Laser, Spark, and Self lgnition of Natural Gas In A Rapid Compression Machine

a rapid compression machine was designed and built to simulate in-cylinder conditions of a modern stationary natural gas fried reciprocating engine tests were performed to determine the ignition boundaries using a laser, a conventional Capacitance Discharge ignition (CDI), and no ignition delay, and minimum required laser energy to ignite a mixture. It was observed that CDI is unable to ignite mixtures leaner than Φ≈0.6. Additionally, ignition is significantly dependent upon pressure using a CDI ignition conversely, laser ignition extends the lean limit of methane-air mixtures all the way to the combustion limit of Φ≈0.5 regardless of pressure. Scans of minimum required energies for successful ignition (MRE) were also performed. ignition delay and pressure rise were also investigated for an initial pressure of 1.5 Bar. It was observed that faster combustion retes and smaller ignition delays occur for laser ignition as compared to a CDI (spark) ignition for 0.6≤Φ≤0.8 and also for Φ=10. However for 0.8≤Φ≤0.9 a reversal of the sforementioned trends was observed.