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UNCLASSIFIED ADA TACTICAL/COMBAT ENGINES CETANE WINDOW EVALUATION INTERIM REPORT TFLRF No. 436 by Gregory A. Hansen, Douglas Yost, & Edwin A. Frame U.S. Army TARDEC Fuels and Lubricants Research Facility ® ® Southwest Research Institute (SwRI ) San Antonio, TX for Patsy Muzzell U.S. Army TARDEC Force Projection Technologies Warren, Michigan Contract No. W56HZV-09-C-0100 (WD0004 – Tasks VIII & XIII) UNCLASSIFIED: Distribution Statement A. Approved for public release January 2013 UNCLASSIFIED UNCLASSIFIED Disclaimers Reference herein to any specific commercial company, product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the Department of the Army (DoA). The opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government or the DoA, and shall not be used for advertising or product endorsement purposes. Contracted Author As the author(s) is(are) not a Government employee(s), this document was only reviewed for export controls, and improper Army association or emblem usage considerations. All other legal considerations are the responsibility of the author and his/her/their employer(s). DTIC Availability Notice Qualified requestors may obtain copies of this report from the Defense Technical Information Center, Attn: DTIC-OCC, 8725 John J. Kingman Road, Suite 0944, Fort Belvoir, Virginia 22060- 6218 Disposition Instructions Destroy this report when no longer needed. Do not return it to the originator. UNCLASSIFIED UNCLASSIFIED TACTICAL/COMBAT ENGINES CETANE WINDOW EVALUATION INTERIM REPORT TFLRF No. 436 by Gregory A. Hansen, Douglas Yost, & Edwin A. Frame U.S. Army TARDEC Fuels and Lubricants Research Facility ® ® Southwest Research Institute (SwRI ) San Antonio, TX for Patsy Muzzell U.S. Army TARDEC Force Projection Technologies Warren, Michigan Contract No. W56HZV-09-C-0100 (WD0004 – Tasks VIII & XIII) ® SwRI Project No. 08.14734.04 UNCLASSIFIED: Distribution Statement A. Approved for public release January 2013 Approved by: Gary B. Bessee, Director U.S. Army TARDEC Fuels and Lubricants Research Facility (SwRI®) UNCLASSIFIED UNCLASSIFIED Form Approved REPORT DOCUMENTATION PAGE OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202- 4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) 31-01-2013 Interim Report April 2009 – January 2013 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W56HZV-09-C-0100 Tactical/Combat Engines Cetane Window Evaluation 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER SwRI 08.14734.04.320 & 350 Hansen, Gregory; Yost, Douglas; Frame, Edwin 5e. TASK NUMBER WD 0004 (Tasks VIII & XIII) 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER U.S. Army TARDEC Fuels and Lubricants Research Facility (SwRI®) TFLRF No. 436 Southwest Research Institute® P.O. Drawer 28510 San Antonio, TX 78228-0510 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) U.S. Army RDECOM U.S. Army TARDEC 11. SPONSOR/MONITOR’S REPORT Force Projection Technologies NUMBER(S) Warren, MI 48397-5000 12. DISTRIBUTION / AVAILABILITY STATEMENT UNCLASSIFIED: Dist A Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The European Stationary Cycle 13 Mode test was performed on a turbocharged inline 6-cylinder diesel engine and a 6.5L turbocharged V-8 diesel engine for every test fuel. Full engine instrumentation was employed including in-cylinder pressure measurements. Engine operating parameters and exhaust gas emissions were recorded. For each engine, clear trends for cetane-related performance were observed in the exhaust gas emissions, and potential cetane-related problems were identified at various conditions. Other fuel properties such as density, and bulk modulus also impacted engine performance. For each engine tested, an appropriate cetane window was identified. 15. SUBJECT TERMS Cetane Number, Synthetic Fuel, JP-8, diesel engine, combustion 16. SECURITY CLASSIFICATION OF: 17. LIMITATION 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON OF ABSTRACT OF PAGES a. REPORT b. ABSTRACT c. THIS PAGE 19b. TELEPHONE NUMBER (include area code) Unclassified Unclassified Unclassified Unclassified 88 Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 UNCLASSIFIED iv UNCLASSIFIED EXECUTIVE SUMMARY A fuel’s cetane number is very important for the operation of modern diesel engines. The U.S. military currently uses petroleum-based jet fuels in diesel engine-powered ground vehicles and is studying the use of alternative jet fuels obtained from a variety of sources. Currently there is no cetane number specification for jet fuels as this property holds no significance for turbine engine operation. Therefore, it is of interest to identify a window, or range, of cetane number which would be acceptable to ensure the reliable operation of diesel engine-powered military ground vehicles. The TARDEC Fuels and Lubricants Research Facility located at Southwest Research Institute identified 15 candidate