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Limitations of Partially Premixed Combustion

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Limitations of Partially Premixed Combustion Limitations of partially premixed combustion Citation for published version (APA): Wang, S. (2017). Limitations of partially premixed combustion. Technische Universiteit Eindhoven. Document status and date: Published: 17/10/2017 Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal. If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Download date: 24. Sep. 2021 Limitations of Partially Premixed Combustion PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Technische Universiteit Eindhoven, op gezag van de rector magnificus, prof.dr.ir. F.P.T. Baaijens, voor een commissie aangewezen door het College voor Promoties, in het openbaar te verdedigen op dinsdag 17 oktober 2017 om 16.00 uur door Shuli Wang geboren te Heilongjiang, China Dit proefschrift is goedgekeurd door de promotoren en de samenstelling van de promotiecommissie is als volgt: voorzitter: prof.dr.ir. M.G.D. Geers 1e promotor: prof.dr. L.P.H. de Goey copromotor: dr.ir. L.M.T. Somers leden: prof.dr. Ö. Andersson (Lund University) prof.dr. H.B. Levinsky (University of Groningen) prof.dr. D.J.E.M. Roekaerts adviseur: dr.ir. C.A.J. Leermakers (DAF Trucks NV) Het onderzoek dat in dit proefschrift wordt beschreven is uitgevoerd in overeenstemming met de TU/e Gedragscode Wetenschapsbeoefening. Shuli Wang (2017). Limitations of Partially Premixed Combustion. Ph.D. thesis, Eindhoven University of Technology, Eindhoven, the Netherlands. Copyright © 2017 by Shuli Wang. All rights reserved. No part of the material protected by this copyright notice may be produced or utilised in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without the prior written permission of the author. A catalogue record is available from the Eindhoven University of Technology Library ISBN: 978-90-386-4349-6 Cover design by Tao Yan and Shuli Wang. PPC chemiluminescence images by the courtesy of Zhenkan Wang. Printed by Ipskamp Printing, Enschede. To my family... Contents Nomenclature v Summary vii 1 Introduction 1 1.1 Background . .1 1.2 Combustion Engine Concepts . .3 1.2.1 Diesel Combustion . .3 1.2.2 Homogeneous Charge Compression Ignition . .4 1.2.3 Reactivity Controlled Compression Ignition . .5 1.2.4 Partially Premixed Combustion . .6 1.3 Fuel Appetite for Partially Premixed Combustion . .7 1.3.1 PPC with Diesel-like Fuels . .7 1.3.2 PPC with Gasoline-like Fuels . .7 1.4 Objective and Contributions . .9 1.5 Outline of the Thesis . 10 2 Experimental Apparatus 11 2.1 The Engine . 11 2.2 Emission Measurement Systems . 14 2.2.1 Horiba Measurement System (Gases) . 14 2.2.2 Smoke Meter (Soot) . 14 2.2.3 Engine Exhaust Particle Sizer (Particle Distribution) . 15 2.2.4 Transmission Electron Microscopy (Particle Morphology) . 17 2.3 Data Acquisition System . 19 2.4 Definition of Related Parameters . 20 2.5 Conclusions . 24 3 Partially Premixed Combustion with RON70 Fuels 25 3.1 Comparison of Injectors . 25 3.1.1 Experimental Details . 26 3.1.2 Differences between the Three Injectors . 26 3.2 Effect of Air-excess . 29 i Contents 3.2.1 Experimental details . 29 3.2.2 Major Combustion Characteristics . 33 3.2.3 Soot and NOx Emissions . 38 3.3 Limitations of PPC at higher loads . 39 3.3.1 Experimental details . 39 3.3.2 Combustion Characteristics . 40 3.3.3 NOx-Soot Trade-off . 41 3.4 Conclusions . 43 4 Low Load Tests with High-octane Fuels 45 4.1 Experimental Details . 45 4.1.1 Test Fuels . 46 4.1.2 Test Conditions — Effects of Intake temperature and CA50 . 46 4.1.3 Test Conditions — Optimize NOx Emissions . 48 4.2 Results and Analysis — Effects of Intake temperature and CA50 . 49 4.2.1 Load I . 49 4.2.2 Load II . 58 4.3 Results and Analysis — Optimize NOx Emissions . 64 4.3.1 Load I . 64 4.3.2 Load II . 67 4.4 Conclusions . 70 5 Particulate Matter Emissions 71 5.1 Introduction . 71 5.2 Tests with Ternary Blends . 73 5.2.1 Test Fuels . 73 5.2.2 Test Conditions . 74 5.2.3 Comparison of Blends of RON70 and Diesel . 75 5.2.4 Comparison of TRF and CRF . 79 5.3 PRF Blends Mix with Different Volumes of Ethanol . 