Detection of NO in a spark-ignition research engine using degenerate four-wave mixing
APPLIED PHYSICS B-LASERS AND OPTICS 74:1 (2002) 105-110
Optical dephasing effects in broadband four-wave mixing in C-2: Implications for broadband FWM thermometry
Journal of Chemical Physics 116 (2002) 1370-1379
Spark ignited hydrogen/air mixtures: Two dimensional detailed modeling and laser based diagnostics
COMBUSTION AND FLAME 128:1-2 (2002) 74-87
Double-pulse PLIF imaging of self-ignition centers in an SI engine
SAE Technical Papers (2001)
Abstract:
In this study, the occurrence of auto-ignition centers in a two-stroke SI engine was investigated using planar laser-induced fluorescence (PLIF). An experimental SI engine equipped with glass windows to enable full optical access into the combustion chamber was operated under knocking conditions. The pulsed output of two XeCl excimer lasers was formed into planar light sheets (300 μm × 4 cm), which were spatially overlapped and directed into the combustion chamber of the operating engine. Unburned fuel components fluoresce strongly when illuminated with XeCl laser radiation; burned regions display no fluorescence. Self-ignited regions therefore show up as dark sites in the fluorescence images, indicating local consumption of the fuel. The resulting PLIF images were recorded using fast-gated ICCD cameras. By delaying the second laser pulse a specific time (100 ns-600 μs), image pairs were acquired which allowed the temporal development and mutual influence of hot-spots to be studied. The short laser pulse duration (20 ns), the two-dimensional nature of the imaged region and the strong signals obtained from our detection scheme yield very detailed information of the self-ignited regions. Approximately 20 000 image pairs were recorded. As important quantities, spatial distribution and expansion velocities were extracted from the PLIF images and investigated statistically. Copyright © 2001 Society of Automotive Engineers, Inc.Comparison of in-cylinder coherent anti-Stokes-Raman scattering temperature measurements with predictions from an engine simulation
International Journal of Engine Research SAGE Publications 2:2 (2001) 149-162