fuels with cetane numbers ranging from 28 to 78. The fuels selected include diesel, jet, and various synthetic fuels. A cetane improver was used to fill out range. The European Stationary Cycle 13 Mode test was performed on a turbocharged inline 6-cylinder diesel engine and a 6.5L turbocharged V-8 diesel engine for every test fuel. Full engine instrumentation was employed including in-cylinder pressure measurements. Engine operating parameters and exhaust gas emissions were recorded. For each engine, clear trends for cetane-related performance were observed in the exhaust gas emissions, and potential cetane-related problems were identified at various conditions. Other fuel properties such as density, and bulk modulus also impacted engine performance. For each engine tested, an appropriate cetane window was identified, as were other fuel properties that should also be of interest. Further work on this topic should include other major diesel engine families. The results from this work should help the military integrate emerging and future fuels into the supply chain. UNCLASSIFIED v UNCLASSIFIED FOREWORD/ACKNOWLEDGMENTS The U.S. Army TARDEC Fuel and Lubricants Research Facility (TFLRF) located at Southwest Research Institute (SwRI), San Antonio, Texas, performed this work during the period April 2009 through January 2013 under Contract No. W56HZV-09-C-0100. The U.S. Army Tank Automotive RD&E Center, Force Projection Technologies, Warren, Michigan administered the project. Mr. Eric Sattler served as the TARDEC contracting officer’s technical representative. Ms. Patsy Muzzell of TARDEC served as project technical monitor. The authors would like to acknowledge the contribution of the TFLRF technical support staff along with the administrative and report-processing support provided by Dianna Barrera. UNCLASSIFIED vi UNCLASSIFIED TABLE OF CONTENTS Section Page EXECUTIVE SUMMARY ............................................................................................................ v FOREWORD/ACKNOWLEDGMENTS ...................................................................................... vi LIST OF TABLES ....................................................................................................................... viii LIST OF FIGURES ....................................................................................................................... ix ACRONYMS AND ABBREVIATIONS ....................................................................................... x 1.0 HISTORICAL BACKGROUND .......................................................................................... 1 2.0 INTRODUCTION ................................................................................................................. 2 3.0 EQUIPMENT ........................................................................................................................ 2 3.1 MAINTENANCE ......................................................................................................... 2 4.0 EUROPEAN STATIONARY CYCLE OPERATING SYSTEM ......................................... 3 4.1 LOAD STEPS ............................................................................................................... 3 4.2 CONTROLS ................................................................................................................. 4 5.0 INSTRUMENTATION ......................................................................................................... 5 5.1 ENGINE SETUP .......................................................................................................... 5 5.2 HIGH SPEED PRESSURE TRANSDUCERS - GEP 6.5T & CAT C7 ...................... 7 5.3 INSTRUMENTED INJECTORS – CAT C7 & GEP 6.5T........................................ 12 6.0 FUEL PROPERTIES ........................................................................................................... 16 7.0 PEAK POWER .................................................................................................................... 20 8.0 EMISSIONS ........................................................................................................................ 24 9.0 IGNITION DELAY ............................................................................................................. 26 10.0 COMBUSTION CHARACTERISTICS .............................................................................. 27 10.1 CAT C7 ENGINE ....................................................................................................... 27 10.2 GEP 6.5T ENGINE ..................................................................................................... 32 11.0 FUEL PROPERTY EFFECTS ON PERFORMANCE ....................................................... 37 11.1 CAT C7 ENGINE RESPONSE TO FUEL VARIABLES ......................................... 