Modeling of Combustion in Gasoline Direct Injection Engines for the Optimization of Engine Management System Through Reduction of Three-Dimensional Models to (nxOne-Dimensional) Models

摘要

Gasoline direct injection (GDI) spark ignition engines may be able to run over a wide range of operating conditions.The GDI process allows combusition with lean mixtures which may lead to improved fuel economy and emissions relative to homogeneous spark ignition (SI) engines To satisfy the different modes of operation the tuning of DGI engines reguires a large number of engine sests which are time-consuming and very expensive To reduce the number of tests a model with a very short cfompuatinal time to simulted the engines in the whole operating range is needed therefore the objective of this paper is to present a reduced model to analyzed the combustion process in DGI engines applied to a homogeneous totichiometric mode The objective of the model is to reduced compuatinal tiem The one-dimensional model is obtined thanks to a reduction methodology based on the geometry of the combustion front computed with three dimensional models of the KIVA-GSM code a modified version of KIVA-II code including a CFM combustion model The model is a set of n one-dimensional equations (i.e.for n ravs) taking into account a thin flame front describved with the flamelet assumption It includes a CFM combustion model and a (k,wpsilon)-model inclluding the mean ari motions (swirl and tumbel).The results of the one-dimensional model are compared to those obtained by the KIVA IIGSM under different engine conditions The comparisin shows that the one-dimensional model overstimates the maximum cyliner pressure which has an insignificant effiect on the net indicated work per cycle.The results obtained by the numerical simulations are close to those goven by the three-dimensional model with a much reduced computation time.