Browsing by Author "Moro, A."

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Eccentric needle displacement effect on spray formation from a multi orifice diesel injector
(Springer Verlag, 2019) Moro, A.; Luo, T.; Wang, C.; Luo, F.
As emission regulations becomes stringent, improving injection process in internal combustion (IC) engines, is one of the ways of enhancing combustion characteristics and reducing pollutants emissions. Hence in this study, the effect of on-axis and off-axis internal needle displacement on injection characteristics from a multi orifice injector, used in direct injection IC engines, were investigated and analyzed. Two stage off-axis needle movement was formulated for the investigation. The first stage was at the initial stage of the needle lift, where the needle continuously glides along the internal cone of the nozzle body, before it completely departs the body. The second stage was considered to be from the moment the needle completely departed the nozzle body. Two different direction of the two stage off-axis needle displacement, were analyzed and their effect on flow and spray characteristics compared to those from on-axis needle displacement. The results showed that, off-axis needle displacements in the immediate areas of the nozzle orifices, causes exponential increment in spray jet penetrations as compared to off-axis needle displacement around the maximum needle lift position. Also, the displacement at the early stages of injection, had more influence on the spreading angles of spray jets from the nozzle orifices than the needle displacement around full needle lift.
Measurement and analysis of injection characteristics among each nozzle hole within a heavy-duty diesel engine
(2021) Luo, F.; Sun, Y.; Moro, A.; Jin, T.; Wang, C.
The mass flow rate from each injector nozzle hole of a diesel engine influences the distribution, atomization, and combustion of fuel in the chamber. Thus affecting the power, the fuel economy, and the emission quality of the diesel engine. A spray momentum flux test bench was built and used to measure the injection rate from each nozzle hole of a multi-hole nozzle in this study. Selected force sensors used for data acquisition were one of the integral parts of the set-up. The influence of the force sensors’ installed position (location in the set-up) on measured results, were analyzed and the optimum position that ensures independence of the results, determined. Additionally, the effects of injection pressure, injection pulse width and injection hole diameter on the injection characteristics were also investigated. Furthermore, in this research, the reliability and robustness of Strain sensor and Piezoelectric sensors were analyzed with regards to their response. The analysis showed that, strain sensors have weak dynamic response characteristic compared to piezoelectric sensors also, the measured result obtained from strain sensors fluctuated greatly. Piezoelectric force sensor gave a more reliable and stable measurement, comparatively. The accuracy of the results were affected by the installation position of the sensors. A distance of 16 mm (between nozzle hole exit and sensor surface) was determined to be adequate for the acquisition of reliable experimental data. As the injection pressure gets higher (during injection), the rate of mass flow increased, the average cycle-to-cycle variation coefficient and nozzle-to-nozzle variability coefficient of injection quantity decreased. Hence, improving the consistency of each cycle and the uniformity of each hole. In addition, increasing the injection pulse width decreased the average cycle-to-cycle variation coefficient. Also, nozzle-to-nozzle variability coefficient had minimal or no influence with regards to injection pressure. At 80 MPa, the uniformity of injection from the multi-hole nozzle improved significantly. In summary, the larger the hole diameters, the higher the maximum value of mass flow rate and the fuel injection quantity.
Measurement and validation of hole-to-hole fuel injection rate from a diesel injector
(Elsevier Ltd, 2018) Luo, T.; Jiang, S.; Moro, A.; Wang, C.; Zhou, L.; Luo, F.
The advancement in technology on data capture procedures has overcome many of the challenges associated with data acquisition for transportation studies. The use of Radio Frequency Identification (RFID) technology is increasingly becoming significant in transport application domains where there is the need to track and analyze patterns of vehicles movement. In this paper, we explore the efficacy of RFID technology, a eulerian perspective on movement, to extract spatial and temporal rhythms of vehicular movements in, Nanjing, China for road traffic analysis. Data mining and geo-computation methods were used to mine and extract vehicular movement. The count data, statistical, visual analytics and Geographic Information System (GIS) methods were used to determine spatial and temporal patterns of vehicular movement. Global Moran’s I, hot spot analysis and kernel density estimations were the spatial statistical methods used to determine spatial patterns of vehicular movements. The study reveals the efficacy of the usage of massive RFID data, which uses a eulerian perspective of movement for determining spatiotemporal patterns for traffic analysis. The study revealed morning peak and evening peak vehicular movements, for weekdays with Thursdays and Fridays displaying the most vehicular movements. Spatial patterns revealed a clustering of low and high vehicular counts for weekdays, weekends, off-peak and peak hours. This explorative study using RFID technology to determine spatial and temporal patterns in vehicular counts has important application for traffic analysts. This study approach supports traffic congestion monitoring, traffic flow statistics and traffic planning as well as helps to determine low and high traffic locations to evaluate the performance of a traffic system.