Study of an innovative three-pole igniter to improve efficiency and stability of gasoline combustion under charge dilution conditions

A diluted cylinder charge helps in engine fuel efficiency but at the same time presents significant challenges to combustion stability. An innovative three-pole spark igniter is researched to explore multi-spot ignition technology and improve the burning process of high-efficiency combustion under diluted conditions. The unique design features three independent pairs of electrodes in a single spark plug and allows new approaches to apply novel ignition strategies. Optical combustion vessels and high-speed imaging techniques are employed to develop fundamental understandings of the multi-spot ignition process. A large number of tests are performed on instrumented combustion vessels to statistically quantify and demonstrate the effect of the three-pole igniter, in comparison with a conventional spark plug. Finally, the prototype three-pole igniter is implemented on a production engine to validate and demonstrate the improvements in engine combustion under low and high dilution conditions. As shown by test results, the three-pole igniter offers shorter ignition delay and faster burning, thereby improving combustion phasing and fuel economy. The three-pole igniter exhibits greater advantages for combustion stability under high dilution conditions that reduce pumping loss and thus gains fuel economy.