Laser Spectroscopic Investigation of Flow Fields and NO-Formation in a Realistic SI Engine

Flow and Combustion in Reciprocating Engines

“…On the whole, higher fluctuations reported in these studies correlate well with higher swirl ratios and squish area ratios. Numerical simulations further support this estimate [86], with the exception of local peaks computed on the bowl centerline [15,33,92]. In general, the homogeneity of the turbulent fluctuations within the bowl suffers with reentrant bowls, although the available measurements suggest that away from the walls the spatial variation in the turbulent fluctuations is within a factor of 2 [9,13,67,80,96].…”

“…Due to their characteristically large A sq , regions of high turbulent fluctuations are observed numerically in the lip region of reentrant bowls, even with no swirl [33,92]. With swirl, both experimental [11,26,27,35,80,84] and numerical [33,46,86,91,92] studies indicate high turbulence regions near the lip.…”

Nitric oxide detection inside the cylinder of an SI engine by direct UV absorption spectroscopy

“…Adding NO to the burning mixture may help us to determinate the lower level of detectable absorption from this molecule under the combustion chamber conditions. Unfortunately, previous works [7,[36][37][38] showed that nitric oxide seeding might change the flame characteristics. Its interaction with the combustion process leads to a reduction in the nitric oxide concentration as a consequence of NO reburn reaction [39].…”

Optical Characterization of Dimethyl Ether (DME) for Laser-based Combustion Diagnostics

“…It is thus likely that anti-Stokes detection of the NO fluorescence in the A-X(O, 0) and A-X(O, 1) bands (blue-shifted from the laser wavelength) will be successful. A significant portion of the fluorescence is emitted in these bands and this detection scheme has been successfully applied for quantitative concentration measurements of NO in running spark-ignition engines (Schultz et al, 1996;Hildenbrand et al, 1998).…”