STEADY STATE AND TRANSIENT EFFICIENCIES OF A FOUR CYLINDER DIRECT INJECTION DIESEL ENGINE FOR IMPLEMENTATION IN A HYBRID ELECTRIC VEHICLE A Thesis Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment of the Requirements for the Degree Masters of Science Charles Van Horn August, 2006 STEADY STATE AND TRANSIENT EFFICIENCIES OF A FOUR CYLINDER DIRECT INJECTION DIESEL ENGINE FOR IMPLEMENTATION IN A HYBRID ELECTRIC VEHICLE Charles Van Horn Thesis Approved: Accepted: Advisor Department Chair Dr. Scott Sawyer Dr. Celal Batur Faculty Reader Dean of the College Dr. Richard Gross Dr. George K. Haritos Faculty Reader Dean of the Graduate School Dr. Iqbal Husain Dr. George R. Newkome Date ii ABSTRACT The efficiencies of a four cylinder direct injection diesel engine have been investigated for the implementation in a hybrid electric vehicle (HEV). The engine was cycled through various operating points depending on the power and torque requirements for the HEV. The selected engine for the HEV is a 2005 Volkswagen 1.9L diesel engine. The 2005 Volkswagen 1.9L diesel engine was tested to develop the steady-state engine efficiencies and to evaluate the transient effects on these efficiencies. The peak torque and power curves were developed using a water brake dynamometer. Once these curves were obtained steady-state testing at various engine speeds and powers was conducted to determine engine efficiencies. Transient operation of the engine was also explored using partial throttle and variable throttle testing. The transient efficiency was compared to the steady-state efficiencies and showed a decrease from the steady- state values. Changes in engine efficiency and how it impacts vehicle fuel economy for steady speeds was also investigated. From the steady-state and transient testing suggested operating points for the engine implementation in the series-parallel HEV developed by The University of Akron were made. The steady-state efficiency data is useful for the determination of operation points for series, parallel, and spilt hybrid modes. Transient efficiencies behavior is useful during acceleration of the vehicle at both high and low speeds, as well as the transition between hybrid operating modes. Engine operating points for other applications may also be derived from this data. iii ACKNOWLEDGEMENTS I would like to thank the following people for their contributions to this project: - Dr. Sawyer, of the Mechanical Engineering Department at the University of Akron, for his guidance and help through this project as well as my graduate and undergraduate studies. - Dr. Gross, of the Mechanical Engineering Department at the University of Akron, for his guidance and development throughout this project. - Dr. Husain, of the Electrical Engineering Department at the University of Akron, for his leadership of the Challenge X program as well as his advisement on this paper. - Mr. Steve Gerbetz for his guidance and assistance with the dynamometer test setup and many other technical issues. - The entire University of Akron Challenge X Team, students, faculty, and staff for making this project a success and allowing me the opportunity to do this research. iv TABLE OF CONTENTS Page LIST OF TABLES vii LIST OF FIGURES viii CHAPTER I. INTRODUCTION 1 1.1 The University of Akron’s Hybrid Electric Vehicle 2 1.2 The University of Akron’s Hybrid Electric Vehicle Engine Selection 4 1.3 Engine Use in a Hybrid Electric Vehicle 9 1.4 Thesis Overview 9 II. BACKGROUND OF THE STUDY 11 2.1 Historical Survey of Previous Work in the Area 11 III. PEAK ENGINE POWER AND TORQUE CURVES 15 3.1 Test Setup 15 3.2 Acceleration Testing 18 IV. STEADY-STATE ENGINE EFFICIENCY 25 4.1 Test Setup 25 4.2 Steady-State Efficiency Calculations 28 4.3 Efficiency Uncertainty 40 4.4 Engine Operating Point 41 v V. TRANSIENT ENGINE EFFICENCY 44 5.1 Partial Throttle Testing 45 5.2 Varying Throttle Testing 50 VI. STEADY-STATE AND TRANSIENT ENGINE EFFICENCY COMPARISION 59 6.1 Steady-State and Partial Throttle Comparisons 59 6.2 Steady-State and Varied Throttle Comparisons 63 6.3 Steady-State and Transient Fuel Economy Comparison 66 VII. SUMMARY 68 REFERENCES 70 APPENDICIES 72 APPENDIX A. VOLKSWAGEN ENGINE DATA 73 APPENDIX B. EXPERIMENTAL TEST SETUP 74 APPENDIX C. CONTACT INFORMATION 77 vi LIST OF TABLES Table Page 4.1.1 Engine Test Speeds and Power 26 4.1.2 Testing Loads and Throttle Percentages for 1500 RPM 28 4.2.1 Steady-State Efficiency Repeatability for 10 HP at 1500 RPM 37 4.2.2 Steady-State Efficiency Repeatability for 20 HP at 2000 RPM 37 4.2.3 Steady-State Efficiencies 39 5.1.1 Engine Efficiency and Uncertainty at 