(Hua_zhao) Homogeneous Charge Compression Ignition

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i HCCI and CAI engines for the automotive industry ii Related titles: The science and technology of materials in automotive engines (ISBN 978-1-85573-742-6) This authoritative book provides an introductory text on the science and technology of materials used in automotive engines It focuses on reciprocating engines, both four- and two-stroke, with particular emphasis on their characteristics and the types of materials used in their construction The book considers the engine in terms of each specific part: the cylinder, piston, camshaft, valves, crankshaft, connecting rod and catalytic converter The materials used in automotive engines are required to fulfil a multitude of functions, resulting in a subtle balance between material properties, essential design and high performance characteristics The intention here is to describe the metallurgy, surface modification, wear resistance, and chemical composition of these materials It also includes supplementary notes that support the core text The book is essential reading for engineers and designers of engines, as well as lecturers and graduate students in the fields of combustion engineering, machine design and materials science looking for a concise, expert analysis of automotive materials The automotive industry and the environment (ISBN 978-1-85573-713-6) The future of car manufacturing may be very different to the current practice of largescale, large-assembly plant construction methods based on economies of scale and the marketing of new vehicles with ever increasing complexity and value-added options A sustainable future is envisaged in this ground-breaking study, which concentrates on the recent research into alternative production methods with an emphasis on life-cycle management, recyclability and manufacture tailored to the customer’s individual specifications IPDS 2006 Integrated Powertrain and Driveline Systems 2006 (ISBN 978-1-84569-197-4) The holistic view of powertrain development that includes engine, transmission and driveline is now well accepted Current trends indicate an increasing range of engines and transmissions in the future with, consequently, a greater diversity of combinations Coupled with the increasing introduction of hybrid vehicles, the scope for research, novel developments and new products is clear This volume presents some of the latest developments in a collection of papers from the Institution of Mechanical Engineers’ Conference Integrated Powertrain and Driveline Systems 2006 (IPDS 2006) organised by the IMechE Automobile Division Main themes include transmissions; concept to market evolution; powertrain integration; and engine integration Novel concepts relating, for example, to continuously variable transmissions (CVTs) and hybridisation are discussed, as well as approaches to modelling and simulation Details of these books and a complete list of Woodhead’s titles can be obtained by: • visiting our website at www.woodheadpublishing.com • contacting Customer Services (e-mail: sales@woodhead-publishing.com; fax: +44 (0) 1223 893694; tel.: +44 (0) 1223 891358, ext 130; address: Woodhead Publishing Limited, Abington Hall, Abington, Cambridge CB21 6AH, England) iii HCCI and CAI engines for the automotive industry Edited by Hua Zhao CRC Press Boca Raton Boston New York Washington, DC WOODHEAD PUBLISHING LIMITED Cambridge England iv Published by Woodhead Publishing Limited, Abington Hall, Abington, Cambridge CB21 6AH, England www.woodheadpublishing.com Published in North America by CRC Press LLC, 6000 Broken Sound Parkway, NW, Boca Raton, FL 33487, USA First published 2007, Woodhead Publishing Limited and CRC Press LLC © 2007, Woodhead Publishing