In recent years, electric automobiles are becoming popular. However, automobiles with combustion engines are expected to account for more than half of sales in the coming decades. Therefore, the thermal efficiency of a spark-ignition engine needs to be significantly improved. One of the ways to improve the thermal efficiency of a spark-ignition engine is fuel-lean burn technology. For this purpose, the development of new ignition systems has been required instead of the conventional spark-ignition systems. Therefore, our laboratory focuses on the application of Nanosecond Repetitively Pulsed Discharges (NRPD) to ignition systems. NRPD can enhance ignition reactions due to the high electron temperature of non-equilibrium plasma generated by nanosecond-order pulsed discharges. However, the ignition processes of NRPD have not been fully understood because of the complex reaction between plasma and combustion during a very short time scale of the reactions.

Our laboratory aims to understand the ignition mechanisms of NRPD. The initial formations of the plasma-assisted ignition kernel in intense turbulence are investigated in experiments. Numerical simulations with detailed plasma and combustion kinetic models are conducted to identify key plasma reactions and investigate appropriate discharge frequencies. These basic studies are essential for introducing NRPD into spark-ignition engines.

Projects participated：SIP "Innovative combustion technology"