . 10... 00:0 eee eer ener ee evans
`10.9 Advance Engineering Project ....... 00000 cree eee
`IRGTCIENCES, o's fa's cline cinta Faiegw sage ae ellawe Seu
`
`ii. Control Technologies in Compression-lgnition
`Engines
`
`Stephen J. Charlton Director, Advanced Diesel Engine Technology,
`Cummins Engine Company, Inc., Indiana, United States
`PET)
`Tertrodnctiony wc Neate lesa ae tntie eta tao
`11.2 Electronic Fuel Systems for Diesel Engines.........,4%
`11.3. Basic Principles of Electronic Control for Diesel Engines .
`11.4 Electronic Hardware for Diesel Engine Control .........
`11:5. Exhaust Aftertreatment 0. ccs cue ice ea ian oes
`RETETOETIOET Foe ates Aad die aia a acon lel aly my om lesaGyola Mw sare
`
`265
`269
`
`278
`
`280
`
`281
`
`283
`
`285
`288
`
`301
`
`306
`
`337
`
`341
`
`350
`
`353
`
`358
`
`359
`365
`374
`390
`406
`417
`
`PART V
`
`TWO-STROKE ENGINES®..... sacsres emreey s eymeres
`
`42\
`
`12.
`
`Introductory Chapter: From a Simple Engine to an
`Electrically Controlled Gasdynamic System
`
`FTZ Research and Technology Association Zwickau,
`Cornel C. Stan
`Westsaxon Institute of Zwickau, Zwickau, Germany
`12,3
`“itradyetioh. ada aceatastecugendmee hs RRs anaas
`
`423
`
`424
`
`11
`
`11
`
`

`

`Contents
`
`R2.2° Pollution Forniation: 6 oj c.cvee dogs eevee re ee hen ea
`12.3 Methods of Mixture Preparation ............-.6.0085
`12.4 Techniques to Reduce Pollution ................005.
`12.5. The Future of the Two-Stroke Engine ..............5.
`REGENCE, 25h cee ahead eed is Hadas es 3k Chee TES
`
`13. Air Pollution from Small Two-Stroke Engines and
`Technologies to ControlIt
`
`Yuji Ikeda and Tsuyoshi Nakjima Department of Mechanical
`Engineering, Kobe University, Rokkodai, Nada, Kobe, Japan
`
`xi
`
`426
`
`429
`433
`436
`442
`
`441
`
`Eran Sher Department of Mechanical Engineering, The Pearlstone
`Centerfor Aeronautical Engineering Studies, Ben-Gurion University,
`Beer-Sheva, Israel
`
`
`13:3)|PolatanG Formation 065 thei aigie a's ela a iateig’s Shewars'aS ns 442
`
`
`
`TS.2.
`‘Pollutant Contyol oo: os :6leaeces ia dec emwiniea © 65lee 8 eee
`448
`
`13.3 Flow and Emission Diagnostics (Experimental Results)..
`456
`R&ierences:
`.2c26.d0 Re Krereah Reo baie a awa R eats
`473
`
`14. Air Pollution from Large Two-Stroke Diesel Engines
`and Technologies to ControlIt
`
`Svend Henningsen MAN B&W Diesel A/S, R&D Department,
`Copenhagen, Denmark
`14.1)
`Introduction 2.0... 6. ccc een eee
`14.2 Regulated Emissions ........ 0.0.00 ccu eee ea eee aes
`14.3 Exhaust Emissions .......... 0.000 ce cece ene eee
`14.4 Exhaust Emission ControlTechnologies—NO, Reduction
`Technigitests:c.4fsieteasbis orandties Patanaly.%,
`14.5 Exhaust Emission Control Technologies—Reduction of
`Clee POMM AIS aon achat ciated ata ahah ahaha tate salads ot te
`Berecénees:
`Sag cits te Pode AR Po 2 SCC OE Pee eke
`
`477
`
`478
`
`479
`
`482
`
`494
`
`516
`530
`
`PARTVI
`
`FUELS 5553 ead ccd oes daddun hahadgcosedoiaecias
`
`535
`
`15.
`
`Introductory Chapter: Fuel Effects
`
`David R. Blackmore Shell Research and Technology Centre, Shell
`Research Ltd., Thornton, Chester, United Kingdom
`15.1 Historical Landmarks .......... 0-0-2... ccc eueveees
`15.2! Recent Developments: oo.) ced aks cetie Pandan nese
`£523) he Pata: 2c3.2 Poe tes at sat avait a anda
`P54)
`TA omega... 2 5 and ese bp dem tis 45.8 Sita tos
`
`537
`
`538
`541
`544
`545
`
`12
`
`

