The very intensive calculations necessary to define a performance map requiring evaluation of over a hundred individual operating points can be efficiently conducted with accelerated multizone for engine cycle simulation, leading to a definition of regions of acceptable and optimum homogeneous charge compression ignition operation. Accelerated multizone for engine cycle simulation has the virtue of enabling accurate evaluation of many operating conditions based on thermal stratification data from a single fluid mechanics run at motored conditions. This is possible because thermal stratification is more sensitive to engine geometry than to operating conditions. In this article, accuracy of accelerated multizone for engine cycle simulation is demonstrated by comparison with experimental data for iso-octane homogeneous charge compression ignition operation over a broad range of lean equivalence ratios (0.14–0.28). The validated accelerated multizone for engine cycle simulation model is then applied to generating a performance map for an engine controlled by appropriately adjusting equivalence ratio and internal exhaust gas recirculation. Regions of acceptable and optimum combustion are identified. It is finally demonstrated that while indicated mean effective pressure remains low for optimum homogeneous charge compression ignition operation (1–4 bar), this is sufficient for a large fraction of typical driving in light-duty vehicles. Much driving including idle can therefore be done in homogeneous charge compression ignition mode at high efficiency and low (essentially zero) NO x and particulate matter emissions.

The study of the combustion in an annular combustor including the radiation heat transfer is presented. The study considers different models of combustion, the turbulence-chemistry interaction and the chemical kinetics. In the analysis a non-premixed, diffuse and turbulent model is considered, applying CFD (Fluent ®). The Chemical Equilibrium and Laminar Flamelet models are considered with one chemical mechanism to natural gas (methane). The results obtained show the radiation heat transfer effect on the temperature distribution in the combustor and compare the results obtained with both combustion models. The radiation heat transfer increases the temperature of the fuel and air input, modifying the temperature profile at the output of the combustor. On the other hand, the Laminar Flamelet model shows better results of temperature profiles at the output of the combustor, to be compared with results presenting in the literature.