PR179-21205-R01 Methane Abatement from LB NG 2-Stroke Cycle Engines Through In-Cylinder Modifications

There are over 7000 of large bore integral compressor engines distributed along the interstate and intrastate natural gas pipelines in the United States for gas compression. Methane emissions from large bore engines stem primarily from poor combustion efficiency. This study aims to improve the combustion efficiency of these engines, by reducing the amount of unburned methane that can escape through the crankcase vent and the exhaust gas emissions. Two broad approaches are taken to achieve this objective using experimental testing and computational studies: hydrogen blending and late cycle high pressure fuel injection (HPFI). Multiple sweeps of natural gas/hydrogen blends are presented on the Cooper-Bessemer GMV-4TF utilizing two different configurations, (1) mechanical gas admission valve (MGAV) fuel injection with open chamber ignition and high-pressure fuel injection (HPFI) with pre-combustion chamber (PCC) ignition. Late-cycle high pressure fuel injection is evaluated by independently varying fuel injection timing at different injection pressures. Fuel/air mixing, methane blowby, and ring pack (crevice volume) methane emissions are quantified and used for performance assessment.