Executive Summary

Skilled research engineer with a doctorate in aerospace engineering and 10+ years of experimental combustion and fluid mechanics experience. Extensive knowledge of advanced combustion systems and complex fluid phenomena leveraged to perform high-value energy efficiency research. Research activities led to 23 peer reviewed journal publications and numerous invited talks. Project management, communication, and interpersonal skills effectively employed to achieve multiple professional objectives.

Professional Experience

Principal Member of the Technical Staff (Jan 2014 – Present)

Engine Combustion Department, Sandia National Laboratories, Livermore, CA

Principal investigator of the Gasoline Combustion Fundamentals (GCF) lab where active research of in-cylinder flow, mixing, and combustion processes is performed for light-duty gasoline engines. Responsibilities include supervision of a postdoctoral research associate, a technologist, and numerous short-term visitors. GCF research is coordinated with activities by other national laboratories, automotive OEMs, universities, and startups. Current research explores fundamental aspects of advanced ignition systems that enable clean and efficient engine combustion strategies. There is particular focus on low-temperature plasma (LTP) systems that feature high-energy streamers created by high-voltage electric pulses, with volumetric ignition due to a combination of fast-gas heating and active radical formation.

  • A custom optically-accessible spark calorimeter has been developed to investigate LTP discharge details at relevant in-cylinder engine conditions.
  • Gas heating measured via calorimetry with key flame radicals (e.g., atomic oxygen) measured by optical emission spectroscopy and laser-induced fluorescence (LIF).
  • LTP ignition is examined in an optically-accessible, single-cylinder research engine, where in situ laser-based spectroscopic measurements complement traditional engine performance metrics.

A recently completed project examined the use of in-cylinder generated fuel reformate—generated by an auxiliary recompression of engine exhaust and added fuel—to improve the controllability for high-efficiency gasoline compression ignition concepts at low loads where combustion stability is problematic.

  • Reformate was collected via a custom sampling valve, with speciation by gas chromatography or a novel photoionization mass spectrometry diagnostic.
  • The impact of reformate addition on engine performance was evaluated. Unexpectedly, for a fixed reformate quantity the lowest fueling rates (i.e., leanest mixture) led to the fastest ignition.
  • Faster ignition was attributed to a combination of increased compression temperatures (from less fuel charge cooling and higher specific heat ratios) along with improved chemical reactivity.
  • A modeling basis was developed to enable optimization of relevant processes.

Senior Member of the Technical Staff (Apr 2010 – Jan 2014)

Hydrogen and Combustion Technologies Department, Sandia National Laboratories, Livermore, CA

Principal Investigator that explored dispersion, ignition, and combustion phenomena for flammable gas releases using non-intrusive laser diagnostics (e.g., particle image velocimetry, Rayleigh scatter imaging), with results used to inform the safe development of hydrogen and natural gas infrastructure. High-fidelity laboratory measurements were complemented by large-scale experiments at outdoor test facilities designed to replicate relevant accident scenarios. Experimental results were used to develop/validate physical behavior models that were then integrated into a heuristic Hydrogen Risk Assessment Model (HyRAM) toolkit. HyRAM was designed to perform parametric scenario analyses that could identify optimal system configurations based on component failure characteristics, operation profiles, and modeled hazards for unintended release scenarios. Responsibilities included the supervision of a postdoctoral research associate and technologist. Research activities were performed in conjunction with partners at other national labs, industrial gas suppliers, and international research organizations.

Additional projects included:

  • Raman spectroscopy diagnostic development that improved the selective detection of hydrocarbon flame intermediates
  • Technology transfer of an in situ carbon monoxide measurement LIF diagnostic to General Electric Global Research for gas turbine research

Postdoctoral Research Engineer (May 2007 – Apr 2010)

Engine Combustion Department, Sandia National Laboratories, Livermore, CA

Research associate that used state-of-the-art optical and laser-based diagnostic capabilities to investigate complex, reacting in-cylinder flows for automotive diesel engines. Primary research activities involved identifying and understanding dominant physical and chemical processes responsible for CO and unburned hydrocarbon emissions from clean-diesel combustion strategies. The objective was achieved through the use of advancing LIF and particle image velocimetry diagnostics used to probe relevant processes. Results were used to benchmark and improve predictive engine combustion simulations.

An additional responsibility was to implement and supervise independent research projects with short-term university visitors. The position required regular publication of results, participation in program development activities, and collaboration with leading researchers from industry, universities, and other technical institutions.

