Abstract
The Rankine cycle system for waste heat recovery of heavy-duty vehicle diesel engines has been regarded as a promising technique to reduce fuel consumption. Its heat dissipation in the condensation process, however, should be taken away in time, which is an energy-consuming process. A fan-assisted auxiliary water-cooling system is employed in this paper. Results at 1300 r/min and 50% load indicate that the cooling pump and cooling fan together consume 7.66% of the recovered power. What’s worse for the heavy load, cooling accessories may deplete of all the recovered power of the Rankine cycle system. Afterwards, effects of the condensing pressure and water feeding temperature are investigated, based on which a cooling power consumption model is established. Finally, an overall efficiency optimization is conducted to balance the electric power generation and cooling power consumption, taking condensing pressure, pressure ratio and exhaust bypass valve as major variables. The research suggests that the priority is to increase condensing pressure and open exhaust bypass valve appropriately at high speed and heavy load to reduce the cooling power consumption, while at low speed and light load, a lower condensing pressure is favored and the exhaust bypass valve should be closed making the waste heat recovered as much as possible. Within the sub-critical region, a larger pressure ratio yields higher overall efficiency improvement at medium-low speed and load. But the effects taper off at high speed and heavy load. For a given vehicular heavy-duty diesel engine, the overall efficiency can be improved by 3.37% at 1300 r/min and 25% load using a Rankine cycle system to recover exhaust energy. The improvement becomes smaller as engine speed and load become higher.
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References
Ringler J, Seifert M, Guyotot V, et al. Rankine cycles for waste heat recovery of IC engines. In: SAE Technical Papers. Detroit: SAE International, 2009. No. 2009-01-0174
Hounsham S, Stobart R, Cooke A, et al. Energy recovery systems for engines. In: SAE Technical Papers. Detroit: SAE International, 2008. No. 2008-01-0309
Chammas R E I, Clodic D. Combined cycle for hybrid vehicles. In: SAE Technical Papers. Detroit: SAE International, 2005. No. 2005-01-1171
Park T, Teng H, Hunter G L, et al. A Rankine cycle system for recovering waste heat from HD diesel engines-Experimental results. In: SAE Technical Papers. Detroit: SAE International, 2011. No. 2011-01-1337
Lee J, Ohn H, Choi J Y, et al. Development of effective exhaust gas heat recovery system for a hybrid electric vehicle. In: SAE Technical Papers. Detroit: SAE International, 2011. No. 2011-01-1171
Stobart R, Weerasinghe R. Heat Recovery and bottoming cycles for SI and CI Engines–A perspective. In: SAE Technical Papers. Detroit: SAE International, 2006. No. 2006-01-0662
Chiew L, Clegg M W, Willats R H, et al. Waste heat energy harvesting for improving vehicle efficiency. In: SAE Technical Papers. Detroit: SAE International, 2011. No. 2011-01-1167
Tian H, Zhang C Y, Li X N, et al. Experimental investigation on diesel engine's waste heat capacity under mapping characteristics. Sci China Tech Sci, 2015. 58: 9–18
Patel P S, Doyle E F. Compounding the truck diesel engine with an organic Rankine-cycle system. In: SAE Technical Papers. Detroit: SAE International, 1976. No. 760343
Heywood J B. Automotive engines and fuels: a review of future options. Prog Energ Combust, 1981. 7: 155–184
Teng H, Regner G, Cowland C. Achieving high engine efficiency for heavy-duty diesel engines by waste heat recovery using supercritical organic-fluid Rankine cycle. In: SAE Technical Papers. Detroit: SAE International, 2006. No. 2006-01-3522
Dolz V, Novella R, García A, et al. HD Diesel engine equipped with a bottoming Rankine cycle as a waste heat recovery system. Part 1: Study and analysis of the waste heat energy. Appl Therm Eng, 2012. 36: 269–278
Hung T C, Shai T Y, Wang S K. A review of organic Rankine cycles (ORCs) for the recovery of low-grade waste heat. Energy, 1997. 22: 661–667
Wang E H, Zhang H G, Fan B Y, et al. Study of working fluid selection of organic Rankine cycle (ORC) for engine waste heat recovery. Energy, 2011. 36: 3406–3418
Wei D, Lu X, Lu Z, et al. Performance analysis and optimization of organic Rankine cycle (ORC) for waste heat recovery. Energ Convers Manage, 2006. 48: 1113–1119
Wei M S, Fang J L, Ma C C. Waste heat recovery from heavy-duty diesel engine exhaust gases by medium temperature ORC system. Sci China Tech Sci, 2011. 54: 2746–2753
Badr O, Naik S, O’Callaghan PW, et al. Expansion machine for a low power-output steam Rankine-cycle engine. Appl Energ, 1991. 39: 93–116
Quoilin S, Lemort V, Lebrun J. Experimental study and modeling of an organic Rankine cycle using scroll expander. Appl Energ, 2010. 87: 1260–1268
Pandiyarajan V, Pandian M C, Malan E, et al. Experimental investigations on heat recovery from diesel engine exhaust using finned shell and tube heat exchanger and thermal storage system. Appl Energ, 2011. 88: 77–87
Xie H, Yang C. Dynamic behavior of Rankine cycle system for waste heat recovery of heavy duty diesel engines under driving cycle. Appl Energ, 2013. 112: 130–141
Yang C, Xie H, Zhou S K. Efficiency analysis of the rankine cycle system used for engine exhaust energy recovery under driving cycle. In: SAE Technical Papers. Detroit: SAE International, 2014. No. 2014-01-0671
Tona P, Peralez J, Sciarretta A. Supervision and control prototyping for an engine exhaust gas heat recovery system based on a steam Rankine cycle. In: IEEE/ASME International Conference on Advanced Intelligent Mechatronics. Kaohsiung, Taiwan: IEEE, 2012. 695–701
Horst T A, Tegethoff W, Eilts P, et al. Prediction of dynamic Rankine Cycle waste heat recovery performance and fuel saving potential in passenger car applications considering interactions with vehicles’ energy management. Energ Convers Manage, 2014. 78: 438–451
Yang S, Tao W. Heat Transfer (in Chinese). 4th ed. Beijing: Higher Education Press, 2006. 243–256
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Yang, C., Xie, H. & Zhou, S.K. Overall optimization of Rankine cycle system for waste heat recovery of heavy-duty vehicle diesel engines considering the cooling power consumption. Sci. China Technol. Sci. 59, 309–321 (2016). https://doi.org/10.1007/s11431-015-5963-4
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DOI: https://doi.org/10.1007/s11431-015-5963-4