40 11.1.1 CAT C7 Emissions, Peak Power, and Idle ..................................................... 40 11.1.2 CAT C7 Engine ESC A-Speed Modal Response to Fuel Variables ............... 43 11.1.3 CAT C7 Engine ESC B-Speed Modal Response to Fuel Variables ............... 46 11.1.4 CAT C7 Engine ESC C-Speed Modal Response to Fuel Variables ............... 49 11.2 GENERAL ENGINE PRODUCTS (GEP) 6.5T ENGINE RESPONSE TO FUEL VARIABLES ....................................................................................................................... 52 11.2.1 GEP 6.5T Emissions, Peak Power, and Idle ................................................... 52 11.2.2 GEP 6.5T Engine ESC A-Speed Modal Response to Fuel Variables............. 55 11.2.3 GEP 6.5T Engine ESC B-Speed Modal Response to Fuel Variables ............. 58 11.2.4 GEP 6.5T Engine ESC C-Speed Modal Response to Fuel Variables ............. 61 11.3 ENGINE COMPARISONS ........................................................................................ 64 12.0 OTHER OBSERVATIONS ................................................................................................. 65 12.1 BULK MODULUS – GEP 6.5T ISSUES................................................................... 65 12.2 GEP 6.5T IDLE QUALITY ISSUES ......................................................................... 68 12.3 EFFECT OF FUEL TYPE ON C7 ECM CONTROL ................................................ 70 13.0 SUMMARY ......................................................................................................................... 74 APPENDIX–A Fuel Properties UNCLASSIFIED vii UNCLASSIFIED LIST OF TABLES Table Page Table 1 . CAT C7 Engine Operating Conditions ........................................................................... 4 Table 2 . GEP 6.5T Engine Operating Conditions......................................................................... 5 Table 3 . Fuel Descriptions with Cetane Number ........................................................................ 16 Table 4 . CAT C7 Peak Power and NOx ..................................................................................... 27 Table 5 . GEP 6.5T Cetane Number and Peak Power ................................................................. 32 Table 6 . GEP 6.5T Physical Transport Delay from Pre to Main Chamber ................................ 34 Table 7 . Fuel Property Cross Correlation Table ......................................................................... 39 Table 8 . Fuel Property effects on CAT C7 Weighted Average Emissions, Peak Power, and Mode 1 Combustion .................................................................................................... 42 Table 9 . CAT C7 European Stationary Cycle A-Speed fuel property effects on Modal Combustion Variables ................................................................................................. 45 Table 10 . CAT C7 European Stationary Cycle B-Speed fuel property effects on Modal Combustion Variables ................................................................................................. 48 Table 11 . CAT C7 European Stationary Cycle C-Speed fuel property effects on Modal Combustion Variables ................................................................................................. 51 Table 12 . Fuel Property effects on GEP 6.5T Weighted Average Emissions, Peak Power, and Mode 1 Combustion ............................................................................................. 54 Table 13 . GEP 6.5T European Stationary Cycle A-Speed fuel property effects on Modal Combustion Variables ................................................................................................. 57 Table 14 . GEP 6.5T European Stationary Cycle B-Speed fuel property effects on Modal Combustion Variables ................................................................................................. 60 Table 15 . GEP 6.5T European Stationary Cycle C-Speed fuel property effects on Modal Combustion Variables ................................................................................................. 63 UNCLASSIFIED viii UNCLASSIFIED LIST OF FIGURES Figure Page Figure 1. Historical Energy Density of JP-8 and Various Alternative Fuels vs. Cetane Index ............................................................................................................................. 1 Figure 2. ESC 13 Mode Cycle Description .................................................................................. 3 Figure 3. Horiba MEXA 1600D Emissions Bench ...................................................................... 6 Figure 4. Injection Line Pressure Transducer (GEP 6.5T) ........................................................... 7 Figure 5. GEP 6.5T Cylinder Pressure Transducers and Instrumented Injector .......................... 