Reciprocating internal combustion engines

reciprocating internal combustion engines performance and examples of reciprocating internal combustion engines
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Part 10: Vehicle Applications, Future of IC Engines Reciprocating Internal Combustion Engines Prof. Rolf D. Reitz Engine Research Center University of Wisconsin-Madison 2014 Princeton-CEFRC 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 in-depth understanding of fundamental engine processes and detailed experiments in engine design optimization. Day 1 (Engine fundamentals) Part 1: IC Engine Review, 0, 1 and 3-D 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, After-treatment and Controls Part 10: Vehicle Applications, Future of IC Engines 2 CEFRC5-10, 2014 Part 10: Vehicle Applications, Future of IC Engines Kokjohn, IJER 2011, SAE 2011, SAE 2009 Light- & heavy-duty 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 Port-injected fuel Gasoline Direct-injected fuel Diesel Fuel 3 CEFRC5-10, 2014 Part 10: Vehicle Applications, Future of IC Engines Kokjohn, IJER 2011 Kokjohn, SAE 2011 Light- & heavy-duty engi ne RCCI Low NOx and soot emissions achieved for 0.3 2010 EPA HD Limit both HD and LD engines Heavy-duty 0.2 81% Light-duty 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 Heavy-Duty: 0.00 89% Gasoline 120 2.4 Light-Duty: 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 CEFRC5-10, 2014 Ringing Int. Soot NOx Gross Ind. 2 g/kW-hr g/kW-hr MW/m Efficiency % Pressure bar Heat Release Rate 1/msPart 10: Vehicle Applications, Future of IC Engines Kokjohn, IJER 2011 Kokjohn, SAE 2011 Light- & heavy-duty engine RCCI 60 56.1 49.5 50 Heavy-duty Light-duty 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 CEFRC5-10, 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 KIVA-Chemkin code and reduced PRF mec hanism Combustion Losses 140 2.8 Heavy-Duty: 89% Gasoline 120 2.4 CFD modeling predicts that the Light-Duty: 83% Gasoline 100 2.0 highest levels of late cycle CO and Solid: Experiment Dash: Simulation 80 1.6 UHC are located in the ring-pack 60 1.2 crevice and near liner region 40 0.8 –Reducing ring-pack crevice volume 20 0.4 improves combustion efficiency 0 0.0 (SAE 2012-01-0383) -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 area-to-volume ratio (LD: 5.6 HD: 2.7 ) –Lower mean piston speed (LD: 5.7 m/s HD: 7.2 m/s) 6 CEFRC5-10, 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 20-40% 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 CEFRC5-10, 2014 GIE %Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 UW-Madison 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 CEFRC5-10, 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) Power-Split (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/Hybrid_vehicle_drivetrain 9 CEFRC5-10, 2014 Part 10: Vehicle Applications, Future of IC Engines Spannbauer, 2014 UW-Madison 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 CEFRC5-10, 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 CEFRC5-10, 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 CEFRC5-10, 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 CEFRC5-10, 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 after-treatment 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 CEFRC5-10, 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 steady-state results from ORNL testing • Points below 10 bar/deg. MPRR limit • Double DI injection, 60-80% PFI ratio, no EGR, 1.2-1.3 bar intake pressure • BTE 34-36%, from 10-22 kW (32 kW 40% BTE, future operating point) • 300EGT200 deg. C, for catalyst light-off 15 CEFRC5-10, 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 stop-and-go 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/fe_test_schedules.shtml 16 CEFRC5-10, 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 CEFRC5-10, 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 CEFRC5-10, 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 CEFRC5-10, 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 on-time 554 sec, Eta_cat=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 W-hr Average Energy = 335 W-hr/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 CEFRC5-10, 2014