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Vehicle Applications, Future of IC Engines

Vehicle Applications, Future of IC Engines 22
Part 10: Vehicle Applications, Future of IC Engines Reciprocating Internal Combustion Engines Prof. Rolf D. Reitz Engine Research Center University of WisconsinMadison 2014 PrincetonCEFRC Summer School on Combustion Course Length: 15 hrs (Mon. Fri., June 23 – 27, 2014) Copyright ©2014 by Rolf D. Reitz. This material is not to be sold, reproduced or distributed without prior written permission of the owner, Rolf D. Reitz. 1 1 CEFRC9 J CEFRC5 une 29, 10, 2014 2012 Part 10: Vehicle Applications, Future of IC Engines Short course outine: Engine fundamentals and performance metrics, computer modeling supported by indepth understanding of fundamental engine processes and detailed experiments in engine design optimization. Day 1 (Engine fundamentals) Part 1: IC Engine Review, 0, 1 and 3D modeling Part 2: Turbochargers, Engine Performance Metrics Day 2 (Combustion Modeling) Part 3: Chemical Kinetics, HCCI SI Combustion Part 4: Heat transfer, NOx and Soot Emissions Day 3 (Spray Modeling) Part 5: Atomization, Drop Breakup/Coalescence Part 6: Drop Drag/Wall Impinge/Vaporization/Sprays Day 4 (Engine Optimization) Part 7: Diesel combustion and SI knock modeling Part 8: Optimization and Low Temperature Combustion Day 5 (Applications and the Future) Part 9: Fuels, Aftertreatment and Controls Part 10: Vehicle Applications, Future of IC Engines 2 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Kokjohn, IJER 2011, SAE 2011, SAE 2009 Light heavyduty engine RCCI Heavy Light Duty Duty Engine CAT GM 1.9 L HD and LD engines compared over IMEP (bar) 9 gasoline/diesel fuel ratio sweep at 9 Engine speed (rev/min) 1300 1900 bar IMEP Mean piston speed (m/s) 7.2 5.7 LD engine intake temperature and Total fuel mass (mg) 94 20.2 EGR () 41 pressure adjusted in to match HD Premixed gasoline () 82 to 89 81 to 84 compression stroke 58 56 Diesel SOI 1 (°ATDC) Engine size scaling laws do not provide Diesel SOI 2 (°ATDC) 37 35 a scaling parameter for engine speed Diesel inj. pressure (bar) 800 500 – Kinetics implies speeds should be equal Intake pressure (bar) 1.74 1.86 (equal ignition delay) Intake runner temp. (°C) 32 39 Air flow rate (kg/min) 1.75 0.46 – To scale convective heat transfer, LD Abs. exhaust engine should be operated at 3800 1.84 1.98 back pressure (bar) rev/min Ave. exhaust – Intermediate speed of 1900 rev/min 271 319 temperature (°C) selected Equivalence ratio () 0.52 0.62 Portinjected fuel Gasoline Directinjected fuel Diesel Fuel 3 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Kokjohn, IJER 2011 Kokjohn, SAE 2011 Light heavyduty engi ne RCCI Low NOx and soot emissions achieved for 0.3 2010 EPA HD Limit both HD and LD engines Heavyduty 0.2 81 Lightduty Ringing intensity (noise) easily controlled by combustion phasing (via gasoline 0.1 82 84 diesel ratio) with only minimal effect on 89 0.0 efficiency 2010 EPA HD Limit Both engines achieve high efficiency; 0.02 however, HD engine shows 5 to 7 higher gross indicated efficiency 0.01 140 2.8 HeavyDuty: 0.00 89 Gasoline 120 2.4 LightDuty: 56 180 83 Gasoline 100 2.0 54 PdV  180 52 GIE 80 1.6 m LHV Fuel 50 60 1.2 48 40 0.8 6 20 0.4 3 bar/deg. 4 0 0.0 30 20 10 0 10 20 30 2 Crank ATDC 0 1 0 1 2 3 4 5 6 7 8 HD Conv. Diesel Efficiency = 48 LD Conv. Diesel Efficiency = 45 CA50 ATDC 4 CEFRC510, 2014 Ringing Int. Soot NOx Gross Ind. 2 g/kWhr g/kWhr MW/m Efficiency Pressure bar Heat Release Rate 1/msPart 10: Vehicle Applications, Future of IC Engines Kokjohn, IJER 2011 Kokjohn, SAE 2011 Light heavyduty engine RCCI 60 56.1 49.5 50 Heavyduty Lightduty 40 31.4 30.5 30 20 14.8 11.4 10 4.3 2.0 0 Gross Ind. Exhaust Heat Transfer Comb. Loss Efficiency Gross indicated efficiency is lower in LD engine due to lower combustion efficiency and higher heat transfer losses Combustion efficiency is 2 lower in LD engine 3.4 more of the fuel energy is lost to heat transfer in LD engine. 