A method of providing a passive ignition pre-chamber for an internal combustion engine. The pre-chamber is typically implemented as a cap on the electrode end of a spark plug and encloses a pre-chamber volume in which fuel is mixed with air to form a consistently ignitable mixture. The pre-chamber is passive in the sense that gas exchange with the engine's main combustion chamber is realized by local flow fields near nozzles into the main chamber and by pressure differences between the pre-chamber and the main chamber. The nozzles are sized such that at least one of the nozzles has a larger diameter than the remaining nozzles, as optimized using flow field and pre-chamber turbulence analysis.
Kevin Hoag; Matthew Hoffmeyer; Bansal Shah; Zainal Abidin