Supercharged Homogeneous Charge Compression Ignition
Author
Summary, in English
The Homogeneous Charge Compression Ignition (HCCI) is the third alternative for combustion in the reciprocating engine. Here a homogeneous charge is used as in a spark-ignited engine, but the charge is compressed to autoignition as in a diesel. The main difference compared with the Spark Ignition (SI) engine is the lack of flame propagation and hence the independence from turbulence. Compared with the diesel engine, HCCI has a homogeneous charge and hence no problems associated with soot and NOdx formation. Earlier research on HCCI showed high efficiency and very low amounts of NOdx, but HC and CO were higher than in SI mode. It was not possible to achieve high IMEP values with HCCI, the limit being 5 bar. Supercharging is one way to dramatically increase IMEP. The influence of supercharging on HCCI was therefore experimentally investigated. Three different fuels were used during the experiments: iso-octane, ethanol and natural gas. Two different compression ratios were used, 17:1 and 19:1. The inlet pressure conditions were set to give 0, 1, or 2 bar of boost pressure. The highest attainable IMEP was 14 bar using natural gas as fuel at the lower compression ratio. The limit in achieving even higher IMEP was set by the high rate of combustion and a high peak pressure.
Numerical calculations of the HCCI process have been performed for natural gas as fuel. The calculated ignition timings agreed well with the experimental findings. The numerical solution is, however, very sensitive to the composition of the natural gas.
Numerical calculations of the HCCI process have been performed for natural gas as fuel. The calculated ignition timings agreed well with the experimental findings. The numerical solution is, however, very sensitive to the composition of the natural gas.
Department/s
Publishing year
1998
Language
English
Publication/Series
SAE Transactions, Journal of Engines
Volume
107
Issue
SAE Technical Paper 980787
Full text
- Available as PDF - 431 kB
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Document type
Journal article
Publisher
Society of Automotive Engineers
Topic
- Atom and Molecular Physics and Optics
- Other Mechanical Engineering
Keywords
- Supercharging
- HCCI
- Combustion
- Engine
Status
Published
ISBN/ISSN/Other
- ISSN: 0096-736X