Streamers Variability Investigation of a Radio-Frequency Corona Discharge in an Optical Access Engine at Different Speeds and Loads

Engine research community interest in the Radio-Frequency corona-based ignition systems is currently gaining importance mainly due to their capability ensure robust combustion at challenging operating conditions such as very lean mixture and/or high EGR dilution. The benefits of Corona low-temperature plasma foster early flame development thanks precursors production and a more energetic volumetric discharge, resulting larger amount involved mixture. corona discharge generates ionizing waves, named streamers, whose temporal spatial variability orientation, length branching can affect onset and, therefore, engine cycle-to-cycle variability. In this work, natural luminosity RF igniter, characterized by four tips electrodes, was recorded an optically accessible via high-speed camera detection. A preliminary statistical analysis streamer performed motored conditions. Four different speeds two loads were explored order deeply investigate behaviour diverse comparison between condition also proposed analyse, specific speed, influence on streamers propagation before start combustion.