1999 Fiscal Year Final Research Report Summary
DeNOx Combustion of Transient High Pressure Spray Using Deoxidization reaction of NO
| Project/Area Number |
10650214
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | The University of Tokushima |
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Principal Investigator |
MIWA Kei The University of Tokushima, Graduate School of Engineering, Professor, 大学院工学研究科, 教授 (00026147)
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| Co-Investigator(Kenkyū-buntansha) |
MOHAMMADE Ali The University of Tokushima, Graduate School of Engineering, Instructor, 大学院工学研究科, 助手 (40314885)
MIYASHIRO Seiji Anan College of Technology, Dept. of Systems and Control Engineering, Professor, 教授 (90018010)
KIDOGUCHI Yoshiyuki The University of Tokushima, Faculty of Engineering, Lecturer, 工学部, 講師 (70294717)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Diesel Combustion / Emission / NOx / Hydrocarbon / Pyrolysis / Combustion Chamber / Turbulence / Combustion Flame |
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| Research Abstract |
This study investigates the formation and reduction mechanism of NOx during diesel combustion, and aims at realizing deNOx combustion.
A four-stroke single cylinder naturally aspirated direct-injection diesel engine is used as a test engine. A high squish combustion chamber with squish lip is employed. According to the results, the high squish chamber can reduce NOx emission by realizing rich combustion. This chamber can also promote diffusion combustion, resulting in low particulate emissions. Direct observation of combustion process in the high squish chamber shows that combustion continues mainly in the piston cavity. CFD calculation supports the results. The high squish combustion chamber has an effect of reducing NOx and particulate emissions because rich and high turbulence combustion continues in the ring region beneath the squish lip and less unburned fuel flows out to the cold piston crown.
In order to understand the deNOx mechanism, deoxidization reaction of NO is simulated usi
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ng the flow reactor. NO is supplied into the reacting furnace where pyrolysis or oxidation of hydrocarbons occurrs. The result shows that NO concentration is reduced by deoxidization reaction caused by decomposed hydrocarbons. Another fundamental study using the rapid compression machine is carried out. Total gas sampling method is employed in order to investigate the time histories of composition of hydrocarbons and NO concentration during diesel combustion. The result shows that NO concentration increases when combustion commences. However, once rich combustion region is formed by strong swirl, NO concentration tends to decrease during diffusion combustion stage. High-speed photography and CFD calculation explain the result that the air motion forms ring flame and fuel is supplied into the flame in the case of high equivalence ratio, leading to produce the rich and homogeneous flame. This process promotes the deoxidization reaction caused by decomposed hydrocarbons, resulting in NO reduction. Less
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