Pure rotational coherent anti-Stokes Raman spectroscopy was used for the simultaneous determination of temperature and exhaust-gas recirculation in a homogeneous charge-compression ignition engine. Measurements were performed in a production-line four-cylinder gasoline engine operated with standard gasoline fuel through small optical line-of-sight accesses. The homogenization process of fresh intake air with recirculated exhaust gas was observed during the compression stroke, and the effect of charge temperature on combustion timing is shown. Single-pulse coherent anti-Stokes Raman spectroscopy spectra could not only be taken in the compression stroke but also during the gas-exchange cycle and after combustion. Consequently, the used method has been shown to be suitable for the investigation of two of the key parameters for self-ignition, namely temperature and charge composition.
© 2006 Optical Society of America
(120.1740) Instrumentation, measurement, and metrology : Combustion diagnostics
(120.6780) Instrumentation, measurement, and metrology : Temperature
(300.6230) Spectroscopy : Spectroscopy, coherent anti-Stokes Raman scattering
Original Manuscript: August 29, 2005
Manuscript Accepted: October 28, 2005
Markus C. Weikl, Frank Beyrau, and Alfred Leipertz, "Simultaneous temperature and exhaust-gas recirculation-measurements in a homogeneous charge-compression ignition engine by use of pure rotational coherent anti-Stokes Raman spectroscopy," Appl. Opt. 45, 3646-3651 (2006)