Limited except for Chapter which is © 2007, Shell Global Solutions The authors have asserted their moral rights This book contains information obtained from authentic and highly regarded sources Reprinted material is quoted with permission, and sources are indicated Reasonable efforts have been made to publish reliable data and information, but the authors and the publishers cannot assume responsibility for the validity of all materials Neither the authors nor the publishers, nor anyone else associated with this publication, shall be liable for any loss, damage or liability directly or indirectly caused or alleged to be caused by this book Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming and recording, or by any information storage or retrieval system, without permission in writing from Woodhead Publishing Limited The consent of Woodhead Publishing Limited does not extend to copying for general distribution, for promotion, for creating new works, or for resale Specific permission must be obtained in writing from Woodhead Publishing Limited for such copying Trademark notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging in Publication Data A catalog record for this book is available from the Library of Congress Woodhead Publishing ISBN 978-1-84569-128-8 (book) Woodhead Publishing ISBN 978-1-84569-354-1 (e-book) CRC Press ISBN 978-1-4200-4459-1 CRC Press order number WP4459 The publishers’ policy is to use permanent paper from mills that operate a sustainable forestry policy, and which has been manufactured from pulp which is processed using acid-free and elementary chlorine-free practices Furthermore, the publishers ensure that the text paper and cover board used have met acceptable environmental accreditation standards Project managed by Macfarlane Production Services, Dunstable, Bedfordshire, England (e-mail: macfarl@aol.com) Typeset by Replika Press Pvt Ltd, India Printed by TJ International Limited, Padstow, Cornwall, England v Contents Contributor contact details xiii Preface xvii Part I Overview Motivation, Definition, and History of HCCI/CAI engines H ZHAO, Brunel University West London, UK 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Introduction Current automotive engines and technologies Historical background of HCCI/CAI type combustion engines Principle of HCCI/CAI combustion engines Definition of HCCI and CAI combustion engines Summary References 10 15 16 16 Part II Gasoline HCCI/CAI combustion engines Overview of CAI/HCCI gasoline engines 21 H ZHAO, Brunel University West London, UK 2.1 2.2 2.3 2.4 2.5 2.6 Introduction Fundamentals of CAI/HCCI gasoline engines Effects of use of exhaust gases as diluents Approaches to CAI/HCCI operation in gasoline engines Summary References 21 21 29 35 40 40 Two-stroke CAI engines 43 P DURET, IFP, France 3.1 Introduction 43 vi Contents 3.2 3.3 3.4 Principles of the two-stroke CAI combustion How to control the two-stroke CAI combustion The potential application of the two-stroke CAI combustion Future trends Sources of further information and advice References 67 72 74 75 Four-stroke gasoline HCCI engines with thermal management 77 3.5 3.6 3.7 46 56 J YANG, USA 4.1 4.2 4.3 4.4 4.5 4.6 Introduction The optimized kinetic process (OKP) HCCI engine Strengths and weaknesses Future trends Sources of further information and advice References 77 79 91 97 99 101 Four-stroke CAI engines with residual gas trapping 103 H ZHAO, Brunel University West London, UK 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Introduction Principle of CAI operation with residual gas trapping CAI operation in a four-stroke port fuel injection (PFI) gasoline engine Effect of direct injection on CAI combustion in the four-stroke gasoline engine Effect of spark ignition on CAI combustion in