PR457-21204-R01 Evaluation of New Ignition Concepts on Large Bore NG Engines for Methane Emissions

Pre-combustion chambers are frequently used in large-bore natural gas engines to improve ignition repeatability and combustion quality while simultaneously enabling substantial engine emission reductions. Specifically, prechambers reduce the carbon footprint of natural gas pipeline engines, and by extension, reduce greenhouse gas emissions from pipeline compressor stations. A study to provide an initial screening of a number of new ignition techniques in a Cooper-Bessemer GMV two-stroke lean burn natural gas engine was conducted using Converge CFD software in order to guide original equipment manufacturers (OEMs) and technology providers in improving combustion processes and reducing methane emissions. Various designs for multi-nozzle and directional prechambers were created and tested for the best performance against an OEM design. Additionally, the pre-ignition introduction of radical species was investigated by implementing a radical-generating prechamber to seed the main combustion chamber with species before ignition by the primary prechamber. Finally, the efficacy of a plasma fuel reforming system tuned to target and fragment methane in the main chamber fuel stream was studied. This study provides an initial numerical screening of new ignition techniques to determine which, if any, techniques are promising for reducing methane emissions through ignition system improvements and should be further examined with on-engine experimental evaluation.