`

`xii
`
`Contents
`
`16.
`
`Fuel Effects on Emissions
`
`Yoram Zvirin, Marcel Gutman and Leonid Tartakovsky Faculty of
`Mechanical Engineering, Technion, Haifa, Israel
`16.5"
`(Backoeoend! wc. cee iva saws SNS er eNews’ BS ETE
`16.2 Gasolines (SL Engines)
`........00eseceeeneceeevees
`16.3 Diesel Fuels (CLE Eneines) os 25 cee oe tind eatdie te cnet
`164) Altemative Fuels. cic cans dotwaeadewr edie iwvin seat
`RGTATeTOOS oS ok wing WN he ae ob <6 wc ee WY
`Appendix:
`| National Gasoline Specifications ........
`Appendix: 2. National Specifications for Automotive
`Pesel Fuel totic este ae ee ate eeaee.t RTE ee eat
`Appendix: 3 US EPA Models for Calculation of Fuel
`Effects on Exhaust Emissions ...-.......-....--.-..
`
`547
`
`548
`550
`§75
`603
`619
`624
`
`639
`
`645
`
`WER asda Cota cat Gane ous Stabe Gian ante bal es
`
`653
`
`13
`
`

`

`List of Contributors
`
`PART|
`
`OVERVIEW
`
`1. Motor Vehicle Emissions Control: Past Achievements, Future Prospects
`
`Prof. John B. Heywood
`Dept. of Mechanical Engineering
`Massachusetts Institute of Technology
`Cambridge, MA 02139
`tel: 617-253-2243
`fax: 617-253-5981]
`e-mail: jheywood @mit.edu
`
`PARTIl
`
`GLOBAL ASPECTS
`
`2. Environmental Aspects of Air Pollution
`
`Prof. Eran Sher
`Dept. of Mechanical Engineering
`Ben-Gurion University
`Beer-Sheva 84 105
`Israel
`tel: 972-7-646-1394
`fax: 972-7-647-2990
`e-mail: sher@menix.bgu.ac.il
`
`3. Health Aspects of Air Pollution
`
`Prof. Rafael Carel
`Soroka Medical Center
`
`Xill
`
`14
`
`

`

`XIV
`
`List of Contributors
`
`Beer-Sheva, Israel
`tel: 972-7-6494-663
`fax: 972-7-649-3934
`e-mail: rcarel @ post.tau.ac.1|
`
`4. Economic and Planning Aspects of Transportation Emission
`
`Dr. Steven E, Plaut
`
`Graduate School of Business Administration
`University of Haifa
`Haifa 31905, Israel
`tel: 972-4824-0110
`fax: 972-4824-9194
`e-mail: rsec792 @uvm_haifa.ac.il
`
`Dr. Pnina O. Plaut
`Faculty of Architecture and Town Planning
`Technion, Haifa, Israel
`
`PARTIil
`
`
`
`SPARK-IGNITION ENGINES
`
`Introductory Chapter; Overview and the Role of Engines
`5.
`with Optical Access
`
`Dr. Richard Stone
`Department of Engineering Science
`University of Oxford
`Oxford OX1 3PJ
`United Kingdom
`tel: 44-1865-273-000
`fax: 44-1865-273-010
`e-mail: richard.stone@eng.ox.ac.uk
`
`6. Combustion-Related Emissions in SI Engines
`
`Prof. Simone Hochgreb
`Dept. of Mechanical Engineering
`Massachusetts Institute of Technology
`Cambridge, MA 02139
`tel: 617-253-0972
`fax: 617-253-9453
`e-mail: simone@ mit.edu
`
`7. Pollution from Rotary Internal Combustion Engines
`
`Dr. Mark Dulger
`Department of Mechanical Engineering
`
`15
`
`15
`
`