the four-stroke gasoline engine Summary References Four-stroke CAI engines with internal exhaust gas recirculation (EGR) 103 103 107 115 129 132 134 136 A FÜRHAPTER, AVL List GmbH, Austria 6.1 6.2 6.3 6.4 6.5 6.6 Introduction Principle of CAI with internal EGR Engine concepts and layout Thermodynamic results and analysis of CAI with internal EGR Transient operation with CAI and internal EGR Future trends 136 137 141 146 155 162 Contents vii 6.7 6.8 Sources of further information and advice References 162 163 HCCI control 164 P TUNESTÅL and B JOHANSSON, Lund University, Sweden 7.1 7.2 7.3 7.4 7.5 7.6 Introduction Control means Combustion timing sensors Methods Summary and future trends References 164 165 171 174 182 182 CAI control and CAI/SI switching 185 N MILOVANOVIC, Delphi Diesel Systems Limited, UK and J TURNER, Lotus Engineering, UK 8.1 8.5 8.6 Introduction about requirements for the control of the CAI engine Problems in controlling the CAI engine Transition between operating modes (CAI-SI-CAI) The ‘mixed mode’ CAI-SI engine in operation: presentation and discussion of the experimental results obtained Summary References Fuel effects in CAI gasoline engines 8.2 8.3 8.4 185 185 188 192 202 203 206 G T KALGHATGI, Shell Global Solutions, UK 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 9.12 Introduction Practical transport fuels Auto-ignition quality of fuels The octane index and the K value The auto-ignition requirement of an HCCI engine and fuel effects in combustion phasing Combustion limits IMEP and indicated efficiency Other approaches to characterising fuel performance in HCCI engines Fuel requirements of HCCI engines Summary References List of notations Appendix – HCCI predictor 206 207 210 217 222 224 226 228 230 233 234 236 237 viii Contents Part III Diesel HCCI combustion engines 10 Overview of HCCI diesel engines 241 J V PaSTOR, J M LUJÁN, S MOLINA and J M GARCÍA, CMT-Motores Térmicos, Spain 10.1 10.2 10.3 10.4 10.5 10.6 Introduction Conventional diesel combustion Fundamentals of HCCI combustion Overview of diesel HCCI engines Summary References 241 242 247 252 261 263 11 HCCI combustion with early and multiple injections in the heavy-duty diesel engine 267 Y AOYAGI, New ACE, Japan 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 12 Introduction Experimental apparatus Early injection HCCI (PREDIC) by low cetane fuel Multiple injections HCCI by low cetane fuel (two-stage combustion, MULDIC) HCCI for normal cetane fuel Summary Acknowledgements References Nomenclature Narrow angle direct injection (NADI™) concept for HCCI diesel combustion 267 268 271 274 277 285 286 286 288 289 B GATELLIER, IFP, France 12.1 12.2 12.3 12.4 12.5 12.6 12.7 Introduction The NADI™ concept overview First results and limitations Development of the concept Evaluation of the concept in a multi-cylinder engine Future trends References 289 290 292 296 307 318 320 13 Low-temperature and premixed combustion concept with late injection 322 S KIMURA, Nissan Motor Company, Japan 13.1 13.2 Introduction Basic concept of low-temperature and premixed combustion 322 323 Contents 13.3 13.4 13.5 13.6 13.7 14 Characteristics of combustion and exhaust emissions with modulated kinetics (MK) combustion Second generation of MK combustion Emission performance improvement of second generation of MK combustion Future trends References HCCI fuel requirements ix 324 330 334 337 340 342 T W RYAN III, SWRI, USA 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 14.9 Introduction Background Diesel fuel HCCI HCCI fuel ignition quality Gasoline HCCI HCCI fuel specification Fundamental fuel factors Future trends References 342 342 345 350 354 358 360 361 362 Part IV HCCI/CAI combustion engines with alternative fuels 15 Natural gas HCCI engines 365 N IIDA, Keio