83 5.3.1 Test Fuels . 83 5.3.2 Test Conditions . 84 5.3.3 Major Results and Discussion . 84 5.4 Tests with Binary Blends . 91 5.4.1 Test Fuels . 92 5.4.2 Test Conditions . 92 5.4.3 Effect of 2-EHN on Combustion Controllability . 94 5.4.4 Physical and Chemical Effects on PM . 97 5.5 Characterization of Agglomerates’ Morphology . 103 5.5.1 Test Conditions . 103 5.5.2 Major Results and Discussion . 104 5.6 Conclusions . 109 6 Conclusions and Outlook 111 Bibliography 115 ii Contents A Engine Exhaust Particle Sizer 127 A.1 How does EEPS works? . 127 A.2 Secondary Dilution Factor . 129 A.3 Normalized Concentrations: dN/dlogDp . 129 Acknowledgement 131 Curriculum Vitae 133 iii Nomenclature AD Aerodynamic diameter AFst Stoichiometric air fuel ratio AM Accumulation mode ATDC After top dead center BD Burn duration BDC Bottom dead center BEV Battery electric vehicles BMEP Brake mean effective pressure BTDC Before top dead center CAD Crank angle degree CA10 The crank angle where 10% of the heat has been released CA50 The crank angle where 50% of the heat has been released CA90 The crank angle where 90% of the heat has been released CI Compression ignition CN Cetane number CO Carbon monoxide CO2 Carbon dioxide COV Coefficient of variation DOC Diesel oxidation catalyst DPF Diesel particulate filter EC Elemental carbon EEPS Engine exhaust particle sizer EGR Exhaust gas recirculation EOI End of injection EVC Exhaust valve close EVO Exhaust valve open FSN Filter smoke number HC Hydrocarbons HCCI Homogeneous charge compression ignition HDDI Heavy duty direct injection v Nomenclature HFR Hydraulic flow rate ID Ignition delay IDw Ignition dwell IMEP Indicated mean effective pressure IMEPg Gross indicated mean effective pressure IMEPn Net indicated mean effective pressure ISFC Indicated specific fuel consumption IVC Intake valve close IVO Intake valve open LHV Lower heating value NM Nucleation mode MON Motor octane number NOx Nitrogen oxides NVO Negative valve overlap ON Octane number PAH Polycyclic aromatic hydrocarbon PF Premixed fraction PM Particulate matter PPC Partially premixed combustion PRF Primary reference fuel PRR Pressure rise rate RCCI Reactivity controlled compression ignition RoHR Rate of heat release RON Research octane number rpm Revolutions per minute SCR Selective catalytic reduction SMPS Scanning mobility particle sizer SOI Start of injection SSCI Spark assisted compression ignition TDC Top dead center TEM Transmission electron microscopy λ Air fuel ratio 2-EHN 2-ethylhexyl nitrate vi Summary The diesel engine is widely used in many applications due to its high efficiency, high stability, and also having an extreme flexibility for a variety of operating conditions. Despite the numerous advantages of diesel engines, society is increasingly concerned about the pollutants emitted by diesel engines. One way to address the pollution problem is to alter the combustion so that less pollutants are created in the first place. Low-temperature combustion is a leading strategy designed to reduce or eliminate the two most problematic pollutants emitted by diesel engines, nitrogen oxides (NOx) and particulate matter (PM). One such combustion concept is Homogeneous Charge Compression Ignition (HCCI), which typically employs long in-cylinder mixing times prior to combustion to produce relatively uniform and lean fuel/air mixtures. As the technique has matured, HCCI has evolved toward Partially Premixed Combustion (PPC) which has a more inhomogeneous fuel/air mixture and temperature field to better control the heat release rate. However, there are still many limitations in the practical application of PPC engines. The Chapter 1 and 2 introduces the research background and experimental equipment, respectively. The Chapter 3 begins with the tests using three injectors with different nozzle geometries to compare their combustion and emission characteristics. Then, the in-cylinder emission control parameter air-excess was investigated under PPC mode to get knowledge about the influences of in-cylinder density and oxygen concentration on exhaust emissions.
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