Impact of the turbo charging on the thermo-mechanical analysis of internal combustion engine exhaust valve’

The valves play a crucial role in turbocharged engines by controlling the exhaust gas flow, which generates the energy required to drive the compressor and increase engine power. This paper investigates the effect of turbocharging on the heat transfer within exhaust valve, by determining the temperature distribution and mechanical stress at different engine loads and speeds, considering both naturel aspiration and turbocharged engine configurations. For this purpose, the valve is subdivided into eight adequate subdivisions to well asses the actual boundary condition surrounding the exhaust valves. The average values of the transient heat transfer coefficient, the adiabatic wall temperature and the mechanical load were evaluated at each subdivision during the engine cycle. The boundary conditionswere applied as curves defined by functions, rather thanas constant average values in order to ensure smooth transitions between subdivisions. Unsteady simulations were performed using in a finite element model implemented in ANSYS. The temperature distribution and mechanical stresses at each valve position and for divers operating condition are obtained and analyzed. The present study permit also to establish correlations to determine boundary conditions of a turbocharged engine from those of a naturally aspirated engine, allowing to quantify the thermal, the mechanical load and therefore, the new temperature map of the valves caused by the turbocharging, which could help industrial engineers to anticipate thermo mechanical variations and prevent valve overheating, thus, improving the engine's thermal efficiency, ensuring its durability, and maximizing its performance without any damage.