DEVELOPMENT OF COMPACT EXHUST GAS TREATMENT EQUIPMENT FOR DIESEL ENGINE USING DIELECTRIC BARRIER DISCHARGE

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The purpose of this project is to refine a three dimensional complex material, like the mold metal frame, by the surface treatment (cleaning, coating) and/or surface refining (ion implantation), making use of the combination of high repetitive pulse modulator for large capacity and high density glow plasma generation and pulse biasing for extraction of ions. The project was performed in the following three subjects to realize the purpose. (1) The first step is to grasp the heat flux from plasma into the material and plasma parameter of the pulsed glow discharge. (2) The second step is to develop a pulse modulator for plasma generation and bias voltage supply. (3) The third is the numerical simulation by the fluid modeling. The results are as follows.1. It was clarified that the plasma parameter of the pulsed glow discharge by probe measurement, current-voltage characteristics, and the spectroscopic analysis. The plasma density 3 x 10^<11> cm^<-3> was sustained over a period of 8 μs app … More roximately. The plasma temperature has increased form 450 ℃ to 650 ℃ in this period. This temperature rise generate the heat flux. Estimating the ratio of the heat flux to the input power, it was found that the ratio came up to 40 % approximately.2. Combining the SOS diode and inductive energy storage system, we produce the pulse generator for ion extraction from ultra thin theath, before the transition form ion matrix to Bohm theath. The specification of the pulse generator are output voltage -20 kV, repetition frequency hundreds Hz, and pulse width 60 ns. The pulse width is short enough compared with the Bohm theath formation time(1 μs).3. The numerical analysis of the 2D fluid model was progressed. It was found that the special plasma distribution was remarkable modified by the earth sealed which guard the electrode material to the suputtering. The probe measurement result of the plasma distribution was consistent with the numerical calculation. We also analyzed the ion number density making use of the chemical reaction models. In nitrogen cases, it was found that N_2^+ and N_4^+ are dominated in this reaction. Less