An Investigation Into the Effects of Cng-Gasoline Operation on Ego Sensor Behavior and Deterioration
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NOTE TO USERS This reproduction is the best copy available. AN INVESTIGATION INTO THE EFFECTS OF CNG-GASOLINE OPERATION ON EGO SENSOR BEHAVIOR AND DETERIORATION June S. Dipchand A thesis submitted in confortnity with the requirements for the degree of Master of Applied Science Graduate Department of Mechanical and Industrial Engineering University of Toronto O Copyright by June Dipchand, 2001 National Library Bibliothèque nationale ofCamda du Canada Acguisitio~et seivices bibliographiques The author has granted a non- L'auteur a accordé une licence non exclusive licence dowing the exclusive permettant à la National Library of Canada to BiblioWque nationale du Canada de reproduce, loan, disûi'bue or sen reproduire, preter, distribuer ou copies of this thesis in microfom, venbe des copies de cette thèse sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation, AN INVESTIGATION INTO THE EFFECTS OF CNG-GASOLINE OPERATION ON EGO SENSOR BEHAVIOR AhFD DETEIUORAT'ION Master of App lied Sciences 2001 June Shanta Dipchand Graduate Depamnent of Mechanical and Industrial Engineering University of Toronto Engine tests were performed to examine exhaust gas oxygen (EGO) sensor behavior and deterioration when operated in a natural gas-gasoline bi-fuel environment. Baseline EGO sensor characteristics from gasoline only aging were compared to those of EGO sensors aged on nins with both compressed natural gas (CNG) and gasoline. EGO sensor voltage output, response time and cycling period are used to characterize sensor behavior. These parameters were monitored over the aging process and compared benveen the gasoline only and bi-fuel tests. Air to Fuel (A/F) ratio sweeps, steady state engine tests and transient fuel switching tests were carried out to monitor the aforementioned characteristics of the EGO sensors during the aging process. Resdts from this study show chat there is no significant difference in EGO sensor performance between sensors aged on gasoline only versus those aged under bi-fuel CNG- gasoline conditions after 160 hours of operation. I would like to thank Dr. Waiiace and Dr. McChan for their guidance and support throughout this project and for providing me with an opportuniry to work on such a wonderful project. 1 aiso would like to express my gratitude to Huuiu Jaaskelainen who graciously accepted and answered my dady bombvdment of questions with a sdeand patiently helped me out while 1 leamed the ropes. To Richard Ancimer, Haifeng Liu and Paul Salanki, please accept my appreciation for your suggestions, help and direction. To the machine shop "guys", thanks so much for all your hard work. To Theresa, Mary Rose, Dan and Sheila, 1 appreciate ail the work you did getting me all the parts 1 needed "yesterday". To Brad, Vito and Radiele who made the lab a great place to work, you are al in my deQ. Above d,1 would like to thank my mom and dad, Beny uid Cecii, and sisters, Anne, Christine, Rosemarie and Elizabeth for their love and support. Finally, 1wodd like to thank Trevor for his support, love and for believing in me. Table of Contents Abstract Acknowledgements Table of Contents List of Tables List of Figures Nomenclature Chapta 1: Introduction Chapta 2: Literature Review 2.1 NadGas As An Alternative Transponation Fuel 2.1.1 Availability and Con 2.1.2 Heaith and Environmentai Impacts 2.1.3 Vehide Compatability 2.1.4 Safety and Consumer Acceptance Oxygen Sensors 2.2.1 Theoiy of Operation 2.2.2 EGO Sensor Behavior 2.2.3 Deviations from Theoreticai EGO Sensor Behavior 2.3 Oxygen Sensor Operation in CNG Exhaust 2.3.1 Naturai Gas Exhaust Emissions E ffects on EGO Sensor Output 2.3.2 NadGas Exhaust Temperature Effects Chapta 3: Experimentai Equipment 3.1 Introduction and Equipment OveMew 3.2 Test Engine 3.3 Engine WirLig 3.4 Gasoline and Naturai Gas Fuel Systems 3.4.1 Gasohe Fuel System 3 A.2 NadGas Fuel System Coohg System Exhaust System 3.6.1 Test Section 3.6.2 Ernissions Sarnphg Lines 3.6.3 Partidate Sampiing Lhe 3h.4 Exhaust Gas Temperature Themiocouples 3.6.5 Heaters & Temperanue Controlers 3.6.6 Test Oxygen Sensors Dynamometer Ernissions Equipment 3.8.1 Exhaust Carbon Monoxide (CO) and Grbon Dioxîde (CO3 Mevuement 3.8.2 Exhaust Nivogen Chade (NO) and Chades of Nimgen (NOJ Measurement 3.8.3 Exhaua Oxygen (03Measurement 3.8.4 Exhaust Total Hydrocarbon (T'HC) Measurement 3.8.5 E-uhaust A/F hdeasurement 3.8.6 h/F False Signal Generator 3.9 Engine Control and Data Acquisition Chapter 4: Experimental Design & Procedure 4.1 