Investigation of multi-species (H2O2 and H2O) sensing and thermometry in an HCCI engine by wavelength-agile absorption spectroscopy

Absorption spectra spanning 1410 - 1490 nm, with a spectral resolution of similar to 0.3 nm, were recorded in a piston engine operating in homogeneous charge compression ignition engine ( HCCI) mode. Spectra were recorded every 126 mu s using a wavelength- agile laser, corresponding to 0.45 crank angle degrees under the 600 rpm condition tested. The dominant absorber is H2O vapour, but a weaker interfering absorption attributed to H2O2 vapour was also observed. H2O2 mole fraction, H2O mole fraction and gas temperature histories were estimated from the measured spectra. Estimated H2O2 mole fractions are compared to mole fractions simulated using Chemkin; the agreement is within a factor of 2. This effort represents the first attempt to monitor H2O2 in a combustion environment; the simultaneous measurement of multiple species in an engine by a single laser is also novel.