CFD ANALYSIS ON DIFFERENT PISTON BOWL GEOMETRIES BY USING SPLIT INJECTION TECHNIQUES
A better spatial distribution is required for the injected fuel throughout the entire space of combustion geometry in DI diesel engine, to obtain a better combustion with lesser emission. In order to effectively make use of gas flows it is mandatory to match the piston bowl geometry with fuel spray characteristics. For obtaining better combustion, matching of combustion chamber geometry, fuel injection and gas flow plays prominent role. The model was developed in computational fluid dynamics (CFD) code, ANSYS FLUENT. The simulations were conducted for the combinations of swirl ratio, three split injection and four piston bowl geometries (Case A,B,C and D). The simulation results revealed that, the pilot injection creates favorable condition for the upcoming main fuel injection in the case of multiple injection. In case of multiple injections there is a considerable reduction in NO formation. The final NO formed is 24% lower than that of normal injection and 22% lower than that of the retarded injection. The combination of split injection with suitable combustion chamber configuration would greatly enhance the engine performance, besides reducing emission level to a greater extent.
DI Diesel engine, Split injection, Combustion, piston bowl configuration, in-cylinder air motion, NOx formation