5 CEFRC510, 2014 Percent Fuel Energy Part 10: Vehicle Applications, Future of IC Engines Kokjohn, IJER 2011 Kokjohn, SAE 2011 CFD modeling to explain losses CFD simulations with KIVAChemkin code and reduced PRF mec hanism Combustion Losses 140 2.8 HeavyDuty: 89 Gasoline 120 2.4 CFD modeling predicts that the LightDuty: 83 Gasoline 100 2.0 highest levels of late cycle CO and Solid: Experiment Dash: Simulation 80 1.6 UHC are located in the ringpack 60 1.2 crevice and near liner region 40 0.8 –Reducing ringpack crevice volume 20 0.4 improves combustion efficiency 0 0.0 (SAE 2012010383) 30 20 10 0 10 20 30 Heat Transfer Losses Crank ATDC LD engine heat transfer is higher due to –Higher swirl (LD: 2.2 HD: 0.7) –Increased surface areatovolume ratio (LD: 5.6 HD: 2.7 ) –Lower mean piston speed (LD: 5.7 m/s HD: 7.2 m/s) 6 CEFRC510, 2014 Pressure bar Heat Release Rate 1/msPart 10: Vehicle Applications, Future of IC Engines Kokjohn, 2012 Future research directions LD RCCI further improved by relaxing constraints (Euro 4 boost, IMT, swirl..) Peak efficiency at Mode 5 is 47.9  CFD says can be increased to 53 Improve heat transfer losses and combustion phasing – Higher boost (1.86 bar vs. 1.6 bar) allows CA50 advance with same PRR and lowers heat transfer losses due to lower F (lower temps) – Lower swirl reduces convective heat transfer losses – Higher wall temps improve combustion efficiency (steel piston) – 8 + 10 consistent with DOE goals of 2040 improvement RCCI Peak GIE pts 11 bar/° 8.8 bar/° Swirl Ratio = 0.7 15 bar/° Hot walls (Approximate Steel Piston) 52 Peak GIE pts 6.7 bar/° Swirl Ratio = 1.5 Steel Piston 10 Peak GIE 15 bar/° 50 Swirl Ratio = 0.7 Cold walls (Aluminum Piston) 8.6 bar/° Peak GIE 18 bar/° Swirl Ratio = 1.5 Selected Aluminum Piston 48 Current Study Numbers show Aluminum Piston Swirl Ratio = 1.5 Peak PRR 0.2 bar Lower Boost 46 2 0 2 4 6 8 10 12 CA50 deg. ATDC 7 CEFRC510, 2014 GIE Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 UWMadison RCCI series hybrid vehicle 2009 Saturn Vue, V6 FWD base model  GM 1.9L diesel engine Installation of 7.5 gal. gasoline and diesel tanks 8 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 Hybrid vehicle architecture Parallel Hybrid Engine always drives the wheels, electric motor is an assist (Honda Insight). Series Hybrid Engine is not mechanically coupled to the drive train. Engine drives a generator to produce electricity which drives the vehicle by an electric motor (UW Hybrid design) PowerSplit (series/parallel) Is a combination of both designs. Can drive on electric only or engine only or a combination of both. (Toyota Prius) http://en.wikipedia.org/wiki/Hybridvehicledrivetrain 9 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 UWMadison RCCI series hybrid vehicle architecture 1.9L GM engine Johnson Controls E450 14 kWh battery UQM 75 kW drive motor Remy 90 kW HVH250 motor 10 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 RCCI engine configuration GM 1.9L Geometry Number of Cylinders 4 Bore (mm) 82.0 Stroke (mm) 90.4 Compression Ratio 17.5 (stock) Compression Ratio 15.1 (RCCI piston) Rated Power (kW) 110 Rated Torque (Nm) 315 PFI Fuel 96 RON gasoline DI Fuel – 46 CN ULSD 11 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 RCCI piston design For the hybrid car, a next generation piston was designed to reduce the crevice volume in order to lower HC emissions. 15.1:1 CR and reduced surface area, with smaller crevice height (4mm vs 8mm). 12 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 Project goals Vehicle testing at Ford Vehicle Emissions Research laboratory: Compare UW hybrid with current PHEVs such as Ford Fusion and Chevy Volt over Federal Test Cycles (FTP75, HWFET and US06) Volt UW Drive Motor 111 kW 75 kW Generator 55 kW 90 kW HV battery 16 kWh 14 kWh Inertia Weight 4000 lbm 4000 lbm, simulated Shake down vehicle Test electric drive operation at high speed (i.e., US06) Starting the engine in RCCI mode Operate RCCI at different power levels over standard EPA test cycles (FTP, HWFET and US06) 13 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 Project methodology Because Vue is heavy (6,000 lbm) prototype, operation of a current PHEV with similar hardware was simulated. For all tests, UW vehicle was simulated as a Ford Fusion (4,000 lbm inertia weight). Results were compared with Volt fuel economy and emissions as they are publicly available and the vehicle drag coefficient is the same as the Ford (Cd =0.28) Operated engine as charge sustaining for each entire test cycle No attempt to pass emissions (no aftertreatment