Awards and Honors

Texas A&M Outstanding Early Professional Achievement Award                                                                            2017

U.S. DRIVE Technical Highlight                                                                                                                                                    2016

Texas A&M Outstanding Young Aerospace Engineer Award                                                                                      2016

SAE Powertrain, Fuels & Lubricants Meeting Best Paper Award                                                                              2015

Sandia National Laboratories Employee Recognition Award                                                                                     2012

Sandia Postdoc Professional Development Program Staff Lead                                                              2010 – 2016

SAE Meyers Award for Outstanding Student Paper                                                                                                        2009

Montgomery GI Bill                                                                                                                                                          2001 – 2006

Southern Regional Education Board Fellowship                                                                                              2001 – 2003

Distinguished Honor Graduate, US Army Primary Leadership Development Course                                  2000

Skills

Experimental: engine combustion, turbulent flames, low-speed/supersonic wind tunnel testing, optics, high-energy tunable lasers, intensified/high-speed cameras, schlieren/shadowgraph photography, particle image velocimetry, laser-induced fluorescence, Raman spectroscopy, Rayleigh scatter, gas analyzers, gas chromatography, mass spectrometry, calorimetry

Programming: MATLAB, Python, CHEMKIN Pro, SolidWorks, Adobe Illustrator, MS Office

Education

Ph.D. Aerospace Engineering                                                                                                                                       December 2006

Texas A&M University, College Station, Texas                                                                                                            3.83 GPA

Advisor: Dr. Rodney Bowersox, Professor

Dissertation: Supersonic Turbulent Boundary Layers with Periodic Mechanical Non-Equilibrium

B.S. Mathematics                                                                                                                                                                December 2000

Fayetteville State University, Fayetteville, North Carolina                                          Magna Cum Laude, 4.0 GPA

Academic Outreach

Organizations: American Society of Mechanical Engineers (ASME), Society of Automotive Engineers (SAE)

Academic Advisory Board: Texas A&M University Department of Aerospace Engineering

Technical Reviewer: SAE, ASME, Combust. Inst., Int J Hydrogen Energy, Int J Engine Research, Aero. Sci. Tech., AIAA J., DOE SBIR Grants

