Development of a fuel injection method and design of a special injection device for use in a diesel engine

Combustion in the cylinder of a diesel engine is a vital parameter which effects efficiency of the engine and the toxic exhaust gasses created by the engine and combustion is controlled greatly by fuel injection process in a diesel engine. Therefore, proper control of fuel injection process has a great importance on combustion. Atomization of the fuel is also crucial in order to arrange heat release rate during combustion. With the known injection devices, the fuel is suddenly injected into the air in the combustion chamber that is heated to a high temperature and is under pressure. This causes an irregular combustion with the consequence of a step increase in pressure and high emission. There are number of advantages of air utilization in today's diesel engine injectors, such as increasing fuel atomization levels, providing fuel economy by enhancing complete combustion diesel fuel, and as a result lowering of engine emissions. Therefore the aim of the thesis is to develop an air assisted injection device for use in a diesel engine which improves combustion of the diesel engine by mixing air and fuel inside itself at optimum ratio. In order to determine optimum air fuel ratio and operation pressure, FLUENT tool of the ANSYS program was used. Examination of the injection process by using of a high speed camera and comparison of the obtained results with the simulation results were realized after determining optimum conditions. Finally the effects of air utilization in a common diesel injector on the engine performance values and exhaust emissions were explored.