Acquiring reliable boundary conditions for three-dimensional simulation of internal combustion engines by means of one-dimensional simulation: an insight on pre chamber design

The pre-combustion chamber is a powerful technology to improve engine performance. By using this technology, the engine is able to stably burn lean mixtures, even helping to reduce air pollutants. To help implement this technology, physical and numerical experiments are being conducted. As numerical tools become faster and more accurate, they are increasingly being used in the development of new engine designs, reducing project time and costs. Therefore, a reliable methodology must be used to correctly predict the fluid dynamic behavior. The current paper aims to develop a methodology for the acquisition of boundary and initial conditions for an internal combustion engine. The methodology is also adapted to simulate the engine while adapted with pre-combustion chamber operating in Otto Cycle. For that, physical experimentation data found on the literature along with one dimensional and three dimensional simulations were used. Initially, a methodology was developed for the acquisition of valve discharge coefficient using three-dimensional numerical simulations. These data, along with physical experimentation data, were used to develop an one-dimensional model in the GT-Suite software. With this developed model, it was possible to generate initial and boundary conditions for the three-dimensional model simulation, performed on the CONVERGE CFD software. Using the proposed methodology, three-dimensional simulations were run. With the results from the simulations run with the current methodology, modifications on the pre-combustion chamber design were proposed and tested. The results of the novel design presented good trends towards improvement in the burn rate, with an homogeneous combustion process.