Double spark ignition system : spectroscopic diagnostic of the plasma

The ignition sparks provided by the classical spark plug do not always assure a fast and complete combustion of the mixture hydrocarbon-air. For this reason we propose a new type of plug with a double spark using two simultaneous discharges generated by a pulsed high voltage power supply. This work presents the spectroscopic analysis of the plasma generated by the classic plug and the proposed plug in different positions in the space between the electrodes. These are supplied with waveforms containing one pulse by period. The waveform has adjustable pulse duration. The experiments have been done in air at atmospheric pressure. In each case it was pursued to identify the species (molecules and atoms) of spectrum in order to study the influence they may have on the development of the combustion. Because the spectra obtained are clear, stable and repeatable, it was possible to determine the temperatures in the plasma column by using two different spectroscopic diagnostic methods based on the molecular band spectra.