8 Figure 6. GEP 6.5T Head Cut Away with Main Chamber Pressure Transducer Location Indicated ........................................................................................................................ 9 Figure 7. CAT C7 Pressure Transducer Adaptor Sleeve ............................................................ 10 Figure 8. CAT C7 Adaptor Sleeve Location .............................................................................. 11 Figure 9. Fully Disassembled CAT C7 HEUI-B Injector .......................................................... 12 Figure 10. CAT C7 Comparison of Needle Lift and Coil Current with HRR Overlay................ 13 Figure 11. CAT C7 Verification of Oil Leaking in Instrumented HEUI-B Injector .................... 14 Figure 12. GEP 6.5T ESC Mode 7 Injection Pressure and Needle Lift ....................................... 15 Figure 13. Fuel Distillation Characteristics .................................................................................. 17 Figure 14. Fuel Normalized Volumetric Energy Density ............................................................ 18 Figure 15. Comparison of Cetane Improved Fuels – WD004 vs WD017 ................................... 19 Figure 16. CAT C7 Peak Power vs. Cetane Number ................................................................... 20 Figure 17. CAT C7 Peak Power vs. Fuel Density ........................................................................ 21 Figure 18. GEP 6.5T Peak Power vs. Cetane Number ................................................................. 22 Figure 19. GEP 6.5T Peak Power vs. Fuel Density ..................................................................... 23 Figure 20. CAT C7 ESC Emissions Results ................................................................................ 24 Figure 21. GEP 6.5T ESC Emissions Results .............................................................................. 25 Figure 22. CAT C7 and GEP 6.5T Ignition Delay Comparison .................................................. 26 Figure 23. CAT C7 ESC Mode 10 HRR Comparison ................................................................. 28 Figure 24. CAT C7 ESC Mode 2 HRR Comparison ................................................................... 29 Figure 25. CAT C7 ESC Mode 1 HRR Comparison ................................................................... 30 Figure 26. CAT C7 ESC Mode 11 HRR Comparison ................................................................. 31 Figure 27. GEP 6.5T ESC Mode 6 -- BSFC vs. Cetane Number ................................................. 32 Figure 28. GEP 6.5T ESC Mode 5 HRR Comparison ................................................................. 33 Figure 29. GEP 6.5T ESC Mode 1 with Jet A Fuel ..................................................................... 35 Figure 30. GEP 6.5T ESC Mode 2 with Jet A Fuel ..................................................................... 36 Figure 31. GEP 6.5T Injection Timing vs. Bulk Modulus ........................................................... 65 Figure 32. Fuel Bulk Modulus vs. Energy Density ...................................................................... 66 Figure 33. GEP 6.5T ESC Mode 1 Injection Line Ringing Frequency........................................ 67 Figure 34. GEP 6.5T ESC Mode 1 MFB ..................................................................................... 68 Figure 35. GEP 6.5T ESC Mode 1 Needle Lift............................................................................ 69 Figure 36. CAT C7 ESC Mode 6 Fuel Hot Swap Forward .......................................................... 71 Figure 37. CAT C7 ESC Mode 6 Fuel Hot Swap Reverse .......................................................... 72 Figure 38. CAT C7 ESC Mode 12 Fuel Hot Swap Forward ........................................................ 73 Figure 39. CAT C7 ESC Mode 12 Fuel Hot Swap Reverse ........................................................ 73 UNCLASSIFIED ix UNCLASSIFIED ACRONYMS AND ABBREVIATIONS 2-EHN 2-Ethylhexyl Nitrate 50MFB 50-Percent Mass Fraction Burned ATDC After Top Dead Center BM Bulk Modulus BMEP Brake Mean Effective Pressure BSFC Brake Specific Fuel Consumption CA50 Crank Angle 50 Timing (or the crank angle at which the 50% MFB occurs) CAD Crank Angle Degrees CN Cetane Number CO Carbon Monoxide DCN Derived Cetane Number ESC European Stationary Cycle FTDSA Fischer Tropsch Diesel from South Africa FTDSH Fischer Tropsch Diesel from Shell HC Hydrocarbon H/C Hydrogen Atom to Carbon Atom Ratio HCCI Homogeneous Charge Compression Ignition HRR Heat Release Rate IVC Intake Valve Close J/CAD Joules per Crank Angle Degree KVis Kinematic Viscosity LPP Location of Peak Pressure MFB Mass Fraction Burned MHRR Maximum Heat Release Rate NOx Oxides of Nitrogen (consisting of NO and NO2) PQIS Petroleum Quality Information System RPM Revolutions Per Minute SOI Start of Injection TDC Top Dead Center UNCLASSIFIED x