A correlation between the rotational temperature and the electrical energy of a cold plasma type electrical discharge produced by a double spark-plug

To improve the combustion process of the air-fuel mixture into the combustion chamber of the engines, an ignition system based on a three electrodes spark-plug and a microcontroller based supply has been proposed. The benefits which can be achieved by using the new system are: reduction the amount of some pollutants such as unburned hydrocarbons from the exhaust gases, improving the engine's efficiency, fuel consumption decreasing and also some unwanted engine processes (misfires, hesitations, detonations, stutters and stumbles) can be avoided. The first phase of the validation process of the new ignition system was to perform a diagnosis of the plasma produced using the new spark plug and to compare the results with the ones obtained from the diagnosis of the plasma produced by a classical spark plug. Also the electrical parameters were measured for both the spark plugs and for different waveforms of the control signals. In this paper we present a correlation between the rotational temperatures of the plasma and the energy consumed by the discharges produced using the classical and the double spark plugs. The spectra used to determine the rotational temperatures have been recorded in air at atmospheric pressure using a spectrometer equipped with a CCD camera. The electrical discharge voltage and current measurement used to calculate the energy of the discharge have been made in air using a high voltage probe and a shunt resistance.