Investigation of Micro-Pilot Fuel Ignition System for Large Bore Natural Gas Engines
This investigation assesses the benefits of retrofitting a diesel micro-pilot ignition system on low BMEP natural gas pipeline engines. Micro-pilot ignition systems hold promise for being highly reliable, thus maintaining pipeline throughput for prolonged operation, and without a fuel or emissions penalty. The pilot fuel injectors are mounted through an adaptor in one of the spark plug holes in a set of dual-spark plug heads. A high pressure, common-rail, diesel fuel delivery system is employed and customizable power electronics control the current signal to the pilot injectors. Pilot fuel is supplied by a variable displacement, high pressure pump that is driven with an electric motor. Software is developed that interfaces with the pump and controls and monitors the fuel rail pressure. The micro-pilot ignition system program is a 3-year research effort, and Year 2 results will be presented. This research builds upon the first year's efforts, which demonstrated the feasibility of retrofit micro-pilot injection. The demonstration system was optimized using redesigned pilot injectors and evaluated using a design of experiments method. Three independent variables: pilot ignition timing, pilot fuel quantity, and pilot fuel rail pressure, are manipulated in order to determine this. Also, overall system design criteria and components specifications were refined. Year 3 involves the field demonstration of the system at two operating compressor stations, and current progress will be reported.