Enhancement of ignition characteristics of lean premixed hydrocarbon–air mixtures by repetitive pulse discharges

Abstract

A newly developed small-sized inductive energy storage (IES) circuit that uses a semiconductor switch for the turn-off action is successfully applied to an ignition system in spark ignition engines operating under lean fuel–air ratios. This IES circuit can generate repetitive nanosecond pulse discharges. Experiments are conducted by means of a spherically expanding flame configuration for C3H8–air mixtures under various conditions. Findings show the investigated ignition system improves the inflammability of lean combustible mixtures in terms of extended flammability limits, shorted ignition delay time, and extended dilution limits, compared with conventional spark ignition systems.