Measurements of Temperature Distribution in Thermal Boundary Layer and Quenching Distance at Combustion Chamber of Internal Combustion Engine

概要

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The thermal boundary layer near the combustion chamber wall of internal combustion engine has the important key to decrease in the cooling loss. And it is thought that the pollutant emission such as unburnt hydrocarbons exists near the wall because combustion flame is quenched when it approaches the wall. Therefore, the thickness and temperature distribution in the boundary layer are important. Then, resistance wire thermometer with tungsten wire of 5μm diameter is developed for the purpose of measuring boundary layer temperature directly. The measurement of temperature distribution of boundary layer is carried out, by using a rapid compression-expansion machine (RCEM). The nitrogen gas is used in order to oxidation prevention of tungsten wire. The measurement of the various positions in the combustion chamber is possible to make the measurement position movable in the vertical direction to wall. As a result of experiment, thermal boundary layer thickness in compression stroke was 0.5mm in maximum. Next, we try to measure a quenching distance of the combustion flame in homogeneous charged compression ignition engine of a mixture of di-methyle ether and air. The quenching distance is shorter than the thermal boundary layer thickness of non-combustion conditions.