30% of Full Throttle 46 5.1.2 Engine Efficiency and Uncertainty at 40% of Full Throttle 47 5.1.3 40% Partial Throttle Efficiency Repeatability 49 vii LIST OF FIGURES Figure Page 1.1 The University of Akron Hybrid Electric Vehicle Architecture 4 1.2 Internal Combustion Engine Piston-Cylinder 5 1.3 Pressure-Volume Diagram for Otto Cycle 6 1.4 Pressure-Volume Diagram for Ideal Diesel Cycle 7 3.1.1 Superflow SF-901 Dynamometer Engine Test Stand 16 3.1.2 Superflow SF-901 Dynamometer Console 17 3.1.3 VW 1.9L Engine Coupled to SF-901 Dynamometer 18 3.2.1 Power and Torque Curves for Test 1 20 3.2.2 STP Corrected Power and Torque Curves for Test 1 20 3.2.3 Targeted Engine Speed vs. Actual Speed for Test 1 21 3.2.4 Engine Power and Torque Curve Comparisons for the Four Tests 22 3.2.5 Total Averaged Engine Power and Torque Curves 23 3.2.6 STP Corrected Total Average Power and Torque Curves 24 4.1.1 Fuel Consumption for Engine Power of 10 HP at 1500 RPM and 50 HP at 2000 RPM 27 4.1.2 Temperature-Entropy Diagram for Carnot and Ideal Diesel Cycles 30 4.2.1 Steady-State Efficiency Points plotted for Engine Power 32 4.2.2 Steady-State Efficiency Points plotted for Engine Torque 32 viii 4.2.3 Best Efficiency Curve 33 4.2.4 Engine Efficiency for 10 HP at Various Engine Speeds 34 4.2.5 Engine Efficiency for 20 HP at Various Engine Speeds 34 4.2.6 Engine Efficiency for 30 HP at Various Engine Speeds 35 4.2.7 Engine Efficiency for 40 HP at Various Engine Speeds 35 4.2.8 Engine Efficiency for 50 HP at Various Engine Speeds 36 4.2.9 Engine Efficiency for 60 HP at Various Engine Speeds 36 4.3.1 Recorded Engine Power for 1500 RPM 40 4.4.1 Engine Operating Temperature 42 4.4.2 Engine Operating Temperature without Thermal Runaway and Overcooling 42 5.1.1 Engine Power and Efficiency at 30% of Full Throttle 48 5.1.2 Engine Power and Efficiency at 40% of Full Throttle 48 5.2.1 Throttle Voltage Input for Transient Testing at 1500 RPM 50 5.2.2 Throttle Voltage Input for Transient Testing at 1750 RPM 51 5.2.3 Torque Relationship for 2000 RPM 52 5.2.4 Transient Efficiencies for 1500 RPM 54 5.2.5 Transient Efficiencies for 1750 RPM 55 5.2.6 Transient Efficiencies for 2000 RPM 56 5.2.7 Transient Efficiencies for 2500 RPM 57 6.1.1 Steady-State and 30% Partial Throttle Comparison for 1500 RPM 60 6.1.2 Steady-State and 30% Partial Throttle Comparison for 2000 RPM 60 6.1.3 Steady-State and 30% Partial Throttle Comparison for 2500 RPM 61 6.1.4 Steady-State and 40% Partial Throttle Comparison for 1500 RPM 61 ix 6.1.5 Steady-State and 40% Partial Throttle Comparison for 2000 RPM 62 6.1.6 Steady-State and 40% Partial Throttle Comparison for 2500 RPM 62 6.2.1 Steady-State and Varied Throttle Efficiency Comparison for 1500 RPM 64 6.2.2 Steady-State and Varied Throttle Efficiency Comparison for 1750 RPM 64 6.2.3 Steady-State and Varied Throttle Efficiency Comparison for 2000 RPM 65 6.2.4 Steady-State and Varied Throttle Efficiency Comparison for 2500 RPM 65 B.1 Modified Transmission Bell Housing 74 B.2 Modified Flywheel 75 B.3 Custom Bell Housing Extension 75 B.4 Modified Innovations Engineering Torque Dampener 76 B.5 Innovations Engineering Dynamometer Adapter 76 x CHAPTER I INTRODUCTION The University of Akron was selected in 2004 to participate in Challenge X, a North American vehicle design competition. The Department of Energy and General Motors Company are the headline sponsors of Challenge X. The goal of the competition is to re-engineer a 2005 Chevrolet Equinox to minimize energy consumption and emissions while maintaining the utility of the vehicle. During the first part of the 2004 school year the team developed a hybrid electric vehicle (HEV) architecture for use in the competition. This development process included a literature review into current and future HEV designs, vehicle simulations using the Powertrain Simulation Analysis Toolkit (PSAT), Greenhouse Gasses Regulated Emissions and Energy Usage Toolkit (GREET), as well as hand calculated derivations. The team also used several marketing research surveys conducted by marketing research groups from The University of Akron’s College of Business Administration. This thesis presents the results of experiments conducted and analysis for the characterization of the internal combustion engine selected for use in The University of Akron’s HEV architecture. The engine was cycled through various operating points depending on the power and torque requirements for the HEV. The selected engine, a 2005 Volkswagen 1.9L diesel engine, was tested to develop the steady-state engine efficiencies and to evaluate the transient effects on these efficiencies.