Combustion and Exhaust Gas Modeling of a Common Rail Diesel Engine - an Approach

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 models are also addressed in this article. Zero-dimensional models are computationally efficient and show good simulation results concerning the in-cylinder pressure. However, by neglecting multi-zonal resolution 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 the calculating of emissions shall be based on a two-zone model. The amount of mass, which is transferred from the unburned to the burned zone, is entered into a chemical model based on the chemical equilibrium for the OCH-system (oxygen/carbon/hydrogen). The result is the total quantity of chemical components in the burned zone.