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.

In this work, the spectra for plasma glow produced by pulseNd:YAG laser (λ=532 and 1064nm) on Ag:Al alloy with same molarratio samples in distilled water were analyzed by studying the atomiclines compared with aluminum and silver strong standard lines. Theeffect of laser energies of the range 300 to 800 mJ on spectral lines,produced by laser ablation, were investigated using opticalspectroscopy. The electron temperature was found to be increasedfrom 1.698 to 1.899 eV, while the electron density decreased from2.247×1015 to 5.08×1014 cm-3 with increasing laser energy from 300to 800 mJ with wavelength of 1064 nm. The values of electrontemperature using second harmonic frequency are greater than of1064 nm, which increased from 2.405 to 2.444 eV, while the electrondensity decreased from 2.210×1015 to 1.516×1015 cm-3 withincreasing laser energy for the same energy range.

Low-pressure capacitively coupled RF discharge Ar plasma has been studied using Langmuir probe. The electron temperature, electron density and Debay length were calculated under different pressures and electrode gap. In this work the RF Langmuir probe is designed using 4MHz filter as compensation circuit and I-V probe characteristic have been investigated. The pressure varied from 0.07 mbar to 0.1 mbar while electrode gap varied from 2-5 cm. The plasma was generated using power supply at 4MHz frequency with power 300 W. The flowmeter is used to control Argon gas flow in the range of 600 standard cubic centimeters per minute (sccm). The electron temperature drops slowly with pressure and it's gradually decreased when expanding the electrode gap. As the gas pressure increases, the plasma density rises slightly at low gas pressure while it drops little at higher gas pressure. The electron density decreases rapidly with expand distances between electrodes.

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