Integrated 1D-3D CFD simulation of SI engine for improvement intake manifold purge distribution

This paper describes a detailed analysis of the unsteady flows of an intake manifold of modern four-cylinder, SI engine by means of numerical tools, which are used for flow analysis inside of manifold. The aim of the research is to improve purge valve location for distribution of gasoline vapor in intake manifold. 1D-3D integrated fluid dynamic model, based on the GTPOWER (1D) and FLUENT (3D) codes, has been applied for purge valve location. A detailed 1D simulation has been carried out to predict complete system performance Intake system, in-cylinder combustion and exhaust system to obtain the input data for CFD analysis. A measured data of pressure loss in intake manifold has been used to validate the 1D model for the simulation. Values of pressures and temperatures for the individual cylinders of the engine in relation to crank angle (time) were generated from the 1D model, used as input for the CFD analysis. The final analysis was performed as transient for several combustion cycles of the engine.