This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Design of Rankine Cycle Systems to Deliver Fuel Economy Benefits over Cold Start Driving Cycles
Technical Paper
2012-01-1713
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Prior papers have shown the potentials of gasoline-like internal combustion engines fitted with waste heat recovery systems (WHR) to deliver Diesel-like steady state fuel conversion efficiencies recovering the exhaust and the coolant waste heat with off-the-shelf components. In addition to the pros of the technology significantly increasing steady state efficiencies - up to 5 % in absolute values and much more in relative values - these papers also mentioned the cons of the technology, increased back pressures, increased weight, more complex packaging, more complex control, troublesome transient operation, and finally the cold start issues that prevent the uptake of the technology. This paper further explores the option to use Rankine cycle systems to improve the fuel economy of vehicles under normal driving conditions. A single Rankine cycle system is integrated here with the engine design. A latest turbocharged 1.6 liter direct injection engine has the coolant circuit modified to serve as pre-heater for the Rankine cycle fluid. This fluid is then vaporized and superheated in the boiler/super heater coaxial to the exhaust pipe located downstream of the turbocharger turbine and the closed coupled catalytic converter. The exhaust ports are insulated to reduce the heat losses. The pump of the Rankine cycle system is electrically operated. The expander of the Rankine cycle system drives a generator to recharge the traction battery pack. The thermal engine is connected to the transmission through an electric clutch and a motor/generator that permits to supplement/replace the thermal engine energy supply, recover the braking energy and start/stop the thermal engine. The integrated Rankine cycle system is intended to permit short warming up profiles, reduced heat losses and reduced weight and packaging issues, delivering significant benefits during cold start driving cycles as the new European driving cycle (NEDC) in addition to the long term, constant load and speed extra urban driving. Prior results for the steady engine gas exchange and combustion, the steady waste heat recovery system with organic Rankine cycles (ORC) and the transient engine gas exchange and combustion inclusive of the thermal analysis have been performed with very well known commercial computer aided engineering tools and have already been peer reviewed in the scientific literature. The novelty of the present paper is the better definition of the novel single circuit Turbo steamer system where the operating fluid is water and the engine coolant passages work as pre-heater/boiler and a first very conservative assessment of the transient performance such a system could deliver when integrated in parallel hybrid vehicle architecture.
Recommended Content
Authors
Topic
Citation
Boretti, A., Osman, A., and Aris, I., "Design of Rankine Cycle Systems to Deliver Fuel Economy Benefits over Cold Start Driving Cycles," SAE Technical Paper 2012-01-1713, 2012, https://doi.org/10.4271/2012-01-1713.Also In
References
- Boretti, A “STOICHIOMETRIC H2ICE WITH WATER INJECTION AND EXHAUST AND COOLANT HEAT RECOVERY THROUGH ORGANIC RANKINE CYCLES” International Journal of Hydrogen Energy 2011 36 19 12591 12600
- Boretti, A “Recovery of exhaust and coolant heat with R245fa organic Rankine cycles in a hybrid passenger car with a gasoline engine” Applied Thermal Engineering 36 April 2012 73 77
- Boretti, A “ENERGY RECOVERY IN PASSENGER CARS” Journal of Energy Resources Technology June 2012 134 2 022203
- Ricardo, “WAVE” www.ricardo.com/What-we-do/Software/Products/WAVE/ January 10 2012
- Gamma technologies “GT-COOL” www.gtisoft.com/img/broch/broch_gtcool.pdf January 10 2012
- Honeywell, “Genetron® 245fa” www51.honeywell.com/sm/chemicals/refrigerants/eu/en/products-n2/organic-n3/organic-genetron 245fa.html?c=25 January 10 2012
- Lotus engineering software “Lotus Vehicle Simulation(LVS)” www.lotuscars.com/engineering/en/lesoft-products January 10 2012
- Ringler, J. Seifert, M. Guyotot, V. Hübner, W. “Rankine Cycle for Waste Heat Recovery of IC Engines,” SAE Int. J. Engines 2 1 67 76 2009 10.4271/2009-01-0174
- bmwheaven.com “BMW unveils the turbosteamer concept” www.bmwheaven.com/index.php/articles-and-reviews-mainmenu-3/bmw-innovations/65-169 January 10 2012
- Boretti, A “TRANSIENT OPERATION OF INTERNAL COMBUSTION ENGINES WITH RANKINE WASTE HEAT RECOVERY SYSTEMS” Applied Thermal Engineering 2012
- Toyota “How hybrids work” www.toyota.com.au/hybrid-synergy-drive/hybrid-technology/how-hybrid-works January 10 2012
- Honda “Hybrid” world.honda.com/Hybrid/ January 10 2012
- Boretti, A. Lodi, F. Watson, H. Brear, M. et al. “Experimental and Numerical Analysis of Engine Gas Exchange, Combustion and Heat Transfer during Warm-Up,” SAE Technical Paper 2008-01-1653 2008 10.4271/2008-01-1653
- Boretti, A.A. Will, F. Watson, H.C. Brear, M.J. Dingli, R. Voice, G. “Comparison of static and dynamic engine models on the transient performance of a passenger vehicle power train” 2008 FISITA World Automotive Congress Munich, Germany September 14 19 2008 F2008-12-287
- Tesla Motors “Energy Efficiency of Tesla Electric Vehicles” www.teslamotors.com/goelectric/efficiency May 20 2012