Considering the soot-free burning characteristics of DME/OME fuel, highly diluted intake charge can be introduced in order to realize ultra-low nitrogen oxides emissions. However, the ignition process of the highly diluted fuel/air mixture is difficult, and an unstable ignition process is detrimental to fuel efficiency and engine performance. In this project, innovative ignition systems including a multi-site ignition system. and volumetric ignition system, together with novel ignition strategies will be developed.