Technical Presentations and Publications

Refereed Journal Articles

  1. Wolk B, Ekoto I, “Calorimetry and Imaging of Plasma Produced by a Pulsed Nanosecond Discharge Igniter in EGR Gases at Engine-Relevant Densities,” SAE Int J Engines, (in press).
  2. Ekoto I, Wolk B, Northrop, W, “Full-Cycle Energy Analysis of Low-Load Low-Temperature Gasoline Combustion with Auxiliary-Fueled Negative Valve Overlap,” SAE Int J Engines, (in press).
  3. Li X, Christopher DM, Hecht ES, Ekoto IW, “Comparison of two-layer model for hydrogen and helium jets with notional nozzle model predictions and experimental data for pressures up to 35 MPa,” Int J Hydrogen Energy, doi: http://dx.doi.org/10.1016/j.ijhydene.2016.05.214.
  4. San Marchi C, Hecht ES, Ekoto IW, Groth KM, LaFleur C, Somerday BP, et al., “Overview of the DOE hydrogen safety, codes and standards program, part 3: Advances in research and development to enhance the scientific basis for hydrogen regulations, codes and standards,” Int J Hydrogen Energy, doi: http://dx.doi.org/10.1016/j.ijhydene.2016.07.014.
  5. Wolk B, Ekoto I, Northrop WF, Moshammer K, Hansen N, “Detailed speciation and reactivity characterization of fuel-specific in-cylinder reforming products and the associated impact on engine performance,” Fuel, 185:348-61, 2016, doi: 10.1016/j.fuel.2016.07.103.
  6. Wolk B, Ekoto I, Northrop W, “Investigation of Fuel Effects on In-Cylinder Reforming Chemistry Using Gas Chromatography,” SAE Int J Engines, 9(2):964-978, 2016, doi: 10.4271/2016-01-0753.
  7. Ekoto I, Skeen S, Steeper RR, Hansen N, “Detailed Characterization of Negative Valve Overlap Chemistry by Photoionization Mass Spectroscopy,” SAE Int J Engines, 9 (1) 2016:26-38, doi: 10.4271/2015-01-1804.
  8. Ekoto I, Peterson B, Szybist J, Northrop W, “Analysis of Thermal and Chemical Effects on Negative Valve Overlap Period Energy Recovery for Low-Temperature Gasoline Combustion,” SAE Int J Engines, 8 (5) 2015:2227-39, doi: 10.4271/2015-24-2451.
  9. Peterson B, Ekoto I, Northrop W, “Investigation of Negative Valve Overlap Reforming Products Using Gas Sampling and Single-Zone Modeling,” SAE Int J Engines, 8 (2):747-57, 2015, doi: 10.4271/2015-01-0818.
  10. Fuest F, Barlow RS, Magnotti G, Dreizler A, Ekoto IW, Sutton JA, “Quantitative acetylene measurements in laminar and turbulent flames using 1D Raman/Rayleigh scattering,” Comb Flame, 162 (5):2248-55, 2015, doi: 10.1016/j.combustflame.2015.01.021.
  11. Ruggles AJ, Ekoto IW, “Experimental investigation of nozzle aspect ratio effects on underexpanded hydrogen jet release characteristics,” Int J Hydrogen Energy, 39 (35):20331-8, 2014, doi: http://dx.doi.org/10.1016/j.ijhydene.2014.04.143.
  12. Ekoto IW, Ruggles AJ, Creitz LW, Li JX, “Updated jet flame radiation modeling with buoyancy corrections,” Int J Hydrogen Energy, 39 (35):20570-7, 2014, doi: http://dx.doi.org/10.1016/j.ijhydene.2014.03.235.
  13. Houf WG, Evans GH, Ekoto IW, Merilo EG, Groethe MA, “Hydrogen fuel-cell forklift vehicle releases in enclosed spaces,” Int J Hydrogen Energy, 38 (19):8179-89, 2013, doi: http://dx.doi.org/10.1016/j.ijhydene.2012.05.115.
  14. Ruggles AJ, Ekoto IW, “Ignitability and mixing of underexpanded hydrogen jets,” Int J Hydrogen Energy, 37 (22):17549-60, 2012, doi: 0.1016/j.ijhydene.2012.03.063.
  15. Ekoto IW, Houf WG, Evans GH, Merilo EG, Groethe MA, “Experimental investigation of hydrogen release and ignition from fuel cell powered forklifts in enclosed spaces,” Int J Hydrogen Energy, 37 (22):17446-56, 2012, doi: 0.1016/j.ijhydene.2012.03.161.
  16. Ekoto IW, Merilo EG, Dedrick DE, Groethe MA, “Performance-based testing for hydrogen leakage into passenger vehicle compartments,” Int J Hydrogen Energy, 36 (16):10169-78, 2011, doi: 10.1016/j.ijhydene.2011.05.007.
  17. Bozic G, Kook S, Ekoto IW, Petersen BR, Miles PC, “Optical Investigation Into Wall Wetting From Late-Cycle Post-Injections Used for Diesel Particulate Filter Regeneration,” J Eng Gas Turb Power, 133 (9) 2011, doi: 10.1115/1.4002917.
  18. Petersen B, Miles P, Ekoto I, “Optical Investigation of UHC and CO Sources from Biodiesel Blends in a Light-Duty Diesel Engine Operating in a Partially Premixed Combustion Regime,” SAE Int J Fuels and Lubricants, 3 (1):414-34, 2010.
  19. Petersen BR, Ekoto IW, Miles PC, “An Investigation into the Effects of Fuel Properties and Engine Load on UHC and CO Emissions from a Light-Duty Optical Diesel Engine Operating in a Partially Premixed Combustion Regime,” SAE Int J Engines, 3(2):38-55, 2010, doi: 10.4271/2010-01-1470.
  20. Ekoto IW, Colban WF, Miles PC, Park SW, Foster DE, Reitz RD, et al., “UHC and CO Emissions Sources from a Light-Duty Diesel Engine Undergoing Dilution-Controlled Low-Temperature Combustion,” SAE Int J Engines, 2(2):411-30, 2009.
  21. Koci CP, Ra Y, Krieger R, Andrie M, Foster DE, Siewert RM, Durrett, RP, Ekoto, I, Miles, P, “Detailed Unburned Hydrocarbon Investigations in a Highly-Dilute Diesel Low Temperature Combustion Regime,” SAE Int J Engines, 2(1):858-879, 2009, doi:10.4271/2009-01-0928.
  22. Ekoto IW, Colban WF, Miles PC, Park S, Foster DE, Reitz RD, “Sources of UHC Emissions from a Light-Duty Diesel Engine Operating in a Partially Premixed Combustion Regime,” SAE Int J Engines, 2(1):1265-1289, 2009, doi:10.4271/2009-01-1446.
  23. Ekoto IW, Bowersox RDW, Beutner T, Goss L, “Response of supersonic turbulent boundary layers to local and global mechanical distortions,” J Fluid Mech, 630:225-65, 2009, doi: 10.1017/S0022112009006752.
  24. Kim D, Ekoto I, Colban WF, Miles PC, “In-cylinder CO and UHC Imaging in a Light-Duty Diesel Engine during PPCI Low-Temperature Combustion,” SAE Int J Engines, 1 (1):933-56, 2008.
  25. Ekoto IW, Bowersox RDW, Beutner T, Goss L, “Supersonic boundary layers with periodic surface roughness,” AIAA J, 46 (2):486-97, 2008, doi: 0.2514/1.31729.