`

`List of Contributors
`
`XV
`
`Ben-Gurion University
`Beer-Sheva 84 105
`
`Israel
`
`tel: 972-7-646-1353
`fax: 972-7-647-2990
`e-mail: markd@menix.bgu.ac.il
`
`8. Control Technologies in Spark-Ignition Engines
`
`Prof. Brian Milton
`School of Mechanical and Manufacturing Engineering
`The University of New South Wales
`Barker Street, Gate 14
`Kensington, Sydney 2052
`Australia
`tel: 61-2-385-4088
`fax: 61-2-663-)]222
`e-mail: milton @unsw.edu.au
`
`PART IV
`
`COMPRESSION-IGNITION ENGINES
`
`9,
`
`Introduction
`
`Prof. Dr. Franz Pischinger
`FEV Motorentechnik GmbH and Co. KG
`Neuenhofstrasse 181
`Aachen D-52078
`Germany
`tel: 49-241-5689-10
`fax: 49-241-5689-224
`
`10. Combustion-Related Emissions in CI Engines
`
`Dr. Gary Hawley
`School of Mechanical Engineering
`University of Bath
`Bath, United Kingdom
`tel: 44-1225-826-860
`fax: 44-1225-826-928
`e-mail: ensjgh@bath.ac.uk
`
`R. W, Horrocks
`Advanced Diesel Engines
`Research and Engineering Centre
`Ford Motor Company, Ltd.
`Laindon, United Kingdom
`
`16
`
`

`

`xvi
`
`List of Contributors
`
`Frank Wallace and Chris Brace
`School of Mechanical Engineering
`University of Bath
`Bath, United Kingdom
`
`11. Control Technologies in Compression-Ignition Engines
`
`Dr. Stephen Charlton
`Director, Advanced Diesel Engine Technology
`Cummins Engine Company,Inc.
`Mail Code 50174
`1900 McKinley Avenue
`Columbus, Indiana 47201
`tel: 812-377-8788
`fax: 812-377-7226
`e-mail: 103173,622@compuserve.com
`
`PART V
`
`TWO-STROKE ENGINES
`
`Introductory Chapter: From a Simple Engine to an Electrically
`12.
`Controlled Gasdynamic System
`
`Prof. Dr. Corne}) Stan
`College of Technology and Economics
`Westsaxon Institute of Zwickau
`Germany
`tel: 49-375-536-1600
`fax: 49-375-536-1193
`e-mail: cornel.stan @ fh-zwickau.de
`
`13. Air Pollution from Small Two-Stroke Engines and Technologies
`to ControlIt
`
`Prof. Yuji Ikeda and Tsuyoshi Nakjma
`Department of Mechanical Engineering
`Kobe University
`Rokkodai, Nada
`Kobe, Japan
`tel: 81-78-803-1114
`
`fax: 81-78-845-2736
`e-mail: ikeda@mech.kobe-u.ac.jp
`
`Prof. Eran Sher
`Dept. of Mechanical Engineering
`Ben-Gurion University
`
`17
`
`

