2. Combustion sub-model

The combustion sub-model must be able to provide an energy release rate or a burned fuel mass rate that reflects the specific mixture preparation arrangements: indirect, direct gasoline or diesel injection, premix, diffusion mixing, homogeneous, stratified... All these choices and other factors (e.g. internal aerodynamics) will have a major impact on the shape of the combustion law.

There are several model families.

The first family is based on phenomenological or empirical laws, which are based on the interpolation of experimental profiles, but require some data to define the model constants. These laws provide little information on the physics of combustion, and can only be extrapolated with great difficulty to operating conditions outside those for which they were established.

The second family of models is based...