Benzin ve Alkol Yakıtları İçin Yağ Filmi Kaynaklı HC Emisyonlarının Matematik Modellenmesi

Öz

Silindir cidarları üzerindeki yağ filmi, hidrokarbon (HC) emisyonlarının oluşmasındaki ana kaynaklardan biri olarak bilinmektedir. Bundan dolayı sunulan çalışmada; bir buji ateşlemeli motorda benzin, etanol ve metanol kullanılması durumunda yağ filmi içine emilen/salınan yakıt miktarı sayısal olarak incelenmiştir. Bu amaç için termodinamik esaslı bir çevrim modeli geliştirilmiş ve ardından söz konusu modele yağ filmi kaynaklı HC’lerin oluşumunu hesaplayan bir model eklenmiştir. Yağ filmi tarafından emilen/salınan etanol ve metanol yakıtının benzinden daha düşük seviyede olduğu görülmüştür. Bu farklılığın en önemli parametresi çözünürlükle ilgili olan Henry sabiti olduğu tespit edilmiştir. Düşük motor devirlerinde yağ filmi yakıt buharı etkileşimine daha uzun süre tanındığı için emilen/salınan HC miktarları artmıştır. Artan sıkıştırma oranı ve giriş basıncı ile birlikte emilen/salınan HC miktarları artmıştır

Anahtar Kelimeler

• Yağ filmi, Henry kanunu, HC emisyonları, SI motoru

Mathematical Modeling of HC Emissions Released by Oil Film for Gasoline and Alcohol Fuels

Öz

Oil film on cylinder liner has been suggested as a major source of engine-out hydrocarbon emissions. So in the present study, the rate of absorption/desorption of the fuel in the oil film has been investigated numerically in a spark ignition engine by using gasoline, ethanol and methanol fuels. To aim this purpose, a thermodynamic cycle model has been developed and then a mathematical modeling for the rate of absorption/desorption of the fuel in the oil film has been developed and adapted for this thermodynamic cycle model.It was seen that the absorption/desorption mechanism of ethanol and methanol into the oil film were lower than gasoline. It was determined that the most dominant parameter of this difference was Henry’s constant, which was related to solubility. As interaction time of oil filmfuel vapor was longer at low engine speeds, the quantities of HC absorbed/desorbed increased. The quantities of HC absorbed/desorbed increased with increasing inlet pressure and compression ratio

Anahtar Kelimeler

• Oil film, Henry’s Law, HC emission, SI engine

Kaynakça

1. Baba, Y., Suzuki, H., Sakai, Y., Wei, D.L.T., Ishima, T., Obokata T. (2007). PIV/LIF Measurements of Oil Film Behavior on the Piston in IC Engine, SAE, Paper No: 2007-24- 0001.
2. Çengel, A.Y. and Bols, M.A. (1990). Thermodynamics an Engineering Approach, McGraw-Hill International Editions.
3. Dhar, A., Agarwal A.K., Saxena V. (2008). Measurement of Lubricating Oil Film Thickness Between Piston Ring-Liner Interface in an Engine Simulator, SAE, Paper No: 2008-28-0071.
4. Dwyer-Joyce, R.S., Green, D.A., Harper, P., Lewis, R., Balakrishnan, S., King, P.D., Rahnejat, H., Howell-Smith, S. (2006). The Measurement of Liner-Piston Skirt Oil Film Thickness by an Ultrasonic Means, SAE, Paper No: 2006-01-0648.
5. Ferguson C.R., Kirkpatrick A. (2001). Internal Combustion Engines Applied Thermosciences, John & Wiley Sons Inc, New York.
6. Hamrin, D.A. (1994). Modeling of Engine-Out HC Emissions for Prototype Production, Master Thesis, Massachusetts Institute of Technology.
7. Hamrin, D.A. and Heywood, J.B. (1995). Modeling of Engine-Out Hydrocarbon Emissions for Prototype Production Engines, SAE, Paper No: 950984.
8. Heywood, J.B. (1989). Internal Combustion Engine Fundementals, McGraw-Hill International Editions, Singapore, 930 s.

9. Heywood, J.B. and Hochgreb, S. (1996). Measurement of Gasoline Absoption into Engine Lubricating Oil, SAE, Paper No: 961229.
10. Karamangil, M.I., Surmen, A., and Gul, Z. (2004). In-Cylinder Expansion of Ring Crevice and Oil film Hydrocarbons in SI Engines, Energy Conversion and Management, Vol. 45, No: 18-19, pp. 3109-3126.
11. Karamangil, M.I., Kaynaklı, O., Sürmen, A. (2006). Parametric Investigation of Cylinder and Jacket Side Convective Heat Transfer Coefficients of Gasoline Engines. Energy Conversion and Management, Vol. 47: 800-816.
12. Kato, M., Fujita, K., Suzuki, H., Baba, Y., Ishima, T., Obokata T. (2009). Analysis of Lubricant Oil Film Behavior on the Piston Surface according with Piston Shapes by means of LIF and PIV, SAE, Paper No: 2009-28-0003.
13. Korematsu, K. (1990). Effects of Fuel Absorbed in Oil Film on Unburnt Hydrocarbon Emissions from Spark Ignition Engines, JSME International Journal Series II, 33(3): 606- 614.
14. Norris, M.G., Hochgreb, S. (1994). Novel Experiment on In-Cylinder Desorption of Fuel from the Oil Layer, SAE, Paper No:941963.
15. Salazar, V. (2008). Unburned Hydrocarbon Emission Mechanisms in Small Engines, Ph. D. Thesis, Mechanical Engineering, University of Wisconsin – Madison, USA.
16. Schramm, J. and Sorenson, S.C. (1990). A Model for Hydrocarbon Emissions from SI Engines, SAE, Paper No: 902169.
17. Shenghua, L., Longbao, Z., Keyu, P., Hui, Z., Xiangfeng Y. (1996). Effects of Cylinder Lubrication Oil Film on Hydrocarbon Emissions of SI Engine, SAE, Paper No: 961913.
18. Yenice, S. (2011). Mathematical Modelling of HC Emissions from Oil Film, Master Thesis, Uludag University.
19. Yu, S., Yi, H., Cho, H., Kim, M., Min, K. (2000). Modeling of the Dynamic Process of Fuel Absorption/Desorption in the Oil Film in SI Engines, JSME International Journal Series B, 43(4): 570-575.
20. Yu, S., Min, K. (2002). Effects of the Oil and Liquid Fuel Film on Hydrocarbon Emissions in Spark Ignition Engines, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 216: 759-771.
21. Makale 21.05.2012 tarihinde alınmış, 03.11.2012 tarihinde düzeltilmiş, 09.11.2012 tarihinde kabul edilmiştir.