会議名: The 10th International Conference on Modeling and Diagnostics for Advanced Engine Systems (COMODIA 2022)
開催日: 2022/07/05 - 2022/07/08
Future transportation requires a variety of power sources, using sustainable and renewable energy sources. Further improvements in engine efficiency are crucial to meet the mandatory CO2 emissions regulations in the future. In this paper, ignition performances of spark based advanced ignition strategies were compared under both quiescent and flow conditions, including transient high current, and boosted glow phase discharge current. A constant volume combustion chamber emulating engine tumble flow was employed to investigate the impacts of spark discharge strategies and discharge control parameters on flame kernel initiation and combustion under lean burn condition. Ignition techniques were developed to generate transient high current (1700 A with 18 J ignition energy within 20 μs), generating an intensified thermal expansion. Efforts were also made to boost glow phase current up to 2 amps lasting 3 ms, which significantly enhance plasma stretching. The transient high current ignition strategy shows the best ignition capability under quiescent conditions because of the turbulence generated by the transient thermal expansion. However, the ignition capability is significantly mitigated under strong flow conditions, because of the much shorter discharge duration compared with traditional ignition strategy. The impacts of discharge current on flame kernel initiation were also investigated under same discharge duration. Under quiescent conditions, the change in discharge current amplitude has limited impacts on the flame propagation process. Under flow conditions, on the other hand, ignition volume is significantly enlarged because of the plasma channel stretching, and the enhancement of spark glow current is effective to enhance the ignition kernel development under high-speed flow. The experimental results indicate that an ignition strategy with moderate discharge current and sufficient discharge duration is most effective under flow conditions.