Measurement of Diesel Combustion by Optical Fiber Thermometer (2nd Report, Local Combustion Behavior in Combustion Chamber)

The authors have proposed new techniques for measuring combustion behavior locally in a DI diesel engine combustion chamber by means of an optical fiber thermometer; one technique is to use two types of light pipe sensor with different measuring spaces and the other is to vary the measuring space only by rotating the axis of the beveled-edge-type light pipe sensor. Results obtained in this experiment are as follows: (1) Cyclic variation of combustion differs significantly from space to space in the combustion chamber. (2) Flame temperature varies a little locally, but the soot concentration varies considerably in the combustion chamber especially at the stage of initial combustion. (3) The soot formation process begins at a crank angle about two degrees after ignition.