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Ignition delays were measured for iso-octane using a rapid compression machine at an equivalence ratio of 1, initial pressure of 300 Torr, and post-compression oxygen density of [O2]Vo=1.0, where Vo is 22,400 cm3/mole. The post-compression temperature were varied by changing specific heat ratio of mixture: this was done by blending different inert gases, i.e., CO2, N2, and Ar. Negative temperature coefficient region was observed between 750 K and 850 K. Two-stage ignition delay characteristic was observed below 830 K. Overall experimental results were found to be in good qualitative agreement with those by Shell's Thornton Research Center. The ignition delays predicted by MIT 19 reaction reduced chemical kinetic model were compared with those from the current experiment. In the model calculation, the measured pressure was fed into the model to calculate the core temperature before there is appreciable heat release due to chemical reaction.

The effect of valve events on engine performance was studied using an engine simulation program. To improve the prediction accuracy, the original quasi-steady thermodynamic model developed by Poulos and Heywood was modified so that the gas flow in the intake manifold could be modelled as an one-dimensional unsteady compressible flow. Various empirical parameters in the model were calibrated against the exsiting experimental data so that the simulation bears any meaningful results. It has been known that the engine performance is more sensitive to the intake valve events than the exhaust valve events, thus only the effect of varing intake valve events was considered for the present study. The intake valve events which were varied include intake valve closing time, intake valve opening time, maximum intake valve lift time, intake valve lift, and the combination of the above.

A rapid compression machine for chemical kinetic studies has been developed. The design objectives of the machine were to obtain: 1)uniform well-defined core gas; 2) laminar flow condition; 3) maximum ratio of cooling to compression time; 4) side wall vortex containment; and, 5) minimum mechanical vibration. A piston crevice volume was incorporated to achieve the side wall vortex containment. Tests with inert gases showed the post-compression pressure matched with the calculated laminar pressure indicating that the machine achieved these design objectives. Measurements of ignition delays for homogeneous PRF/O2/N2/Ar mixture in the rapid compression machine have been made with five primary reference fuels (ON 100, 90, 75, 50, and 0) at an equivalence ratio of 1, a diluent (s)/oxygen ratio of 3.77, and two initial pressures of 500 Torr and 1000 Torr. Post-compression temperatures were varied by blending Ar and N2 in different ratios.