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

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Emission Reduction Characteristics of Three-way Catalyst with Engine Operating Condition Change in an Ultra-lean Gasoline Direct Injection Engine

초희박 직접분사식 가솔린 엔진용 삼원촉매의 운전조건에 따른 배기저감 특성

  • Park, Cheol Woong (Environmental System Research Division / Engine Research Team, Korea Institute of Machinery and Materials) ;
  • Lee, Sun Youp (Environmental System Research Division / Engine Research Team, Korea Institute of Machinery and Materials) ;
  • Yi, Ui Hyung (Dept. of Mechanical Engineering, Gachon Univ.) ;
  • Lee, Jang Hee (Environmental System Research Division / Engine Research Team, Korea Institute of Machinery and Materials)
  • 박철웅 (한국기계연구원 그린동력연구실) ;
  • 이선엽 (한국기계연구원 그린동력연구실) ;
  • 이의형 (가천대학교 기계공학과) ;
  • 이장희 (한국기계연구원 그린동력연구실)
  • Received : 2015.02.20
  • Accepted : 2015.06.27
  • Published : 2015.09.01
Download PDF
⟨ Previous Next ⟩

Abstract

Recently, because of the increased oil prices globally, there have been studies investigating the improvement of fuel-conversion efficiency in internal combustion engines. The improvements realized in thermal efficiency using lean combustion are essential because they enable us to realize higher thermal efficiency in gasoline engines because lean combustion leads to an increase in the heat-capacity ratio and a reduction of the combustion temperature. Gasoline direct injection (GDI) engines enable lean combustion by injecting fuel directly into the cylinder and controlling the combustion parameters precisely. However, the extension of the flammability limit and the stabilization of lean combustion are required for the commercialization of GDI engines. The reduction characteristics of three-way catalysts (TWC) for lean combustion engines are somewhat limited owing to the high excess air ratio and low exhaust gas temperature. Therefore, in the present study, we assess the reaction of exhaust gases and their production in terms of the development of efficient TWCs for lean-burn GDI engines at 2000 rpm / BMEP 2 bar operating conditions, which are frequently used when evaluating the fuel consumption in passenger vehicles. At the lean-combustion operating point, $NO_2$ was produced during combustion and the ratio of $NO_2$ increased, while that of $N_2O$ decreased as the excess air ratio increased.

세계적으로 유가 상승에 따른 내연기관의 에너지 변환 효율을 높이고자 하는 연구가 활발히 진행되고 있다. 가솔린엔진에서 높은 열효율을 실현하기 위해서는 희박연소에 의한 비열비의 증가 및 단열화염온도의 저감에 의한 열효율 향상이 필수적이다. 직접분사식 가솔린 엔진은 연료를 직접 연소실에 공급하고 정밀한 연소제어를 통해 희박 연소가 가능하게 하지만 희박연소 한계의 확대와 안정된 희박연소제어가 요구된다. 희박연소 엔진에 대한 삼원촉매의 배출가스 저감특성은 높은 공기과잉률 및 낮은 배기가스 온도로 인해 매우 제한적이다. 이에 효과적인 삼원촉매의 개발을 위해 승용 차량용 엔진의 주요 연비시험 운전조건인 2000 rpm BMEP 2bar 조건에서 공기과잉률의 변화에 따른 배출가스 반응 및 생성 특성을 비교하였다. 희박연소 조건에서 $NO_2$가 생성되었으며, $NO_2$의 비율은 공기과잉률이 증가할수록 증가하고 $N_2O$는 감소하였다.

