CFD Analysis of Flow Field Development in a Direct Injection Diesel Engine with Different Manifolds

Abstract

Air motion inside the intake manifold is one of the important factors, which govern the engine performance and emission of multi-cylinder diesel engines. Hence the flow phenomenon inside the intake manifold should be fully understood in order to consider the current requirement of higher engine efficiency and lower emission. In this project work, the internal flow characteristic in the intake manifold of a diesel engine is investigated computationally for the different intake manifold (Helical, Spiral and Helical-Spiral) configurations. The governing equations for unsteady, three-dimensional, compressible, turbulent flow are solved with the two equation RNG k-e model to consider the complexity of the geometry and fluid motion. The overall flow field inside the intake manifold and various quantities, such as swirl and tumble ratios were examined for all three types of manifolds. It was concluded that spiral and helical-spiral manifold creates higher swirl than normal inlet manifold. However, volumetric efficiency was observed to be higher for helical manifold.