Investigation of multi-event spark discharge strategy for lean methane-air combustion

Abstract

The characterization of the single-coil repetitive discharge and the dual-coil offset discharge was conducted in a constant volume combustion chamber to better understand the operating principle of the multi-event spark ignition strategies. A parametric study of the dual-coil offset discharge was carried out through electric and optical diagnosis to identify the effective operational parameters, including coil working frequency, charging voltage, and coil inductances. Combustion tests under both quiescent and flow conditions with methane-air mixture were performed to demonstrate the ignition capability of the dual-coil offset strategy. Test results have shown that constantly depositing spark energy through offset discharge is beneficial to secure flame kernel. However, the offset discharge strategy requires a high working frequency, an elevated charging voltage, and fast reacting coils to maintain the spark plasma channel under high background pressure and intensified flow conditions.