system installed) No regenerative braking to minimize number of times starting the engine First ever test with new pistons and engine was not broken in Modified RCCI calibration on the fly during the tests 14 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 Hybrid RCCI operating conditions 32 kW 22 kW 15 kW 10 kW RCCI operating conditions derived from steadystate results from ORNL testing • Points below 10 bar/deg. MPRR limit • Double DI injection, 6080 PFI ratio, no EGR, 1.21.3 bar intake pressure • BTE 3436, from 1022 kW (32 kW 40 BTE, future operating point) • 300EGT200 deg. C, for catalyst lightoff 15 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 FTP75 drive cycle “Represents urban driving, in which a vehicle is started with the engine cold and driven in stopandgo rush hour traffic” Start with engine cold, we started with warm engine Includes a 600 second cold soak period after 1369 seconds http://fueleconomy.gov/feg/fetestschedules.shtml 16 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 FTP75 drive cycle HC, CO and NOx vs. Distance for EPA FTP75 Drive Cycle 14000 500 Restart after 600 Startup emissions 450 second heat soak 12000 400 10000 350 Cal changes 300 8000 250 6000 200 150 4000 100 2000 50 0 0 0 2 4 6 8 10 12 Distance (mi) THC CO NOx 17 CEFRC510, 2014 HC and CO (PPM) NOx (PPM) Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 FTP75 drive cycle Cumulative Emissions vs. Distance for FTP75 Drive Cycle 250.00 2.50 RCCI Operating Point 2.25 Speed = 1,500 rpm 200.00 2.00 Load = 4.2 bar Power = 10 kW 1.75 150.00 1.50 1.25 100.00 1.00 0.75 50.00 0.50 0.25 0.00 0.00 0 1 2 3 4 5 6 7 8 9 10 11 12 Distance (mi) THC CO NOx 18 CEFRC510, 2014 CO and HC (g) NOx (g) Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 FTP75 drive cycle FTP weighted avg 0.04 g/mi 19 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 FTP75 drive cycle 20 kW Cat EGR UW w/10 kW w/20 kW Volt BL g/mile w/Cat w/EGR w/cal 8.45 5.400 0.081 0.065 0.052 0.0577 HC 18.21 8.737 0.131 0.105 0.084 1.2435 CO 0.149 0.159 0.159 0.127 0.064 0.0219 NOx 0.041 0.022 0.011 0.009 0.009 PM Assumptions: engine ontime 554 sec, Etacat=0.985, EGR=20, PM reduced 50, Calibration improvements of 20 HC/CO and 50 NOx, no additional startup emissions Nearly charge sustaining (+1.5 SOC), 8.9 kW used Total Energy (Drive motor and 12v system) = 3,725 Whr Average Energy = 335 Whr/mi Charge Sustaining Fuel Efficiency UW w/10 w/20 kW w/30kW Volt BL Assumptions: logged HV battery kW, kW 35 BTE, 70 PFI and pump fuel properties 34 +/ 2 46.5 +/3 48.4 +/3 45 MPG Volt fuel economy data from ANL Downloadable Dynamometer Database (http://www.transportation.anl.gov/D3/), emissions data from EPA http://www.epa.gov/otaq/tcldata.htm 20 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 EPA highway fuel economy test “Represents a mixture of rural and Interstate highway driving with a warmedup engine, typical of longer trips in freeflowing traffic.” http://fueleconomy.gov/feg/fetestschedules.shtml 21 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 HWFET Test 20 kW Cat EGR w/15 kW w/20 kW Volt BL g/mile w/Cat w/EGR w/cal 6.14 3.893 0.058 0.047 0.037 0.0102 HC 10.39 6.587 0.099 0.079 0.063 0.44 CO 0.098 0.062 0.062 0.050 0.035 0.0049 NOx 0.033 0.021 0.01 0.008 0.008 PM Assumptions: engine ontime 485 sec, Etacat=0.985, EGR=20, PM reduced 50, Calibration improvements of 20 HC/CO and 50 NOx, no additional startup emissions Charge sustaining (net 0 SOC), 14.8 kW used Total Energy (Drive motor and 12V system) = 2,967 Whr Average Energy = 288 Whr/mi Charge Sustaining Fuel Efficiency UW w/15 w/20 kW w/30kW Volt BL Assumptions: logged HV battery kW, 35 kW BTE, 70 PFI and pump fuel properties 40 +/ 2 49.3 +/3 51.4 +/3 48 MPG 22 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 US06 test “Represents city and highway driving at higher speeds with more aggressive acceleration and braking.” Speeds in excess of 80 mph Harshest acceleration and decelerations: 8.46 mph/sec maximum acceleration http://fueleconomy.gov/feg/fetestschedules.shtml 23 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 US06 test 20 kW Cat EGR w/20 kW Volt BL g/mile w/Cat w/EGR w/cal 8.11 0.122 0.097 0.078 0.011 HC 13.12 0.197 0.157 0.126 1.789 CO 0.239 0.239 0.191 0.096 0.008 NOx PM