2003 Fiscal Year Final Research Report Summary
Effect of the Flanged Spark Plug on Ignition Characteristics in Natural Gas Engine
| Project/Area Number |
14550201
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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 | Nihon University |
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Principal Investigator |
UJIIE Yasushige NIHON UNIVERSITY, COLLEGE OF INDUSTRIAL TECHNOLOGY DEPARTMENT OF MECHANICAL ENGINEERING, PROFESSOR, 生産工学部, 教授 (20060197)
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| Co-Investigator(Kenkyū-buntansha) |
NOMURA Hiroshi NIHON UNIVERSITY, COLLEGE OF INDUSTRIAL TECHNOLOGY DEPARTMENT OF MECHANICAL ENGINEERING, SSOCIATE PROFESSOR, 生産工学部, 助教授 (30246847)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Spark Ignition Engine / Natural Gas Engine / Ignition Characteristic / Spark plug / Ignition Energy / Flange / Turbulent Field / Shock Wave |
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| Research Abstract |
Spark ignition characteristics of the flanged spark plug, which had devised by head investigator have been studied experimentally Experiments were performed using a constant volume combustion chamber and a natural gas engine. Flanged spark plugs were made by remolding spark plugs on the market. The minimum ignition energy was employed to evaluate the ignition characteristics of the flanged spark plugs. It was found that the flanged spark plug reduces the minimum ignition energy It was observed by schlieren photography that the shock wave was reflected by the flanges and concentrated on a flame kernel. This fact suggests that the adiabatic compression due to the shock concentration reduces the minimum ignition energy There is little effect of the flange on the flame speed, although it is well known that the existence of flanges prevents the initial growth of the flame kernel. It was found that, in actual engine test, the ignition probability is increased and the lean limit is extended.
The lean limit of combustible mixture in actual engine using conventional spark plugs is about 0.65 in equivalence ratio. Using the flanged spark plug, the lean limit was extended to 0.55. On the effect of reduction of minimum ignition energy equivalent ignition probability was obtained, although the ignition energy was reduced to half compared with using conventional spark plugs. It was found that the optimum flange gap is about 4 mm for actual engines.
In this work, following questions were given.
1. It is necessary to consider on design of flange shape relating to suppression of main flow velocity including turbulence and good reflection of shock wave.
2. It is necessary to give full consideration to the durability before actual use.
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