US Patent 11757262 Prechamber spark plug and method of manufacturing the same

A prechamber spark plug that includes an internal reservoir, a flow passage portion, and a prechamber and is designed to operate efficiently across a wide variety of operating conditions and ranges. The internal reservoir includes upper and lower internal reservoir sections, the prechamber includes upper and lower prechamber sections, and the flow passage portion fluidly connects the lower internal reservoir section and the upper prechamber section so that burnt air/fuel gases can be exchanged therebetween. A ground electrode assembly with a ground electrode ring may be positioned in the prechamber such that it separates the upper and lower prechamber sections, whereas a modular prechamber cap may be used to define the shape and size of the lower prechamber section. In one example, the flow passage portion has a total cross-sectional area (AFC) and the internal reservoir has a total volume (VRES), and the ratio AFC:VRES is greater than or equal to 0.015 (1/mm).