Düşük-Yüklü Dizel Motor Operasyonlarında İç Egzoz Gazı Devridaimi Yoluyla Egzoz Sıcaklığı Yönetiminin İyileştirilmesi

Modern karayolu otomotiv araçları sıkı emisyon yönetmeliklerini karşılamak için genellikle egzoz arıtım sistemleri (EAS) kullanmaktadırlar. Bu sistemler emisyon oranlarını azaltmada çoğu zaman etkili olsa da, düşük-yüklerde düşük egzoz sıcaklıkları (250oC'nin altında) yüzünden etkisiz olmaktadırlar. Bu çalışma, bir dizel motor modeli üzerinde, egzoz sıcaklıklarının düşük yüklerde iç egzoz gazı devridaimi (İEGD) metoduyla 250oC'nin üzerine çıkarılabileceğini göstermektedir. Motor sistemi 1700 devir/dakika hızda ve 2,5-4,5 bar fren ortalama efektif basınç motor yükleri arasında çalışmaktadır. İEGD silindir-içi sıcak artık egzoz gazı miktarını arttırmakta ve bu yüzden önemli bir egzoz sıcaklığı artışına (70o C'ye kadar) sebep olmaktadır. Daha sıcak egzoz sistemi, EAS emisyon dönüşüm verimini çoğunlukla % 90'ın üstünde tutar ve arttırılan ısı transfer oranlarıyla (% 142'ye kadar) EAS katalizör yatağının daha hızlı ısınmasını sağlar. İEGD geleneksel EAS ısıtma teknikleri kadar yakıt tüketici değildir ve yakıt tüketimi artışını % 5'in altında tutabilmektedir.

Improving Exhaust Temperature Management At Lowloaded Diesel Engine Operations Via Internal Exhaust Gas Recirculation

Modern on-road automotive vehicles mostly utilize exhaust after-treatment (EAT) systems to meet the stringent emission regulations. Although those systems are generally effective to reduce emission rates, they are ineffectual at low loads due to low exhaust temperatures (below 250oC). This study demonstrates on a diesel engine model that exhaust temperatures can be increased above 250oC at light loads through internal exhaust gas recirculation (IEGR) method. Engine system operates at 1700 RPM engine speed and within 2.5-4.5 bar brake mean effective pressure (BMEP) engine loads. IEGR increases the amount of in-cylinder hot residual exhaust gas and thus causes a considerable exhaust temperature rise (up to 70oC). Warmer exhaust system keeps EAT emission conversion efficiency mostly above 90 % and accelerates EAT catalyst bed warm-up through increased (up to 142 %) heat transfer rates. IEGR is not as fuel-consuming as conventional EAT warming techniques and can keep the fuel consumption rise below 5 %.