`

`List of Contributors
`
`Beer-Sheva 84 105
`Israel
`
`xvii
`
`14. Air Pollution from Large Two-Stroke Diesel Engines
`and Technologics to ControlIt
`
`Dr. Svend Henningsen
`MANand B&W Diesel A/S
`Copenhagen SV
`DK-2450
`
`Denmark
`tel: 45-3385-1100
`fax: 45-3385-1030
`e-mail: svend.henningsen/copenhagen @manbw.dk
`
`PART VI
`
`FUELS
`
`15.
`
`Introductory Chapter; Fuel Effects
`
`Dr. David Blackmore
`
`Research Centre
`Shell Research, Ltd.
`Thornton P.O, |
`Chester CHI 3SH
`United Kingdom
`tel: 44-151-373-5768
`fax: 44-151-373-5674
`
`16. Fuel Effects on Emissions
`
`Prof. Yoram Zvirin
`Department of Mechanical Engineering
`Technion, Haifa 32000,Israel
`tel; 972-4-292-070
`fax: 972-4-324-533
`e-mail: meryzvi@tx.technion.ac.il
`
`18
`
`

`

`This Page Intentionally Left Blank
`
`19
`
`

`

`Acknowledgments
`
`The editor wishes to acknowledge the following organizations for their support
`and cooperation: Ford Motor Co. Ltd., Advanced Diesel Engines Research and
`Engineering Centre, UK; FEV Motorentechnik GmbH & Co KG, Aachen,
`Germany; Cummins Engine Company,Inc., Advanced Diesel Engine Technology
`Columbus, Indiana, USA; MAN and B&W Diesel A/S, Copenhagen Denmark;
`Research Centre, Shell Research Ltd., Chester UK; and the Pearlstone Center for
`Aeronautical Studies, Ben-Gurion University, Israel.
`Academic Press and the editor would like to express their thanks to the fol-
`lowing reviewers and other helpful persons for their invaluable comments and
`suggestions: David Blackmore, Shell Research Ltd., Chester UK; Mark Dulger,
`Ben-Gurion University, Israel; Elbert Hendricks, The Technical University of
`Denmark, Lyngby, Denmark;Itzik Henig, Ford Motor Co., UK; Simone Hochgreb,
`MIT, Cambridge, Massachusetts, USA; Uri Regev, Ben-Gurion University, Israel;
`Zvi Ruder, Academic Press, Boston, Massachusetts, USA; Roger Sierens, Uni-
`versity of Gent, Gent, Belgium; Cornel Stan, Westsaxon Institute of Zwickau,
`Germany; Richard Stone, Oxford University, Oxford, UK; and Desmond Winter-
`bone, UMIST, Manchester, UK.
`The authors and editor wish to acknowledge the following publishers for their
`kind permission to reproducefigures from their publications: The Society of Au-
`fomotive Engineers, American Society of Mechanical Engineers, The Institution
`ot Mechanical Engineers, Gordon and Breach Science Publishers, The Combus-
`tion Institute, Elsevier Science Publishing Company, Edward Arnold Publishers,
`Macmillan Press, Automotive Matters International Ltd., and TNO Road-Vehicles
`ResearchInstitute.
`Special thanks are due to Elizabeth Voit of Academic Press, and to Ian Vino-
`gradov and[lai Sher for a careful preparation of someofthe figures andillustrations
`in the handbook.
`
`Eran Sher
`Department of Mechanical Engineering
`The Pearlstone Centerfor Aeronautical Studies
`Ben-Gurion University of the Negev, Beer-Sheva, Israel
`
`xx
`
`20
`
`20
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`
`21
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`

`Handbook of
`Air Pollution from
`Internal Combustion Engines
`Pollutant Formation and Control
`
`22
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`
`23
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`

`

`
`
`PART|
`
`Overview
`
`1 Motor Vehicle Emissions Control: Past Achievements, Future Prospects
`John B. Heywood
`
`24
`
`24
`
`

