Investigation of the combustion process in an auxiliary heating system using dual‐pump CARS

Abstract A dual‐pump coherent anti‐Stokes Raman spectroscopy (CARS) setup was used for the simultaneous determination of temperature and oxygen/nitrogen ratio in an automotive auxiliary heating system. The auxiliary heating system was equipped with eight windows to provide four line‐of‐sight optical accesses at two different downstream levels. The usable laser pulse energies, which are essentially limited by the damage threshold of the glass windows, were increased by the application of an optical pulse stretcher. Measurements were performed for standard diesel fuel for full‐ and part‐load operation as well as for the model fuel n ‐dodecane for full‐load operation. The n ‐dodecane measurements can directly be compared with numerical predictions, whereas the results for diesel fuel provide information about the possibility of transfer of the n ‐dodecane simulations to real fuel conditions. Copyright © 2006 John Wiley & Sons, Ltd.