Experimental study of the diesel injector nozzle sediment effect on fuel spray behavior

High pressure amount of fuel in new generation diesel engines’ injector equipped with multiple and small nozzle holes has created significant improvement in the outgoing spray behavior and engine performance. On the other hand, poor fuel quality and injector nozzle embedded in high temperature combustion chamber form fundamental deposits on the nozzle leading to fuel spray inappropriate behavior. Regarding the engine functional characteristics close correlation with fuel outlet spray behavior, in this study, the destructive effects of the fuel flow interaction with injectors nozzle sediment have been analyzed in terms of injector different operating time. The deposition process of injectors is carried out with standard fuel under specified experimental circumstances. Non-destructive electron microscopy methods have been used to analyze the sediment characteristics formed on the injectors nozzle. In order to analyze the outlet fuel spray characteristics, the spray evolution images of injectors with different operating time are processed by the code provided in MATLAB software at different pressures of the constant volume chamber and fuel injection. The imaging process was carried out in a constant volume chamber with a high speed camera. the injector deposits intensification increases the fuel injection delay and deteriorates the injector outlet spray behavior. The spray deposit destructive effects are alleviated through increasing the fuel injection pressure.