Effect of the engine speed and loading on the heat transfer within exhaust valves

The aim of the present paper is to investigate numerically the heat transfer within exhaust valves by considering the actual boundary conditions provided from an internal combustion engine at differentload and speed. For this purpose, the valve is subdivided into seven adequate subdivisions to better assess the effect of each engine parts, therefore, an average value of the transient heat transfer coefficient (HTC) and the adiabatic wall temperature (AWT) for each subdivisions are evaluated during one cycle. These two parameters are introduced as boundary condition in a FEM model. The simulations are done at diverse engine regime, and therefore, the trend of the real boundary condition in term of HTC and AWT are given versus engine speed at different load. The findings show that the HTC increases linearly with engine speed however, the AWT decrease slightly at partial load and increase in the case of full engine load. The obtained model is used to highlight the temperature map, which will certainly help to avoid any damage to the exhaust valve.