Optical investigation of prechamber combustion in an RCEM

Abstract

In this study, detailed investigations of scavenged prechamber engine combustion are performed experimentally in a Rapid Com-pression Expansion Machine (RCEM), which allows optical access into the main chamber. OH* chemiluminescence measurements combined with pressure measurements are used to study the effect of varying ignition timing on combustion and cycle-to-cycle varia-tions. The variation of ignition timing (pressure at ignition) showed an optimum ignition point for a given injection duration. Earlier ignition resulted in weaker but more reactive jets, coupled to increased cyclic variations. Later ignition did not significantly affect heat release rate, but increased cyclic variation.

Prechamber optimal selection for a two stage turbulent jet ignition type combustion system in CNG-fuelled engine

“…This value is the lean combustion limit for conventional spark ignition systems, but can be further extended with the implementation of turbulent jet ignition (TJI), which can deliver much higher activation energy to start the combustion process of a lean mixture. Such a system can be used either without injection to the ignition chamber (passive or unscavenged configuration) or with prechamber injection (active or scavenged configuration) [2,3,12]. Hence the active TJI has been introduced to the engine, stable operation has been achieved for λ ~ 2.2, in parallel with better indicated net thermal efficiency values from λ > 1.2 and also 2% greater η t_max (at λ ~ 1.6).…”