SI Engines 1D Modeling: Prediction of Brake Performance Parameters and Emissions.

1D simulation codes, including thermodynamic, fluid dynamic and chemical models, are fundamental tools for engine design and optimization. The GASDYN code, developed by the authors at the Politecnico of Milano, has been used to analyze the operations of a Maserati S.I., naturally aspirated, V8 engine. An experimental campaign was previously carried out on this engine, including the measurement of brake performance parameters and exhaust emissions and in-cylinder pressure cycles, for several operating conditions at both full and partial load. This large amount of data allowed the authors to set up and validate at full load a numerical model of the engine. A multi-zone fractal model has been employed to predict combustion heat release, as well as NO, CO and HC emissions. After the experimental validation, the engine model has been used to calculate engine performances and emissions at partial load. A very satisfactory agreement was found.