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Injection rate, injection quantity and injection timing of fuel are controlled precisely by electric control in CRDI system. Particularly, injection rate being influenced with injection pressure affects to spray characteristics and fuel-air ratio, so it is a very important factor in diesel combustion. In this study, injection rates in accordance with injection pressure at a constant ambient pressure were measured with Zeuch`s method. Under the same condition, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. Injection start time and injection period were practically affected with injection pressure. Also, initial injection rate, spray penetration, spray angle and breakup of high density droplets region in the spray were affected with injection pressure. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for common rail direct injection system.

As RFID systems are applied to various fields and applications such as supply chain management, asset management, location based applications etc. the requirements becomes diverse. For example, Much higher performance, TCP/IP protocol stack are required in some applications. However, low end processors based systems such as 8051 processor can not meet such requirements due to their low processing capacity and limited size of memory. In this paper a UHF band RFID system which meets the EPC Class-1 Generation-2 specification with ARM920T-based processor is implemented and tested.

In this paper, a dual processor structure sensor node for dual mode operation is presented for ultra-low power energy harvesting environments. Energy harvesting environments have the two disadvantages: low amounts of usable energy and large deviations. To overcome the disadvantages, two solutions are applied to the sensor node. First, the sensor node is designed for dual mode operation where it operates differently depending on the amount of usable energy. The sensor node executes only the most fundamental functions and defers the remains while it has insufficient energy, and executes the deferred functions after it obtains sufficient energy. Second, an event handling co-processor (EHCP) is added to the sensor node. Because it would be too excessive to use a heavy-weight general-purpose CPU for such simple operations when there is little usable energy. So, the EHCP is designed with the minimum basic instruction sets so that only the most basic functions are processed. Through this study, a new technique of operating a sensor node is proposed for ultra-low power energy harvesting environments with low amounts of usable energy and large deviations.

This paper proposes an ultra-low power sensor network system for energy harvesting environments. The system is composed of two types of sensor nodes: master nodes, which can acquire relatively sufficient energy from batteries or mains, form the backbone of the entire system; and slave nodes, which are powered by using energy harvesting technology, are scattered around the master nodes. To overcome the limitation of harvestable energy, a slave node is usually turned off and is activated when a master node sends a request signal which contains the ID of the slave node. To verify the energy effectiveness of the proposed architecture and techniques, a simple pilot system is implemented and tested. The experimental results show that the proposed techniques drastically reduce energy consumption of the sensor nodes.