This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Methods of Increasing the BMEP (Power Output) for Natural Gas Spark Ignition Engines
Annotation ability available
Sector:
Language:
English
Abstract
The present levels of the BMEP for natural gas fueled spark ignition engines, the BMEP of 1.0MPa for stoichiometric burn and 1.2MPa for lean burn, are lower than those of diesel engines. This paper discusses the reasons. The factors that limit the BMEP are mainly engine knocking and thermal loading such as exhaust temperature and boost pressure.
The Miller cycle and cooled EGR were applied to a turbo-charged, 324kW natural gas engine for co-generation. A lower compression ratio prevents engine knocking and a higher expansion ratio reduces the exhaust temperature in the Miller cycle. The EGR also improves the knock limit by reducing the exhaust temperature.
In the Otto cycle, the BMEP is limited by the EGR ratio (COV_IMEP) which is used to control the engine knocking and decrease the exhaust temperature, but in the Miller cycle with its high expansion ratio and low compression ratio, is limited by the boost pressure. The combination of the Miller cycle and EGR system demonstrates promising performance, substantially improving the BMEP to 1.7MPa under stoichiometric conditions compared to 1.0MPa by conventional engines. In this case, the following conditions were kept to ensure engine reliability.
Recommended Content
Authors
Topic
Citation
Zhang, F., Okamoto, K., Morimoto, S., and Shoji, F., "Methods of Increasing the BMEP (Power Output) for Natural Gas Spark Ignition Engines," SAE Technical Paper 981385, 1998, https://doi.org/10.4271/981385.Also In
Combustion Processes in Engines Utilizing Gaseous Fuels, 1998
Number: SP-1371; Published: 1998-05-04
Number: SP-1371; Published: 1998-05-04
References
- ZHANG Fu-Rong et al. Effect of Miller Cycle on Gas Engine for Generation Transactions of the Society of Automotive Engineers of Japan 27 1 January 1996 79 84
- ZHANG Fu-Rong Miller Cycle Gas Engine Internal Combustion Engine 34 434 1995 11 105 112
- Okamoto Kazuhisa et al. Study on Miller Cycle Gas Engine for Co-Generation Systems SAE Paper No. 960949
- ZHANG Fu-Rong et al. Development of the Miller Cycle for Natural Gas Engines ASME 1996 Fall Technical Conference 1 27-1 35 44
- SIMOGATA Satoshi et al. Study on Miller Cycle Gas Engine for Co-Generation Systems - 2nd report: Numerical Analysis for Improvement of Efficiency and Power - Proceedings of JSAE Spring Conference paper No.9633009 1996-5 41 44
- Okamoto Kazuhisa et al. Development of a Late Intake-Valve Closing (IVC) Miller Cycle for Stationary Natural Gas Engines - Effect of EGR SAE 972948
- Yamamoto Y. et al. Study of Combustion Characteristics of Compressed Natural Gas (CNG) Proceedings of JSAE Spring Conference paper No. 9302448 1993-5 117 120
- Sakonji Tatsuo et al. Study on Improvement of Natural Gas Fueled Spark Ignition Engines - Effect of EGR Utilization - SAE paper No. 971714