Assumptions: Etacat=0.985, EGR=20, PM reduced 50, Calibration improvements of 20 HC/CO and 50 NOx, no additional startup emissions Battery charge not sustained (6 SOC), 18.63 kW engine power + 5.11 kW of electricity used Total Energy (Drive motor and 12V system) = 3,586 Whr Average Energy = 446 Whr/mi Charge Sustaining Fuel Efficiency UW w/20 Volt Assumptions: logged HV battery kW, w/30kW kW BL subtracted 6 SOC fuel, 35 BTE, 70 PFI and pump fuel properties 27 +/2 31 +/2 32.5 MPG 24 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 UW RCCI vehicle test summary 1. Successfully installed UW designed 2nd generation RCCI pistons and RCCI engine into a series hybrid vehicle 2. Operated an RCCI powered vehicle at 3 different power levels over 3 different Federal Test Cycles 3. Preliminary results encouraging First test with new piston geometry, Engine not broken in before testing, No dyno or CFD testing for calibration reference, only previous MCE tests 4. Saw similar engineout emissions as previous laboratory tests • Far from optimal engine calibrations 5. Fuel economy comparable to Chevy Volt • No regenerative braking, rough RCCI calibration, etc. 6. Future tests planned at ORNL in late April 2014 • Same test points but using updated operating strategy (regenerative braking, EGR, calibration, etc.) and hardware (i.e., DOC/DPF, etc.) 25 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Reitz, 2014 RCCI summary Advanced engine combustion strategies such as RCCI show promise for fuel efficiency and emissions improvements RCCI shown in single and multicylinder engine, plus vehicle tests to yield clean, quiet, and efficient combustion over wide load/speed range HD: EPA 2010 NOx/PM emissions met incylinder with peak GIE 55 LD: Low NOx and PM emissions with less EGR needed over FTP cycle Multimode LD RCCI strategy uses optimized high EGR diesel combustion at low load (idle) and then no EGR up to Mode 5 (9 bar IMEP) RCCI LD modeling indicates 8 improvement in fuel consumption over CDC+SCR over FTP cycle using same engine and conditions. RCCI meets Tier 2 bin 5 without need for NOx aftertreatment or DPF, but DOC will likely be needed for UHC reduction Modeling indicates that further RCCI optimization requires: higher boost pressure, higher piston temps, reduced swirl, reduced surface area steel piston, optimized crevice design Future experiments/modeling in HD and LD engines will continue to explore RCCI with optimized pistons and alternative fuels. 26 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Future of IC engines new directions New technologies are needed to improve efficiency of gasoline and diesels. Engines need to be optimized to balance emissions, fuel cost, and market competitiveness. Advanced CFD models and optimization methods increasingly used by the industry. 4 made possible by dramatic increases in computer speeds (x10 in last 15 years) significantly reduces requirements for expensive experimental testing Development of predictive models for engine physical processes has been an additional enabling factor for advanced concepts in engine design CFD tools are mature enough to guide the development of more efficient and cleaner internal combustion engines. New low temperature combustion (LTC) concepts, such as: Homogeneous Charge Compression Ignition (HCCI), Premixed Charge Compression Ignition (PCCI) and Reactivity Controlled Compression Ignition (RCCI), ……. offer promise of dramatically improved engine efficiencies can be explored/optimized with CFD tools. 27 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Hu, 2007 Future of engine CFD modeling Incrementally improved models, used for engine design with less engine testing. Experiment LES CHEMKIN RANS CHEMKIN Models are a storehouse of current knowledge Engine CFD Timeline (1960’s) no local resolution (197080’s) 12D physics subgrid scale (1990’s) 3D 1mm grids subgrid scale models (2000’s) all relevant gasphase scales resolved (2020’s) all liquid and gas scales resolved + Detailed kinetics + nozzle processes 28 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 The long term future: How Do We Supply the World’s Energy Needs Derek Abbott, University of Adelaide, Australia “ABSTRACT We take a fresh look at the major nonrenewable and renewable energy sources and examine their longterm viability, scalability, and the sustainability of the resources that they use. We achieve this by asking what would happen if each energy source was a single supply of power for the world, as a gedanken experiment. From this perspective, a solar hydrogen economy emerges as a dominant solution to the world’s energy needs.” 