CFD SIMULATION OF A 6-CYLINDER DIESEL ENGINE INTAKE AND EXHAUST MANIFOLD

摘要

Exhaust gas recirculation (EGR) is a nitrogen oxide (NO_x) emissions reduction technique used in petrol/gasoline and diesel engines. By recirculating a portion of an engine's exhaust, inert gas displaces combustible matter in the cylinder. Because NO_x forms primarily when a mixture of nitrogen and oxygen is subjected to high temperature, the lower combustion chamber temperatures caused by EGR decrease the amount of NO_x combustion generates. This project aims at optimizing the location of the EGR ports, which are crucial to the operation and efficiency of the EGR system. The Computational Fluid Dynamics (CFD) code ANSYS FLUENT was used to analyze the intake and exhaust manifold working processes. In order to conduct numerical optimization on determining the best EGR port location, a transient CFD model was developed. Real operational transient boundary conditions were applied to the model through user defined functions (UDF), and the results of flow characteristics and EGR distribution was analyzed in detail. The EGR mass flow rate mal-distribution was presented at the transient simulation. This model can be utilized for further optimization purposes.