Performance Assessment of a Single Jet, Dual Diverging Jets, and Dual Converging Jets in an Auxiliary Fueled Turbulent Jet Ignition System

Abstract

An auxiliary fueled prechamber ignition system can be used in an IC engine environment to provide lean limit extension with minimal cyclic variability and low emissions. Geometry and distribution of the prechamber orifices form an important criterion for performance of these systems since they are responsible for transferring and distributing the ignition energy into the main chamber charge. Combustion performance of nozzles with a single jet, dual diverging jets and dual converging jets for a methane fueled prechamber ignition system is evaluated and compared in a rapid compression machine (RCM). Upon entering the main chamber, the dual diverging jets penetrate the main chamber in opposite directions creating two jet tips, while the dual converging jets, after exiting the orifices, converge into a single location within the main chamber. Both these configurations minimize jet-wall impingement compared to the single jet. The total cross-sectional area of the orifice(s) are maintained the same for all the nozzles while for the dual jet configurations, the angle between the nozzle holes are kept constant. High speed color images along with pressure records obtained from the experiments are further processed to extract derived quantities such as burn duration, flame edge and flame area. Experimental results revealed that the single jet and converging jets offer a slightly higher lean limit extension while the dual diverging jets offer overall superior combustion performance.