One-dimensional modeling of the interaction between close-coupled injection events for a ballistic solenoid injector

Abstract

In the current paper, an investigation of a solenoid common-rail injector has been carried out to understand the hydraulic interactions between close-coupled injections events. For this purpose, a one-dimensional model of the injector was developed on GT-Suite software. The geometrical and hydraulic characteristics of the internal elements of the injector, needed to construct the model, were obtained by means of different custom-made experimental tools. The dynamic behavior of the injector was characterized using an EVI Rate of Injection meter. The hydraulic results from the model show a good alignment with the experiments for single injections, and a varied degree of success for multiple injections. Once the model was validated, it has been used to understand the injector performance under multiple injection strategies. The mass of a second injection has shown to highly depend on the electrical dwell time, especially at low values, mostly due to the dynamic pressure behavior in the needle seat. The critical dwell time, defined as the minimum electrical dwell time needed to obtain two independent injection events, has been numerically obtained on a wide range of operating conditions and correlated to injection pressure and energizing time of the first injection. Finally, the increase in the needle opening velocity of the second injection compared to the single-injection case has been analyzed for close-coupled injection events.

Measurements of the mass allocation for multiple injection strategies using the rate of injection and momentum flux signals

“…In addition, at lower rail pressures, closed-couple pilots produced a faster rate of the SOI for the main event, probably due to the effect of pressure waves within the injector sac and control volume. 33,46–48 This was quantified by calculating the average SOI speed as the maximum opening slope of the curve for the conditions presented in the previous plot, and results are shown in Figure 10. The impact of the pressure waves can be somewhat visualized in the ROI signal, as local oscillations are observed at the beginning of the main injection signal for the shorter dwell cases, and they get smoother when increasing the dwell time.…”

“…When including a pilot mass, the variability of the main injection marginally increases compared to the reference case, probably due to pressure waves within the sac of the nozzle affecting the dynamic of the needle for the second pulse. 15,33,43,48…”

Effects of fuel injection parameters on premixed charge compression ignition combustion and emission characteristics in a medium-duty compression ignition diesel engine

“…In PCCI combustion, the injection scheme defines the air–fuel mixing process, which is also considerably influenced by the in-cylinder conditions (pressure and temperature). 24 To control the in-cylinder conditions at the instant of main injection, researchers used split fuel injection strategies. Hashizume et al 22 proposed a strategy of multiple stage diesel combustion (MULDIC), in which the fuel was injected in two stages to promote the low temperature combustion (LTC).…”

A Novel Design Concept of Electromagnetic Valve Actuator with High Starting Force

“…This challenge in independent ICE valve electromagnetic control is being approached by developing an electromagnetic valve actuator design with an appropriate force-stroke characteristic, which would enable a high level of flexibility in valve timing control and lifting [2,5]. However, so far finding an appropriate solution for successful electromagnetic valve timing control has been a demanding task due to the pronounced nonlinearity of the force stroke characteristic and high landing velocity [2,4,11,12,[16][17][18][19][20].…”