抄録
This report explained the local equivalence ratio (air fuel ratio) measurements of engine exhaust gas and
direct fuel injection in engine cylinder using laser-induced breakdown spectroscopy (LIBS) and sparkinduced
breakdown spectroscopy (SIBS). When we use LIBS/SIBS in combustion system, we can
discuss simultaneous laser/spark ignition and equivalence ratio measurement of premixed mixture. The
intensity ratio of H/O or H/N showed a good agreement with preset equivalence ratio in engine exhaust
gas and premixed mixture in engine cylinder. The influence of spark discharge characteristics on
emission spectra was investigated by simultaneous measurement of spark discharge visualization and
spectroscopy. The relationship between air-fuel ratio and the emission intensity ratio was obtained in
premixed gas combustion in a spark ignition engine. There was a tendency that local air-fuel ratio
decreases with advance of the injection timing from the fixed ignition timing. It was observed that spark
discharge was affected by the flow due to injection. LIBS/SIBS is very good tool to discuss the
combustion characteristics in real engine researches.