`

`This Page Intentionally Left Blank
`
`25
`
`

`

`
`
`CHAPTER 6
`
`Combustion-Related
`Emissions in SI Engines
`
`
`
`Simone Hochgreb
`Department of Mechanical Engineering, MIT, Massachusetts, USA
`
`
`
`6,1
`
`6,2
`
`6.3
`
`6.4
`
`6.5
`
`Introduction |19
`6.1.1 Main Regulated Pollutants: NOy ,CO, HC, and Toxics
`6.1.2 Maximum Allowed Emission Levels
`120
`6.1.3 Overview of Emission Sources
`121
`NO, Formation 124
`6.2.1
`NQOy, Production Mechanism 124
`6.2.2 Modeling NO Formation 126
`6.2.3. Effect of Operating Conditions on NO Formation
`6.2.4 Advanced Low-NO Engine Designs
`135
`Carbon Monoxide
`135
`
`130
`
`119
`
`6.3.1 Mechanism of CO Formation
`
`135
`
`6.3.2 CO Formation Models
`
`135
`
`137
`HC Emissions
`139
`6.4.1 HC Sources
`6.4.2 Effect of Operating Conditions on HC Emissions
`6.4.3
`Postflame Oxidation
`159
`Summary 163
`References
`164
`
`156
`
`ISBN; 0-12-639855-0
`$25.00
`
`118
`
`26
`
`Copyright © 1998 by Academic Press
`All rights of reproduction in any form reserved.
`
`26
`
`

`

`61
`
`Introduction
`
`il?
`
`él
`
`-
`
`INTRODUCTION
`
`The design of spark-ignition (SI) engine systemshas been increasingly constrained
`by the need to minimize vehicle pollutant emissions. Regulations requiring ever
`more stringent maximum emission levels have posed difficult challenges to the
`automotive industry. Significant engineering advances in combustion systems
`and emission control methods have led to major improvements in emissions per
`vehicle over the past 20 years, particularly in ambient carbon monoxide levels [1,
`2]. Owing to the increase in vehicle miles traveled, however, these improvements
`have not always translated into improved urbanair quality.
`Emissions from properly operating modern vehicles are at least one order
`of magnitude lower than original precontrol levels. Further reductions are being
`mandated,calling for better fueling and operation control, new catalytic materials.
`and innovative engineering solutions.
`In this chapter, the production mechanisms of combustion-related pollutants
`from four-stroke, spark-ignited engines are discussed, as well as techniques for
`minimizing sources upstream ofthe emissionsaftertreatment process. This section
`offers an overview of the mechanismsleading to emissions in SI engines. Section
`6.2 describes the process of nitric oxide formation, and Section 6.3 discusses the
`origins of carbon monoxide. Sources of hydrocarbon emissions are examined in
`Section 6.4.
`
`61.1 Main Regulated Pollutants: NO, , CO, HC, and Toxics
`
`The main pollutants of concern in the case of spark-ignition engines are nitric
`oxides (NO and NOs in general, but primarily NO in spark-ignition engines),
`carbon monoxide (CO), hydrocarbons (HC), and organic toxics (currently regu-
`lated toxics in the United States are benzene, acetaldehyde, formaldehyde, and
`1,3-butadiene). Nitric oxides, carbon monoxide, and toxic compoundshavedirect
`effects on human health. Nitric oxides and hydrocarbons contribute, in addition,
`to the formation of tropospheric ozone and smog, which lead to deleteriouseffects
`on visibility and human health. Particulate matter, a very important pollutantin
`the case of compression-ignition engines, is produced only in very small amounts
`in Sl engines. However, concerns about health effects of small-size particulate
`matter (<2 jzm) have been increasing, and maylead tostricter standards.
`Nitric oxides and carbon monoxide are formed during the combustion pro-
`cess, leaving the engine with other combustion products. Hydrocarbonsand toxics
`emissions, however, may originate both from thetailpipe in the form of unburned or
`partially burned fuel, as well as in the form of evaporative emissionsfrom the fuel
`tank, fuel lines, and losses during the refueling process. Evaporative losses of HC
`are estimated to be about the same order of magnitude as the contribution from the
`
`27
`
`27
`
`