University, Japan 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 15.10 15.11 15.12 15.13 15.14 CNG HCCI engine experiment and calculation conditions CNG composition Influence of equivalence ratio Auto-ignition timing and combustion duration Auto-ignition temperature and auto-ignition pressure Exhaust emission, maximum cycle temperature and combustion efficiency Influence of n-butane on auto-ignition and combustion in methane/n-butane/air mixtures Summary of naturally aspirated natural gas HCCI engine Supercharged natural gas HCCI engine setup and experiments Performance and exhaust gas characteristics at a compression ratio of 17 Performance and emission characteristics at a compression ratio of 21 Potential of natural gas turbocharged HCCI engines Summary References 365 366 369 371 372 374 376 383 383 385 388 389 391 392 522 Index radical reactions 248–9 rapid compression machine (RCM) 211 modelling auto-ignition in 445–51 re-breathing 8–9, 36–7, 136–63, 167–8, 185–6, 187, 203, 507 compared with trapping method 137–8 comparison of re-breathing methods 138–40 engine concepts and layout 141–6 approaches to CAI combustion 141 operation strategies with a combined mechanical electrohydraulic valve train 144–6 re-breathing with a combined mechanical electro-hydraulic valve train 141–4, 145 future trends 162 thermodynamic results and analysis 146–55 energy balance analysis 154–5, 156 four-cylinder engine 148–54 single-cylinder research engine 146–8 transient operation 155–62 combustion control 155–9 real driving transient operation of four-cylinder engine 159–62 see also internal EGR recompression see residual gas trapping reduced chemical kinetic models 453 Research Octane Number (RON) 214–17 residual gas 49–50, 78, 79, 95 control using VVA 166–8, 179 expanding the operating range of the OKP engine 89–90 residual gas trapping (negative valve overlap) 8–9, 36–7, 80–1, 103–35, 185–6, 203, 507, Plate 4, Plate 5, Plate compared with re-breathing 137–8 control using VVA 166–7 direct injection 115–29, 134 early injections during valve overlap period 116–21, 122, 123, 124, 126 mid and late injections during intake and compression strokes 121–4, 125–6 split fuel injections 124–9 port fuel injection (PFI) engine 107–15 combined variable valve lift and variable valve timing 115 fuel consumption and emission characteristics 112–14 performance and combustion characteristics 107–12 principle of 103–7 sequential phases 115–16 spark assisted CAI combustion 129–32, 133, 134, Plate 8, Plate road load curve 46–7 ‘run-on’ (‘after-run’) sapphire 476 scooters 44, 45, 69 Semenov, Nikolai 7–8 sensitivity auto-ignition quality 214 estimation from stationary maps 176 sensors, combustion timing 171–4, 182 Shell auto-ignition model 119–21, 122, 175 Shell middle distillate synthesis (SMDS) 208, 232 signal collection devices 480 simultaneous LIF measurements 493–4 single zone models 451–2, 462, 464, 470 Souk Hong Jo 43 spark assisted CAI combustion 38, 97–9, 129–32, 133, 134, Plate 8, Plate spark ignition (SI) combustion 5–6, 7, 10–11, 428, Plate compared with CAI combustion 48–9 heat release characteristics 11, 12 performance and emission characteristics 13 SI/CAI switching see mode switching thermal efficiency of SI engines 91 two-stroke engines 49–50 management of transition between SI and CAI combustion 55–6 spectrally resolved absorption measurement 481–2, 483, 484, 485 split fuel injections NADI 297, 298, Plate 13 residual gas trapping 124–9 stratification Index charge see charge stratification partially stratified combustion 458, 468, 471 thermal 38–9, 90–1, 93–4, 425 stratified-charge direct-injection sparkignition (SC-DISI) engine 83–6 thermal efficiency 83–4, 91–2 super clean diesel engine 267–8 super ultra low emission vehicle (SULEV) target 