29 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 How much energy do we use 15 TeraWatts We use the equivalent energy of every person on earth (6 billion) running 25, 100 W light bulbs. 30 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 How to supply world’s 15 TeraWatt energy needs At current rates, to supply the world’s energy use, we have enough: uranium for nuclear for 5 years, fossil oil for 42 years, natural gas 60 years, and coal for 130 years. But, centuries from now we will still need fuels to make fertilizers, plastics and to lubricate machinery, And a billion years from now when sun turns into a red giant, we will probably need nuclear so some of us can escape to a new solar system. 31 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 Nonsustainability Assume 5 billion people drive a car with a 50 kW engine for 1 hour per day  10 TJ consumed in world each second i.e., 10 TW: 2/3 current world energy consumption. Abbott’s point is that we cannot afford to recklessly deplete precious nonrenewable sources of energy for man’s continued survival on earth. Abbott considers fossil, nuclear, wind, hydroelectric, wave, geothermal energy sources and concludes that the only sustainable long term energy scenario is a Solar Hydrogen Economy. (wind, hydroelectric, wave come from the sun anyway, and the sun is a fusion reactor) 32 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 Solar energy incident on the earth in one month is more than all the energy in the world’s fuel resources combined. 33 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 Large amount of energy from the sun Usable Solar Power incident on earth is 5,000 times our global energy consumption. Deserts are 9 of world’s surface area If we tap sunlight on 1 of earth’s surface at conversion efficiency of 1, we can meet current world energy demand. 34 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 Solar collection – proven technology 35 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 Solar H Economy 2 36 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 H for transportation – infrastructure 2 60 million vehicles/year: For battery electric we have enough lithium on earth for only 23 years Fuel cells require exotic rare Materials IC engine is sustainable (available materials) 37 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Liquid hydrogen hydrogen gas engines BMW Hydrogen 7 (2006) Ford E450 (2008) 260 HP twelvecylinder engine Mazda H Rotary RX8 (2008) 2 17.6 lb of liquid H storage tank, 2 cruising range 125 miles, 062.1 mph in 9.5s IC engine: transportation powerplant field of engine research will be alive for next billion or so years 38 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Abbott, 2010 Solar hydrogen economy reversible, sustainable future with unlimited energy supply 39 CEFRC510, 2014 Part 10: Vehicle Applications, Future of IC Engines Closure Availability of cheap energy has led to distorted world economies/priorities Next 3040 years will require major innovations in IC engines dwindling resources and minimized environmental impact current energy usage rates are clearly unsustainable. Many energy “solutions” (battery, fuel cell, nuclear) are only short term and resources are better saved for future generations The only really longterm sustainable energy source is solar hydrogen Research will be needed to improve efficiency of electricity generation, H 2 production/storage and engine efficiency The switch to the H economy will take considerable time and effort 2 Until this occurs, research on more efficient usage of fossil and other fuels is urgently needed “I’d put my money on the sun and solar energy. What a source of power I hope we don’t have to wait until oil and coal run out before we tackle that.” Thomas Edison (1931) in conversation with Henry Ford and Harvey Firestone. 40 CEFRC510, 2014
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