TY - JOUR
T1 - In situ measurement of hydrocarbon fuel concentration near a spark plug in an engine cylinder using the 3.392 μm infrared laser absorption method
T2 - Discussion of applicability with a homogeneous methane-air mixture
AU - Tomita, Eiji
AU - Kawahara, Nobuyuki
AU - Shigenaga, Masahiro
AU - Nishiyama, Atsushi
AU - Dibble, Robert W.
PY - 2003/8
Y1 - 2003/8
N2 - A fibre optic system was developed to determine the fuel concentration near a spark plug using an infrared absorption method. The system was linked to an optical sensor installed in the spark plug, from which light could pass through the combustion chamber. By using this modified spark plug, successive measurements of the fuel concentration near the spark plug before ignition were performed in a spark-ignition engine burning homogeneously mixed methane-air. The fuel concentration was determined from the Lambert-Beer law by considering the dependence of the methane molar absorption coefficient on pressure and temperature. Three main conclusions were drawn from this study. First, the methane molar absorption coefficient was greater for lower pressures and decreased with increasing temperature and pressure above atmospheric pressure. The temperature and pressure effects were offset by each other, since the temperature effects were positive and the pressure effects were negative. Second, precise time-series data for the local fuel concentration were obtained by considering the in-cylinder pressure and temperature from an estimate of the methane molar absorption coefficient. And third, the measured air/fuel ratio near the spark plug before ignition agreed with the preset value when the developed optical sensor was used under motoring and firing conditions.
AB - A fibre optic system was developed to determine the fuel concentration near a spark plug using an infrared absorption method. The system was linked to an optical sensor installed in the spark plug, from which light could pass through the combustion chamber. By using this modified spark plug, successive measurements of the fuel concentration near the spark plug before ignition were performed in a spark-ignition engine burning homogeneously mixed methane-air. The fuel concentration was determined from the Lambert-Beer law by considering the dependence of the methane molar absorption coefficient on pressure and temperature. Three main conclusions were drawn from this study. First, the methane molar absorption coefficient was greater for lower pressures and decreased with increasing temperature and pressure above atmospheric pressure. The temperature and pressure effects were offset by each other, since the temperature effects were positive and the pressure effects were negative. Second, precise time-series data for the local fuel concentration were obtained by considering the in-cylinder pressure and temperature from an estimate of the methane molar absorption coefficient. And third, the measured air/fuel ratio near the spark plug before ignition agreed with the preset value when the developed optical sensor was used under motoring and firing conditions.
KW - Air/fuel ratio
KW - Fibre-optic sensor
KW - Infrared absorption method
KW - Internal combustion engine
KW - Laser diagnostics
KW - Molar absorption coefficient
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U2 - 10.1088/0957-0233/14/8/321
DO - 10.1088/0957-0233/14/8/321
M3 - Article
AN - SCOPUS:0041909288
VL - 14
SP - 1350
EP - 1356
JO - Measurement Science and Technology
JF - Measurement Science and Technology
SN - 0957-0233
IS - 8
ER -