A Design Modification of the Delivery Valve and the Constant Pressure Valve in a Medium Speed Diesel Engine Fuel Injection System for the Prevention of Cavitation Damage and Secondary Injection

A fuel injection with high pressure in a medium speed diesel engine would increase the possibility of cavitation damage in the fuel injection system or secondary injection to the combustion chamber. The purpose of this study is to prevent cavitation and secondary injection in a medium speed diesel engine by modifying the design of the delivery valve and the constant pressure valve in a fuel injection system. Three-dimensional flow analyses for the fuel injection nozzle, delivery valve, constant pressure valve and spill port were performed using FLUENT S/W to calculate loss coefficients of them. Simulation of fuel injection system with loss coefficients from results of three-dimensional flow analyses were performed using FLOWMASTER2 S/W and the simulation results were compared with the experimental data. The delivery valve and constant pressure valve were modified to prevent cavitation and secondary injection and proved in the field test.