A control volume based procedure has been developed that makes possible the materially meaningful inclusion of radiation heat transfer in full simulation calculations for the axisymmetric version of the “ modified discretized-intensity method.” Included in this procedure is an innovative technique that splits the radiation problem in two. Bach subprob-lem, in turn, can be solved more effectively than if the problem had not been split, making the overall approach just as effective in optically thin absorbing-emitting media as it is in optically thick media. The mass absorption coefficients used in the formulation are based on a molecular band analysis and are computed at a finite number of discrete locations along each intensity ray. The model has applicability to any control volume energy balance formulation. A description of the incorporation of the model into a primitive variable approach is given. Application of the model is made to the solution of a portion of the combustion stroke of a four-stroke piston engine to demonstrate the utility of the model in moving boundary problems