Interferometric Techniques for Crank-Angle Resolved Measurements of Gas Spectra in Engines

We discuss combustion gas spectra measured by interference spectrometers and their relevance for engine studies. First, we discuss infrared H₂O thermal emission spectra from in-cylinder piston engine gases with a novel operation mode of a standard FTIR. Second, we discuss ultraviolet OH absorption spectra in an atmospheric-pressure flame using a spatial heterodyne spectrometer (SHS) suitable for single-shot measurements of spectra from engines. We emphasize the unique ability of interference spectrometers to gather high-resolution spectra at high throughput and the associated value to the engine researcher.