2001 Fiscal Year Final Research Report Summary
Characteristics of Mixture Formation and Combustion in Premixed Combustion Type Diesel Engine Using Hollow Cone Spray
| Project/Area Number |
11650206
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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 | Gunma University |
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Principal Investigator |
OBOKATA Tomio Gunma University, Department of Mechanical Engineering, Professor, 工学部, 教授 (10107477)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIMA Tsuneaki Gunma University, Department of Mechanical Engineering, Associate Professor, 工学部, 助教授 (40261862)
SHIGA Seiichi Gunma University, Department of Mechanical Engineering, Associate Professor, 工学部, 助教授 (00154188)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Diesel combustion / premixed auto-ignition / HCCI / Hollow cone spray / NOx-Soot trade off / Visualization / KIVA / Simulation |
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| Research Abstract |
Large angle hollow cone spray proposed for "hot-premixed combustion type Diesel engine" or "homogeneous charge premised combustion Diesel engine" which was expected to realize simultaneous reduction of NOx and soot was investigated by means of flow visualization, PDA and PIV techniques, numerical simulation, and was finally applied to a Diesel engine. Results are summarized as follows.
1) Conical spray shape is sensitive to the ambient pressure. At high ambient pressure, the spray shape becomes smaller and rounded. The numerical simulation gives reasonable consistency with the results of visualization.
2) PIV measurements provide the velocity map during the initial development of the spray. It is reasonably shown that the value of velocity range is close to the results obtained by PDA.
3) The mean velocity and Sauter mean diameter distributions have unsymmetrical shape. It is important to do the temporal analysis for the intermittent spray to know the structure.
4) From the engine test, it is shown that there are three zones of overcoming the NOx-Soot trade-off relation. Most effective zone of the second one is in the injection timing earlier than 65 degree BTDC for the excess air ratio of 3.1, where both NOx and Soot are almost zero.
5) All emission levels are lower in this homogeneous charge compression ignition engine comparing with conventional Diesel engine, although the operating zone is critical and limited. Then, continuing and detailed experiments are expected to optimize the combustion chamber, airflow and spray characteristics.
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