1996 Fiscal Year Final Research Report Summary
A Low-NOx High-Efficiency Engine System for Alternative Fuels by Mean of Ultra-Lean Homogeneous-Charge Premixed Combustion
| Project/Area Number |
07555071
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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| Research Field |
Thermal engineering
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
IKEGAMI Makoto Kyoto Univ., Graduate School of Eng., Professor, エネルギー科学研究科, 教授 (70025914)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAMURA Hideo Isuzu Ceramics Research Institute Co., Ltd., 取締役(研究職)
YAMANE Koji The Univ.of Shiga Prefecture, School of Eng., Assoc.Professor, 工学部, 助教授 (10210501)
KAWANABE Hiroshi Kyoto Univ., ibid, Instructor, エネルギー科学研究科, 助手 (60273471)
SHIOJI Masahiro Kyoto Univ., ibid, Professor, エネルギー科学研究科, 教授 (80135524)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Alternative Fuel / Lean-Burn Engine / Premixed Combustion / Mixture Heteogeneity / Thermodynamic Model / NOx Formation / Exhaust Measurement / CFD Simulation |
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| Research Abstract |
This study aims at the establishment of the high-efficiency low-NOx engine for alternative fuels at lean homogeneous-charge combustion. The contents of the present study are summarized as follows :
1.Lean limits of homogeneous premixture were investigated in a spark-ignition engine fueled by naturalgas and LPG,and the factors for determining the limit and the method for extending it were shown.
2.Experiments for a variety of engine types and sizes at lean-burning operations show that a homogeneous mixture allows much more reduction of the exhaust NOx concentration than a heterogeneous mixture. In addition, the histories of temperature and NO concentration were calculated using a thermodynamic model based on the measured rates of heat release for the mixture having different degrees of heterogeneity. It was shown that a lean-burn engine with a more homogeneous mixture is desirable, and that much reduction of NO may be achieved once the burnt gas is artificially mixed during combustion to
… More
make the burnt zone more uniform.
3.Real-time measurement of exhaust gas emissions in a lean-burn gas engine was carried out by using Fourier transform infrared spectroscopy analyzer. From the measured results, it was shown that not only unburnt HC but also combustion-generated HC increase in lean combustion. Furthermore, the characteristics of exhaust emissions under a cold start condition were measured, and high concentrations of HCs were detected just after the firing operation, whereas NOx gradually increases from the start.
4.A three-dimensional model for the combustion process and NO formation in a homogeneous-charge engine was established based on a submodel for flame development. Computations carried out for different conditions gave a good reproduction of the entire combustion process. The spatial profiles of heat-release rates, the flame temperature and the NO concentration were investigated to clarify the mechanism of NO formation with special attention to mixing of heat and mass in the combustion process. Less
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