Abstract
The purpose of this study was a fundamental investigation of the effects of multi-point spark ignition on a natural gas engine. Tests showed that multi-point ignition enhanced thermal efficiency through improved combustion stability. Under conditions where combustion fluctuation increased before misfire occurred, it was found that increasing the number of ignition points made it possible to extend the lean limit by increasing heat release during early stages of combustion. Under conditions where misfire occurred before combustion fluctuation increased, it was found that increasing the number of ignition points where flame propagation distance was reduced made it possible to extend the lean limit.
