Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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A Study About the Effect of EGR Ratio on DME HCCI Combustion Process

EGR 율이 DME HCCI 엔진연소과정에 미치는 영향에 관한 연구

  • Lim, Ocktaeck (School of Mechanical Engineering, Univ. of Ulsan)
  • 임옥택 (울산대학교 기계공학부)
  • Received : 2012.04.23
  • Accepted : 2013.09.03
  • Published : 2013.10.01
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Abstract

This study aims to provide helpful suggestions for understanding the effect of high EGR on DME HCCI combustion. This study determined which between oxygen partial pressure and oxygen concentration was the main factor affecting the LTHR heating ratio. Furthermore, EGR and the supercharging effect were investigated. To define the parameters for the EGR ratio and supercharging pressure, a numerical analysis of the chemical reaction was conducted under the following conditions: (1) variation of EGR ratio, oxygen concentration, and oxygen content; (2) variation of oxygen partial pressure while the oxygen concentration was almost constant; and (3) variation of oxygen concentration while oxygen partial pressure was constant with EGR and supercharging. The results show that an increase in EGR reduces the combustion duration. On the other hand, an increase in boost pressure increases the combustion duration. Finally, the EGR and boost pressure affect the amount of increase in LTHR.

본 연구에서는 고농도 EGR을 사용하는 DME 예혼합압축자기착화 연소의 근본적인 연소메커니즘을 이해하기 위해 수치해석 시뮬레이션을 수행하였다. EGR과 과급의 영향을 조사하면서 동시에 산소 분압과 산소 농도중 어느 것이 LTR 발열비율을 결정하는 핵심요소인지 확인하였다. EGR 비율과 과급압력을 매개변수 정하기 위해서 1) EGR 비율변화에 따라 산소농도, 산소함유량을 변화시키는 조건 2) 산소농도를 거의 일정하게 유지하면서 과급을 하여 산소 분압을 변화시키는 조건, 3) EGR과 과급을 조합하면서 산소 분압을 일정하게 유지 하기 위해 산소농도를 변화시키는 조건 세가지 조건에서 화학반응수치계산을 수행하여 검증했다. 연구결과 EGR율이 증가하면 연소의 시작, 종료시기가 지연되고, 과급을 하게 되면 연소의 시작, 종료시기가 앞당겨지는 것을 확인했다. EGR과 과급이 LTHR 발열비율 증가에 영향을 미치는 것도 확인하였다.

Keywords

Acknowledgement

Supported by : 한국연구재단

References

  1. Andreae, M. M., Cheng, W. K., Kenney, T. and Yang, J., 2007, "On HCCI Engine Knock," SAE 2007-01-1858.
  2. Yamashita, D., Soonpyo, K., Sato, S. and Iida, N., 2005, "The Study on Auto-ignition and Combustion Process of the Fuel Blended with Methane and DME in HCCI Engine," Transactions of Society of Automotive Engineers of Japan, Vol.36 No.6 pp.85-90.
  3. Sjoberg, M., Dec, J. E. and Cernansky, N. P., 2005, "Potential of Thermal Stratification and Combustion Retard for Reducing Pressure-Rise Rates in HCCI Engines, Based on Multi-Zone Modeling and Experiments," SAE Paper 2005-01-0113.
  4. Luz A.E., Rupley, F. and Miller, J.A., 1998, Sandia National Laboratories Report, SAND87-8248B.
  5. Luz, A.E., Rupley F. and Miller, J.A., 1989, Sandia National Laboratories Report, SAND89-8009B.
  6. Kanehara, M. and Iida, N., 2011, "Influence of Compression Speed on HCCIIgnition and Combustion," The 22th Internal Combustion Engine Sympojium.
  7. Curran, H. J., Pitz, W. J., Westbrook, C. K., Dagaut, P., Boettner, J.-C. and Cathonnet, M., 1998,"A Wide Range Modeling Study of Dimethyl Ether Oxidation," International Journal Chemical Kinetics, 30-3, pp. 229-241, https://doi.org/10.1002/(SICI)1097-4601(1998)30:3<229::AID-KIN9>3.0.CO;2-U
  8. Kwon, O. S., Jeong, D. W., Lim, O. T. and Iida, N., 2009, "Effect of the Boost Pressure on Thermal Stratification in an HCCI Engine Using Multi-Zone Model," SAE Paper 20097141.
  9. Kanehara, D. and Mitsuru, K., 2008, "Characteristics of Low Temperature Reaction in DME/Air HCCI Process," JSME Conference, Ibaraki.
  10. Nagae, M., Iida, N., 2007, "Effect of Intake gas Pressure and Temperature on HCCI Combustion Process by Using Numerical Analysis," Proceedings of the 45th Symposium on Combustion, Sendai International center.