Application of low pressure cooled EGR to suppress engine knock is increasing because of advantages of engine downsizing, high compression ratio. Purpose of this study is to develop ignition system to extend EGR limit. This paper summarizes the experimental result obtained by using reinforce conventional ignition coil. As engine speed (mixture flow velocity between plug-gap) and EGR ratio were increased, secondary energy requirement of ignition coil was increased. The results show effectiveness of high energy ignition system for extending EGR area.