Comparative analysis of three simulation models applied on a motored internal combustion engine

The motivation of the present work is to comparatively evaluate the computational time and the results obtained using three computational models of increasing complexity, for the simulation of the closed part of the cycle of an internal combustion engine with a bowl-in-piston design, running under motoring conditions in the range of 1200–3000 rpm. The first model is a single-zone thermodynamic model, the second one is a hybrid quasi-dimensional model, and the third one is a computational fluid dynamics (CFD) model. From the analysis conducted it is concluded that the single-zone model calculates with reasonable accuracy the in-cylinder pressure, while it rather underestimates the peak in-cylinder mean gas temperature near the top dead center (TDC). Its main advantageous feature is the very low computational time (1 s) compared to the 6 min and 20 h required by the quasi-dimensional and CFD models, respectively. On the other hand, the quasi-dimensional model provides information concerning the local in-cylinder temperature distribution, and describes qualitatively correctly the way the cylinder design affects the in-cylinder flow and temperature fields, as revealed by comparing its results with the corresponding ones obtained with the more accurate and time consuming CFD model.

► Three simulation models of increasing complexity have been comparatively evaluated.
► All models adequately predict the cylinder pressure diagram at all engine speeds.
► For engine simulation, 1D, Q-D and CFD models need 1 s, 6 min and 20 h respectively.
► Q-D model predicts qualitatively correctly the in-cylinder temperature and velocity field.
► Q-D model offers a compromise between the detailed CFD models and the multi-zone ones.