Keywords

References

  1. European Commission, 2013, "Climate Action: Building a World We Like, with a Climate We Like," Luxembourg, Publications Office.
  2. United Nations, 2013, "United Nations Global Compact International Yearbook 2013," United Nations Pubns.
  3. Alkiad, A. C. and Eltary, S. H., 2003, "Contributors to the Fuel Economy Advantage of DISI Engines Over PFI Engines," SAE Technical paper, 2003-01-3101.
  4. Lee, J., Kang, J. and Kim, D., 2003, "Effect of Injection Timing and Intake Flow on In-cylinder Fuel Behavior in a GDI Engine," Trans. Korean Soc. Auto. Eng., Vol. 11, No. 6, pp. 7-13.
  5. Szekely, G. A. and Alkiads, A. C., 2005, "Combustion Characteristics of a Spray-Guided Direct Injection Stratified-Charge Engine with a High Squish Piston," SAE Technical paper, 2005-01-1937.
  6. Choi, B. C., 2001, "Technologies for Emission Aftertreatment," Baro Press Co., pp. 351-352.
  7. Borgan, M. S., Brisley, R. J., Walker, A. P., Webster, D. E., Boegner, W., Fekete, N. P., Kramer, M., Krutzsch, B. and Voigtlander, D., 1995, "Evaluation of NOx Storage Catalysts as an Effective System for NOx Removal from the Exhaust Gas of Leanburn Gasoline Engine," SAE Technical paper, 952490.
  8. Lee, C. H., Choi, B. C. and Juhng, W. N., 2004, "Comparison of NOx Reduction Characteristics of NOx Adsorption Catalyst with TWC for Lean-burn Natural Gas Vehicles," 2004 KSAE Spring Conference, pp. 579-584.
  9. Piock, W. F., Weyand, P., Wolf, E. and Heise, V., 2010, "Ignition Systems for Spray-Guided Stratified Combustion," SAE Technical paper, 2010-10-0598.
  10. Husted, H. L., Piock, W. and Ramsay, G., 2009, "Fuel Efficiency Improvements from Lean, Stratified Combustion with a Solenoid Injector," SAE Technical paper, 2009-10-1485.
  11. Baek, K. H., Yoo, S. Y., Bae, G. S., Woo, M. S. and Kim, W. G., 2010, "A Study on Regeneration Strategies of Cordierite-DPF Applied to a Diesel Vehicle," 2010 KSAE Annual Conference and Exhibitions, pp. 833-840.
  12. Prigent, M. and Soete, G. De, 1989, "Nitrous Oxide $N_2O$ in Engine Exhaust Gases-A Frist Appraisal of Catalyst Impact," SAE Technical paper, 890492.
  13. Torres, J. Q., Royer, S., Bellat, J. P., Giraudon, J. M. and Lamonier, J. F., 2013, "Formaldehyde: Catalytic Oxidation as a Promising Soft Way of Elimination," Che. Sus. Chem. Vol. 6, pp. 578-592. https://doi.org/10.1002/cssc.201200809
  14. Kwon, D. W., Seo, P. W., Kim, G. J. and Hong, S. C., 2015, "Characteristics of the HCHO Oxidation Reaction over Pt/$TiO_2$ Catalysts at Room Temperature: The Effect of Relative Humidity on Catalytic Activity," Applied Catalysis B: Environmental, Vol. 163, pp.436-443. https://doi.org/10.1016/j.apcatb.2014.08.024
  15. Choi, B. C., "Characteristics of Formaldehyde and $N_2O$ Formation from Catalytic Reaction of Methane," Trans. Korean Soc. Auto. Eng., Vol. 3, No. 2, pp. 95-101.
  16. Burch, R., Daniells, S. T. and Hu, P., 2002, "$N_2O$ and $NO_2$ Formation on Pt(111): A Density Functional Theory Study," The Journal of Chemical Physics, Vol. 117, pp. 2902-2908. https://doi.org/10.1063/1.1490338
  17. 'A-Centeno, I. M. and Fuentes, G. A., 2009, "Nitrous Oxide Formation During Light-Off Over a Commercial Pd-Containing Three-Way Catalytic Converter: The Effect of Low-Sulfur Gasoline," Chem. Eng. Comm., Vol. 196, pp. 1140-1151. https://doi.org/10.1080/00986440902831664
  18. Perez, V. R., 2013, "Optimizatio of N2O Decomposition RhOx/ceria Catalysts and Design of a High N2-selective deNOx System for Diesel Vehicles," Ph.D Thesis, Universidad de Alicante.
  19. Zhang, C. B. and He H., 2007, "A Comparative Study of TiO2 Supported Noble Metal Catalysts for the Oxidation of Formaldehyde at Room Temperature," Catalysis Today, Vol. 126, pp. 345-350. https://doi.org/10.1016/j.cattod.2007.06.010