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Exhaust Gas Recirculation (EGR) is employed widely in compression-ignited engines and currently under consideration for being implemented into spark-ignited engines. EGR cylinder-to-cylinder dispersion is one of the features of such engines that developers are challenged to abate, because low EGR rates increase NOx emissions and excessive EGR rates can produce a significant amount of particulate matter. Taking into account the complex geometries of some automotive manifolds, the treatment of this topic through 3D computational fluid-dynamics (CFD) simulations seems mandatory to study the transport phenomena in a proper way. The main objective of this work is the analysis of the influence of the numerical setup main parameters (mesh, time-step size, turbulence modeling) in a CFD URANS simulation of an automotive engine intake manifold in the EGR distribution.

The present paper aims at developing a novel methodology to create a one-dimensional simulation model for an automotive turbocharged gasoline engine. The gas-path modeling of the engine, which includes a variable nozzle turbine (VNT) and variable valve timing (VVT) strategies, is described in detail. The model calibration procedure is mainly distinguished by isolating the different engine parts, decoupling the turbocharger, using PI controls to find fitting parameters and checking and validating mean and crank-angle resolved variables. To handle model limitations, it requires experimental data and a previous combustion analysis of some steady operating points. The methodology is completed with the determination of fitting correlations to estimate heat losses and pressure drops in engine systems. It also includes the training of an Artificial Neural Network (ANN) to predict the combustion process and the integration into the model and final validation.

Upcoming emissions regulations will force to optimize aftertreatment system to reduce emissions looking for lack of fuel penalty. Despite advances in purely aftertreatment aspects, the performance of the diverse aftertreatment devices is very dependent on the operating temperature. This makes them rely on the engine design and calibration because of the imposed turbine outlet temperature. The need to reach target conversion efficiency and to complete regeneration processes requires controlling additional parameters during the engine setup. For that reason, exploring the potential of different solutions to increase inlet aftertreatment temperature is becoming a critical topic. Nevertheless, such studies cannot be tackled without considering concerns on the engine fuel consumption. In this paper, the influence of several design parameters is studied by modelling approach under steady state operating conditions in a Diesel engine.

0D-1D codes allow researchers to obtain a prediction of the behavior of internal combustion engines with little computational effort. One of the submodels of such codes is devoted to the centrifugal compressor. This model is often based on the compressor performance maps, therefore requiring the extrapolation of the maps so that all possible operating conditions are covered. Particularly, a suitable extrapolation of isentropic efficiency map is sought. This work first examines different available methods for compressor efficiency extrapolation into off-design conditions. No method is found to provide satisfactory results at all extrapolated regions: low and high compressor speeds and low compression ratio at measured speeds. Hence, a new method is proposed and its accuracy is assessed with the aid of compressor off-design measurements.