Intake Manifold Flow Assessment on a 3-cylinder Natural Aspirated Downsized Engine Using CFD and GT-SUITE

In this paper the intake manifold as the most effective part on engine’s volumetrice efficiency is in vestigated in detail with emphesizing on flow behavior and characterestics. The eight different design have been  prepared  and  imported to CFD software. Five objective functions for investigation of flow have been connsidered and applied in TOPSIS with different weights. Mass flow rate,massflow rate deviation between runners,flow coefficient,turbulence intensity and velocity at runner end have been objective functions in flow detail assesment. Then all geometrical dimentions are applied to a verified ESC. The engine simulation model is developed  for I3 engine with turbulence combustion model named “ SI-TURB” which will be validated by experimental combustion profile data. The experimental and numerical combustion pressure has a good accuracy, so that the ESC can simulate and predict the engine performance by 6.15% accuracy. It has to be stated that the hybridation of 3D analysis with engine simulation code in the closed loop method for developing of IM is nessassery in order to have the best compromising design. Finally combination of CFD with ESC results showed that, considering the same weight in TOPSIS for flow objective functions have more compatibility in point of engine power out put.