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Burning velocities for unleaded conventional gasoline (CR-87) and air mixtures were determined experimentally over an extensive range of equivalence ratios at 353 K and 500 K and at atmospheric pressure. Nitrogen dilution effects on the laminar flame speed were also studied for selected equivalence ratios at these same conditions. Experimental measurements employed the stagnation jet-wall flame configuration and Particle Image Velocimetry (PIV). The laminar burning velocity was obtained using linear extrapolation of stretched flame data to zero stretch rate. The measured flame speeds were compared with numerical predictions using a minimized detailed kinetic model for primary reference fuel (PRF) mixtures, which was developed based on stirred reactor, shock tube and flow reactor data.

Simulations of DI Diesel engine combustion have been performed using a modified KIVA-II package with a recently developed phenomenological soot model. The phenomenological soot model includes generic description of fuel pyrolysis, soot particle inception, coagulation, and surface growth and oxidation. The computational results are compared with experimental data from a Cummins N14 single cylinder test engine. Results of the simulations show acceptable agreement with experimental data in terms of cylinder pressure, rate of heat release, and engine-out NOx and soot emissions for a range of fuel injection timings considered. The numerical results are also post-processed to obtain time-resolved soot radiation intensity and compared with the experimental data analyzed using two-color optical pyrometry. The temperature magnitude and KL trends show favorable agreement.

Predictive models of soot formation during Diesel combustion are of great practical interest, particularly in light of newly proposed strict regulations on particulate emissions. A modified version of the phenomenological model of soot formation developed previously has been implemented in KIVA-II CFD code. The model includes major generic processes involved in soot formation during combustion, i.e., formation of soot precursors, formation of surface growth species, soot particle nucleation, coagulation, surface growth and oxidation. The formulation of the model within the KIVA-II is fully coupled with the mass and energy balances in the system. The model performance has been tested by comparison with the results of optical in-cylinder soot measurements in a single cylinder Cummins NH Diesel engine. The predicted soot volume fraction, number density and particle size agree reasonably well with the experimental data.