In lean burn combustion, jet ignition is such a promising technology that is
often used to improve the ignition and enhance combustion stability when
ignition failure and misfire might occur. Four different orifice configurations
are applied in the fueled pre-chamber and lean main chamber system to
investigate the effect of orifice configurations on flame propagation and
pressure oscillation. The combustion phases of jet ignition, pressure wave
propagation, and mechanism of jet combustion with various orifice configurations
considered are presented. In the present work, three phases of jet ignition
propagation are observed. Besides, it is found that when the total orifice area
is the same, the single-orifice configuration presents the fastest flame
propagation and pressure oscillation. The viscosity effect and interactions
between jet flows in multi-orifice configurations account for this phenomenon.
The two-stage burn in the jet combustion phase, i.e., stoichiometric combustion
and lean combustion in the mixing layer, is presented. The former imposes a
global heating effect on the lean mixture, while the latter manifests a local
influence by sustaining and transferring the flame. In the last section, the
end-gas autoignition and pressure oscillation under various orifice
configurations is investigated. The present work focuses on the flame
propagation and pressure oscillation in an active pre-chamber system, with the
underlying mechanism of two-stage combustion explored. In summary, the present
work extends the understanding of the flame propagation process in an active
pre-chamber system. However, the initial turbulence is ignored in the present
work, and further work is supposed to be done to investigate the effect of
turbulence inside the pre-chamber.