Measurement and theoretical analysis of the displacement characteristics of moving components in a solenoid injector in view of wave phenomena

The optimization of the combustion process in internal combustion engines requires a thorough knowledge of the phenomena that take place inside injection system components responsible for fuel delivery. The beginning and end of fuel injection is difficult to accurately determine because fuel is delivered at very high pressure, the displacement of moving components generally does not exceed 500 mu m. The article proposes an original solution for accurate and reliable measurement of the displacement of an injector's moving components. Injector characteristics can be accurately described based on the registered values of displacement and the electrical pulse that controls injector opening. A mathematical model that describes injection processes and accounts not only for electric and hydraulic phenomena, but also for the pressure-induced strain of the control piston was also proposed. The model was developed on the assumption that injection pressure is propagated by the fuel supply line and the injector's moving components. The conducted measurements and modeling results indicate that the deformation of the control piston and pressure propagation resulting from changes in fuel pressure significantly affect the injector's operating parameters. This aspect has been largely neglected by the research studies conducted to date.