`

`120
`
`Fig. 6.1.
`
`10
`
`8}
`
`3 6 t
`
`=
`wo
`
`= Z
`
`'
`1970
`
`; ee ee
`1980
`1990
`
`2000
`
`2010
`
`4}
`
`a 0
`
`1960
`
`Year
`
`Evolution of aggregate light-duty vehicle fleet emissions and associated uncertainties, as esti-
`tated by flect aggregate simulations (symbols and lines) and historical evolution of standards
`(lines) [2],
`
`In this chapter, however, only combustion-related (nonevaporative)
`exhaust [2].
`sources are considered.
`Enormous progress has been madein reducingtailpipe emissions since the
`introduction of catalytic converters 25 years ago (Figure 6.1). Emissions from
`properly operating modern vehiclesare at least one order of magnitude lower than
`precontrol levels.
`
`6.1.2 Maximum Allowed Emission Levels
`
`Emissions standards are permanently evolving throughout the world, reflecting
`demands for air quality as well as expectations on the minimum technically feasi-
`ble emission levels. The state of California has led the way in lowering maximum
`allowable emission levels to address the severe air quality problems in southern
`California; however, many other countries have continuously moved to increas-
`ingly lower admissible levels.
`Maximum allowed emissions levels in the largest consumer markets (the
`United States, Europe, and Japan) govern manufacturers’ decisions in emission
`control implementation. Standards are defined relative io representative driving
`schedules in each region, so that absolute emission levels are not directly com-
`parable. The different schedules for passenger vehicle tests, as well as the cor-
`responding emission levels for spark-ignition engines are outlined in Figure 6.2
`and Table 6.1. These driving schedules, designed to representa “typical” driv-
`ing pattern, include a cold-start period, followed by moderate accelerations and
`
`28
`
`Chapter 6: Combustion-Related Emissions in SI Engines
`
`
`
`—a— NO (g/mi)
`—#— Exhaust HC (g/mi)
`—— NOstd (g/mi)
`..».+HC std (g/mi)
`
`—a—CO (g/mi)
`
`— —-CO std (g/mi)
`
`
`
`28
`
`

`

`6.1
`
`Introduction
`
`Fig. 6.2.
`
`(ECE + Epc)
`
`om
`1
`
`121
`
`
`ta
`an
`as
`r]
`
`“a
`
`*
`vst
`
`(EUROPE)
`
`Part one (urban)
`(ECE)
`
`Part two (extre-urban)
`(EUDC)
`
`Length 211.007 km=Total duration | 12205
`
`
`Max. speed: 120 kmvh=Average speed : 33.6 knv/h
`
`10415 MODE HOT CYCLE
`ma
`
`w0 “ a .
`
`m " *
`
`ee ee eeieee
`
` :4.16km
`Length
`Max, Speed: 70 km/h
`
`6605
`Duration
`Average speed : 22.7 kavh
`
`(JAPAN)
`
`
`
`=
`
`oy a
`
`ay
`
`Cold transient
`Phase (I)
`
`Cold stabilized
`Phase (It)
`
`Hol Soak
`(9-11 min)
`
`Hot transient
`Phase (Ill)
`
`(US)
`
`Length
`:17,8 km
`Total duration
`: 18778
`Max.epeed:91.2knvh=Average speed : 34.1 knvh
`
`Driving schedules for emissions testing in Europe, Japan, and the United States.
`
`decelerations. The cold-start period contributes a disproportionate fraction of the
`emissions (particularly hydrocarbons), as the catalytic converter requires tens of
`seconds to warm up and reach maximum removalefficiency. Therefore, much of
`the effort in designing effective emission controls has been targeted at the initial
`cold-start phase. This will become clear in the following discussions and in the
`description of emission control technology in Chapter8.
`
`6.1.3 Overview of Emission Sources
`
`The origin oftailpipe (i.c., nonevaporative) emissionsfrom spark-ignition engines
`is shown schematically in Figure 6.3. Nitric oxides and carbon monoxide are
`formed via oxidation of molecular nitrogen and fuel in the bulk gases, whereas
`
`29
`
`29
`
`

