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Heltzel, Robert
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In-Use Efficiency of Oxidation and Three-Way Catalysts Used in High-Horsepower Dual Fuel and Dedicated Natural Gas Engines

SAE International Journal of Engines

West Virginia University-Derek Johnson, Mahdi Darzi, Nigel Clark, Andrew Nix, Robert Heltzel
  • Journal Article
  • 03-11-03-0026
Published 2018-07-01 by SAE International in United States
Directional drilling rigs and hydraulic stimulation equipment typically use diesel fueled compression ignition (CI) engines. The majority of these engines are compliant with US Environmental Protection Agency (EPA) Tier 2 standards. To reduce fuel costs, industry is investing in dual fuel (DF) and dedicated natural gas (DNG) engines. DF engines use diesel oxidation catalysts (DOCs) to reduce CO and NMHC emissions. DNG engines may be either lean-burn or rich-burn and the latter uses three-way catalysts (TWC) to reduce CO, NMHC, and NOx emissions. This research presents in-use catalyst efficiency data collected pre- and post-catalyst for three DF engines and two DNG engines. One DF engine was converted earlier and did not include a DOC. Data were collected from six Tier 2 engines, two CI drilling engines converted to operate as DF, two CI hydraulic fracturing engines converted to operate as DF, and two SI DNG drilling engines. DF engines with DOCs were able to reduce CO and NMHC during DF operation by >90 and >50%, respectively. The DOCs did not reduce methane and NOx emissions.…
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Effects of EGR Addition onto Combustion Stability and Alternator Performance Variability of a Small, Single-Cylinder Diesel Generator

West Virginia University-Marc Cyrill Besch, April Nicole Covington, Derek Johnson, Nathan Fowler, Robert Heltzel
Published 2016-11-08 by SAE International in United States
The aim of this investigation was to improve understanding and quantify the impact of exhaust gas recirculation (EGR) as an emissions control measure onto cyclic variability of a small-bore, single-cylinder, diesel-fueled compression-ignition (CI) power generation unit. Of special interest were how cycle-to-cycle variations of the CI engine affect steady-state voltage deviations and frequency bandwidths. Furthermore, the study strived to elucidate the impact of EGR addition onto combustion parameters, as well as gaseous and particle phase emissions along with fuel consumption. The power generation unit was operated over five discrete steady-state test modes, representative of nominal 0, 25, 50, 75, and 100% engine load (i.e. 0-484kPa BMEP), by absorbing electrical power via a resistive load bank. The engine was equipped with a passive EGR system that directly connected the exhaust and intake runners through a small passage.Analysis of combustion parameters indicated no distinct increase in cycle-to-cycle variability observed during EGR addition to the intake charge. Moreover, absolute combustion parameters proved conclusive to published literature. COVIMEP was observed to slightly increase for low load modes, however, reduce…
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