PLASMA JET IGNITION OF LEAN HYDROGEN-AIR MIXTURES.

Plasma jet ignition is known as one of the prospective enhanced ignition systems, and it has a great potential to improve ignition reliability and burning rate of lean mixtures. Therefore, in order to confirm the performance and characteristics of plasma jet ignition quantitatively, combustion tests of lean hydrogen-air mixtures are carried out with varying the governing parameters of plasma jet igniter (plasma cavity size, orifice diameter, discharge energy). From the series of tests, the combustion enhancement by the plasma jet ignition is revealed only in the initial stage of combustion. Then a comparing parameter of the performance of plasma jet ignition in its initial stage of combustion is proposed by comparing the pressure diagram of plasma jet ignition and that of conventional single-point center ignition. The performance and the characteristics of plasma jet ignition are revealed quantitatively by the comparing parameter.