Design of an inlet track of a small I.C. engine for swirl enhancement

Abstract

The purpose of this project was to re-design the inlet port of a small Internal Combustion Engine in order to enhance the production of turbulence by swirl. A good swirl promotes fast combustion and improves the efficiency. A small internal combustion engine was designed to be part of a very efficient vehicle to enter a consumption marathon. The engine should run at low speeds, in order to have low mechanical losses but the combustion should be fast, enabling good combustion efficiency. Therefore high turbulence should be produced prior to combustion within the cylinder, so swirl was induced by the inlet channel within the cylinder head. To perform this task the help of three software programs is required, Solid Works, Gambit and Fluent. The first was required to produce the CAD-geometry. To build the geometry it is important to bear in mind that there are some restrictions for casting and fuel injection. In the next step, Gambit meshes the geometry in the design by using a volume mesh. At last; Fluent calculates the flow within the engine by using a suitable turbulence model. Initially the current geometry was tested and proved to create low swirl, so the geometry was changed several times until reaching a good result in terms of generated swirl. The tests include just steady flow, where the air enters the inlet port and leaves the bottom of the cylinder continuously. The flow within the cylinder is examined at specific sections, namely at various heights of the cylinder (horizontal sections) and pathlines are also evaluated. The flow is calculated for various valve lifts at a specific engine condition.