PDF

___

Charlton, S., Dollmeyer, T., Grana, T. 2010. Meeting the us heavy-duty epa 2010 standards and providing increased value for the customer, SAE International Journal of Commercial Vehicles, Volume 3 (1), p. 101-110.
Pipitone, E., Genchi, G. 2016. NOx reduction and efficiency improvements by means of the Double Fuel HCCI combustion of natural gas gasoline mixtures, Applied Thermal Engineering, Volume 102, p. 1001-1010.
Benajes, J., Pastor, JV., Garcia, A., Monsalve-Serrano, J. 2015. The potential of RCCI concept to meet EURO VI NOx limitation and ultra-low soot emissions in a heavy-duty engine over the whole engine map, Fuel, Volume 159, p. 952-961.
Dubey, P., Gupta, R. 2017. Effects of dual bio-fuel (Jatropha biodiesel and turpentine oil) on a single cylinder naturally aspirated diesel engine without EGR, Applied Thermal Engineering, Volume 115, p. 1037-1047.
Song, X., Surenahalli, H., Naber, J., Parker, G., Johnson, J.H. 2013. Experimental and modeling study of a diesel oxidation catalyst (DOC) under transient and CPF active regeneration conditions, SAE Technical Paper, No. 2013-01-1046.
Girard, J., Cavataio, G., Snow, R., Lambert, C. 2009. Combined Fe-Cu SCR systems with optimized ammonia to NOx ratio for diesel NOx control, SAE Int. J. Fuels Lubr., Volume 1(1), p. 603-610.
Honardar, S., Busch, H., Schnorbus, T., Severin, C., Kolbeck, A.F., Körfer, T. 2011. Exhaust temperature management for diesel engines assessment of engine concepts and calibration strategies with regard to fuel penalty, SAE Technical Paper, No. 2011-24-0176.
Cavina, N., Mancini, G., Corti, E., Moro, D. et al. 2013. Thermal management strategies for SCR after treatment systems, SAE Technical Paper, No. 201324-0153.
Bohac, S.V., Assanis, D.N. 2004. Effect of exhaust valve timing on gasoline engine performance and hydrocarbon emissions, SAE Technical Paper, No. 2004-01-3058.
Roberts, L., Magee, M., Shaver, G. 2015. Modeling the impact of early exhaust valve opening on exhaust thermal management and efficiency for compression ignition engines, International Journal of Engine Research, Volume 16(6), p. 773-794.
Bharath, A.N., Kalva, N., Reitz, R.D., Rutland, C.J. 2014. Use of early exhaust valve opening to improve combustion efficiency and catalyst effectiveness in a multi-cylinder RCCI engine system - a simulation study. ASME 2014 Internal Combustion Engine Division Fall Technical Conference, 19-22 October, Columbus, IN, USA.
Gehrke, S., Kovacs, D., Eilts, P. 2013. Investigation of VVA-based exhaust management strategies by means of a HD single cylinder research engine and rapid prototyping systems, SAE Technical Paper, No. 2013-01-0587.
Ding, C., Roberts, L., Fain, D.J. et al. 2016. Fuelefficient exhaust thermal management for compression ignition engines during idle via cylinder deactivation and flexible valve actuation, International Journal of Engine Research, Volume 17(6), p. 619-630.
Garg, A., Magee, M., Ding, C. et al. 2016. Fuel-efficient exhaust thermal management using cylinder throttling via intake valve closing timing modulation, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, Volume 230(4), p. 470-478.
Ramesh, A.K., Shaver, G.M., Allen, C.M. et al. 2017. Utilizing low airflow strategies, including cylinder deactivation, to improve fuel efficiency and aftertreatment thermal management, International Journal of Engine Research, Volume 18(10), p. 10051016.
Basaran, H.U., Ozsoysal, O.A. 2017. Effects of application of variable valve timing on the exhaust gas temperature improvement in a low-loaded diesel engine, Applied Thermal Engineering, Volume 122, p. 758-767.
Winterbone, D.E., Pearson, R.J. 2000. Theory of engine manifold design - Wave action methods for IC Engines. Professional Engineering Publications, London.
Heywood, J.B. 1998. Internal combustion engine fundamentals. McGraw -Hill, Inc.
Lotus Engineering Software, Lotus Engine Simulation (LES) 2013 verison, Lotus Engineering, Hethel, Norfolk.
Getting started with Lotus Engine Simulation, 2013. http://www.lotusproactive.files.wordpress. com/2013/08/getting-started-with-lotus-enginesimulation.pdf (Erişim Tarihi: 12.06.2018).
Watson, N., Pilley, A.D. 1980. A combustion correlation for diesel engine simulation, SAE Technical Paper, No. 800029.
Ahmad, N., Babu, M.G. 2006. Simulation and experimental studies on combustion and performance characteristics for a turbocharged and naturally aspirated multi-cylinder compression ignition engine, SAE Technical Paper, No. 2006-013487.
Zheng, M., Reader, G.T., Hawley, J.G. 2004. Diesel engine exhaust gas recirculation - a review on advanced and novel concepts, Energy Conversion and Management, Volume 45(6), p. 883-900.
Johnson, T.V., 2009. Diesel emission control in review, SAE International Journal of Fuels and Lubricants, Volume 1(1), p. 68-81.
Joshi, M.C., Gosala, D.B., Allen, C.M. et al. 2017. Reducing diesel engine drive cycle fuel consumption through use of cylinder deactivation to maintain aftertreatment component temperature during idle and low load operating conditions, Frontiers in Mechanical Engineering, Volume 3(8).