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According the actual structure and working principle of a fuel injector to build a model of the common-rail injector, including the control valve, the solenoid valve, and the needle valve of the injector. The model includes the leakage model for the control piston and needle valve that takes into account increasing leakage at high pressure. The performance of the fuel injector is investigated using a one-dimensional numerical model. Analyzing the effect of the system and structure parameters including common-rail pressure, injection pulse width, inlet and outlet hole diameter, and the injection nozzle on the injection characteristics of the fuel injector. Results show that the geometric parameter is the main property affecting the flow characteristic of the injector, which includes the flow rate of inlet and outlet hole, pressure waves in the control chamber and injection rate. The common-rail pressure, injection pulse width and the geometric parameters mainly affect the injection performance, such as the injection rate and injected volume. The investigation result can provide some useful information to improve the injection characteristic in follow-up studies. [ABSTRACT FROM AUTHOR]

The dynamic mechanism of liquid-glass transition for Mg7Zn3 alloy is studied by the molecular dynamics simulations. The temperature dependences of dynamic properties during the liquid-glass transition are investigated. Two relaxation processes are clearly observed near the glass transition temperature. The diffusivity deviates from the Arrhenius law after the melting temperature Tm and satisfies the power law before the dynamic singularity temperature Tc owing to the cage effect. The solid- and liquid-like atoms are defined according to the vibration characteristic of atoms. It is found that the solid-like atoms have higher local packing density, lower mobility and potential energy than the liquid-like ones. Based on the evolutions of solid- and liquid-like atoms, the atomic mechanism of dynamic liquid-glass transition is systematically elucidated, which is consistent with the potential energy landscape. [ABSTRACT FROM AUTHOR]