In-Situ Fuel Concentration Measurement Using an IR Spark Plug Sensor by Laser Infrared Absorption Method - Pressure and temperature dependence of gasoline molar absorption coefficient

摘要

An infrared absorption method with a 3.392 μm He-Ne laser was used to determine the gasoline fuel concentration near the spark plug in a spark-ignition engine. A database of the molar absorption coefficients of regular and premium gasoline at different pressures and temperatures was established in advance using constant-volume vessel. The molar absorption coefficient of gasoline decreased with increasing pressure above atmospheric pressure. A procedure for obtaining accurate gasoline concentration measurements using the infrared absorption technique was demonstrated. The history of the molar absorption coefficient for gasoline during the experiment was obtained from the established database using measured in-cylinder pressures and temperatures estimated by taking the residual gas into consideration.