Evaluation on the influence of piping geometry and valve opening time on an internal combustion engine

Abstract

This research aims to find the best camshaft profile suitable for a single cylinder internal combustion engine aiming at its maximum volumetric efficiency. The methodology employed was an iterative search of the best length and diameter of inlet and exhaust pipes using Lotus Engine Simulation Software. The behavior of the high-pressure pulses due to the acoustic and aerodynamic phenomena of the intake manifold, together with the time of opening and closing of the valves, was considered. A numerical model was validated when compared to the experimental model using a Robin Subaru EH 17-2 engine. The results obtained when comparing the third with the last simulation showed that there was an increase of 11.5% in the maximum power and 6.3% in the torque. There were gains in the specific fuel consumption in almost every rotation regime. In relation to the volumetric efficiency, an improvement was made in its value for the new configuration of opening and closing of the valves and geometry of the pipes. It is concluded that the obtained arrangement of the pipes ensured that the frequency and amplitude of the pressure waves were synchronized to the dynamics of opening and closing the valves to stimulate the filling of the cylinders.

Keywords

• intake system
• exhaust
• volumetric efficiency
• lotus engine simulation
• intake manifold