Chemical Imaging in a Diesel-Ignited Dual-Fuel Optical Engine Using High-Speed Infrared Narrowband Imaging

Lowering fuel consumption and reducing soot formation are among the challenges being addressed when seeking to improve engine designs. In this work, ICE characterization was carried out on an optical engine consisting of an elongated single-cylinder diesel engine and a common rail injection system. High-speed infrared chemical imaging was carried out at 26 kHz using five different spectral bandpass filters: broadband, carbon dioxide (CO2), through-flame, hydrocarbon and methane (CH4). Results obtained through simultaneous used of both high-speed visible and infrared cameras are also presented. In order to compare different 2D image sequences, cumulative histogram time-series (CHST) diagrams were used. The diagrams obtained under various engine-operating conditions, the impact on the combustion dynamic can readily be visualized. The results illustrate how high-speed IR imaging can provide unique insights for research on ICEs.