Experimental Study on Combustion in Miniature Glow Ignition Engine: Detection of Spontaneous Light Emission and Pressure

Combustion characteristics of a miniature four-stroke glow-ignition engine which has 4.89 cc of swept volume were investigated experimentally with applying an optical technique. As combustion characteristics, crank angle of ignition timing and combustion period were measured directly by the detection of spontaneous light emission. To investigate the effect of engine speed and fuel component on ignition timing and soot formation, elapsed time change of the light intensity was measured under the various engine speed and fuel composition with operating this engine at the largest engine power. Ignition timing can be estimated with comparing light intensity with rate of heat release which was measured at the different time and generation status of soot particles in the engine can be supposed by the light intensity. As a result, when the amount of the nitromethane in the fuel is large, ignition timing advances and soot formation was inhibited.