4, 322–3 MK and meeting SULEV standard 337–40 supercharged natural gas engines 383–91 performance and exhaust gas characteristics CR of 17 385–8 CR of 21 388–9, 390 potential of 389–91 set-up and experiments 383–5 surging range 46–7 surrogate fuel mixture models 211, 452 switching between modes see mode switching system identification control methods 175–8 taxation 3, TDC split injection 297, 298, Plate 13 temperature auto-ignition temperature 372–4, 379–80, 382 ceiling temperature 438 compression temperature and autoignition quality of fuel 220–2, 349–50, 355, 356, 357 coolant temperature 38, 62–3, 334 DME engine 396–7, 425, 426, 427, 428 calculation 415–16, 417 initial temperature 400–1, 402, 403 maximum temperature 403–6, 407, 411–12, 418–20 effect of hot burned gases 33 intake temperature and BSN for fuel blends 345–6 measurement with thermographic phosphors 498–500, 501 natural gas engines 370–1, 372–4 auto-ignition temperature 372–4, 379–80, 382 influence of n-butane in methane/ 523 n-butane/air mixtures 379–80, 380–3 maximum temperature 374–6, 380–3 operating region and intake temperature 366–7, 368 premixed compression ignition combustion 278–80, 281 re-breathing and charge temperature 139–40, 146–7 regimes of auto-ignition 437–45 intermediate and high temperature chain branching 444–5, 461–2 low temperature kinetics 437–43, 459–61 spark assisted auto-ignition 98–9 two-stroke engines 49–50 effect of overall temperature 62–3 termination reactions 435–7 thermal efficiency 100 diesel engines 91–3 DME engine 421, 422 MK combustion 326, 327 OKP engine 83–4, 91–3 premixed compression ignition combustion 280–2 supercharged natural gas engines 385, 386, 388, 389–91 thermal management 35, 37, 77–102, 186 available thermal energy sources 77–8 utilisation of 78–9 combustion control 96, 170–1, 180, 181, 182 direction of research 100 EGR and coolant temperature control 99–100 future trends 97–9 OKP engine see optimised kinetic process (OKP) engine strengths and weaknesses 91–7 VCR-HCCI engine 79, 91–6, 100 thermal stratification 38–9, 93–4 DME engine 425 OKP engine 90–1 two-stroke engine 57 thin-film thermocouple 326–7, 328 thermographic phosphors 498–500, 501 three-dimensional fuel visualisation 497–8 three-dimensional LIF imaging 497 524 Index Thring, R.H throttle valve 13 toluene 210, 360, 361, 488, 494 top dead centre (TDC) 165 TDC split injection 297, 298, Plate 13 total heating value 367–8, 369 Toyota tracers, fuel see fuel tracers transfer throttling 45, 52–4 two-stroke engines 54–5, 57, 64–6 combined with exhaust throttling 66–7 transient operation 155–62 transition state ring 439–40 TS (Toyota-Soken) process 43 turbochargers 319 natural gas engines 383–91 turbulence 458 two-stage exhaust cam system 414 two-stage ignition 212–13, 438, 443, 460–1 two-stroke CAI engines 8, 35, 43–76, 77 combustion control 56–67 associated technologies and control devices 63–7 relevant control parameters 56–63 early research on CAI 43–5 future of 72–3 potential application 67–72 automotive engines 70–2 small generators 67–8 two-wheeler engines 68–70 principles of 46–56 advantages and benefits of CAI/SI 50–4 basic principles and in-cylinder conditions 48–50 combustion modes 46–8 drawbacks and difficulties 54–6 transferring knowledge to development of four-stroke engines 73 two-stroke diesel model aeroplane engine two-stroke operation in two-stroke/fourstroke switching engines 38 uncontrolled combustion 55 UNIBUS system 257–8 United States permitted emission levels 3–5 valve lift curves EHVA system 144 ‘mixed mode’ engine 194–5 residual gas trapping 104–5, 106 two-stage exhaust cam system for DME engine 414 variable cam timing (VCT) 80–1, 104–6 see also cam profile switching and phaser VVT system (CPS-P) variable compression ratio (VCR) 36, 