Presentations: international conferences, workshops, meetings, and *invited seminars

  1. *Ekoto I, “Tailoring charge reactivity using fuel reformate for gasoline compression ignition strategies”, 3rd International Flame Chemistry Workshop, Seoul, July 30, 2016.
  2. Kane S, Northrop W, Wolk B, Ekoto I, “Stochastic reactor model for predicting engine exhaust composition using experimental in-cylinder pressure data,” Spring Technical Meeting, Central States Section of the Combustion Institute, Knoxville TN, May 15-17, 2016.
  3. Wolk B, Ekoto I, “Calorimetry and Atomic Oxygen Planar Laser-Induced Fluorescence of Low-Temperature Plasma Discharges and Nanosecond Pulsed Discharges at Above-Atmospheric Pressures.” Proc 3rd International Conference on Ignition Systems for Gasoline Engines, Berlin, Germany, Nov 3-4, 2016.
  4. Ekoto I, Wolk B, Northrop W, Moshammer K, Hansen N, “Tailoring Charge Reactivity Using In-Cylinder Generated Reformate for Gasoline Compression Ignition Strategies,” International Combustion Engine Fall Technical Conference, Greenville, South Carolina, ASME ICEF2016-9458, 2016.
  5. Wolk B, Ekoto I, “Calorimetry and O-PLIF of Pulsed Nanosecond Discharges at Above-Atmospheric Pressures,” AEC Program Review Meeting, Livermore CA, Aug 15-18, 2016.
  6. Ekoto I, “Investigation of In-Cylinder Generated Reformate on Fuel Reactivity Characteristics,” AEC Program Review Meeting, Livermore CA, Feb 8-11, 2016.
  7. Wolk B, Ekoto I, “O-atom TALIF and Calorimetry of Nanosecond Pulsed Discharges at Above-Atmospheric Pressures,” AEC Program Review Meeting, Livermore CA, Feb 8-11, 2016.
  8. Ekoto IW, Ruggles AJ, Li X, Creitz LW, Updated Jet Flame Radiation Modeling with Corrections for Buoyancy. Proc International Conference on Hydrogen Safety 5, Brussels, Belgium, 2013.
  9. Ekoto IW, Aronsson U, Park SW, Coban WF, Andersson O, Foster DE, et al., “UHC and CO Emissions Sources from a Light-Duty Diesel Engine Undergoing Late-Injection Low-Temperature Combustion,” ASME Internal Combustion Engine Division Fall Technical Conference 2009, Proceedings:163-72, 2010.
  10. Aronsson, U., Andersson, O., Egnell, R., Miles, P.C., Ekoto, I.W., Influence of spray-target and squish height on sources of CO and UHC in a HSDI diesel engine during PPCI low-temperature combustion, SAE Technical Paper 2009-01-2810, 2009, doi:10.4271/2009-01-2810.
  11. Agarwal, G., Rediniotis, O.K., Ekoto, I., Application of active flow control technology in an unmanned aerial vehicle, 46th AIAA Aerospace Sciences Meeting and Exhibit, 2008-0282, 2008.

News Articles

  1. “A burning question: Sandia explores aggressive high-efficiency sparkplug-free gasoline auto engines”, Sandia Lab News, June 10, 2016 – multiple third party reprints.
  2. “Playing with fire”, Sandia Lab News, August 9, 2013.
  3. “Sandia research drives cleaner diesel engine design”, Sandia Lab News, September 12, 2008 – multiple third party reprints.

Professional References

Available upon request