PROPOSAL OF A ROTARY VALVE SYSTEM FOR AN INTERNAL COMBUSTION ENGINE

Resumo

The aim of this paper is to propose a Rotary Valve System (RVS) for a single cylinder, air-cooled, four-stroke, 35cm³ engine. First, a brief study of the previous systems is carried out. Then, a Rotary Valve System is proposed and a 3D computational model presented. Valves are dimensioned keeping most of baseline engine original parameters such as valve timing, valve overlap and maximum engine speed. Finally, a numerical simulation of in-cylinder motion is conducted with the purpose of a qualitative analysis. The system proposed allows easily changes in the valve timing and the valve overlap, which represents an improvement compared with most of the systems proposed previously. Results of the numerical simulation suggest an increase in volumetric efficiency compared to the baseline engine and a predominance of the swirl flow on the in-cylinder air motion. It is concluded that further development of the system is needed, although initial results show that rotary valves could be a great alternative to the current poppet valve systems.