Numerical Analysis of In-cylinder Tumble Flow Structures – Parametric 0D Model Development

Both in the automotive and in the motorcycle fields the requirement of step-by-step improvements for optimizing the engine cycle is still present. In particular the focus of the optimization process is to reduce the raw emissions and at the same time to not penalize the engine performance. In this research field the engine modeling is of great importance because the application field of the experimental measurements is very narrow, time-consuming and expensive. Hence the modeling technique is a wide used and a wide recognized instrument for helping in the design process. Another important function of the modeling is to provide the engine designers with the most important guidelines. The main focus is to fast provide designers with some fundamentals during the first designing stage which, if not the conclusive, is close to the final project. The present paper deals with the development of a theoretic-interpretative 0D model which could highlight the most significant parameters in the engine design process and in particular in the determination of: • The tumble velocity at IVC and its residual value at TDC; • The squish velocity at TDC; • Their mutual interaction. These parameters are well recognized to be especially meaningful because they determine, at different times of the combustion process, the combustion velocity. The faster the combustion velocity, the lower the engine cycle-by-cycle variability. © 2013 The Authors.