Esperimentai Design Ove~ew 4.2 T'est Modes 4.2.1 Aging Tcst Mode 4.3.2 Emissions Test Mode 4.2.3 A/F Sweep Test Mode 4.2.4 Step Test Mode 4.2.5 Transient Fuel Switching Test Mode Test ScheduIes 4.3.1 Gasoline Oniy Test Schedules 4.3.2 CNG - Gasohe Switchuig Test Schedule Tcst Procedures Data Collection and Analysis 4.5.1 AgingTestModeDataAnalysis 4.5.2 Emissions (Step) Test Mode Data Analysis 4.5.3 A/F Sweep Data Analysis 4.5.4 Fuel Switching Test Mode Data Andysis Chapter 5: Results and Discussion 5.1 Introduction 5.2 Fuel Analysis Test Resulu 5.3 Aging Test Reds 5.4 Emissions Test Results 5.5 NFSweep Test Resdts 5.6 Sensor Steady State Operation Resdts 5.7 Transient Fuel Switching Test Resdts Chapter 6: Conclusions and Recornmendations 6.1 Condusions 6.2 Recornmendations References Appendix A: Fuel Analysis Reports Appendix B: Equipment Calibration Information Appendix C: Orighai Test EGO Sensor Data Sheets Appendix D: Dynamometes and Step AMA Cycle Derivations Appcndix E: Test Schedules Appendix F: Test kocedures Appendix G: LabView kograms AppendUr H: MatLab Data Andysis Programs Appendix C: Emissions Results Summvy and Graphs Appendix J: CANMET Patticulate Fiiter Analysis Report Appendix K: A/F Swcep Results Appendix L: A/F Sweep EGO Sensor Sîatistics vii List of Tables Table 2.1 Typical Nanual Gas Composition Table 2.2 Published Emissions Data for the Chevrolet Bi-Fuel 2.2 L Engine Table 3.1 List of Experirnental Equiprnent Shown in Figure 3.1 Table 3.2 Engine Speufications Table 3.3 Location and Details of Heater and Temperature Controllers Table 3.4 Cornputer Specifications Table 3.5 PCI-6071E National Instruments DAQ Board Speufications Table 4.1 Speed and Load Conditions for Emissions (Step AMA) Cycle Table 4.2 DAQ Board Andog Input Channel Lia Table 4.3 Data Acquisition Channels for Each Test Mode Table 5.1 Gasoline Analysis Resdts Table 5.2 Typical Naturai Gas Composition Table 5.3 H/C and Stoichiometric A/F for Gasoline and Natusal Gas Table 5.4 Averages of Emissions for Final Tests from Giisoline Only and Gasoline @-Fuel) Operation Table 5.5 Difference Li Emissions for Finai Emissions Cycles of Gasoline Only and Gasoline Bi-Fuel Tests Table 5.6 Emissions for First and Fina Gasolkie and CNG Bi-Fuel Tests viii Table 5.7 Difference in Emissions for Final Emissions Cydes of Gasoline and CNG Bi-Fuel Tests 5-26 Table 5.8 Su- of CANMET Partidate Filter Ana&s Resdts 5-32 Table 5.9 Difference in Maximum and Minimum First Derivative Between Fim and Final Tests from Gasohe Oniy and Gasoline (Bi-Fuel) Teshg 5-50 Table 5.10 Stabilization Theand Related Exhaust Gas Temperames for Gasoline and CNG Operation Table B.1 Load Ce11 Calibration Data Table B.2 NTK Calibration Record Table B.3 Themocouple Circuit Calibration Trial # 1 Data Table B.4 Thennocouple Cucuit Calibration Trial #2 Data Table B.5 Thermocouple Circuit Caiibration Trial #3 Data Table B.6 Thermocouple Circuit Caibration Trial #4 Data Table B.7 Thennocouple Circuit Calibration Trial #5 Data Table B.8 Themocouple OmJt Calibration Trial #6 Data Table B.9 Thennocouple Circuit Calibraton Trial Surnmary Data Table B.10 Thermocouple Circuit abration Check Data Table B. 11 Ernissions An* Details Table B. 12 Emissions Equipment Caiibration Cwe Information Table B. 13 Emissions Aaalyzers Calibration Gases Table B. 14 Ambient Conditions During Testing Table D.1 Engine Toque as a Function of Vehide Speed Caldations Table D.2 Acceleration Chart for 1998 2.4 L Chevrolet Cavalier D-6 Table D.3 Light Acceleration & Deceleration Times from O mph D-7 Table D.4 Light Accelemtion & Deceleration Tunes from 20 mph D-7 Table D.5 Dyno Sirnulateci AMA Cyde Lap Engine Speed, Torque and Time D-8 Table D.6 Step/Emissions AMA Cyde Engine Speed, Torque and Time D-13 Table E. 1 Gasohe Only Test Schedule E-2 Table E.2 Gasoline - CNG Bi-Fuel Test Schedule E-5 Table L. 1 Overail NTK A/F Ratio and Oxygen Sensor Statistics Over Gasohe Ody NFSweep Data Table Le2 Overail MX A/F Ratio and menSensor Statistics Over Gasohe (Bi-Fuel) MFSweep Data L-5 Table Le3 OwdNTK A/F Ratio and menSensor Statistics Over CNG (Bi-Fuel) A/F Sweep Data L-8 List of Figures Figure 1.1 2.2L Bi-fuel Chewolet Cavalier Setup Figure 2.1 Effect of F/A EqUvdence Ratio on Exhaust Gas Emissions from a Gasoiine Application Figure 2.2 Conversion Efficiency of Cataiytic Converters for (a) gasoline and (b) CNG Applications 2-10 Figure 2.3 GeneralGred 20,Sensor Operation 2-11 Figure 2.4 210, Sensor 2-12 Figure 2.5 Exarnple of EGO Sensor Mount in Exhaust Gas Manifold 2-14 Figure 2.6 Reactions at Platinum Electrodes 2-15 Figure 2.7 Lean Operation Correlation Between EGO Output and l/ln