Electrical modeling of a double spark at atmospheric pressure

Since the spark produced by the classic spark plug does not always ensure a complete and efficient combustion, various other types of spark plugs have been proposed for internal combustion engines (ICE). Among these different technical solutions have been found to be effective: pulsed LASER ignition, [1], system with multi ignition points, [2], electrical Corona or GlidArc discharges, [3], [4], multi - electrodes plug, developed by Bosch, [5], pulse jet combustor etc. We propose an ignition system with a double spark, achieved by placing between the high voltage electrode and the ground one, of a third unpowered electrode, having floating potential, with the shape of a washer. The validation of this type of plug by the chemical results corresponding to a better combustion, involves optimizing its construction in terms of breakdown of the double spark, using the optimal positioning of the auxiliary electrode. In order to achieve the optimization the equivalent electric capacity of the double spark plug is calculated, before the spark ignition. The parametric value of the capacity is introduced into an electrical schema similar to the classic spark ignition model. The schema has been simulated by using MULTISIM software, [6]. The simulated voltage characteristic was compared to the real voltage waveform. The perturbation values associated with working of the double spark plug in air were checked by measuring electromagnetic radiation perturbations near the ignition system with a spectrum analyzer. In the case of the double spark ignition into a combustion chamber, at different high pressure values, electromagnetic radiation perturbation is very low, so the described method could not be used for optimization of double spark construction. For this reason, all the experimental analyses such the voltage and electromagnetic radiation perturbation measurements have been realized for the discharge produced in air, at atmospheric pressure and humidity.