Fundamental insights on ignition and combustion of natural gas in an active fueled pre-chamber spark-ignition system

Pre-chamber spark-ignition (PCSI), either fueled or non-fueled, is a leading concept with the potential to enable diesel-like efficiency in medium-duty (MD) and heavy-duty (HD) natural gas (NG) engines. However, inadequate scientific base simulation tools describe/predict underlying processes governing PCSI systems one of key barriers market penetration for MD/HD NG To this end, experiments were performed heavy-duty, optical, single-cylinder engine fitted an active module. The spatial temporal progress ignition subsequent combustion lean-burn using system studied optical diagnostic imaging heat release analysis based on main-chamber pre-chamber pressure measurements. Optical diagnostics involving simultaneous infrared (IR) high-speed (30 kfps) broadband filtered OH* chemiluminescence are used probe process. Following early rise pre-chamber, IR reveals initial ejection unburnt fuel-air mixture from into main-chamber. this, jets exhibit chemical activity vicinity region followed by delayed spread chemiluminescence, as they continue penetrate further signal radially until merge, which sets up limit first stage, jet-momentum driven, mixing-controlled (temperature field) premixed combustion. This then deceleration jets, caused decrease driving difference (ΔP) well charge entrainment, resulting flame front evolution, where mixing not only driver. Chemical-kinetic calculations possibility propagation sequential auto-ignition second stage Finally, phenomenological features summarized so provide fundamental insights complex fluid-mechanical chemical-kinetic that govern near lean-limits high-efficiency engines employing system.