Engine modeling and exhaust gas estimation for DI-diesel engines

Engine models are a basis for better controlling combustion process and the exhaust emissions resulting from it. Currently the zero- and quasi-dimensional models are mostly used. These types of model are also addressed in this article. Zero-dimensional models are computationally efficient but they are not able to describe fuel efficiency or the generation of pollutants. It is therefore necessary to enhance combustion process models with phenomenological fuel spray and vaporization models, with a local resolution of at least two zones. The chemical model for calculating emissions is based on the two-zone model. The amount of mass, which is transferred from the unburned to the burned zone, is the input for a chemical model based on the equilibrium for the OCH-system (oxygen/carbon/hydrogen). The nitrogen-oxide emissions are calculated by using the advanced Zeldovich-mechanism which uses the reaction-kinetic approach rather than the less accurate chemical equilibrium assumption. The NO/sub x/-emissions (nitrogen-oxides) can be influenced by changing the exhaust-gas recirculation (EGR) rate.