81, 180, 182, 186, 507 VCR-HCCI engine 79, 100 operating range 93–6 thermal efficiency 91–3 variable geometry compressor 319 variable valve actuation (VVA) 37, 80–1, 104–5, 166–70, 182, 203 combined continuous variable lift and timing devices 115 combined mechanical electrohydraulic valve train 141–6 effective compression ratio control 168–70 ‘mixed mode’ engine AVT system 189, 191–2, 193–6, 199–202, 203 cam profile switching and phasing device VVT system 189–91, 194–9, 203 in operation 193–202 valve train requirements 188–9 residual gas control 166–8, 179 vehicle speed 159–62 volatility characteristics of fuels 208, 209 Volvo 8–9 wall wetting problem 10 warm-up 96–7 windows 476–7 xylene 210, 488 unburned hydrocarbon emissions see hydrocarbon emissions zero emissions vehicles (ZEVs) Diesel (CI) Gasoline (SI) Non-premixed air/fuel mixture Diffusion combustion CAI HCCI Premixed air/ fuel mixture Flame propagation Multiple ignition and combustion Plate Salient features of three combustion modes Plate Direct visualisation of controlled auto-ignition combustion in a gasoline engine Mass fraction burnt (%) 100 80 60 40 20 300 350 400 Crank angles (CA) 450 500 Plate Mass fraction burnt curves of 100 CAI combustion cycles Injection timing = 90 cad BTDC F/A Eq ratio 1.5 0.5 Crank angle = 278.0 deg 2500 tr/min, bar, IT: 25, 75, 90, 110 Plate Injection calculation in HPC mode, Start of injection 90 crank angle before top dead centre Pressure [bar] Pressure [bar] –40 11 13 15 –40 11 13 15 –30 [°CA] ATDC 90 [°CA] ATDC –10 10 Crank angle [°CA] ATDC –40 [°CA] ATDC –10 [°CA] ATDC –20 TDC –30 [°CA] ATDC 110 [°CA] ATDC –10 10 Crank angle [°CA] 30 30 –20 [°CA] ATDC 20 –20 [°CA] ATDC 20 Plate In-cylinder pressure traces during the negative valve overlap period –30 –20 –40 [°CA] ATDC –10 [°CA] ATDC –30 TDC 40 40 Heat release rate [J/°CA] Heat release rate [J/°CA] –1.5 –50 –1.0 –0.5 0.0 0.5 1.0 1.5 –1.5 –50 –1.0 –0.5 0.0 0.5 1.0 1.5 –20 –30 –20 –40 [°CA] ATDC –10 [°CA] ATDC –30 –10 –30 [°CA] ATDC 90 [°CA] ATDC 10 20 Crank angle [°CA] TDC –30 [°CA] ATDC 110 [°CA] ATDC –10 10 20 Crank angle [°CA] 40 40 –20 [°CA] ATDC 30 –20 [°CA] ATDC 30 50 50 Plate In-cylinder thermal process during the negative valve overlap period –40 [°CA] ATDC –10 [°CA] ATDC –40 –40 TDC 60 60 Φ Temp (K) HRR (J/CA) 1500 5.0 1.0 1250 2.8 0.5 1000 0.5 0.0 (a) TDCoverlap (Case of SOI at –75°ATDC) Φ Temp (K) HRR (J/CA) 1500 5.0 1.0 1250 2.8 0.5 1000 0.5 0.0 (b) TDCoverlap (Case of SOI at –40°ATDC) Φ Temp (K) HRR (J/CA) 1500 5.0 1.0 1250 2.8 0.5 1000 0.5 0.0 (c) TDCoverlap (Case of SOI at –20°ATDC) Plate Distributions of temperature, equivalence ratio and heat release rate at TDCoverlap for three injection timings at λ = 1.2 10 1.5 0.9 0.4 1050 1000 HRR (J/CA) 10 HRR (J/CA) 1100 (b) SOI at 218° ATDCoverlap 0.4 1000 Φ 0.9 1050 (a) SOI at 98° ATDCoverlap 1.5 1100 Φ Plate In-cylinder spatial distributions of temperature, equivalence ratio and heat release rate at 10°CA BTDC with injections at 98° and 218° ATDC Temp (K) Temp (K) SI combustion CAI combustion 110 Intake valve opening (CA deg ATDC) 105 3.0 100 3.5 2.8 95 90 3.0 3.0 85 2.6 80 3.0 2.6 3.2 3.2 2.8 3.2 3.4 3.2 75 3.5 3.2 3.0 70 65 Spark assisted region 60 55 50 55 60 65 70 75 80 85 90 Exhaust valve closing (CA deg BTDC) 95 100 105 Plate Combustion modes in a DI gasoline engine with negative valve overlap with SOI @30 CA deg ATDC, lambda 1.2 and 1500 rpm Plate 10 Image of a flame with a NADI-type combustion chamber and narrow angle injection nozzle Crank angle: 350 deg Crank angle: 360 deg F/A Eq ratio 1.5 0.5 (b) (a) Crank angle: 370 deg Crank angle: 375 deg (c) (d) Crank angle: 390 deg Crank angle: 380 deg (e) (f) Plate 11 Computed combustion process at 4000 rpm, full load – conventional combustion chamber (a–f) Crank = 350.0 dv