`

`122
`
`EU
`
`Chapter 6: Combustion-Related Emissions in SI Engines
`
`Table 4.1
`
`Emissions standards for passenger vehicles
`
`1 go" b
`Gasoline
`
`1996
`
`2000°
`
`Test
`Emissions
`Units
`(=Diesel)
`Gasoline
`Diesel
`Gasoline
`Diesel
`
`
`EU
`
`HC+NO x
`co
`PM
`
`g/km
`
`0.97
`2.72
`0.14
`
`0.5
`2.2
`
`0.7
`1.0
`0.08
`
`0.2
`1.7
`
`0.5
`0.5
`0.04
`
`“For passenger cars (<6 passsengers, 2.5 tons gross weight).
`Deterioration factors for 80,000 km: Gasoline: 1.2; Diesel: HC+NO,:1.1, CO:1.1, PM21.2.
`
`“Proposed.
`
`Japan
`
`Vehicle®
`Test
`Emissions
`Units
`Mean®
`Max?
`
`
`Gasoline
`
`10-5 mode
`
`Diesel
`
`10-5 mode
`
`HC
`co
`NO,
`
`HC
`co
`NO,
`PM
`
`e/km
`
`g/km
`
`0.25
`2.1
`0.25
`
`0.4
`21
`0.5
`02
`
`0.39
`27
`0.48
`
`0.62
`2.7
`0.72
`0.34
`
`“Light-duty vehicles.
`'Meanapplies to imports, max to nonimports-
`
`US
`
`Test”
`
`US
`FIP
`
`Emissions
`
`HC
`NMHC
`
`Units
`
`g/mile
`
`co
`
`NO,
`
`PM
`
`Durability
`(miles)
`
`50,000
`50,000
`100,000
`50,000
`100,000
`50,000
`100,000
`50,000
`100,000
`
`199]
`
`1904
`2003
`ULEV?
`
`
`0.41
`
`34
`
`1.0
`
`().2
`
`0.41
`0.25
`0.31
`34
`4.2
`0.4
`0.6
`0.08
`0.10
`
`0.125
`
`L7
`
`0.2
`0.08
`
`—
`0.040
`0.055
`1.7
`2.1
`0.2
`0.3
`=
`0.04
`
`“Forlight duty vehicles and trucks (<12 passsengers).
`PULEV:ultralow vehicles emissions (California), mandated manufacturers’ fleet average.
`HC: hydrocarbons. NOx: nitric oxides, PM: particulate matter, NMHC: nonmethane hydrocarbons.
`
`30
`
`30
`
`

`

`61
`
`Introduction
`
`Fig. 6.3.
`
`liquid fuel
`
`123
`
`crevices
`
`intake Valve
`di
`posits
`
`combustion chamber deposits
`
`oul layer
`
`quench |
`
`Sources Of pollutant formation in spark-ignited engines
`
`unburned hydrocarbons are produced primarily around cold regions where the
`flame does not propagate.
`Nitric oxide (NO) is formed during combustion as the high flame temper-
`atures break down molecular oxygen and nitrogen from the inducted air, which
`then recombine into NO (although nitric oxides are usually referred to as NO,,
`the level of NO2 formed in spark-ignited engines is negligible). As will be shown,
`the production of NO dependsprimarily on the peak temperatures achieved during
`combustion.
`Carbon monoxide (CQ)results from the incomplete oxidation of the fuel to
`carbon dioxide. Carbon monoxide formation increases steeply with decreasing
`air-fuel ratio, as not enough oxygenis available to completely oxidize the mixture.
`Excursions into fuel-rich operation during cold start and transients are responsible
`for the bulk of carbon monoxide emissions in modern engines.
`Unburned hydrocarbons (HC), unlike CO and NO,result from multiple pro-
`cesses in which fuel escapes the main combustion event during flame passage.
`As will be discussed in greater detail in the following sections, these processes
`include flame quenching near cold walls and within narrow gapson the surfaces of
`the combustion chamber, absorption of fuel on layers such as lubricating oils and
`combustion chamber deposits, and the presence of liquid fuel, particularly during
`cold start. A large fraction of the hydrocarbons escaping combustion through one
`of these processes reenters the combustion chamber during the cycle, mixes with
`the bumedgases, andis partially or completely oxidized before the exhaust gases
`leave the system. The so-called engine-out hydrocarbon emissions(i.e., emissions
`before catalytic converter treatment) are composedofthe original fuel compounds,
`as well as partially oxidized hydrocarbonsnotoriginally presentin the fuel.
`Figure 6.4 shows the typical behavior of exhaust emissions with air-fuel
`ratio in ST engines. The exhaustgasescollected in the exhaust manifold then flow
`
`31
`
`31
`
`

