Experimental Analysis of the Start of Fuel Cycle-to-Cycle Variations of Solenoid-Actuated High Pressure Fuel Injectors

This paper presents an experimental investigation to quantify the start of fuel cycle-to-cycle variations of solenoid-actuated high pressure fuel injectors. The approach is based on building a probability presence image by recording a set of highly magnified images of the liquid fuel emerging from the injector tip at a specified delay time after the start of injection logic pulse. The analysis has been applied to two production-intent fuel injectors for direct injection spark ignition engine applications. The results show that the magnitude of the cycle-to-cycle variation at each delay time can be captured and well represented in a quantitative manner based on monitoring the liquid presence probability over the injection cycles. It is a useful diagnostic tool to quickly evaluate the start of fuel variation and can be used in support of injector development process for fuel injected engine applications.