Crank = 360.0 dv (a) (b) Crank = 376.0 dv Crank = 370.0 dv (c) (d) Crank = 385.0 dv Crank = 380.0 dv (e) (f) Plate 12 Computed combustion process at 4000 rpm, full load – NADITM combustion chamber Crank angle = 350.0 deg Crank angle = 352.5 deg F/A Eq ratio F/A Eq ratio 1.5 0.5 1.5 0.5 (a) (b) Crank angle = 375.5 deg Crank angle = 362.5 deg F/A Eq ratio F/A Eq ratio 1.5 0.5 1.5 0.5 (c) (d) Crank angle = 370.0 deg Crank angle = 372.5 deg F/A Eq ratio F/A Eq ratio 1.5 0.5 1.5 0.5 (e) (f) Crank angle = 375.0 deg Crank angle = 377.5 deg F/A Eq ratio F/A Eq ratio 1.5 0.5 1.5 0.5 (g) Plate 13 CFD of a split injection strategy (h) Low swirl (SR = 3) 15 deg ATDC A High swirl (SR = 9) A Ne = 1200 rpm BMEP = bar IT = TDC O2 = 16% 25 deg ATDC 3.0 φ 0.5 Plate 14 Distribution of equivalent ratio of low and high swirl Filtered heat release rate 140 6.9 Bar NMEP 6.6 Bar NMEP 6.3 Bar NMEP 5.8 Bar NMEP 5.3 Bar NMEP 4.5 Bar NMEP 4.1 Bar NMEP 3.8 Bar NMEP 3.3 Bar NMEP Bar NMEP 2.8 Bar NMEP 2.3 Bar NMEP 1.9 Bar NMEP 120 J/CAD 100 80 60 40 20 –20 –30 –20 –10 CAD 10 20 Plate 15 Heat release rate diagrams at various loads (SwRI) 30 2 3 4 5 6 7 Intake value Combustion chamber Visible area (at TDC) Luminescence intensity A.U 32 64 96128160192 224256 Exhaust Quartz window φ60 value Chamber φ82.6 Plate 16 Luminescence images in the combustion chamber (comparison for case of homogeneous mixture and inhomogeneous mixture) [20] (b) (a) DME/air φ=0.32 Tin = 373K Pin=0.1MPa Ne=600rpm ε=7.2 I.I Gain 500 18.3 Cylinder pressure [bar] 366 2000 4000 6000 8000 10000 12000 14000 16000 40 35 30 25 20 360 45 50 55 70 65 60 Homogeneous 362 (a) 367 (b) 374 368 369 Crank angle [°CA] 370 Model iso-octane φ = 0.45 371 Phi = 0.68 Phi = 0.59 Phi = 0.50 Phi = 0.41 Phi = 0.32 Single Zone, Phi = 0.45 372 96 bar/°CA 364 366 368 370 Crank angle [°CA] φ = 0.45 Model iso-octane Fuel-stratified Plate 17 Predicted heat release rate diagrams for a fuel with no low temperature reactions at various loads HRR [J/°CA] Plate 18 Geometrical distribution of the mass that burns to completion, the mass that reacts partially into CO, the mass that reacts partly into intermediate hydrocarbons and fuel, and the mass that does not react at all and remains as unburned fuel (Aceves et al., 2004) The geometrical distribution is shown at 6°BTDC for four values of equivalence ratio φ = 0.26, 0.16, 0.10 and 0.04 The figure shows that the case with φ = 0.26 burns to completion, and HC and CO are only produced at the crevices and boundary layer As the equivalence ratio is reduced, the fraction of fuel that does not burn to completion increases rapidly At φ = 0.10, most of the fuel partially oxidizes into CO At φ = 0.04, much of the fuel remains unreacted or partially reacted into intermediate hydrocarbons Unburned fuel Fuel, IHC, CO High CO Complete combustion φ = 0.04 φ = 0.10 φ = 0.16 φ = 0.26 ... Controlled Auto -Ignition (CAI) and Homogeneous Charge Compression Ignition (HCCI) combustion are radically different from the conventional spark ignition (SI) combustion in a gasoline engine and compression. .. 48188 USA E-mail: Hua. Zhao@ brunel.ac.uk Chapter Chapters 1, 2, and 20 H Zhao School of Engineering and Design Brunel University West London Uxbridge Middlesex, UB8 3PH UK E-mail: Hua. Zhao@ brunel.ac.uk... Introduction Kinetics of auto -ignition Reaction types Temperature regimes of auto -ignition Illustrations of auto -ignition in the rapid compression machine Kinetic models for HCCI ignition Summary References
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Xem thêm: (Hua_zhao) Homogeneous Charge Compression Ignition, (Hua_zhao) Homogeneous Charge Compression Ignition, Motivation, definition and history of HCCI/CAI engines, Narrow angle direct injection (NADI) concept for HCCI diesel combustion