The effect of Intake Manifold Runners Length on the Volumetric Efficiency by 3-D CFD Model

It is quite wellknown that a properly designed Intake Manifold is vital for the optimal performance of an IC engine. This paper will present 3-D Simulation of a XU7 Engine Intake Manifold and the results will be discussed. Both steady and unsteady state simulations have been accomplished for this case. Steady state simulation results are compared with flow bench rig data for validation. Boundary condition for unsteady state simulation was obtained from 1-D WAVE code. In the present research the effect of length of runners on the volumetric efficiency has been analyzed by 3-D CFD model at different speeds. Three hypothetical models have been made that all of their runners' length is increased to 110,120 and 130% of initial value. In the model with 20% extended runners, the volumetric efficiency increases at 3500 and 4500 rpm. Finally according to the results of steady and unsteady simulations, some suggestions are recommended to improve the performance of this Intake Manifold.