Studies on Improvement of Intake Manifold for Compressed Natural Gas Engine

Abstract

Geometrical design of intake manifold is very important for the good performance of an I.C. Engine. Unequal velocity distribution of intake air at runner’s outlets of intake manifold makes it less efficient. The reported work aims to make this unequal distribution of velocity in nearly equal manner with increase of velocity at outlets without any major modification in design of intake manifold. Maruti Wagnor (petrol version) engine intake manifold is used for experimental testing, to examine the variation of velocity of air flow at outlet of four runners. To modify the intake manifold first a 3-D model of actual manifold is made in design software (PRO-E) and then validation of design model is done by using commercial CFD software FLUENT. To achieve the desired improve results two other models of same intake manifold with different design configuration are made in software then examine the result of these two models with original one to find out pressure and velocity losses. After analysis of models it noticed that the hidden projections of nut, projected stiffeners and depth cuts at extreme of plenum causes pressure losses due to which uneven distribution take place at runner’s outlets. The nearly equal velocities in all four runners are achieved in the inlet manifold by redesigning the plenum of intake manifold and free it from unwanted hidden projection inside the plenum. The results show nearly equal distribution in all four runners with an increase in velocity of air flow by 14% in outlet-1 and 5% to 7% approx. in other three runners of inlet manifold.