FUEL PROPERTY IMPACT ON A PREMIXED DIESEL COMBUSTION MODE by Andrew M. Ickes A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Mechanical Engineering) in the University of Michigan 2009 Doctoral Committee: Professor Dionissios N. Assanis, Co-Chair Assistant Research Scientist Stani V. Bohac, Co-Chair Professor James F. Driscoll Professor Volker Sick Patrick G. Szymkowicz, General Motors Corporation © Andrew M. Ickes 2009 ACKNOWLEDGEMENTS As expected, there are many people whose contribution over the course of my graduate studies bears acknowledgement. I am gratefully indebted to all who either contributed to the work described within this dissertation or to me personally during the time spent working on it. First and foremost, I must thank Professor Dennis Assanis for the opportunity to work in his laboratory and for his years of support. Additionally, I must acknowledge the contributions of Research Scientist Stani Bohac, my other co-chair, who has provided substantial guidance for this work. I am grateful for the financial support of General Motors Corporation, who sponsored this work through the framework of the General Motors/University of Michigan Collaborative Research Laboratory in Engine Systems Research. I am additionally thankful for the technical reviews, planning, and intellectual advice offered by staff of the GM Diesel Research group. I must also recognize two people who have provided and coordinated opportunities that have contributed significantly to where I am now: Scott Fiveland of Caterpillar, and Professor Bryan Willson of Colorado State University. I am ever so grateful for my longstanding friendship with Kristen Mills. A true friend, and present through so much of my graduate school years. Finally, but certainly not of least merit, I thank my family: my parents, who pushed me over the years and whose support was absolutely essential, and my brother Nathan whom I could commiserate with as we worked towards our degrees. ii TABLE OF CONTENTS ACKNOWLEDGEMENTS ................................................................................................ ii LIST OF FIGURES ......................................................................................................... viii LIST OF TABLES ........................................................................................................... xiv LIST OF ACRONYMS .................................................................................................... xv ABSTRACT .................................................................................................................... xvii CHAPTER 1 INTRODUCTION AND MOTIVATION .......................................................................... 1 1.1 Engine Research and Development .......................................................................... 1 1.2 Exhaust Emission Regulatory Legislation ................................................................ 1 1.3 Addressing New Emissions Standards...................................................................... 4 1.3.1 Advanced Combustion Strategies ...................................................................... 4 1.3.2 Implementation in Production Engines .............................................................. 6 1.4 Project Objective and Motivation ............................................................................. 7 1.5 Expansion of Published Research ............................................................................. 7 1.6 Overview of Dissertation .......................................................................................... 9 CHAPTER 2 BACKGROUND .............................................................................................................. 10 2.1 Summary ................................................................................................................. 10 2.2 Premixed Diesel Combustion – Historical Perspective .......................................... 10 2.2.1 Required Combustion Properties ..................................................................... 11 2.2.2 Achieving Low Temperature Combustion ....................................................... 11 2.2.3 Achieving Premixed Combustion .................................................................... 11 2.3 Diesel Fuel .............................................................................................................. 14 2.3.1 Diesel Fuel Chemical Composition ................................................................. 14 2.3.2 Principal Fuel Property - Ignitability ............................................................... 15 iii 2.3.3 Legislated Diesel Fuel Properties .................................................................... 17 2.4 Fuel Property Effect on Conventional Diesel Combustion ..................................... 20 2.4.1 Influence on Mixing Process and Ignition Delay ............................................ 20 2.4.2 Cetane Number Effect...................................................................................... 21 2.4.3 Effect of Aromatics .......................................................................................... 23 2.5 Fuel Effect on Premixed Diesel Combustion – Existing Literature ....................... 25 CHAPTER 3 EXPERIMENTAL METHODS........................................................................................ 28 3.1 Experimental Setup ................................................................................................. 28 3.1.1 Engine System ................................................................................................. 28 3.1.2 Engine Swirl Control ....................................................................................... 30 3.1.3 Fuel Injection System ...................................................................................... 30 3.1.4 Intake System ................................................................................................... 31 3.1.5 Exhaust System ................................................................................................ 31 3.1.6 Exhaust Gas Recirculation ............................................................................... 32 3.1.7 Engine Coolant System .................................................................................... 32 3.1.8 Lubrication System .......................................................................................... 33 3.1.9 Fuel System ...................................................................................................... 33 3.1.10 Exhaust Emissions Measurement .................................................................. 33 3.1.11 Data Acquisition ............................................................................................ 34 3.2 Principal Operating Condition Development.......................................................... 35 3.2.1 Derivation of Single-Cylinder Equivalent Condition ...................................... 36 3.2.2 Operating Condition Parameters ...................................................................... 37 3.3 Measurements ......................................................................................................... 37 3.3.1 Gaseous Emissions Indexes ............................................................................. 37 3.3.2 EGR Rate ......................................................................................................... 38 3.3.3 Particulate Emissions ....................................................................................... 38 3.3.4 Equivalence Ratio ............................................................................................ 39 3.3.5 Intake Oxygen Concentration .......................................................................... 40 3.3.6 Combustion Efficiency .................................................................................... 40 3.3.7 Noise ................................................................................................................ 41 3.4 Heat Release Analysis Based Parameters ............................................................... 41 3.4.1 Heat Release Details ........................................................................................ 41 iv 3.4.2 Ignition Delay .................................................................................................. 42 3.4.3 Combustion Phasing ........................................................................................ 44 3.5 Determination of Experimental Uncertainty ........................................................... 45 3.5.1 Combining Uncertainties and Uncertainty Propagation .................................. 46 3.5.2 Operating Range .............................................................................................. 47 3.5.3 Soot Emissions ................................................................................................. 47 3.5.4 Gaseous Emissions Indices .............................................................................. 48 3.5.5 Other Emissions-based Calculated Parameters ................................................ 49 3.5.6 Ignition Delay .................................................................................................. 49 3.5.7 Combustion Phasing ........................................................................................ 50 3.5.8 Temperatures...................................................................................................