`

`Chapter 6: Combustion-Related Emissions in SI Engines
`
`a
`&
`s
`g
`
`5
`
`88
`
`
`
`
`
`
`©
`g
`$s
`
`85
`
`8
`
`124
`
`Fig. 6.4.
`
`Variation of exhaust emissions with relative air-fuel ratio (Harrington and Shisu [3]).
`
`through the catalytic converter, where most of the NO, CO, and HCis converted
`to molecular nitrogen, carbon dioxide, and water vapor.
`Nitric oxide concentrations peak aroundthe lean side of the stoichiometric
`air-fuel ratio,* since thatis close to the point where the mixture temperature is high-
`est. Carbon monoxide and HClevels increase at fuel-rich conditions ducto the lack
`of oxygen and low temperatures. Clearly, one would like to operate underfuel-lean
`conditions from the point of view of minimizing emissions. However, the process
`of conversion of NO backto nitrogen and oxygenin the catalytic converter requires
`the presence of hydrocarbonsas reducing agentsfor best efficiency. The maximum
`air-fuel ratio is also limited by the occurrence of misfires, which lead to poor op-
`eration and high hydrocarbon emissions. Most engines are therefore designed to
`operate under stoichiometric conditions. The use of lean burn enginesis currently
`limited by their inability to meet the strictest NO emissionlevels, since there are
`at the momentno high-efficiency NO, catalytic converters for fuel-lean operation.
`
`
`
`6.2
`
`NO, FORMATION
`
`6.2.1 NO, Production Mechanism
`
`The process of NO, formation during combustion has been extensively studied
`since the initial work by Zeldovich [4], Although one generally refers to nitric
`
`ts the theoretical proportion of air required for
`*The stoichiometric air-fuel ratia (A/F),
`complete conversion of fuel to carbon dioxide and water. The equivalence ratio @ and relative air-fuel
`ratio A are defined as A = 1/¢ = (A/F)/(A/F),.
`
`32
`
`32
`
`

`

`6.2 NOx Formation
`
`(25
`
`oxides, only NOis of relevance in spark-ignition engines operating under approx-
`imately stoichiometric conditions, while NO»is present in a substantial amounts
`only in compression-ignition engines. NO is formed in the hot burned gases dur-
`ing combustion. The formation rate is slow, relative to the overall combustion
`process, and the rates increase exponentially with bumed gas temperatures. The
`major route to the formation of NO in a combustion systemis the so-called thermal
`route or the Zeldovich-Keck mechanism [4, 5]:
`
`N2 +0 + NO+N
`
`N+0; +NO+0
`
`N+OH + NO+H
`
`(RI)
`
`(R2)
`
`(R3)
`
`The oxygen atomspresent behind the flame in the burned gasesinitiate the
`decomposition of molecular nitrogen to form N atoms. The activation energy of
`reaction R1 is of the order of 75 kcal/mol (Table 6.1), which is typically the rate-
`limiting step in the formation of NO under most engi