An Advanced Ignition System for High Efficiency Engines

A pragmatic approach to meeting future CO2 regulations while delivering vehicles that customers want and can afford will require the synergistic integration of advanced tech-nologies that enhance engine efficiency by minimizing loss mechanisms and maximi-zing work recovery. Aggressive downsizing, higher compression ratios, increased le-vels of charge dilution, and homogeneous stoichiometric operation at wide open throttle with acceptable peak pressure levels are essential technologies to meet these challenging objectives. Many of these enabling technologies pose significant challen-ges for the conventional spark ignition system. To maximize gasoline engine efficiency, the ignition system should enhance early flame kernel development to support robust spark ignition combustion, should be able to enhance mixture reactivity to support part-load lean low-temperature combustion, and should tolerate high heat fluxes to support high speed and load operation without compromise. In this paper, we demonstrate a single, passive, lowtemperature plasma ignition concept that simultaneously addres-ses all these challenges. The groundless barrier discharge igniter (GBDI) can enhance early flame kernel development through the local deposition of high energy reactants, enable lean low-temperature combustion control through the generation of pre-com-bustion ozone, enhance knock tolerance by reducing early flame kernel variability, and enhance overall engine robustness through the elimination of ground straps, spark gaps, and heat ranges.